Nutrition and Your Health
From Wikipedia
Nutrition science studies the relationship between diet and states of health and disease. Dieticians are Health professionals who are specialized in this area of expertise, highly trained to provide safe, evidence-based dietary advice and interventions. There is a spectrum ranging from malnutrition to optimal health, including many common symptoms and diseases which can often be prevented or alleviated with better nutrition.
Deficiencies, excesses and imbalances in diet can produce negative impacts on health, which may lead to diseases such as scurvy, obesity or osteoporosis, as well as psychological and behavioral problems. Moreover, excessive ingestion of elements that have no apparent role in health, (e.g. lead, mercury, PCBs, dioxins), may incur toxic and potentially lethal effects, depending on the dose. The science of nutrition attempts to understand how and why specific dietary aspects influence health.
Overview
Nutrition science seeks to explain metabolic and physiological responses of the body to diet. With advances in molecular biology, biochemistry, and genetics, nutrition science is additionally developing into the study of integrative metabolism, which seeks to connect diet and health through the lens of biochemical processes.
The human body is made up of chemical compounds such as water, amino acids (proteins), fatty acids (lipids), nucleic acids (DNA/RNA), and carbohydrates (e.g. sugars and fiber). These compounds in turn consist of elements such as carbon, hydrogen, oxygen, nitrogen, and phosphorus, and may or may not contain minerals such as calcium, iron, or zinc. Minerals ubiquitously occur in the form of salts and electrolytes. All of these chemical compounds and elements occur in various forms and combinations (e.g. hormones/vitamins, phospholipids, hydroxyapatite), both in the human body and in organisms (e.g. plants, animals) that humans eat. The human body necessarily comprises the elements that it eats and absorbs into the bloodstream. The digestive system, except in the unborn fetus, participates in the first step which makes the different chemical compounds and elements in food available for the trillions of cells of the body. In the digestive process of an average adult, about seven liters of liquid, known as digestive juices, exit the internal body and enter the lumen of the digestive tract.
The digestive juices help break chemical bonds between ingested compounds as well as modulate the conformation and/or energetic state of the compounds/elements. However, many compounds/ elements are absorbed into the bloodstream unchanged, though the digestive process helps to release them from the matrix of the foods where they occur. Any unabsorbed matter is excreted in the feces. But only a minimal amount of digestive juice is eliminated by this process; the intestines reabsorb most of it; otherwise the body would rapidly dehydrate; (hence the devastating effects of persistent diarrhea).
Study in this field must take carefully into account the state of the body before ingestion and after digestion as well as the chemical composition of the food and the waste. Comparing the waste to the food can determine the specific types of compounds and elements absorbed by the body. The effect that the absorbed matter has on the body can be determined by finding the difference between the pre-ingestion state and the post-digestion state. The effect may only be discernible after an extended period of time in which all food and ingestion must be exactly regulated and all waste must be analyzed. The number of variables (e.g. 'confounding factors') involved in this type of experimentation is very high. This makes scientifically valid nutritional study very time-consuming and expensive, and explains why a proper science of human nutrition is rather new.
In general, eating a variety of fresh, whole (unprocessed) plant foods has proven hormonally and metabolically favorable compared to eating a monotonous diet based on processed foods. In particular, consumption of whole plant foods slows digestion and provides higher amounts and a more favorable balance of essential and vital nutrients per unit of energy; resulting in better management of cell growth, maintenance, and mitosis (cell division) as well as regulation of blood glucose and appetite. A generally more regular eating pattern (e.g. eating medium-sized meals every 3 to 4 hours) has also proven more hormonally and metabolically favorable than infrequent, haphazard food intake.
History
Humans have evolved as omnivorous hunter-gatherers over the past 250,000 years. Early diets were primarily vegetarian with infrequent game meats and fish where available. Agriculture developed about 10,000 years ago in multiple locations throughout the world, providing grains such as wheat, rice, and maize, with staples such as bread and pasta. Farming also provided milk and dairy products, and sharply increased the availability of meats and the diversity of vegetables. The importance of food purity was recognized when bulk storage led to infestation and contamination risks. Cooking developed as an often ritualistic activity, due to efficiency and reliability concerns requiring adherence to strict recipes and procedures, and in response to demands for food purity and consistency.
Antiquity through Enlightenment
c. 475 BC: Anaxagoras states that food is absorbed by the human body and therefore contained "homeomerics" (generative components), thereby deducing the existence of nutrients.
c. 400 BC: Hippocrates says, "Let food be your medicine and medicine be your food."
The first recorded nutritional experiment is found in the Bible's Book of Daniel. Daniel and his friends were captured by the king of Babylon during an invasion of Israel. Selected as court servants, they were to share in the king's fine foods and wine. But they objected, preferring vegetables (pulses) and water in accordance with their Jewish dietary restrictions. The king's chief steward reluctantly agreed to a trial. Daniel and his friends received their diet for 10 days and were then compared to the king's men. Appearing healthier, they were allowed to continue with their diet.
1500s: Scientist and artist Leonardo da Vinci compared metabolism to a burning candle.
1747: Dr. James Lind, a physician in the British navy, performed the first scientific nutrition experiment, discovering that lime juice saved sailors who had been at sea for years from scurvy, a deadly and painful bleeding disorder. The discovery was ignored for forty years, after which British sailors became known as "limeys." The essential vitamin C within lime juice would not be recognized by scientists until the 1930s.
1770: Antoine Lavoisier, the "Father of Nutrition and Chemistry" discovered the details of metabolism, demonstrating that the oxidation of food is the source of body heat.
1790: George Fordyce recognized calcium necessary for fowl survival.
Modern era through 1941
Early 1800s: The elements carbon, nitrogen, hydrogen and oxygen were recognized as the primary components of food, and methods to measure their proportions were developed.
1816: François Magendie discovers that dogs fed only carbohydrates and fat lost their body protein and died in a few weeks, but dogs also fed protein survived, identifying protein as an essential dietary component.
1840: Justus Liebig discovers the chemical makeup of carbohydrates (sugars), fats (fatty acids) and proteins (amino acids.)
1860s: Claus Bernard discovers that body fat can be synthesized from carbohydrate and protein, showing that the energy in blood glucose can be stored as fat or as glycogen.
Early 1880s: Kanehiro Takaki observed that Japanese sailors developed beriberi (or endemic neuritis, a disease causing heart problems and paralysis) but British sailors did not. Adding milk and meat to Japanese diets prevented the disease.
1896: Baumann observed iodine in thyroid glands.
1897: Christiaan Eijkman worked with natives of Java, who also suffered from beriberi. Eijkman observed that chickens fed the native diet of white rice developed the symptoms of beriberi, but remained healthy when fed unprocessed brown rice with the outer bran intact. Eijkman cured the natives by feeding them brown rice, discovering that food can cure disease. Over two decades later, nutritionists learned that the outer rice bran contains vitamin B1, also known as thiamine.
Early 1900s: Carl Von Voit and Max Rubner independently measure caloric energy expenditure in different species of animals, applying principles of physics in nutrition.
1906: Wilcock and Hopkins showed that the amino acid tryptophan was necessary for the survival of mice. Gowland Hopkins recognized "accessory food factors" other than calories, protein and minerals, as organic materials essential to health but which the body cannot synthesise.
1907: Stephen M. Babcock and Edwin B. Hart conduct the Single-grain experiment. This experiment runs through 1911.
1912: Casmir Funk coined the term vitamin, a vital factor in the diet, from the words "vital" and "amine," because these unknown substances preventing scurvy, beriberi, and pellagra, were thought then to be derived from ammonia.
1913: Elmer V. McCollum discovered the first vitamins, fat soluble vitamin A, and water soluble vitamin B (in 1915; now known to be a complex of several water-soluble vitamins) and names vitamin C as the then-unknown substance preventing scurvy.
1919: Sir Edward Mellanby incorrectly identified rickets as a vitamin A deficiency, because he could cure it in dogs with cod liver oil.
1922: McCollum destroys the vitamin A in cod liver oil but finds it still cures rickets, naming vitamin D.
1922: H.M. Evans and L.S. Bishop discover vitamin E as essential for rat pregnancy, originally calling it "food factor X" until 1925.
1925: Hart discovers trace amounts of copper are necessary for iron absorption.
1927: Adolf Otto Reinhold Windaus synthesizes vitamin D, for which he won the Nobel Prize in Chemistry in 1928.
1928: Albert Szent-Gyorgyi isolates ascorbic acid, and in 1932 proves that it is vitamin C by preventing scurvy. In 1935 he synthesizes it, and in 1937 he wins a Nobel Prize for his efforts. Szent-Gyorgyi concurrently elucidates much of the citric acid cycle.
1930s: William Cumming Rose identifies essential amino acids, necessary proteins which the body cannot synthesize.
1935: Underwood and Marston independently discover the necessity of cobalt.
1936: Eugene Floyd Dubois shows that work and school performance are related to caloric intake.
1938: The chemical structure of vitamin E is discovered by Erhard Fernholz, and it is synthesized by Paul Karrer.
1941: The first Recommended Dietary Allowances (RDAs) were established by the National Research Council.
Recent
1992 The U.S. Department of Agriculture Introduces Food Guide Pyramid.
2002 Study shows relation between nutrition and violent behavior..
2005 Obesity may be caused by adenovirus in addition to bad nutrition.
Nutrition and Health
There are six main nutrients in which the body needs to receive. These nutrients include carbohydrates, proteins, fats, vitamins, minerals, and water. It is important to consume these six nutrients on a daily basis to build and maintain healthy body systems.
Ill health can be caused by an imbalance of nutrients, producing either an excess or deficiency, which in turn affects body functioning cumulatively. Moreover, because most nutrients are, in some way or another, involved in cell-to-cell signalling (e.g. as building block or part of a hormone or signalling 'cascades'), deficiency or excess of various nutrients affects hormonal function indirectly. Thus, because they largely regulate the expression of genes, hormones represent a link between nutrition and how our genes are expressed, i.e. our phenotype.
The strength and nature of this link are continually under investigation, but observations especially in recent years have demonstrated a pivotal role for nutrition in hormonal activity and function and therefore in health. One source of articles on nutrition and health is the quarterly newsletter of the Nutrition for Optimal Health Association (NOHA). Articles since 1984 are indexed by subject, name, and chronology.
Essential and non-essential amino acids
The body requires amino acids to produce new body protein (protein retention) and to replace damaged proteins (maintenance) that are lost in the urine. In animals amino acid requirements are classified in terms of essential (an animal cannot produce them) and non-essential (the animal can produce them from other nitrogen containing compounds) amino acids.
Consuming a diet that contains adequate amounts of essential (but also non-essential) amino acids is particularly important for growing animals, who have a particularly high requirement.
Fatty acids
In addition to sufficient intake, an appropriate balance of essential fatty acids - omega-3 and omega-6 fatty acids - has been discovered to be crucial for maintaining health. Both of these unique "omega" long-chain polyunsaturated fatty acids are substrates for a class of eicosanoids known as prostaglandins which function as hormones. The omega-3 eicosapentaenoic acid (EPA) (which can be made in the body from the omega-3 essential fatty acid alpha-linolenic acid (LNA), or taken in through marine food sources), serves as building block for series 3 prostaglandins (e.g. weakly-inflammation PGE3). The omega-6 dihomo-gamma-linolenic acid (DGLA) serves as building block for series 1 prostaglandins (e.g. anti-inflammatory PGE1), whereas arachidonic acid (AA) serves as building block for series 2 prostaglandins (e.g. pro-inflammatory PGE 2). Both DGLA and AA are made from the omega-6 linoleic acid (LA) in the body, or can be taken in directly through food. An appropriately balanced intake of omega-3 and omega-6 partly determines the relative production of different prostaglandins, which partly explains the importance of omega-3/ omega-6 balance for cardiovascular health. In industrialized societies, people generally consume large amounts of processed vegetable oils that have reduced amounts of essential fatty acids along with an excessive amount of omega-6 relative to omega-3.
The rate of conversions of omega-6 DGLA to AA largely determines the production of the respective prostaglandins PGE1 and PGE2. Omega-3 EPA prevents AA from being released from membranes, thereby skewing prostaglandin balance away from pro-inflammatory PGE2 made from AA toward anti-inflammatory PGE1 made from DGLA. Moreover, the conversion (desaturation) of DGLA to AA is controlled by the enzyme delta-5-desaturase, which in turn is controlled by hormones such as insulin (up-regulation) and glucagon (down-regulation). Because different types and amounts of food eaten/absorbed affect insulin, glucagon and other hormones to varying degrees, not only the amount of omega-3 versus omega-6 eaten but also the general composition of the diet therefore determine health implications in relation to essential fatty acids, inflammation (e.g. immune function) and mitosis (i.e. cell division).
Sugars
Several lines of evidence indicate lifestyle-induced hyperinsulinemia and reduced insulin function (i.e. insulin resistance) as a decisive factor in many disease states. For example, hyperinsulinemia and insulin resistance are strongly linked to chronic inflammation, which in turn is strongly linked to a variety of adverse developments such as arterial microinjuries and clot formation (i.e. heart disease) and exaggerated cell division (i.e. cancer).
Hyperinsulinemia and insulin resistance (the so-called metabolic syndrome) are characterized by a combination of abdominal obesity, elevated blood sugar, elevated blood pressure, elevated blood triglycerides, and reduced HDL cholesterol. The negative impact of hyperinsulinemia on prostaglandin PGE1/PGE2 balance may be significant.
The state of obesity clearly contributes to insulin resistance, which in turn can cause type 2 diabetes. Virtually all obese and most type 2 diabetic individuals have marked insulin resistance. Although the association between overfatness and insulin resistance is clear, the exact (likely multifarious) causes of insulin resistance remain less clear. Importantly, it has been demonstrated that appropriate exercise, more regular food intake and reducing glycemic load (see below) all can reverse insulin resistance in overfat individuals (and thereby lower blood sugar levels in those who have type 2 diabetes).
Obesity can unfavourably alter hormonal and metabolic status via resistance to the hormone leptin, and a vicious cycle may occur in which insulin/leptin resistance and obesity aggravate one another. The vicious cycle is putatively fuelled by continuously high insulin/leptin stimulation and fat storage, as a result of high intake of strongly insulin/leptin stimulating foods and energy.
Both insulin and leptin normally function as satiety signals to the hypothalamus in the brain; however, insulin/leptin resistance may reduce this signal and therefore allow continued overfeeding despite large body fat stores. In addition, reduced leptin signalling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate.
There is debate about how and to what extent different dietary factors -- e.g. intake of processed carbohydrates, total protein, fat, and carbohydrate intake, intake of saturated and trans fatty acids, and low intake of vitamins/minerals -- contribute to the development of insulin- and leptin resistance. In any case, analogous to the way modern man-made pollution may potentially overwhelm the environment's ability to maintain 'homeostasis', the recent explosive introduction of high Glycemic Index- and processed foods into the human diet may potentially overwhelm the body's ability to maintain homeostasis and health (as evidenced by the metabolic syndrome epidemic).
Antioxidants are another recent discovery. As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as radical oxygen species or free radicals form as a result. For normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds, some produced by the body with adequate precursors (glutathione, Vitamin C in most animals) and those that the body cannot produce may only be obtained through the diet through direct sources (Vitamin C in humans, Vitamin A, Vitamin K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight). Different antioxidants are now known to function in a cooperative network, e.g. vitamin C can reactivate free radical-containing glutathione or vitamin E by accepting the free radical itself, and so on. Some antioxidants are more effective than others at neutralizing different free radicals.
Some cannot neutralize certain free radicals. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas). When interacting with a free radical, some antioxidants produce a different free radical compound that is less dangerous or more dangerous than the previous compound. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect.
Intestinal bacterial flora
Some information in this article or section has not been verified and may not be reliable. Please check for any inaccuracies, and modify and cite sources as needed. It is now also known that the human digestion system contains a population of a range of bacteria which are essential to digestion, and which are also affected by the food we eat. The role and significance of the intestinal bacterial flora is under investigation. Both good and bad bacteria inhabit the digestive system. It is estimated that in the Western world, most people are no longer in a homeostatic balance. It is ideal to have 80% good to 20% bad, typically differentiated by gram negative and gram positive staining, respectively; however, in western diets it is more likely to be the other way around. Consuming processed food that are low in nutrients and high in sugar will allow bad bacteria to flourish.
Phytochemicals
Blackberries are a source of polyphenol antioxidants. A growing area of interest is the effect upon human health of trace chemicals, collectively called phytochemicals, nutrients typically found in edible plants, especially colorful fruits and vegetables (see Whole Foods Diet, below). Unlike the anecdotal and sometimes specious nutritional claims of medicinal herbs and compounds, the effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. One of the principal classes of phytochemicals are polyphenol antioxidants, chemicals which are known to provide certain health benefits to the cardiovascular system and immune system. These chemicals are known to down-regulate the formation of reactive oxygen species, key chemicals in cardiovascular disease.
Perhaps the most rigorously tested phytochemical is zeaxanthin, a yellow- pigmented carotenoid present in many yellow and orange fruits and vegetables. Repeated studies have shown a strong correlation between ingestion of zeaxanthin and the prevention and treatment of age-related macular degeneration (AMD). Less rigorous studies have proposed a correlation between zeaxanthin intake and cataracts. A second carotenoid, lutein, has also been shown to lower the risk of contracting AMD. Both compounds have been observed to collect in the retina when ingested orally, and they serve to protect the rods and cones against the destructive effects of light.
Another caretenoid, beta-cryptoxanthin, appears to protect against chronic joint inflammatory diseases, such as arthritis. While the association between serum blood levels of beta-cryptoxanthin and substantially decreased joint disease has been established, neither a convincing mechanism for such protection nor a cause-and-effect have been rigorously studied. Similarly, a red phytochemical, lycopene, has substantial credible evidence of negative association with development of prostate cancer.
The correlations between the ingestion of some phytochemicals and the prevention of disease are, in some cases, enormous in magnitude. For example, several studies have correlated high levels of zeaxanthin intake with roughly a 50% reduction in AMD. The difficulties in demonstrating causative properties and in applying the findings to human diet, however, are similarly enormous.
The standard for rigorous proof of causation in medicine is the double-blind study, a time-consuming, difficult and expensive process, especially in the case of preventative medicine. While new drugs must undergo such rigorous testing, pharmaceutical companies have a financial interest in funding rigorous testing and may recover the cost if the drug goes to market. No such commercial interest exists in studying chemicals that exist in orange juice and spinach, making funding for medical research difficult to obtain.
Even when the evidence is obtained, translating it to practical dietary advice can be difficult and counter-intuitive. Lutein, for example, occurs in many yellow and orange fruits and vegetables and protects the eyes against various diseases. However, it does not protect the eye nearly as well as zeaxanthin, and the presence of lutein in the retina will prevent zeaxanthin uptake.
Additionally, evidence has shown that the lutein present in egg yolk is more readily absorbed than the lutein from vegetable sources, possibly because of fat solubility. At the most basic level, the question "should you eat eggs?" is complex to the point of dismay, including misperceptions about the health effects of cholesterol in egg yolk, and its saturated fat content.
As another example, lycopene is prevalent in tomatoes (and actually is the chemical that gives tomatoes their red color). It is more highly concentrated, however, in processed tomato products such as commercial pasta sauce, or tomato soup, than in fresh "healthy" tomatoes. Such sauces, however, tend to have high amounts of salt, sugar, other substances a person may wish or even need to avoid.
for more details go to
http://www.consumersresearchcncl.org/Healthcare/Ophthalmologists/ophth_nutrition.html
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Automatically translated into French thanks to WorldLingo
La nutrition et votre santé
de la science
de nutrition de Wikipedia étudie le rapport entre le régime et les états de santé et de maladie. Les diététiciens sont des professionnels de santé qui sont spécialisés dans ce domaine de spécialisation, fortement qualifié pour fournir le coffre-fort, le conseil diététique évidence-basé et les interventions. Il y a un spectre s'étendant de la malnutrition à la santé optimale, y compris beaucoup de symptômes et maladies communs qui peuvent souvent être empêchés ou allégés avec une meilleure nutrition.
Les insuffisances, les excès et les déséquilibres dans le régime peuvent produire des impacts négatifs sur la santé, qui peut mener aux maladies telles que le scorbut, l'obésité ou l'ostéoporose, aussi bien que des problèmes psychologiques et comportementaux. D'ailleurs, ingestion excessive des éléments qui n'ont aucun rôle apparent dans la santé, (par exemple. le fil, le mercure, PCBs, dioxines), peuvent encourir des effets toxiques et potentiellement mortels, selon la dose. La science de la nutrition essaye de comprendre comment et pourquoi les aspects diététiques spécifiques influencent la santé.
La science
de nutrition de vue d'ensemble cherche à expliquer des réponses métaboliques et physiologiques du corps au régime. Avec des avances dans la biologie, la biochimie, et la génétique moléculaires, la science de nutrition se développe en plus en étude de métabolisme intégrateur, qui des recherches pour relier le régime et la santé par l'objectif des processus biochimiques.
Le corps humain se compose des composés chimiques tels que l'eau, des acides aminés (protéines), des acides gras (lipides), des acides nucléiques (DNA/RNA), et des hydrates de carbone (par exemple. sucres et fibre). Ces composés se composent à leur tour des éléments tels que le carbone, l'hydrogène, l'oxygène, l'azote, et le phosphore, et peuvent ou peuvent ne pas contenir des minerais tels que le calcium, le fer, ou le zinc. Les minerais se produisent omniprésent sous forme de sels et d'électrolytes. Tous ces composés et éléments chimiques se produisent dans diverses formes et combinaisons (par exemple. hormones/vitamines, phospholipides, hydroxyapatite), dans le corps humain et dans les organizations (par exemple. les usines, les animaux) ces des humains mangent. Le corps humain comporte nécessairement les éléments qu'il mange et absorbe dans la circulation sanguine. Le système digestif, excepté dans le foetus à venir, participe à la première étape qui fait les différents composés et éléments chimiques en nourriture disponible pour les trillions des cellules du corps. Dans le processus digestif d'un adulte moyen, environ sept litres de liquide, connus sous le nom de jus digestifs, sortent le corps interne et écrivent le lumen de la région digestive.
Les jus digestifs aident à casser les liaisons chimiques entre les composés ingérés comme modulez la conformation et/ou l'état énergique des composés/des éléments. Cependant, beaucoup d'éléments de composés sont absorbés dans la circulation sanguine sans changement, bien que le processus digestif aide à les libérer de la matrice des nourritures où ils se produisent. Unabsorbed la matière sont excrétés dans les résidus. Mais seulement on élimine une quantité minimale de jus digestif par ce processus ; les intestins réabsorbent sa majeure partie ; autrement le corps déshydraterait rapidement ; (par conséquent les effets dévastateurs de la diarrhée persistante).
L'étude dans ce domaine doit tenir compte soigneusement de l'état du corps avant l'ingestion et après digestion aussi bien que la composition chimique de la nourriture et de la perte. Comparer la perte à la nourriture peut déterminer les types spécifiques de composés et des éléments absorbés par le corps. L'effet que la matière absorbée a sur le corps peut être déterminé en trouvant la différence entre l'état de pré-ingestion et l'état de poteau-digestion. L'effet peut seulement être perceptible après une période prolongée l'où toutes les nourriture et ingestion doivent être exactement réglées et toute la perte doit être analysée. Le nombre de variables (par exemple. les « facteurs de confusion ») impliqués dans ce type d'expérimentation est très haut. Ceci effectue scientifiquement l'étude alimentaire valide très longue et chère, et explique pourquoi une science appropriée de la nutrition humaine est plutôt nouvelle.
Manger généralement une variété d'aliments végétaux (non-traités) frais et entiers s'est avéré de façon hormonale et métaboliquement favorable comparé à manger un régime monotone basé sur les nourritures traitées. En particulier, la consommation des nourritures de plantes entières ralentit la digestion et fournit des montants plus élevés et un équilibre plus favorable des aliments essentiels et essentiels par unité d'énergie ; ayant pour résultat une meilleure gestion de croissance, d'entretien, et de mitose de cellules (division de cellules) aussi bien que le règlement du glucose et de l'appétit de sang. Un modèle généralement plus régulier de manger (par exemple. mangeant les repas moyens toutes les 3 à 4 heures) s'est également avérées plus de façon hormonale et métaboliquement favorable que l'ingestion de nourriture peu fréquente et aléatoire.
Les humains
d'histoire ont évolué en tant que chasseur-ramasseurs omnivores au cours des 250.000 dernières années. Les régimes tôt étaient principalement végétariens avec des viandes et les poissons peu fréquents de jeu là où disponibles. L'agriculture s'est développée il y a environ 10.000 ans dans des endroits multiples dans le monde entier, fournissant aux grains tels que le blé, au riz, et au maïs, des agrafes telles que le pain et des pâtes. Cultivant le lait et les produits laitiers également fournis, et brusquement accru la disponibilité des viandes et la diversité des légumes. L'importance de la pureté de nourriture a été identifiée quand la mémoire de grande capacité a mené aux risques d'infestation et de contamination. La cuisine développée comme activité souvent ritualiste, due à l'efficacité et à la fiabilité concerne exiger l'adhérence aux recettes et aux procédures strictes, et en réponse aux demandes pour la pureté et l'uniformité de nourriture.
Antiquité par l'éclaircissement
c. 475 AVANT JÉSUS CHRIST : Anaxagoras déclare que la nourriture est absorbée par le corps humain et donc le « homeomerics » contenu (les composants génératifs), déduisant de ce fait l'existence des aliments.
c. 400 AVANT JÉSUS CHRIST : Hippocrate dit, « laissez la nourriture soit votre médecine et la médecine soit votre nourriture. »
L'expérience alimentaire d'abord enregistrée est trouvée dans le livre de la bible de Daniel. Daniel et ses amis ont été capturés par le roi de Babylone pendant une invasion de l'Israel. Choisi comme domestiques de cour, ils étaient de partager en nourritures fines et vin du roi. Mais ils ont objecté, préférant les légumes (impulsions) et l'eau selon leurs restrictions diététiques juives. L'administrateur en chef du roi était à contre-coeur d'accord sur une épreuve. Daniel et ses amis ont reçu leur régime pendant 10 jours et ont été puis comparés aux hommes du roi. Semblant plus sains, on leur a permis de continuer leur régime.
1500s : Le da Vinci de Leonardo de scientifique et d'artiste a comparé le métabolisme à une bougie brûlante.
1747: Dr. James Lind, un médecin dans la marine britannique, a exécuté la première expérience scientifique de nutrition, découvrant que le jus de limette a sauvé les marins qui avaient été en mer pendant des années du scorbut, d'un désordre mortel et douloureux de saignement. La découverte a été ignorée pendant quarante années, après quoi les marins britanniques sont devenus notoires en tant que « calcaires. » La vitamine C essentielle dans le jus de limette ne serait pas identifiée par des scientifiques jusqu'aux années 30.
1770: Antoine Lavoisier, le « père de la nutrition et de la chimie » a découvert les détails du métabolisme, démontrant que l'oxydation de la nourriture est la source de chaleur de corps.
1790: George Fordyce a identifié le calcium nécessaire pour la survie de volaille.
Ère moderne par 1941
1800s tôt : Les éléments carbone, azote, hydrogène et oxygène ont été identifiés comme composants primaires de nourriture, et des méthodes pour mesurer leurs proportions ont été développées.
1816: François Magendie découvre que les chiens ont alimenté seulement des hydrates de carbone et la graisse a perdu leur protéine de corps et est morte en quelques semaines, mais les chiens ont également alimenté la protéine ont survécu, identifiant la protéine comme composant diététique essentiel.
1840: Justus Liebig découvre le maquillage chimique des hydrates de carbone (sucres), des graisses (acides gras) et des protéines (les acides aminés.)
1860s : Claus Bernard découvre que de la graisse du corps peut être synthétisée de l'hydrate de carbone et de la protéine, prouvant que l'énergie en glucose de sang peut être stockée comme grosse ou comme glycogène.
1880s tôt : Kanehiro Takaki a observé que les marins japonais ont développé le beriberi (ou la névrite endémique, une maladie causant des problèmes et la paralysie de coeur) mais les marins britanniques pas. Ajouter le lait et la viande aux régimes de Japonais a empêché la maladie.
1896: Iode observé par Baumann dans des glandes thyroïdes.
1897: Christiaan Eijkman a fonctionné avec les indigènes de Java, qui ont également souffert du beriberi. Eijkman a observé que les poulets ont alimenté le régime indigène du riz blanc ont développé les symptômes du beriberi, mais sont restés sains quand riz brun non-traité de Fédéral avec le son externe intact. Eijkman a guéri les indigènes en leur alimentant le riz brun, découvrant que la nourriture peut traiter la maladie. Plus de deux décennies plus tard, les nutritionnistes ont appris que le son de riz externe contient la vitamine B1, également connue sous le nom de thiamine.
Les années 1900 tôt : Karl Von Voit et maximum Rubner mesurent indépendamment la dépense énergétique calorique dans différentes espèces des animaux, appliquant des principes de la physique en nutrition.
1906: Wilcock et Hopkins ont prouvé que le tryptophane d'acide aminé était nécessaire pour la survie des souris. Gowland Hopkins a identifié « des facteurs accessoires de nourriture » autre que des calories, protéine et minerais, en tant que matériaux organiques essentiels à la santé mais que le corps ne peut pas synthétiser.
1907: Stephen M. Babcock et Edwin B. Conduite de cerf l'expérience de Simple-grain. Cette expérience fonctionne par 1911.
1912: La trouille de Casmir a inventé la vitamine de limite, un facteur essentiel dans le régime, des mots « essentiels » et de la « amine, » parce qu'on a pensé alors ces substances inconnues empêchant le scorbut, le beriberi, et le pellagra, pour être dérivé de l'ammoniaque.
1913: Elmer V. McCollum a découvert les premières vitamines, la vitamine A soluble dans la graisse, et la vitamine hydrosoluble B (en 1915 ; maintenant connu pour être un complexe de plusieurs vitamines hydrosolubles) et de vitamine C de noms comme substance alors-inconnue empêchant le scorbut.
1919: Monsieur Edouard Mellanby a inexactement identifié le rachitisme comme insuffisance de vitamine A, parce qu'il pourrait la traiter chez les chiens avec de l'huile de foie de morue.
1922: McCollum détruit la vitamine A dans l'huile mais des trouvailles de foie de morue qu'elle traite toujours le rachitisme, appelant la vitamine D.
1922: H.M. Evans et L.S. L'évêque découvrent la vitamine E comme essentiel pour la grossesse de rat, à l'origine l'appelant le « facteur X de nourriture » jusqu'en 1925.
1925: Le cerf découvre que des traces de cuivre sont nécessaire pour l'absorption de fer.
1927: Adolf Otto Reinhold Windaus synthétise la vitamine D, Pour laquelle il a gagné le prix Nobel en chimie en 1928.
1928: Albert Szent-Gyorgyi isole l'acide ascorbique, et en 1932 montre que c'est vitamine C en empêchant le scorbut. En 1935 il le synthétise, et en 1937 il gagne un prix Nobel pour ses efforts. Szent-Gyorgyi élucide concurremment une grande partie du cycle d'acide citrique.
les années 30 : William Cumming Rose identifie les acides aminés essentiels, les protéines nécessaires que le corps ne peut pas synthétisent.
1935: Underwood et Marston découvrent indépendamment la nécessité du cobalt.
1936: Eugene Floyd Dubois prouve que l'exécution de travail et d'école sont liées à l'apport calorique.
1938: La structure chimique de la vitamine E est découverte par Erhard Fernholz, et elle est synthétisée par Paul Karrer.
1941: Les allocations diététiques d'abord recommandées (RDAs) ont été établies par le Conseil " Recherche " national.
Récent
1992 les États-Unis Le ministère de l'agriculture présente la pyramide de guide de nourriture.
Relation de 2002 expositions d'étude entre la nutrition et le comportement violent.
L'obésité 2005 peut être provoquée par l'adénovirus en plus de la mauvaise nutrition.
La nutrition et la santé
là sont six aliments principaux en lesquels le corps doit recevoir. Ces aliments incluent des hydrates de carbone, des protéines, des graisses, des vitamines, des minerais, et l'eau. Il est important de consommer ces six aliments quotidiennement pour établir et maintenir les systèmes sains de corps.
La santé mauvaise peut être provoquée par un déséquilibre des aliments, produisant un excès ou l'insuffisance, qui affectent alternativement le corps fonctionnant cumulativement. D'ailleurs, parce que la plupart des aliments sont, d'une manière quelconque ou des autres, impliqué dans la signalisation de cellule-à-cellule (par exemple. comme module ou partie d'une hormone ou de signalisation « cascade »), insuffisance ou l'excès de divers aliments affecte la fonction hormonale indirectement. Ainsi, parce qu'elles règlent en grande partie l'expression des gènes, les hormones représentent un lien entre la nutrition et comment nos gènes sont exprimés, c.-à-d. notre phénotype.
La force et la nature de ce lien sont continuellement à l'étude, mais les observations particulièrement ces dernières années ont démontré un rôle pivotal pour la nutrition dans l'activité et la fonction hormonales et donc dans la santé. Une source des articles sur la nutrition et la santé est le bulletin trimestriel de la nutrition pour l'association optimale de santé (NOHA). Articles puisque 1984 sont classés par le sujet, le nom, et la chronologie.
Les acides aminés essentiels et non essentiels
le corps exige des acides aminés de produire la nouvelle protéine de corps (conservation de protéine) et de remplacer les protéines endommagées (entretien) qui sont perdues dans l'urine. Chez les animaux des conditions d'acide aminé sont classifiées en termes de (l'animal peut les produire à partir d'autres composés contenant de l'azote) acides aminés essentiels (un animal ne peut pas les produire) et non essentiels.
La consommation d'un régime qui contient à quantités proportionnées d'acides aminés essentiels (mais également non essentiels) est particulièrement importante pour les animaux grandissants, qui ont une condition particulièrement élevée.
Des acides gras
en plus de la suffisamment de prise, un équilibre approprié des acides gras essentiels - les acides gras omega-3 et omega-6 - a été découverts pour être cruciaux pour la santé de maintien. Tous les deux acides gras polyinsaturés à longue chaîne uniques de « Omega » sont des substrats pour une classe des eicosanoids connus sous le nom de prostaglandines qui fonctionnent comme hormones. L'acide omega-3 eicosapentaenoic (EPA) (qui peut être fait dans le corps à partir de l'acide alpha-linolénique essentiel de l'acide gras omega-3 (LNA), ou pris dedans par des sources marines de nourriture), servir de module à la série 3 prostaglandines (par exemple. faible-inflammation PGE3). L'acide omega-6 dihomo-gamma-linolénique (DGLA) sert de module aux prostaglandines de la série 1 (par exemple. PGE1 anti-inflammatoire), tandis que l'acide arachidonique (aa) sert de module à la série 2 prostaglandines (par exemple. PGE pro-inflammatoire 2). DGLA et aa sont faits à partir de l'acide omega-6 linoléique (LA) dans le corps, ou peuvent être pris dedans directement par la nourriture. Une prise convenablement équilibrée d'omega-3 et d'omega-6 détermine en partie la production relative de différentes prostaglandines, qui explique en partie l'importance de l'équilibre d'omega-3/omega-6 pour la santé cardiovasculaire. Dans les sociétés industrialisées, peuplez consomment généralement de grandes quantités d'huiles végétales traitées qui ont réduit des quantités d'acides gras essentiels avec une quantité excessive d'omega-6 à omega-3 relatif.
Le taux de conversions d'omega-6 DGLA en aa détermine en grande partie la production des prostaglandines respectives PGE1 et PGE2. Omega-3 EPA empêche l'aa d'être libéré des membranes, biaisant de ce fait l'équilibre de prostaglandine loin de PGE2 pro-inflammatoire fait à partir de l'aa vers PGE1 anti-inflammatoire fait à partir de DGLA. D'ailleurs, la conversion (désaturation) de DGLA en aa est commandée par l'enzyme delta-5-desaturase, qui alternativement est commandée par des hormones telles que l'insuline (vers le haut-règlement) et le glucagon (vers le bas-règlement). Puisque les différents types et les quantités de nourriture mangés/absorbés affectent l'insuline, le glucagon et d'autres hormones aux degrés variables, non seulement la quantité d'omega-3 contre omega-6 mangée mais également la composition générale du régime déterminent donc des implications de santé par rapport aux acides gras essentiels, inflammation (par exemple. fonction immunisée) et mitose (c.-à-d. division de cellules).
Sucre
plusieurs lignes d'évidence indiquent le hyperinsulinemia style de vie-induit et la fonction réduite d'insuline (c.-à-d. résistance d'insuline) comme facteur décisif dans beaucoup d'états de la maladie. Par exemple, la résistance de hyperinsulinemia et d'insuline sont fortement liées à l'inflammation chronique, qui alternativement est fortement liée à une variété de développements défavorables tels que les microinjuries et la formation artériels de caillot (c.-à-d. maladie de coeur) et division exagérée de cellules (c.-à-d. cancer).
Hyperinsulinemia et résistance d'insuline (le prétendu syndrome métabolique) sont caractérisés par une combinaison de l'obésité abdominale, du sucre de sang élevé, de la tension artérielle élevée, des triglycérides élevés de sang, et du cholestérol réduit de HDL. L'impact négatif du hyperinsulinemia sur l'équilibre de la prostaglandine PGE1/PGE2 peut être significatif.
L'état d'obésité contribue clairement à la résistance d'insuline, qui alternativement peut causer le type 2 diabète. Pratiquement tous les obèses et la plupart de type 2 individus diabétiques ont marqué la résistance d'insuline. Bien que l'association entre l'overfatness et la résistance d'insuline soit claire, les causes exactes (multiforme probable) de la résistance d'insuline demeurent moins claires. D'une manière primordiale, on l'a démontré que l'exercice approprié, l'ingestion de nourriture plus régulière et la réduction de la charge glycémique (voir ci-dessous) toute peuvent renverser la résistance d'insuline dans des individus d'overfat (et abaisser de ce fait des taux du sucre dans le sang dans ceux qui ont le type 2 diabète).
Obesity can unfavourably alter hormonal and metabolic status via resistance to the hormone leptin, and a vicious cycle may occur in which insulin/leptin resistance and obesity aggravate one another. The vicious cycle is putatively fuelled by continuously high insulin/leptin stimulation and fat storage, as a result of high intake of strongly insulin/leptin stimulating foods and energy.
Both insulin and leptin normally function as satiety signals to the hypothalamus in the brain; however, insulin/leptin resistance may reduce this signal and therefore allow continued overfeeding despite large body fat stores. In addition, reduced leptin signalling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate.
There is debate about how and to what extent different dietary factors -- e.g. intake of processed carbohydrates, total protein, fat, and carbohydrate intake, intake of saturated and trans fatty acids, and low intake of vitamins/minerals -- contribute to the development of insulin- and leptin resistance. In any case, analogous to the way modern man-made pollution may potentially overwhelm the environment's ability to maintain 'homeostasis', the recent explosive introduction of high Glycemic Index- and processed foods into the human diet may potentially overwhelm the body's ability to maintain homeostasis and health (as evidenced by the metabolic syndrome epidemic).
Antioxidants are another recent discovery. As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as radical oxygen species or free radicals form as a result. For normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds, some produced by the body with adequate precursors (glutathione, Vitamin C in most animals) and those that the body cannot produce may only be obtained through the diet through direct sources (Vitamin C in humans, Vitamin A, Vitamin K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight). Different antioxidants are now known to function in a cooperative network, e.g. vitamin C can reactivate free radical-containing glutathione or vitamin E by accepting the free radical itself, and so on. Some antioxidants are more effective than others at neutralizing different free radicals.
Some cannot neutralize certain free radicals. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas). When interacting with a free radical, some antioxidants produce a different free radical compound that is less dangerous or more dangerous than the previous compound. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect.
Intestinal bacterial flora
Some information in this article or section has not been verified and may not be reliable. Please check for any inaccuracies, and modify and cite sources as needed. It is now also known that the human digestion system contains a population of a range of bacteria which are essential to digestion, and which are also affected by the food we eat. The role and significance of the intestinal bacterial flora is under investigation. Both good and bad bacteria inhabit the digestive system. It is estimated that in the Western world, most people are no longer in a homeostatic balance. It is ideal to have 80% good to 20% bad, typically differentiated by gram negative and gram positive staining, respectively; however, in western diets it is more likely to be the other way around. Consuming processed food that are low in nutrients and high in sugar will allow bad bacteria to flourish.
Phytochemicals
Blackberries are a source of polyphenol antioxidants. A growing area of interest is the effect upon human health of trace chemicals, collectively called phytochemicals, nutrients typically found in edible plants, especially colorful fruits and vegetables (see Whole Foods Diet, below). Unlike the anecdotal and sometimes specious nutritional claims of medicinal herbs and compounds, the effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. One of the principal classes of phytochemicals are polyphenol antioxidants, chemicals which are known to provide certain health benefits to the cardiovascular system and immune system. These chemicals are known to down-regulate the formation of reactive oxygen species, key chemicals in cardiovascular disease.
Perhaps the most rigorously tested phytochemical is zeaxanthin, a yellow- pigmented carotenoid present in many yellow and orange fruits and vegetables. Repeated studies have shown a strong correlation between ingestion of zeaxanthin and the prevention and treatment of age-related macular degeneration (AMD). Less rigorous studies have proposed a correlation between zeaxanthin intake and cataracts. A second carotenoid, lutein, has also been shown to lower the risk of contracting AMD. Both compounds have been observed to collect in the retina when ingested orally, and they serve to protect the rods and cones against the destructive effects of light.
Another caretenoid, beta-cryptoxanthin, appears to protect against chronic joint inflammatory diseases, such as arthritis. While the association between serum blood levels of beta-cryptoxanthin and substantially decreased joint disease has been established, neither a convincing mechanism for such protection nor a cause-and-effect have been rigorously studied. Similarly, a red phytochemical, lycopene, has substantial credible evidence of negative association with development of prostate cancer.
The correlations between the ingestion of some phytochemicals and the prevention of disease are, in some cases, enormous in magnitude. For example, several studies have correlated high levels of zeaxanthin intake with roughly a 50% reduction in AMD. The difficulties in demonstrating causative properties and in applying the findings to human diet, however, are similarly enormous.
The standard for rigorous proof of causation in medicine is the double-blind study, a time-consuming, difficult and expensive process, especially in the case of preventative medicine. While new drugs must undergo such rigorous testing, pharmaceutical companies have a financial interest in funding rigorous testing and may recover the cost if the drug goes to market. No such commercial interest exists in studying chemicals that exist in orange juice and spinach, making funding for medical research difficult to obtain.
Even when the evidence is obtained, translating it to practical dietary advice can be difficult and counter-intuitive. Lutein, for example, occurs in many yellow and orange fruits and vegetables and protects the eyes against various diseases. However, it does not protect the eye nearly as well as zeaxanthin, and the presence of lutein in the retina will prevent zeaxanthin uptake.
Additionally, evidence has shown that the lutein present in egg yolk is more readily absorbed than the lutein from vegetable sources, possibly because of fat solubility. At the most basic level, the question "should you eat eggs?" is complex to the point of dismay, including misperceptions about the health effects of cholesterol in egg yolk, and its saturated fat content.
As another example, lycopene is prevalent in tomatoes (and actually is the chemical that gives tomatoes their red color). It is more highly concentrated, however, in processed tomato products such as commercial pasta sauce, or tomato soup, than in fresh "healthy" tomatoes. Such sauces, however, tend to have high amounts of salt, sugar, other substances a person may wish or even need to avoid.
for more details go to
http://www.consumersresearchcncl.org/Healthcare/Ophthalmologists/ophth_nutrition.html
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Automatically translated into Spanish thanks to WorldLingo
La nutrición y su salud
de la ciencia
de la nutrición de Wikipedia estudia la relación entre la dieta y los estados de la salud y de la enfermedad. Los dietético son los profesionales de salud que se especializan en este campo de especialización, entrenado altamente para proporcionar la caja fuerte, el consejo dietético evidencia-basado e intervenciones. Hay un espectro que se extiende de la desnutrición a la salud óptima, incluyendo muchos síntomas y enfermedades comunes que se puedan prevenir o aliviar a menudo con una nutrición mejor.
Las deficiencias, los excesos y los desequilibrios en dieta pueden producir impactos negativos en la salud, que puede conducir a las enfermedades tales como escorbuto, obesidad u osteoporosis, así como problemas psicologicos y del comportamiento. Por otra parte, ingestión excesiva de los elementos que no tienen ningún papel evidente en salud, (e.g. el plomo, el mercurio, PCBs, dioxins), pueden incurrir en efectos tóxicos y potencialmente mortales, dependiendo de la dosis. La ciencia de la nutrición procura entender cómo y porqué los aspectos dietéticos específicos influencian salud.
La ciencia
de la nutrición de la descripción intenta explicar las respuestas metabólicas y fisiológicas del cuerpo a la dieta. Con avances en biología, bioquímica, y genéticas moleculares, la ciencia de la nutrición se está convirtiendo además en el estudio del metabolismo integrante, que las búsquedas para conectar dieta y salud a través de la lente de procesos bioquímicos.
El cuerpo humano se compone de compuestos químicos tales como agua, aminoácidos (proteínas), ácidos grasos (lípidos), ácidos nucleic (DNA/RNA), y carbohidratos (e.g. azúcares y fibra). Estos compuestos alternadamente consisten en elementos tales como carbón, hidrógeno, oxígeno, nitrógeno, y fósforo, y pueden o no pueden contener los minerales tales como calcio, hierro, o cinc. Los minerales ubicuo ocurren bajo la forma de sales y electrólitos. Todos estos compuestos y elementos químicos ocurren en varias formas y combinaciones (e.g. hormonas/vitaminas, phospholipids, hydroxyapatite), en el cuerpo humano y en organismos (e.g. las plantas, los animales) esas los seres humanos comen. El cuerpo humano abarca necesariamente los elementos que come y absorbe en la circulación sanguínea. El sistema digestivo, excepto en el feto del unborn, participa en el primer paso que hace los diversos compuestos y elementos químicos en el alimento disponible para los trillones de las células del cuerpo. En el proceso digestivo de un adulto medio, cerca de siete litros de líquido, conocidos como jugos digestivos, salen del cuerpo interno e incorporan el lumen de la zona digestiva.
Los jugos digestivos ayudan a romper vínculos químicos entre los compuestos injeridos tan bien como module la conformación y/o el estado enérgio de los compuestos/de los elementos. Sin embargo, muchos elementos de los compuestos se absorben en la circulación sanguínea sin cambiar, aunque el proceso digestivo ayuda a lanzarlos de la matriz de los alimentos donde ocurren. Cualesquiera unabsorbed la materia se excretan en las heces. Pero solamente una cantidad mínima de jugo digestivo es eliminada por este proceso; los intestinos lo reabsorban la mayor parte de; si no el cuerpo deshidrataría rápidamente; (por lo tanto los efectos devastadores de la diarrea persistente).
El estudio en este campo debe tomar cuidadosamente en consideración el estado del cuerpo antes de la ingestión y después de la digestión así como la composición química del alimento y de la basura. Comparar la basura al alimento puede determinar los tipos específicos de compuestos y los elementos absorbidos por el cuerpo. El efecto que la materia absorbida tiene en el cuerpo puede ser determinado encontrando la diferencia entre el estado de la pre-ingestión y el estado de la poste-digestión. El efecto puede solamente ser perceptible después de un período del tiempo extendido en el cual todo el alimento e ingestión deban ser regulados exactamente y toda la basura debe ser analizada. El número de variables (e.g. los “factores de la confusión”) implicados en este tipo de experimentación son muy altos. Esto hace científico estudio alimenticio válido muy desperdiciador de tiempo y costoso, y explica porqué una ciencia apropiada de la nutrición humana es algo nueva.
Generalmente comer una variedad de fortalecedores de plantas (sin procesar) frescos, enteros ha probado hormonal y metabólico favorable comparado a comer una dieta monótona basada en los alimentos procesados. Particularmente, la consumición de fortalecedores de plantas enteros retarda la digestión y proporciona cantidades más altas y un equilibrio más favorable de alimentos esenciales y vitales por la unidad de la energía; dando por resultado una gerencia mejor del crecimiento, del mantenimiento, y de la mitosis de la célula (división de célula) así como la regulación de la glucosa y del apetito de la sangre. Un patrón generalmente más regular el comer (e.g. comiendo comidas de tamaño mediano cada 3 a 4 horas) también han probado más hormonal y metabólico favorable que toma de comida infrecuente, casual.
Los seres humanos
de la historia se han desarrollado como cazador-gatherers omnivorous sobre los últimos 250.000 años. Estaban sobre todo vegetarianas las dietas tempranas con las carnes y los pescados infrecuentes del juego donde disponibles. La agricultura se convirtió hace aproximadamente 10.000 años en localizaciones múltiples a través del mundo, proveyendo de granos tales como trigo, del arroz, y del maíz, las grapas tales como pan y pastas. Cultivando la leche y los productos lácteos también proporcionados, y agudamente aumentado la disponibilidad de carnes y la diversidad de vehículos. La importancia de la pureza del alimento fue reconocida cuando almacenamiento en montón conducido a los riesgos de la infestación y de la contaminación. El cocinar desarrollado como actividad a menudo ritualista, debido a la eficacia y a la confiabilidad se refiere a requerir adherencia a las recetas y a los procedimientos terminantes, y en respuesta a las demandas para la pureza y la consistencia del alimento.
Antigüedad con la aclaración
c. 475 A.C.: Anaxagoras indica que el alimento es absorbido por el cuerpo humano y el “homeomerics por lo tanto contenido” (los componentes generativos), de tal modo deduciendo la existencia de alimentos.
c. 400 A.C.: Hippocrates dice, “deje el alimento sea su medicina y la medicina sea su alimento.”
El experimento alimenticio primero registrado se encuentra en el libro de la biblia de Daniel. Al rey de Babylon capturaron a Daniel y a sus amigos durante una invasión de Israel. Seleccionado como criados de la corte, eran compartir en los alimentos finos y el vino del rey. Pero se opusieron, prefiriendo vehículos (pulsos) y agua de acuerdo con sus restricciones dietéticas judías. El principal administrador del rey convino renuente un ensayo. Daniel y sus amigos recibieron su dieta por 10 días y después fueron comparados a los hombres del rey. Apareciendo más sanos, fueron permitidos continuar con su dieta.
1500s: El da Vinci de Leonardo del científico y del artista comparó metabolismo a una vela ardiente.
1747: El Dr. James Lind, médico en la marina de guerra británica, realizó el primer experimento científico de la nutrición, descubriendo que el jugo de cal ahorró a marineros que habían estado en el mar por años del escorbuto, de un desorden mortal y doloroso de la sangría. El descubrimiento fue no hecho caso por cuarenta años, después de lo cual los marineros británicos se conocían como “limeys.” La vitamina C esencial dentro del jugo de cal no sería reconocida por los científicos hasta los años 30.
1770: Antoine Lavoisier, el “padre de la nutrición y de la química” descubrió los detalles del metabolismo, demostrando que la oxidación del alimento es la fuente del calor del cuerpo.
1790: George Fordyce reconoció el calcio necesario para la supervivencia de las aves.
Era moderna con 1941
1800s temprano: Los elementos carbón, nitrógeno, hidrógeno y oxígeno fueron reconocidos como los componentes primarios del alimento, y los métodos para medir sus proporciones fueron desarrollados.
1816: François Magendie descubre que los perros alimentaron solamente los carbohidratos y la grasa perdió su proteína del cuerpo y murió en algunas semanas, pero los perros también alimentaron la proteína sobrevivieron, identificando la proteína como componente dietético esencial.
1840: Justus Liebig descubre el maquillaje químico de los carbohidratos (azúcares), de las grasas (ácidos grasos) y de las proteínas (los aminoácidos.)
1860s: Claus Bernard descubre que las grasas de cuerpo se pueden sintetizar del carbohidrato y de la proteína, demostrando que la energía en glucosa de la sangre se puede almacenar como gorda o como glicógeno.
1880s temprano: Kanehiro Takaki observó que los marineros japoneses desarrollaron beriberi (o la neuritis endémica, una enfermedad que causaba problemas y parálisis del corazón) pero los marineros británicos no. La adición de la leche y de la carne a las dietas del japonés previno la enfermedad.
1896: Yodo observado Baumann en glándulas de tiroides.
1897: Christiaan Eijkman trabajó con los naturales de Java, que también sufrieron de beriberi. Eijkman observó que los pollos alimentaron la dieta nativa del arroz blanco desarrollaron los síntomas del beriberi, pero seguían siendo sanos cuando arroz moreno sin procesar del fed con el salvado externo intacto. Eijkman curó a naturales alimentándoles el arroz moreno, descubriendo que el alimento puede curar enfermedad. Sobre dos décadas más adelante, los nutricionistas aprendieron que el salvado de arroz externo contiene la vitamina B1, también conocida como tiamina.
1900s tempranos: Carl Von Voit y máximo Rubner mide independientemente gastos energéticos calóricos en diversa especie de animales, aplicando principios de la física en nutrición.
1906: Wilcock y Hopkins demostraron que el tryptophan del aminoácido era necesario para la supervivencia de ratones. Gowland Hopkins reconoció “factores accesorios del alimento” con excepción de las calorías, proteína y minerales, como materiales orgánicos esenciales para la salud pero que el cuerpo no puede sintetizar.
1907: Stephen M. Babcock y Edwin B. Conducta del ciervo el experimento del Solo-grano. Este experimento funciona con 1911.
1912: El canguelo de Casmir acuñó la vitamina del término, un factor vital en la dieta, de las palabras “vitales” y de la “amina,” porque estas sustancias desconocidas que prevenían escorbuto, beriberi, y pellagra, entonces fueron pensadas para ser derivadas del amoníaco.
1913: Elmer V. McCollum descubrió las primeras vitaminas, la vitamina A soluble en la grasa, y la vitamina soluble en agua B (en 1915; ahora sabido para ser un complejo de varias vitaminas solubles en agua) y de la vitamina C de los nombres como la sustancia entonces-desconocida que previene escorbuto.
1919: Sir Edward Mellanby identificó incorrectamente raquitismo como deficiencia de la vitamina A, porque él podría curarla en perros con aceite del hígado de bacalao.
1922: McCollum destruye la vitamina A en aceite pero hallazgos del hígado de bacalao que todavía cura el raquitismo, nombrando la vitamina D.
1922: H.M. Evans y L.S. El obispo descubre la vitamina E como esencial para el embarazo de la rata, originalmente llamándolo el “factor X del alimento” hasta 1925.
1925: El ciervo descubre que las cantidades de rastro de cobre es necesario para la absorción del hierro.
1927: Adolf Otto Reinhold Windaus sintetiza la vitamina D, para la cual él ganó el premio Nobel en química en 1928.
1928: Albert Szent-Gyorgyi aísla el ácido ascórbico, y en 1932 prueba que es vitamina C previniendo escorbuto. En 1935 él lo sintetiza, y en 1937 él gana un premio Nobel para sus esfuerzos. Szent-Gyorgyi aclara concurrentemente mucho del ciclo del ácido cítrico.
los años 30: Guillermo Cumming Rose identifica los aminoácidos esenciales, las proteínas necesarias que no puede el cuerpo sintetiza.
1935: Underwood y Marston descubren independientemente la necesidad del cobalto.
1936: Eugene Floyd Dubois demuestra que el funcionamiento del trabajo y de la escuela está relacionado con la aportación calórica.
1938: La estructura química de la vitamina E es descubierta por Erhard Fernholz, y es sintetizada por Paul Karrer.
1941: Los permisos dietéticos primero recomendados (RDAs) fueron establecidos por el consejo de investigación nacional.
Reciente
1992 los E.E.U.U. El Ministerio de Agricultura introduce la pirámide de la guía del alimento.
Relación de 2002 demostraciones del estudio entre la nutrición y el comportamiento violento.
La obesidad 2005 se puede causar por el adenovirus además de la mala nutrición.
La nutrición y la salud
allí son seis alimentos principales en los cuales el cuerpo necesita recibir. Estos alimentos incluyen los carbohidratos, las proteínas, las grasas, las vitaminas, los minerales, y el agua. Es importante consumir estos seis alimentos sobre una base diaria para construir y para mantener sistemas sanos del cuerpo.
La mala salud se puede causar por un desequilibrio de alimentos, produciendo un exceso o la deficiencia, que alternadamente afectan el cuerpo que funciona acumulativo. Por otra parte, porque son la mayoría de los alimentos, de cierta manera u otros, implicado en señalar de la célula-a-célula (e.g. como bloque de edificio o parte de una hormona o de señalar “conecta en cascada”), deficiencia o el exceso de varios alimentos afecta la función hormonal indirectamente. Así, porque regulan en gran parte la expresión de genes, las hormonas representan un acoplamiento entre la nutrición y cómo se expresan nuestros genes, es decir. nuestro phenotype.
La fuerza y la naturaleza de este acoplamiento están continuamente bajo investigación, pero las observaciones estos últimos años han demostrado especialmente un papel giratorio de la nutrición en actividad y la función hormonales y por lo tanto en salud. Una fuente de artículos sobre la nutrición y la salud es el boletín de noticias trimestral de la nutrición para la asociación óptima de la salud (NOHA). Artículos puesto que 1984 son puestos en un índice por el tema, el nombre, y la cronología.
Los aminoácidos esenciales y no esenciales
el cuerpo requieren los aminoácidos producir la proteína nueva del cuerpo (retención de la proteína) y substituir las proteínas dañadas (mantenimiento) que se pierden en la orina. En animales los requisitos del aminoácido se clasifican en términos de (el animal puede producirlos del otro nitrógeno que contiene compuestos) aminoácidos esenciales (un animal no puede producirlos) y no esenciales.
Consumir una dieta que contenga cantidades adecuadas de aminoácidos esenciales (pero también no esenciales) es particularmente importante para los animales crecientes, que tienen un requisito particularmente alto.
Los ácidos grasos
además del suficiente producto, un equilibrio apropiado de ácidos grasos esenciales - los ácidos grasos omega-3 y omega-6 - se han descubierto para ser cruciales para la salud que mantenía. Ambos ácidos grasos polyunsaturated de larga cadena únicos de “Omega” son substratos para una clase de los eicosanoids conocidos como prostaglandinas que funcionen como las hormonas. El ácido eicosapentaenoic omega-3 (EPA) (que se puede hacer en el cuerpo del ácido alfa-linolenic esencial del ácido graso omega-3 (LNA), o tomado adentro con fuentes marinas del alimento), servicios como bloque de edificio para la serie 3 prostaglandinas (e.g. débil-inflamación PGE3). El ácido dihomo-gamma-linolenic omega-6 (DGLA) sirve como bloque de edificio para las prostaglandinas de la serie 1 (e.g. PGE1 antiinflamatorio), mientras que el ácido arachidonic (AA) sirve como bloque de edificio para la serie 2 prostaglandinas (e.g. PGE favorable-inflamatorio 2). DGLA y el AA se hacen del ácido linoleic omega-6 (LA) en el cuerpo, o se pueden tomar adentro directamente a través del alimento. Un producto apropiadamente equilibrado de omega-3 y de omega-6 determina en parte la producción relativa de diversas prostaglandinas, que explica en parte la importancia del balance de omega-3/omega-6 para la salud cardiovascular. En sociedades industrializadas, pueble consumen generalmente cantidades grandes de aceites vegetales procesados que han reducido cantidades de ácidos grasos esenciales junto con una cantidad excesiva de omega-6 omega-3 en relación con.
El índice de conversiones de omega-6 DGLA al AA determina en gran parte la producción de las prostaglandinas respectivas PGE1 y PGE2. Omega-3 EPA evita que el AA sea lanzado de las membranas, de tal modo sesgando el balance de la prostaglandina lejos de PGE2 favorable-inflamatorio hecho del AA hacia PGE1 antiinflamatorio hecho de DGLA. Por otra parte, la conversión (desaturación) de DGLA al AA es controlada por la enzima delta-5-desaturase, que alternadamente es controlada por las hormonas tales como insulina (para arriba-regulación) y glucagon (abajo-regulación). Porque diversos tipos y las cantidades de alimento comidos/absorbidos afectan la insulina, el glucagon y otras hormonas a los grados que varían, no sólo la cantidad de omega-3 contra omega-6 comida pero también la composición general de la dieta por lo tanto determina las implicaciones en lo referente a los ácidos grasos esenciales, inflamación de la salud (e.g. función inmune) y mitosis (es decir. división de célula).
Azucara
varias líneas de la evidencia indican hyperinsulinemia forma de vida-inducido y la función reducida de la insulina (es decir. resistencia de insulina) como factor decisivo en muchos estados de la enfermedad. Por ejemplo, la resistencia del hyperinsulinemia y de insulina se liga fuertemente a la inflamación crónica, que alternadamente se liga fuertemente a una variedad de progresos adversos tales como microinjuries y formación arteriales del coágulo (es decir. enfermedad cardíaca) y división de célula exagerada (es decir. cáncer).
Hyperinsulinemia y la resistencia de insulina (el síndrome metabólico supuesto) son caracterizados por una combinación de la obesidad abdominal, del azúcar de sangre elevada, de la presión arterial elevada, de los triglycerides elevados de la sangre, y del colesterol reducido de HDL. El impacto negativo del hyperinsulinemia en balance de la prostaglandina PGE1/PGE2 puede ser significativo.
El estado de la obesidad contribuye claramente a la resistencia de insulina, que alternadamente puede causar el tipo 2 diabetes. Virtualmente todos los obesos y la mayoría del tipo 2 individuos diabéticos han marcado resistencia de insulina. Aunque la asociación entre el overfatness y la resistencia de insulina está clara, las causas exactas (probable multifarious) de la resistencia de insulina siguen siendo menos claras. Importantemente, se ha demostrado que el ejercicio apropiado, una toma de comida más regular y la reducción de la carga glycemic (véase abajo) toda pueden invertir resistencia de insulina en individuos del overfat (y de tal modo bajar niveles de azúcar de sangre en los que tienen tipo 2 diabetes).
Obesity can unfavourably alter hormonal and metabolic status via resistance to the hormone leptin, and a vicious cycle may occur in which insulin/leptin resistance and obesity aggravate one another. The vicious cycle is putatively fuelled by continuously high insulin/leptin stimulation and fat storage, as a result of high intake of strongly insulin/leptin stimulating foods and energy.
Both insulin and leptin normally function as satiety signals to the hypothalamus in the brain; however, insulin/leptin resistance may reduce this signal and therefore allow continued overfeeding despite large body fat stores. In addition, reduced leptin signalling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate.
There is debate about how and to what extent different dietary factors -- e.g. intake of processed carbohydrates, total protein, fat, and carbohydrate intake, intake of saturated and trans fatty acids, and low intake of vitamins/minerals -- contribute to the development of insulin- and leptin resistance. In any case, analogous to the way modern man-made pollution may potentially overwhelm the environment's ability to maintain 'homeostasis', the recent explosive introduction of high Glycemic Index- and processed foods into the human diet may potentially overwhelm the body's ability to maintain homeostasis and health (as evidenced by the metabolic syndrome epidemic).
Antioxidants are another recent discovery. As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as radical oxygen species or free radicals form as a result. For normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds, some produced by the body with adequate precursors (glutathione, Vitamin C in most animals) and those that the body cannot produce may only be obtained through the diet through direct sources (Vitamin C in humans, Vitamin A, Vitamin K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight). Different antioxidants are now known to function in a cooperative network, e.g. vitamin C can reactivate free radical-containing glutathione or vitamin E by accepting the free radical itself, and so on. Some antioxidants are more effective than others at neutralizing different free radicals.
Some cannot neutralize certain free radicals. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas). When interacting with a free radical, some antioxidants produce a different free radical compound that is less dangerous or more dangerous than the previous compound. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect.
Intestinal bacterial flora
Some information in this article or section has not been verified and may not be reliable. Please check for any inaccuracies, and modify and cite sources as needed. It is now also known that the human digestion system contains a population of a range of bacteria which are essential to digestion, and which are also affected by the food we eat. The role and significance of the intestinal bacterial flora is under investigation. Both good and bad bacteria inhabit the digestive system. It is estimated that in the Western world, most people are no longer in a homeostatic balance. It is ideal to have 80% good to 20% bad, typically differentiated by gram negative and gram positive staining, respectively; however, in western diets it is more likely to be the other way around. Consuming processed food that are low in nutrients and high in sugar will allow bad bacteria to flourish.
Phytochemicals
Blackberries are a source of polyphenol antioxidants. A growing area of interest is the effect upon human health of trace chemicals, collectively called phytochemicals, nutrients typically found in edible plants, especially colorful fruits and vegetables (see Whole Foods Diet, below). Unlike the anecdotal and sometimes specious nutritional claims of medicinal herbs and compounds, the effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. One of the principal classes of phytochemicals are polyphenol antioxidants, chemicals which are known to provide certain health benefits to the cardiovascular system and immune system. These chemicals are known to down-regulate the formation of reactive oxygen species, key chemicals in cardiovascular disease.
Perhaps the most rigorously tested phytochemical is zeaxanthin, a yellow- pigmented carotenoid present in many yellow and orange fruits and vegetables. Repeated studies have shown a strong correlation between ingestion of zeaxanthin and the prevention and treatment of age-related macular degeneration (AMD). Less rigorous studies have proposed a correlation between zeaxanthin intake and cataracts. A second carotenoid, lutein, has also been shown to lower the risk of contracting AMD. Both compounds have been observed to collect in the retina when ingested orally, and they serve to protect the rods and cones against the destructive effects of light.
Another caretenoid, beta-cryptoxanthin, appears to protect against chronic joint inflammatory diseases, such as arthritis. While the association between serum blood levels of beta-cryptoxanthin and substantially decreased joint disease has been established, neither a convincing mechanism for such protection nor a cause-and-effect have been rigorously studied. Similarly, a red phytochemical, lycopene, has substantial credible evidence of negative association with development of prostate cancer.
The correlations between the ingestion of some phytochemicals and the prevention of disease are, in some cases, enormous in magnitude. For example, several studies have correlated high levels of zeaxanthin intake with roughly a 50% reduction in AMD. The difficulties in demonstrating causative properties and in applying the findings to human diet, however, are similarly enormous.
The standard for rigorous proof of causation in medicine is the double-blind study, a time-consuming, difficult and expensive process, especially in the case of preventative medicine. While new drugs must undergo such rigorous testing, pharmaceutical companies have a financial interest in funding rigorous testing and may recover the cost if the drug goes to market. No such commercial interest exists in studying chemicals that exist in orange juice and spinach, making funding for medical research difficult to obtain.
Even when the evidence is obtained, translating it to practical dietary advice can be difficult and counter-intuitive. Lutein, for example, occurs in many yellow and orange fruits and vegetables and protects the eyes against various diseases. However, it does not protect the eye nearly as well as zeaxanthin, and the presence of lutein in the retina will prevent zeaxanthin uptake.
Additionally, evidence has shown that the lutein present in egg yolk is more readily absorbed than the lutein from vegetable sources, possibly because of fat solubility. At the most basic level, the question "should you eat eggs?" is complex to the point of dismay, including misperceptions about the health effects of cholesterol in egg yolk, and its saturated fat content.
As another example, lycopene is prevalent in tomatoes (and actually is the chemical that gives tomatoes their red color). It is more highly concentrated, however, in processed tomato products such as commercial pasta sauce, or tomato soup, than in fresh "healthy" tomatoes. Such sauces, however, tend to have high amounts of salt, sugar, other substances a person may wish or even need to avoid.
for more details go to
http://www.consumersresearchcncl.org/Healthcare/Ophthalmologists/ophth_nutrition.html
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Automatically translated into Italian thanks to WorldLingo
La nutrizione e la vostra salute
dalla scienza
di nutrizione di Wikipedia studia il rapporto fra la dieta e dichiara di salute e della malattia. I dietisti sono professionisti del settore medico-sanitario che sono specializzati in questo campo di specializzazione, altamente addestrato per fornire la cassaforte, prova-hanno basato il consiglio e gli interventi dietetichi. Ci è uno spettro che varia dalla malnutrizione alla salute ottimale, compreso molti sintomi e malattie comuni che possono essere evitati o alleviati spesso con nutrizione migliore.
Le mancanze, gli eccessi e gli squilibri nella dieta possono produrre gli effetti negativi su salute, che può condurre alle malattie quali scurvy, l'obesità o il osteoporosis, così come i problemi psicologici e del comportamento. Inoltre, ingestione eccessiva degli elementi che non hanno ruolo apparente nella salute, (per esempio. il cavo, il mercurio, PCBs, dioxins), possono subire gli effetti tossici e potenzialmente mortali, secondo la dose. La scienza di nutrizione tenta di capire come e perchè le funzioni dietetiche specifiche influenzano la salute.
La scienza
di nutrizione di descrizione cerca di spiegare le risposte metaboliche e fisiologiche del corpo alla dieta. Con gli avanzamenti nella biologia, nella biochimica e nella genetica molecolari, la scienza di nutrizione sta sviluppandosi ulteriormente nello studio su metabolismo integrante, che ricerche per collegare dieta e salute tramite l'obiettivo dei processi biochimici.
Il corpo umano si compone dei residui chimici quali acqua, amminoacidi (proteine), acidi grassi (lipidi), acidi nucleici (DNA/RNA) ed i carboidrati (per esempio. zuccheri e fibra). Questi residui a loro volta consistono degli elementi quali carbonio, idrogeno, ossigeno, azoto e fosforo e possono o meno contenere i minerali quali il calcio, il ferro, o lo zinco. I minerali ubiquistmente si presentano sotto forma d'i sali e gli elettroliti. Tutti questi residui ed elementi chimici si presentano in varie forme e combinazioni (per esempio. ormoni/vitamine, fosfolipidi, hydroxyapatite), sia nel corpo umano che negli organismi (per esempio. le piante, gli animali) quei esseri umani mangiano. Il corpo umano necessariamente contiene gli elementi che mangia ed assorbe nella circolazione sanguigna. Il sistema digestivo, tranne nel feto del unborn, partecipa al primo punto che fa i residui e gli elementi chimici differenti in alimento disponibile per i trilioni delle cellule del corpo. Nel processo digestivo di un adulto medio, circa sette litri di liquido, conosciuti come le spremute digestive, rimuovono il corpo interno e forniscono il lumen del tratto digestivo.
Le spremute digestive contribuiscono a rompere i legami chimici fra i residui come pure moduli la conformazione e/o energico ingeriti dichiarano dei residui/elementi. Tuttavia, molti elementi dei residui sono assorbiti nella circolazione sanguigna identicamente, benchè il processo digestivo contribuisca a liberarlo dalla tabella degli alimenti in cui accadono. C'è ne unabsorbed la materia sono espulsi nei feces. Ma soltanto una quantità minima di spremuta digestiva è eliminata tramite questo processo; gli intestini gli riassorbiscono la maggior parte; altrimenti il corpo si disidraterebbe velocemente; (quindi gli effetti devastating di diarrea persistente).
Lo studio in questo campo deve prendere con attenzione in considerazione il dichiarare del corpo prima di ingestione e dopo digestione così come la composizione chimica dell'alimento e dello spreco. Confrontando lo spreco all'alimento può determinare i tipi specifici di residui e gli elementi assorbiti dall'ente. L'effetto che la materia assorbita ha sul corpo può essere determinata trovando la differenza fra l'pre-ingestione dichiara e la alberino-digestione dichiarano. L'effetto può soltanto essere distinguibile dopo un periodo di tempo esteso in où tutti gli alimento ed ingestione devono essere regolati esattamente e tutto lo spreco deve essere analizzato. Il numero di variabili (per esempio. “i fattori di confusione„) addetti a questo tipo di esperimento è molto alti. Ciò effettua scientificamente lo studio nutrizionale valido molto che richiede tempo e costoso e spiega perchè una scienza adeguata dell'alimentazione umana è piuttosto nuova.
Generalmente, mangiare una varietà di alimenti vegetali (non trattati) freschi e interi è risultato ormonalmente e metabolicamente favorevole confrontato a mangiare una dieta monotona basata sugli alimenti trasformati. In particolare, il consumo degli alimenti di piante intere ritarda la digestione e fornisce le quantità elevate e un equilibrio più favorevole delle sostanze nutrienti essenziali e vitali per l'unità di energia; con conseguente amministrazione migliore di sviluppo, di manutenzione e della mitosi delle cellule (divisione delle cellule) così come la regolazione del glucosio e dell'appetito di anima. Un modello generalmente più normale di consumo (per esempio. mangiando i pasti di medie dimensioni ogni 3 - 4 ore) inoltre è risultato più ormonalmente e metabolicamente favorevole che l'ingestione di cibo rara e aleatoria.
Gli esseri umani
di storia si sono evoluti come cacciatore-gatherers omnivorous in questi ultimi 250.000 anni. Le diete iniziali erano soprattutto vegetariane con le carni ed i pesci rari del gioco dove disponibili. L'agricoltura si è sviluppata circa 10.000 anni fa nelle posizioni multiple nel mondo intero, fornendo ai grani quale frumento, al riso ed al mais, le graffette quali pane e pasta. Coltivando latte ed i latticini anche forniti ed acutamente aumentato la disponibilità delle carni e diversità delle verdure. L'importanza della purezza dell'alimento è stata riconosciuta quando l'immagazzinamento alla rinfusa ha condotto ai rischi di contaminazione e di infestazione. La cottura sviluppata come attività spesso ritualistic, dovuto efficienza ed affidabilità interessa richiedere l'aderenza per le ricette e le procedure rigorose ed in risposta alle richieste per la purezza e la consistenza dell'alimento.
Antichità con il chiarimento
c. 475 BC: Anaxagoras dichiara che l'alimento è assorbito dal corpo umano e “dal homeomerics„ quindi contenuto (componenti generativi), quindi deducenti l'esistenza delle sostanze nutrienti.
c. 400 BC: Hippocrates dice, “lasci l'alimento è la vostra medicina e la medicina è il vostro alimento.„
L'esperimento nutrizionale in primo luogo registrato è trovato nel libro della bibbia di Daniel. Daniel ed i suoi amici sono stati bloccati dal re di Babylon durante l'invasione dell'Israele. Selezionato come servi della corte, erano di ripartirsi in alimenti fini e vino del re. Ma hanno obiettato, preferendo le verdure (impulsi) e l'acqua in conformità con le loro limitazioni dietetiche ebree. L'amministratore principale del re ha accosentito riluttante ad una prova. Daniel ed i suoi amici hanno ricevuto la loro dieta per 10 giorni ed allora sono stati confrontati agli uomini del re. Sembrando più sani, sono stati permessi continuare con la loro dieta.
1500s: Il da Vinci del Leonardo dell'artista e dello scienziato ha confrontato il metabolismo ad una candela burning.
1747: Dott. James Lind, un medico nel blu marino britannico, ha effettuato il primo esperimento scientifico di nutrizione, scoprente che il succo di cedro ha conservato i marinai che erano stati in mare per gli anni da scurvy, da un disordine mortale e doloroso di spurgo. La scoperta è stata ignorata per quaranta anni, dopo di che i marinai britannici sono stato conosciuti come “i limeys.„ La vitamina C essenziale all'interno del succo di cedro non sarebbe riconosciuta dagli scienziati fino ai 1930s.
1770: Antoine Lavoisier, “il padre di nutrizione e di chimica„ ha scoperto i particolari di metabolismo, dimostranti che l'ossidazione di alimento è la fonte di calore del corpo.
1790: George Fordyce ha riconosciuto il calcio necessario per la sopravvivenza dei gallinacei.
Era moderna con 1941
1800s iniziale: Gli elementi carbonio, azoto, idrogeno ed ossigeno sono stati riconosciuti come i componenti primari di alimento ed i metodi per misurare le loro proporzioni sono stati messi a punto.
1816: François Magendie scopre che i cani hanno alimentato soltanto i carboidrati ed il grasso ha perso la loro proteina del corpo ed è morto in alcune settimane, ma i cani inoltre hanno alimentato la proteina sono sopravvissuto, identificando la proteina come componente dietetico essenziale.
1840: Justus Liebig scopre il trucco chimico dei carboidrati (zuccheri), dei grassi (acidi grassi) e delle proteine (amminoacidi.)
1860s: Claus Bernard scopre che il grasso di corpo può essere sintetizzato dal carboidrato e dalla proteina, indicanti che l'energia in glucosio di anima può essere memorizzata come grassa o come glicogeno.
1880s iniziale: Kanehiro Takaki ha osservato che i marinai giapponesi hanno sviluppato il beriberi (o la neurite endemica, una malattia che causa i problemi e la paralisi del cuore) ma i marinai britannici non. Aggiungendo il latte e la carne alle diete del giapponese ha impedito la malattia.
1896: Iodio osservato Baumann in ghiandole tiroidi.
1897: Christiaan Eijkman ha funzionato con i nativi di Java, che inoltre hanno sofferto dal beriberi. Eijkman ha osservato che i polli hanno alimentato la dieta natale di riso bianco hanno sviluppato i sintomi del beriberi, ma sono rimasto sani quando riso sbramato non trattato del fed con la crusca esterna intatta. Eijkman ha curato i nativi alimentando loro il riso sbramato, scoprente che l'alimento può curare la malattia. Oltre due decadi più successivamente, i dietisti hanno imparato che la crusca di riso esterna contiene la vitamina B1, anche conosciuta come tiamina.
1900s in anticipo: Carl Von Voit e massimo Rubner misura indipendentemente il dispendio energetico calorico nella specie differente di animali, applicante i principii della fisica in nutrizione.
1906: Wilcock e Hopkins hanno indicato che il triptofano dell'amminoacido era necessario per la sopravvivenza dei mouse. Gowland Hopkins ha riconosciuto “i fattori accessori dell'alimento„ tranne le calorie, proteina e minerali, come materiali organici essenziali a salute ma che il corpo non può sintetizzare.
1907: Stephen M. Babcock e Edwin B. Comportamento del cervo maschio l'esperimento del Singolo-grano. Questo esperimento funziona con 1911.
1912: Il Funk di Casmir ha coniato la vitamina di termine, un fattore vitale nella dieta, dalle parole “vitali„ e “dall'ammina,„ perché queste sostanze sconosciute che impediscono lo scurvy, il beriberi e il pellagra, allora si sono pensate per essere derivate da ammoniaca.
1913: Elmer V. McCollum ha scoperto le prime vitamine, la vitamina A solubile nel grasso e la vitamina solubile in acqua B (in 1915; ora saputo per essere un complesso di parecchie vitamine solubili in acqua) e della vitamina C di nomi come la sostanza allora-sconosciuta che impedisce scurvy.
1919: Il sir Edward Mellanby ha identificato in modo errato il rachitismo come mancanza della vitamina A, perché potrebbe curarlo in cani con l'olio del fegato di merluzzo.
1922: McCollum distrugge la vitamina A nell'olio ma nei ritrovamenti che del fegato di merluzzo ancora cura il rachitismo, chiamante la vitamina D.
1922: H.M. Evans e L.S. Il Bishop scopre la vitamina E come essenziale per la gravidanza del ratto, originalmente denominandola “fattore X dell'alimento„ fino al 1925.
1925: Il cervo maschio scopre che tracce di rame è necessario per assorbimento del ferro.
1927: Adolf Otto Reinhold Windaus sintetizza la vitamina D, per cui ha vinto il premio Nobel nella chimica in 1928.
1928: Albert Szent-Gyorgyi isola l'acido ascorbico e in 1932 dimostra che è vitamina C impedendo lo scurvy. In 1935 lo sintetizza e in 1937 vince un premio Nobel per i suoi sforzi. Szent-Gyorgyi delucida simultaneamente gran parte del ciclo dell'acido citrico.
1930s: William Cumming Rosa identifica gli amminoacidi essenziali, proteine necessarie che il corpo non può sintetizza.
1935: Underwood e Marston scoprono indipendentemente la necessità di cobalto.
1936: Eugene Floyd Dubois indica che le prestazioni della scuola e del lavoro sono collegate con apporto calorico.
1938: La struttura chimica della vitamina E è scoperta da Erhard Fernholz ed è sintetizzata da Paul Karrer.
1941: I permessi dietetichi in primo luogo suggeriti (RDAs) sono stati stabiliti dal Consiglio di ricerca nazionale.
Recente
1992 gli Stati Uniti Il ministero dell'agricoltura introduce la piramide della guida dell'alimento.
Un rapporto di 2002 esposizioni di studio fra nutrizione e comportamento violento.
L'obesità 2005 può essere causata dall'adenovirus oltre che nutrizione difettosa.
La nutrizione e la salute
là sono sei sostanze nutrienti principali in cui il corpo deve ricevere. Queste sostanze nutrienti includono i carboidrati, le proteine, i grassi, le vitamine, i minerali e l'acqua. È importante consumare queste sei sostanze nutrienti su una base quotidiana per sviluppare ed effettuare i sistemi sani del corpo.
L'affezione può essere causata da uno squilibrio delle sostanze nutrienti, producendo un eccesso o la mancanza, che a sua volta interessano il corpo che funziona cumulativamente. Inoltre, perché la maggior parte delle sostanze nutrienti sono, in qualche modo o un altro, coinvolto nella segnalazione della cellula--cellula (per esempio. come il blocchetto di costruzione o parte di un ormone o di segnalazione “procede in sequenza„), mancanza o l'eccesso di varie sostanze nutrienti interessa indirettamente la funzione ormonale. Quindi, perché in gran parte regolano l'espressione dei geni, gli ormoni rappresentano un collegamento fra nutrizione e come i nostri geni sono espressi, cioè. il nostro fenotipo.
La resistenza e la natura di questo collegamento sono continuamente in esame, ma le osservazioni negli ultimi anni hanno dimostrato particolarmente un ruolo chiave per nutrizione nell'attività e nella funzione ormonali e quindi nella salute. Una fonte degli articoli su nutrizione e su salute è il bollettino trimestrale della nutrizione per l'associazione ottimale di salute (NOHA). Articoli poiché 1984 sono spostati ad incrementi dall'oggetto, dal nome e dalla cronologia.
Gli amminoacidi essenziali e non indispensabili
il corpo richiede gli amminoacidi produrre la nuova proteina del corpo (ritegno della proteina) e sostituire le proteine danneggiate (manutenzione) che sono perse nell'urina. In animali i requisiti dell'amminoacido sono classificati in termini di (l'animale può produrlo da altri residui contenenti azoto) amminoacidi essenziali (un animale non può produrlo) e non indispensabili.
Consumare una dieta che contiene gli importi sufficienti degli amminoacidi essenziali (ma anche non indispensabili) è particolarmente importante per gli animali crescenti, che hanno un requisito particolarmente alto.
Gli acidi grassi
oltre che presa sufficiente, un equilibrio adatto degli acidi grassi essenziali - acidi grassi omega-3 e omega-6 - è stato scoperto per essere cruciali per salute effettuante. Entrambi acidi grassi poli-insaturi a catena lunga unici “del omega„ sono substrati per un codice categoria dei eicosanoids conosciuti come le prostaglandine che funzionano come ormoni. Omega-3 l'acido eicosapentaenoic (EPA) (che può essere fatto nel corpo dall'acido alfa-linolenico essenziale dell'acido grasso omega-3 (LNA), o preso dentro con le fonti marine dell'alimento), serv da blocchetto di costruzione per la serie 3 prostaglandine (per esempio. debole-infiammazione PGE3). Omega-6 l'acido dihomo-gamma-linolenico (DGLA) serve da blocchetto di costruzione per le prostaglandine di serie 1 (per esempio. PGE1 antinfiammatorio), mentre l'acido arachidonico (aa) serve da blocchetto di costruzione per la serie 2 prostaglandine (per esempio. PGE pro-infiammatorio 2). Sia DGLA che l'aa sono fatti omega-6 dall'acido linoleico (LA) nel corpo, o possono essere presi dentro direttamente attraverso alimento. Una presa giustamente equilibrata di omega-3 e di omega-6 determina parzialmente la produzione relativa delle prostaglandine differenti, che spiega parzialmente l'importanza dell'equilibrio di omega-3/omega-6 per salute cardiovascolare. Nelle società industrializzate, popoli generalmente consumano i grandi importi degli oli vegetali trasformati che hanno ridotto gli importi degli acidi grassi essenziali con una quantità eccessiva di omega-6 a omega-3 relativo.
Il tasso delle conversioni di omega-6 DGLA all'aa in gran parte determina la produzione delle prostaglandine rispettive PGE1 e PGE2. Omega-3 EPA impedisce l'aa essere liberato dalle membrane, quindi danti all'equilibrio una direzione obliqua della prostaglandina via da PGE2 pro-infiammatorio fatto dall'aa verso PGE1 antinfiammatorio fatto da DGLA. Inoltre, la conversione (desaturazione) di DGLA all'aa è controllata dall'enzima delta-5-desaturase, che a sua volta è controllato dagli ormoni quali insulina (in su-regolazione) e glucagon (giù-regolazione). Poiché i tipi differenti e gli importi di alimenti mangiati/assorbiti interessano l'insulina, il glucagon ed altri ormoni ai gradi di variazione, non solo la quantità di omega-3 contro omega-6 mangiata ma inoltre la composizione generale della dieta quindi determina le implicazioni rispetto agli acidi grassi essenziali, infiammazione di salute (per esempio. funzione immune) e mitosi (cioè. divisione delle cellule).
Zucchera
parecchie linee di prova indicano il hyperinsulinemia lifestyle-indotto e la funzione ridotta dell'insulina (cioè. la resistenza di insulina) come fattore decisivo in molti malattia dichiara. Per esempio, la resistenza di insulina e di hyperinsulinemia è collegata fortemente ad infiammazione cronica, che a sua volta è collegata fortemente ad una varietà di sviluppi avversi quali i microinjuries e la formazione arteriosi del grumo (cioè. malattia di cuore) e divisione esagerata delle cellule (cioè. cancro).
Hyperinsulinemia e la resistenza di insulina (la cosiddetta sindrome metabolica) sono caratterizzati tramite una combinazione dell'obesità addominale, dello zucchero di anima elevato, della pressione sanguigna elevata, dei trigliceridi elevati di anima e del colesterolo ridotto di HDL. L'effetto negativo del hyperinsulinemia sull'equilibrio della prostaglandina PGE1/PGE2 può essere significativo.
Il dichiarare dell'obesità contribuisce chiaramente a resistenza di insulina, che a loro volta può causare il tipo 2 il diabete. Virtualmente tutti gli obesi e la maggior parte del tipo 2 individui diabetici hanno contrassegnato la resistenza di insulina. Anche se l'associazione fra il overfatness e la resistenza di insulina è chiara, (le cause esatte multifarious probabile) di resistenza di insulina rimangono meno chiare. D'importanza, è stato dimostrato che l'esercitazione adatta, l'ingestione di cibo più normale e ridurre il carico glycemic (veda sotto) tutto possono invertire la resistenza di insulina negli individui del overfat (e quindi abbassare le glicemie in coloro che ha tipo 2 il diabete).
Obesity can unfavourably alter hormonal and metabolic status via resistance to the hormone leptin, and a vicious cycle may occur in which insulin/leptin resistance and obesity aggravate one another. The vicious cycle is putatively fuelled by continuously high insulin/leptin stimulation and fat storage, as a result of high intake of strongly insulin/leptin stimulating foods and energy.
Both insulin and leptin normally function as satiety signals to the hypothalamus in the brain; however, insulin/leptin resistance may reduce this signal and therefore allow continued overfeeding despite large body fat stores. In addition, reduced leptin signalling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate.
There is debate about how and to what extent different dietary factors -- e.g. intake of processed carbohydrates, total protein, fat, and carbohydrate intake, intake of saturated and trans fatty acids, and low intake of vitamins/minerals -- contribute to the development of insulin- and leptin resistance. In any case, analogous to the way modern man-made pollution may potentially overwhelm the environment's ability to maintain 'homeostasis', the recent explosive introduction of high Glycemic Index- and processed foods into the human diet may potentially overwhelm the body's ability to maintain homeostasis and health (as evidenced by the metabolic syndrome epidemic).
Antioxidants are another recent discovery. As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as radical oxygen species or free radicals form as a result. For normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds, some produced by the body with adequate precursors (glutathione, Vitamin C in most animals) and those that the body cannot produce may only be obtained through the diet through direct sources (Vitamin C in humans, Vitamin A, Vitamin K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight). Different antioxidants are now known to function in a cooperative network, e.g. vitamin C can reactivate free radical-containing glutathione or vitamin E by accepting the free radical itself, and so on. Some antioxidants are more effective than others at neutralizing different free radicals.
Some cannot neutralize certain free radicals. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas). When interacting with a free radical, some antioxidants produce a different free radical compound that is less dangerous or more dangerous than the previous compound. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect.
Intestinal bacterial flora
Some information in this article or section has not been verified and may not be reliable. Please check for any inaccuracies, and modify and cite sources as needed. It is now also known that the human digestion system contains a population of a range of bacteria which are essential to digestion, and which are also affected by the food we eat. The role and significance of the intestinal bacterial flora is under investigation. Both good and bad bacteria inhabit the digestive system. It is estimated that in the Western world, most people are no longer in a homeostatic balance. It is ideal to have 80% good to 20% bad, typically differentiated by gram negative and gram positive staining, respectively; however, in western diets it is more likely to be the other way around. Consuming processed food that are low in nutrients and high in sugar will allow bad bacteria to flourish.
Phytochemicals
Blackberries are a source of polyphenol antioxidants. A growing area of interest is the effect upon human health of trace chemicals, collectively called phytochemicals, nutrients typically found in edible plants, especially colorful fruits and vegetables (see Whole Foods Diet, below). Unlike the anecdotal and sometimes specious nutritional claims of medicinal herbs and compounds, the effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. One of the principal classes of phytochemicals are polyphenol antioxidants, chemicals which are known to provide certain health benefits to the cardiovascular system and immune system. These chemicals are known to down-regulate the formation of reactive oxygen species, key chemicals in cardiovascular disease.
Perhaps the most rigorously tested phytochemical is zeaxanthin, a yellow- pigmented carotenoid present in many yellow and orange fruits and vegetables. Repeated studies have shown a strong correlation between ingestion of zeaxanthin and the prevention and treatment of age-related macular degeneration (AMD). Less rigorous studies have proposed a correlation between zeaxanthin intake and cataracts. A second carotenoid, lutein, has also been shown to lower the risk of contracting AMD. Both compounds have been observed to collect in the retina when ingested orally, and they serve to protect the rods and cones against the destructive effects of light.
Another caretenoid, beta-cryptoxanthin, appears to protect against chronic joint inflammatory diseases, such as arthritis. While the association between serum blood levels of beta-cryptoxanthin and substantially decreased joint disease has been established, neither a convincing mechanism for such protection nor a cause-and-effect have been rigorously studied. Similarly, a red phytochemical, lycopene, has substantial credible evidence of negative association with development of prostate cancer.
The correlations between the ingestion of some phytochemicals and the prevention of disease are, in some cases, enormous in magnitude. For example, several studies have correlated high levels of zeaxanthin intake with roughly a 50% reduction in AMD. The difficulties in demonstrating causative properties and in applying the findings to human diet, however, are similarly enormous.
The standard for rigorous proof of causation in medicine is the double-blind study, a time-consuming, difficult and expensive process, especially in the case of preventative medicine. While new drugs must undergo such rigorous testing, pharmaceutical companies have a financial interest in funding rigorous testing and may recover the cost if the drug goes to market. No such commercial interest exists in studying chemicals that exist in orange juice and spinach, making funding for medical research difficult to obtain.
Even when the evidence is obtained, translating it to practical dietary advice can be difficult and counter-intuitive. Lutein, for example, occurs in many yellow and orange fruits and vegetables and protects the eyes against various diseases. However, it does not protect the eye nearly as well as zeaxanthin, and the presence of lutein in the retina will prevent zeaxanthin uptake.
Additionally, evidence has shown that the lutein present in egg yolk is more readily absorbed than the lutein from vegetable sources, possibly because of fat solubility. At the most basic level, the question "should you eat eggs?" is complex to the point of dismay, including misperceptions about the health effects of cholesterol in egg yolk, and its saturated fat content.
As another example, lycopene is prevalent in tomatoes (and actually is the chemical that gives tomatoes their red color). It is more highly concentrated, however, in processed tomato products such as commercial pasta sauce, or tomato soup, than in fresh "healthy" tomatoes. Such sauces, however, tend to have high amounts of salt, sugar, other substances a person may wish or even need to avoid.
for more details go to
http://www.consumersresearchcncl.org/Healthcare/Ophthalmologists/ophth_nutrition.html
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Automatically translated into German thanks to WorldLingo
Nahrung und Ihre Gesundheit
von der Wikipedia
Nahrungwissenschaft studiert das Verhältnis zwischen Diät und Gesundheitszuständen und Krankheit. Diätetiker sind medizinische Fachkräfte, die auf diesen Bereich der Sachkenntnis spezialisiert werden, in hohem Grade ausgebildet, um Safe, Beweis-gegründeten diätetischen Rat und Interventionen zur Verfügung zu stellen. Es gibt ein Spektrum, das von der Unterernährung bis zu optimaler Gesundheit, einschließlich viele allgemeine Symptome und Krankheiten, die, reicht mit besserer Nahrung häufig verhindert werden oder vermindert werden können.
Mängel, überflüsse und Ungleichheiten in der Diät können negative Auswirkungen auf Gesundheit produzieren, die zu Krankheiten wie Skorbut, Korpulenz oder Osteoporose, sowie die psychologischen und Verhaltensprobleme führen kann. Außerdem übermäßige Einnahme der Elemente, die keine offensichtliche Rolle in der Gesundheit haben, (z.B. Leitung, Quecksilber, PCBs, Dioxine), können auf die giftigen und möglicherweise lebensgefährlichen Effekte, abhängig von der Dosis sich nehmen. Die Wissenschaft von Nahrung versucht, zu verstehen wie und warum spezifische diätetische Aspekte Gesundheit beeinflussen.
Überblick-
Nahrungwissenschaft sucht, die metabolischen und physiologischen Antworten des Körpers Diät zu erklären. Mit Fortschritten in der molekularen Biologie, in der Biochemie und in den Genetik, entwickelt sich Nahrungwissenschaft zusätzlich zur Studie des integrativen Metabolismus, die die Suchvorgänge, zum von Diät und von Gesundheit durch das Objektiv der biochemischen Prozesse anzuschließen.
Der menschliche Körper besteht chemische Mittel wie Wasser, Aminosäuren (Proteine), Fettsäuren (Lipide), Nukleinsäuren (DNA/RNA) und Kohlenhydrate (z.B. Zucker und Faser). Diese Mittel bestehen der Reihe nach aus Elementen wie Carbon, Wasserstoff, Sauerstoff, Stickstoff und Phosphor und können oder können möglicherweise nicht Mineralien wie Kalzium, Eisen oder Zink enthalten. Mineralien treten überall vorhanden in Form von Salzen und Elektrolyten auf. Alle diese chemischen von und von Elemente treten in den verschiedenen Formen und in den Kombinationen auf (z.B. Hormone/Vitamine, Phospholipide, hydroxyapatite), im menschlichen Körper und in den organismen (z.B. die diese Betriebe, Tiere) Menschen essen. Der menschliche Körper enthält notwendigerweise die Elemente, die er in den Blutstrom ißt und aufsaugt. Das Verdauungssystem, ausgenommen in das unborn Fötus, nimmt am ersten Schritt teil, der die unterschiedlichen chemischen Mittel und die Elemente in der Nahrung bildet, die für die Trillionen der Zellen des Körpers vorhanden ist. Im verdauungsfördernden Prozeß eines durchschnittlichen Erwachsenen, nehmen ungefähr sieben Liter Flüssigkeit, bekannt als Verdauungsflüssigkeiten, den internen Körper heraus und tragen das Lumen der verdauungsfördernden Fläche ein.
Die Verdauungsflüssigkeiten helfen, chemische Bindungen zwischen eingenommenen Mitteln, sowie zu brechen modulieren Sie die Anpassung und/oder den energischen Zustand der Mittel/der Elemente. Jedoch werden viele Mittelelemente in den Blutstrom unverändert aufgesogen, obwohl der verdauungsfördernde Prozeß hilft, sie von der Matrix der Nahrungsmittel zu befreien, in denen sie auftreten. Irgendwelche unabsorbed Angelegenheit wird ausgeschieden in den Rückständen. Aber nur eine minimale Menge Verdauungsflüssigkeit wird durch diesen Prozeß beseitigt; die Därme resorbieren Meiste; andernfalls würde der Körper schnell entwässern; (folglich die verheerenden Effekte der hartnäckigen Diarrhöe).
Studie diesbezüglich fangen muß den Zustand des Körpers vor Einnahme und nach Verdauung sowie den chemischen Aufbau der Nahrung und der Vergeudung sorgfältig in Betracht ziehen auf. Das Vergleichen der Vergeudung mit der Nahrung kann die spezifischen Arten der Mittel und die Elemente feststellen, die durch den Körper aufgesogen werden. Der Effekt, den die aufgesogene Angelegenheit auf dem Körper hat, kann festgestellt werden, indem man den Unterschied zwischen dem Voreinnahme Zustand und dem Pfostenverdauung Zustand findet. Der Effekt kann nach einem ausgedehnten Zeitabschnitt wahrnehmbar nur sein, in dem alle Nahrung und Einnahme genau reguliert werden müssen und alle Vergeudung muß analysiert werden. Die Zahl Variablen (z.B. „die Verwirrenfaktoren“) mit einbezogen in diese Art des Experimentierens ist sehr hoch. Dieses bildet wissenschaftlich gültige Ernährungsstudie sehr zeitraubend und kostspielig und erklärt, warum eine korrekte Wissenschaft der menschlichen Nahrung ziemlich neu ist.
Im allgemeinen hat das Essen einer Vielzahl der frischen, vollständigen (unverarbeiteten) Betriebsnahrungsmittel hormonal und metabolisch vorteilhaftes verglichen mit dem Essen einer monotonen Diät geprüft, die auf verarbeiteten Nahrungsmitteln basiert. Insbesondere verlangsamt Verbrauch der Vollpflanzennahrungsmittel Verdauung und liefert höhere Mengen und eine aktivere Bilanz der wesentlichen und lebenswichtigen Nährstoffe pro Maßeinheit von Energie; mit dem Ergebnis des besseren Managements des Zelle Wachstums, der Wartung und des Mitosis (Zellteilung) sowie Regelung der Blutglukose und -appetits. Ein im Allgemeinen regelmäßigeres Essenmuster (z.B. mittelgrosse Mahlzeiten essend, hat alle 3 bis 4 Stunden) auch hormonaler und metabolisch vorteilhaft als seltener, zufälliger Nahrungsmitteleinlaß geprüft.
Geschichte
Menschen haben als omnivorous Jägersammler über den letzten 250.000 Jahren entwickelt. Frühe Diäten waren mit seltenem Spielfleisch und -fischen hauptsächlich vegetarisch, wo vorhanden. Vor Landwirtschaft entwickelte ungefähr 10.000 Jahren in den mehrfachen Positionen weltweit und versah Körner wie Weizen, Reis und Mais, mit Heftklammern wie Brot und Teigwaren. Auch zur Verfügung gestellte Milch und Milchprodukte bewirtschaften und scharf erhöht der Verwendbarkeit des Fleisches und der Verschiedenartigkeit des Gemüses. Der Wert der Nahrungsmittelreinheit wurde erkannt, als Großraumspeicher zu Plage- und Verschmutzungsgefahren führte. Das Kochen entwickelt als häufig ritualistic Tätigkeit, wegen der Leistungsfähigkeit und der Zuverlässigkeit betrifft das Erfordern von Haftfähigkeit zu den strengen Rezepten und zu den Verfahren und in Erwiderung auf Nachfragen für Nahrungsmittelreinheit und -übereinstimmung.
Altertum durch Aufklärung
c. 475 BC: Anaxagoras gibt an, daß Nahrung durch den menschlichen Körper und folglich das enthaltene „homeomerics“ (generative Bestandteile) aufgesogen wird, dadurch ableitet man das Bestehen der Nährstoffe.
c. 400 BC: Hippokrates sagt, „lassen Sie Nahrung ist Ihre Medizin und Medizin ist Ihre Nahrung.“
Das zuerst notierte Ernährungsexperiment wird im Buch der Bibel von Daniel gefunden. Daniel und seine Freunde wurden vom König von Babylon während einer Invasion von Israel gefangengenommen. Vorgewählt als Gerichtbedienstete, waren sie, in des feinen den Nahrungsmitteln und im Wein Königs zu teilen. Aber sie wendeten ein und bevorzugten Gemüse (Impulse) und Wasser in übereinstimmung mit ihren jüdischen diätetischen Beschränkungen. Der HauptVerwalter des Königs stimmte widerstrebend einem Versuch zu. Daniel und seine Freunde empfingen ihre Diät für 10 Tage und wurden dann mit den Männern des Königs verglichen. Aussehend gesuender, wurden sie mit ihrer Diät fortfahren lassen.
1500s: Wissenschaftler und Künstler Leonardo da Vinci verglich Metabolismus mit einer brennenden Kerze.
1747: Dr. James Lind, ein Arzt in der britischen Marine, führte das erste wissenschaftliche Nahrungexperiment durch und entdeckte, daß Limettensaft Seeleute speicherte, die am Meer für Jahre vom Skorbut, von einer tödlichen und schmerzlichen Blutenstörung gewesen waren. Die Entdeckung wurde für vierzig Jahre ignoriert, nachdem wurden britische Seeleute bekannt als „limeys.“ Das wesentliche Vitamin C innerhalb des Limettensaftes würde nicht von den Wissenschaftlern bis die dreißiger Jahre erkannt.
1770: Antoine Lavoisier, der „Vater von Nahrung und von Chemie“ entdeckte die Details des Metabolismus und zeigte, daß die Oxidation der Nahrung die Quelle der Körperhitze ist.
1790: George Fordyce erkannte das Kalzium, das für Geflügelüberleben notwendig ist.
Moderne ära durch 1941
Frühes 1800s: Die Elemente Carbon, Stickstoff, Wasserstoff und Sauerstoff wurden als die Primärbestandteile der Nahrung erkannt, und die Methoden, zum ihrer Anteile zu messen wurden entwickelt.
1816: François Magendie entdeckt, daß Hunde nur Kohlenhydrate einzogen und Fett ihr Körperprotein verlor und in einigen Wochen starb, aber Hunde zogen auch Protein überlebten ein und kennzeichneten Protein als wesentlicher diätetischer Bestandteil.
1840: Justus Liebig entdeckt die chemische Verfassung der Kohlenhydrate (Zucker), der Fette (Fettsäuren) und der Proteine (Aminosäuren.)
1860s: Klaus Bernard entdeckt, daß Körperfett vom Kohlenhydrat und von Protein synthetisiert werden kann und zeigen, daß die Energie in der Blutglukose gespeichert werden kann, wie fett oder als Glycogen.
Frühes 1880s: Kanehiro Takaki beobachtete, daß japanische Seeleute beriberi (oder endemische Neuritis, eine Krankheit entwickelten, die Herzprobleme und -paralyse verursacht), aber britische Seeleute nicht. Das Hinzufügen von Milch und von Fleisch Japanerdiäten verhinderte die Krankheit.
1896: Baumann beobachtetes Jod in den Schilddrüsedrüsen.
1897: Christiaan Eijkman arbeitete mit Eingeborenen von Java, die auch unter beriberi litten. Eijkman beobachtete, daß Hühner die gebürtige Diät des weißen Reises entwickelten die Symptome von beriberi einzogen, aber blieben gesund als FBI-Agent unverarbeiteter brauner Reis mit der äußeren intakten Kleie. Eijkman kurierte die Eingeborenen, indem er ihnen den braunen Reis einzog und entdeckte, daß Nahrung Krankheit kurieren kann. Über zwei Dekaden später, erlernten Ernährungssachversta5ndiger, daß die äußere Reiskleie Vitamin B1 enthält, alias Thiamin.
Frühe 1900s: Karl Von Voit und Maximum Rubner messen unabhängig Wärmeenergieaufwand in der unterschiedlichen Sorte der Tiere und wenden Grundregeln von Physik in der Nahrung an.
1906: Wilcock und Hopkins zeigten, daß das Aminosäuretryptophan für das überleben der Mäuse notwendig war. Gowland Hopkins erkannte „zusätzliche Nahrungsmittelfaktoren“ anders als Kalorien, Protein und Mineralien, als organische Materialien, die zur Gesundheit wesentlich sind, aber die der Körper nicht synthetisieren kann.
1907: Stephen M. Babcock und Edwin B. Hartführung das Einzeln-Korn Experiment. Dieses Experiment läuft durch 1911.
1912: Casmir riesige Angst prägte das Bezeichnung Vitamin, einen lebenswichtigen Faktor in der Diät, von den „lebenswichtigen“ Wörtern und „vom Amin,“, weil diese unbekannten Substanzen, die Skorbut, beriberi und pellagra verhindern, dann gedacht wurden, vom Ammoniak abgeleitet zu werden.
1913: Elmer V. McCollum entdeckte die ersten Vitamine, das fettlösliche Vitamin A und das wasserlösliche Vitamin B (1915; jetzt gewußt, um ein Komplex einiger wasserlöslicher Vitamine) und des Namen Vitamins C als die dann-unbekannte Substanz zu sein, die Skorbut verhindert.
1919: Sir Edward Mellanby kennzeichnete falsch Rachitis als Vitamin Amangel, weil er ihn in den Hunden mit Dorschleberöl kurieren könnte.
1922: McCollum zerstört das Vitamin A im Dorschleberöl aber -entdeckungen, die es noch die Rachitis kuriert und nennt Vitamin D.
1922: H.M. Evans und L.S. Bishop entdecken Vitamin E, wie wesentlich für Ratteschwangerschaft und ursprünglich nennen sie „Nahrungsmittelfaktor X“ bis 1925.
1925: Hart entdeckt, daß Spur Mengen Kupfer für Eisenabsorption notwendig sind.
1927: Adolf Otto Reinhold Windaus synthetisiert Vitamin D, für das er den Nobelpreis in der Chemie 1928 gewann.
1928: Albert Szent-Gyorgyi lokalisiert Ascorbinsäure und 1932 prüft, daß es Vitamin C ist, indem es Skorbut verhindert. 1935 synthetisiert er es, und 1937 gewinnt er einen Nobelpreis für seine Bemühungen. Szent-Gyorgyi klärt gleichzeitig viel des Zitronensäurezyklus auf.
dreißiger Jahre: William Cumming Rose kennzeichnet essentielle Aminosäuren, notwendige Proteine, die der Körper nicht synthetisieren kann.
1935: Underwood und Marston entdecken unabhängig die Notwendigkeit von Kobalt.
1936: Eugene Floyd Dubois zeigt, daß Arbeit und Schuleleistung mit Kalorienaufnahme zusammenhängen.
1938: Die chemische Struktur von Vitamin E wird von Erhard Fernholz entdeckt, und sie wird von Paul Karrer synthetisiert.
1941: Die zuerst empfohlenen diätetischen Genehmigungen (RDAs) wurden vom nationalen Forschung Rat hergestellt.
Neu
1992 die US Landwirtschaftsministerium führt Nahrungsmittelführer-Pyramide ein.
Relation mit 2002 Studie Erscheinen zwischen Nahrung und heftigem Verhalten.
Korpulenz 2005 kann durch Adenovirus zusätzlich zur schlechten Nahrung verursacht werden.
Nahrung und Gesundheit
dort sind sechs Hauptnährstoffe, in denen der Körper empfangen muß. Diese Nährstoffe schließen Kohlenhydrate, Proteine, Fette, Vitamine, Mineralien und Wasser mit ein. Es ist wichtig, diese sechs Nährstoffe auf einer täglichen Grundlage zu verbrauchen, um gesunde Körpersysteme zu errichten und beizubehalten.
Kranke Gesundheit kann durch eine Ungleichheit der Nährstoffe verursacht werden und entweder einen überfluß oder Mangel produzieren, die der Reihe nach den Körper beeinflußt, der kumulativ arbeitet. Außerdem weil die meisten Nährstoffe sind, auf gewisse Weise oder andere, mit einbezogen beim Zelle-zuzelle Signalisieren (z.B. als Baustein oder Teil eines Hormons oder des Signalisierens „kaskadiert“), Mangel, oder überfluß der verschiedenen Nährstoffe beeinflußt hormonale Funktion indirekt. So weil sie groß den Ausdruck der Gene regulieren, stellen Hormone eine Verbindung zwischen Nahrung und wie unsere Gene ausgedrückt werden, d.h. dar. unser Phänotypus.
Die Stärke und die Natur dieser Verbindung sind fortwährend in Untersuchung, aber Beobachtungen besonders in den letzten Jahren haben eine Angelrolle für Nahrung in der hormonalen Tätigkeit und in der Funktion und folglich in der Gesundheit gezeigt. Eine Quelle der Artikel auf Nahrung und Gesundheit ist das vierteljährliche Rundschreiben der Nahrung für optimale Gesundheit Verbindung (NOHA). Artikel, da 1984 durch Thema, Namen und Chronologie registriert werden.
Wesentliche und unwesentliche Aminosäuren
der Körper erfordert Aminosäuren, neues Körperprotein (Proteinzurückhalten) zu produzieren und beschädigte Proteine (Wartung) zu ersetzen die im Urin verloren sind. In den Tieren werden Aminosäureanforderungen in den wesentlichen (ein Tier kann nicht sie produzieren) und unwesentlichen (das Tier kann sie aus anderen nitrogenhaltigen Mitteln produzieren), Aminosäuren ausgedrückt eingestuft.
Eine Diät zu verbrauchen, die ausreichende Mengen der wesentlichen (aber auch unwesentlichen) Aminosäuren enthält, ist für wachsende Tiere besonders wichtig, die eine besonders hohe Anforderung haben.
Fettsäuren
zusätzlich zum genügenden Einlaß, eine passende Balance der wesentlichen Fettsäuren - Fettsäuren omega-3 und omega-6 - ist entdeckt worden, um für beibehaltene Gesundheit entscheidend zu sein. Beide dieser einzigartigen „Omega“ langkettigen mehrfach ungesättigten Fettsäuren sind Substrate für eine Kategorie eicosanoids, die als Prostaglandine bekannt sind, die als Hormone arbeiten. Die eicosapentaenoic Säure omega-3 (EPA) (die im Körper von der wesentlichen Alpha-Linolensäure der Fettsäure omega-3 (LNA) gebildet werden kann oder innen genommen worden durch Marinenahrungsmittelquellen), Serves als Baustein für Reihe 3 Prostaglandine (z.B. Schwachentzündung PGE3). Die dihomo-Gamma-Linolensäure omega-6 (DGLA) dient als Baustein für Reihe 1 Prostaglandine (z.B. anti-inflammatory PGE1), während arachidonische Säure (AA) als Baustein für Reihe 2 Prostaglandinen dient (z.B. Pro-entzündliches PGE 2). werden DGLA und AA von der Linolsäure omega-6 (LA) im Körper gebildet oder können direkt durch Nahrung innen genommen werden. Ein passend ausgeglichener Einlaß von omega-3 und von omega-6 stellt teils die relative Produktion der unterschiedlichen Prostaglandine fest, die teils den Wert omega-3/omega-6 der Balance für Herzgefäß- Gesundheit erklärt. In industrialisierten Gesellschaften bevölkeren Sie verbrauchen im Allgemeinen große Mengen der verarbeiteten Pflanzenöle, die Mengen der wesentlichen Fettsäuren zusammen mit einer übermäßigen Menge omega-6 relative to omega-3 verringert haben.
Der Umrechnungskurs von omega-6 DGLA zu AA stellt groß die Produktion der jeweiligen Prostaglandine PGE1 und PGE2 fest. Omega-3 EPA verhindert AA an von den Membranen freigegeben werden, dadurch skewing Prostaglandinbalance weg von Pro-entzündlichem PGE2, das von AA in Richtung zu anti-inflammatory PGE1 gebildet wird, das von DGLA gebildet wird. Außerdem wird die Umwandlung (Verweißlichung) von DGLA zu AA durch das Enzym delta-5-desaturase gesteuert, das der Reihe nach durch Hormone wie Insulin (Obenregelung) und Glucagon (Untenregelung) gesteuert wird. Weil unterschiedliche Arten und die Mengen Nahrung gegessen/aufgesogen Insulin, Glucagon und andere Hormone zu unterschiedlichen Grad beeinflussen, nicht nur stellen die Menge von omega-3 gegen omega-6 gegessen aber auch der allgemeine Aufbau der Diät folglich Gesundheit Implikationen in Beziehung zu wesentlichen Fettsäuren, Entzündung fest (z.B. immune Funktion) und Mitosis (d.h. Zellteilung).
Zuckert
einige Linien des Beweises anzeigen Lebensstil-verursachtes hyperinsulinemia und verringerte Insulinfunktion (d.h. Insulinresistenz) als entscheidender Faktor in vielen Krankheitzuständen. Z.B. werden hyperinsulinemia und Insulinresistenz stark mit chronischer Entzündung verbunden, die der Reihe nach stark mit einer Vielzahl der nachteiligen Entwicklungen wie arterielle microinjuries und Klumpenanordnung verbunden wird (d.h. Herzkrankheit) und übertriebene Zellteilung (d.h. Krebs).
Hyperinsulinemia und Insulinresistenz (das sogenannte metabolische Syndrom) werden durch eine Kombination von Abdominal- Korpulenz, von erhöhtem Blutzucker, von erhöhtem Blutdruck, von erhöhten Bluttriglyzeriden und von verringertem HDL Cholesterin gekennzeichnet. Die negative Auswirkung von hyperinsulinemia auf Balance des Prostaglandins PGE1/PGE2 kann bedeutend sein.
Der Zustand von Korpulenz trägt offenbar zur Insulinresistenz bei, die Art 2 Diabetes der Reihe nach verursachen kann. Praktisch alle beleibten und die meiste Art 2 zuckerkranke Einzelpersonen haben Insulinresistenz gekennzeichnet. Obgleich die Verbindung zwischen overfatness und Insulinresistenz klar ist, bleiben die genauen (wahrscheinliches vielgestaltiges) Ursachen der Insulinresistenz weniger frei. Wichtig ist es demonstriert worden, daß passende übung, regelmäßigerer Nahrungsmitteleinlaß und das Verringern der glycemic Last (sehen Sie unten), alle Insulinresistenz in den overfat Einzelpersonen aufheben können (und Blutzuckerspiegel in denen dadurch senken, die Art 2 Diabetes haben).
Obesity can unfavourably alter hormonal and metabolic status via resistance to the hormone leptin, and a vicious cycle may occur in which insulin/leptin resistance and obesity aggravate one another. The vicious cycle is putatively fuelled by continuously high insulin/leptin stimulation and fat storage, as a result of high intake of strongly insulin/leptin stimulating foods and energy.
Both insulin and leptin normally function as satiety signals to the hypothalamus in the brain; however, insulin/leptin resistance may reduce this signal and therefore allow continued overfeeding despite large body fat stores. In addition, reduced leptin signalling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate.
There is debate about how and to what extent different dietary factors -- e.g. intake of processed carbohydrates, total protein, fat, and carbohydrate intake, intake of saturated and trans fatty acids, and low intake of vitamins/minerals -- contribute to the development of insulin- and leptin resistance. In any case, analogous to the way modern man-made pollution may potentially overwhelm the environment's ability to maintain 'homeostasis', the recent explosive introduction of high Glycemic Index- and processed foods into the human diet may potentially overwhelm the body's ability to maintain homeostasis and health (as evidenced by the metabolic syndrome epidemic).
Antioxidants are another recent discovery. As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as radical oxygen species or free radicals form as a result. For normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds, some produced by the body with adequate precursors (glutathione, Vitamin C in most animals) and those that the body cannot produce may only be obtained through the diet through direct sources (Vitamin C in humans, Vitamin A, Vitamin K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight). Different antioxidants are now known to function in a cooperative network, e.g. vitamin C can reactivate free radical-containing glutathione or vitamin E by accepting the free radical itself, and so on. Some antioxidants are more effective than others at neutralizing different free radicals.
Some cannot neutralize certain free radicals. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas). When interacting with a free radical, some antioxidants produce a different free radical compound that is less dangerous or more dangerous than the previous compound. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect.
Intestinal bacterial flora
Some information in this article or section has not been verified and may not be reliable. Please check for any inaccuracies, and modify and cite sources as needed. It is now also known that the human digestion system contains a population of a range of bacteria which are essential to digestion, and which are also affected by the food we eat. The role and significance of the intestinal bacterial flora is under investigation. Both good and bad bacteria inhabit the digestive system. It is estimated that in the Western world, most people are no longer in a homeostatic balance. It is ideal to have 80% good to 20% bad, typically differentiated by gram negative and gram positive staining, respectively; however, in western diets it is more likely to be the other way around. Consuming processed food that are low in nutrients and high in sugar will allow bad bacteria to flourish.
Phytochemicals
Blackberries are a source of polyphenol antioxidants. A growing area of interest is the effect upon human health of trace chemicals, collectively called phytochemicals, nutrients typically found in edible plants, especially colorful fruits and vegetables (see Whole Foods Diet, below). Unlike the anecdotal and sometimes specious nutritional claims of medicinal herbs and compounds, the effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. One of the principal classes of phytochemicals are polyphenol antioxidants, chemicals which are known to provide certain health benefits to the cardiovascular system and immune system. These chemicals are known to down-regulate the formation of reactive oxygen species, key chemicals in cardiovascular disease.
Perhaps the most rigorously tested phytochemical is zeaxanthin, a yellow- pigmented carotenoid present in many yellow and orange fruits and vegetables. Repeated studies have shown a strong correlation between ingestion of zeaxanthin and the prevention and treatment of age-related macular degeneration (AMD). Less rigorous studies have proposed a correlation between zeaxanthin intake and cataracts. A second carotenoid, lutein, has also been shown to lower the risk of contracting AMD. Both compounds have been observed to collect in the retina when ingested orally, and they serve to protect the rods and cones against the destructive effects of light.
Another caretenoid, beta-cryptoxanthin, appears to protect against chronic joint inflammatory diseases, such as arthritis. While the association between serum blood levels of beta-cryptoxanthin and substantially decreased joint disease has been established, neither a convincing mechanism for such protection nor a cause-and-effect have been rigorously studied. Similarly, a red phytochemical, lycopene, has substantial credible evidence of negative association with development of prostate cancer.
The correlations between the ingestion of some phytochemicals and the prevention of disease are, in some cases, enormous in magnitude. For example, several studies have correlated high levels of zeaxanthin intake with roughly a 50% reduction in AMD. The difficulties in demonstrating causative properties and in applying the findings to human diet, however, are similarly enormous.
The standard for rigorous proof of causation in medicine is the double-blind study, a time-consuming, difficult and expensive process, especially in the case of preventative medicine. While new drugs must undergo such rigorous testing, pharmaceutical companies have a financial interest in funding rigorous testing and may recover the cost if the drug goes to market. No such commercial interest exists in studying chemicals that exist in orange juice and spinach, making funding for medical research difficult to obtain.
Even when the evidence is obtained, translating it to practical dietary advice can be difficult and counter-intuitive. Lutein, for example, occurs in many yellow and orange fruits and vegetables and protects the eyes against various diseases. However, it does not protect the eye nearly as well as zeaxanthin, and the presence of lutein in the retina will prevent zeaxanthin uptake.
Additionally, evidence has shown that the lutein present in egg yolk is more readily absorbed than the lutein from vegetable sources, possibly because of fat solubility. At the most basic level, the question "should you eat eggs?" is complex to the point of dismay, including misperceptions about the health effects of cholesterol in egg yolk, and its saturated fat content.
As another example, lycopene is prevalent in tomatoes (and actually is the chemical that gives tomatoes their red color). It is more highly concentrated, however, in processed tomato products such as commercial pasta sauce, or tomato soup, than in fresh "healthy" tomatoes. Such sauces, however, tend to have high amounts of salt, sugar, other substances a person may wish or even need to avoid.
for more details go to
http://www.consumersresearchcncl.org/Healthcare/Ophthalmologists/ophth_nutrition.html
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O Nutrition e sua saúde
da ciência
do Nutrition de Wikipedia estudam o relacionamento entre a dieta e os estados de saúde e de doença. Os dietistas são os profissionais de saúde que são especializados nesta área de perícia, treinada altamente para fornecer o cofre, o conselho dietético evidência-baseado e as intervenções. Há um spectrum que varia do malnutrition à saúde optimal, including muitos sintomas e doenças comuns que podem frequentemente ser impedidos ou aliviado com nutrition melhor.
As deficiências, os excessos e os desequilíbrios na dieta podem produzir impactos negativos na saúde, que pode conduzir às doenças tais como o scurvy, o obesity ou o osteoporosis, as well as problemas psicológicos e behavioral. Além disso, ingestion excessivo dos elementos que não têm nenhum papel aparente na saúde, (por exemplo. a ligação, o mercúrio, PCBs, dioxins), podem incorrer efeitos tóxicos e potencial letais, dependendo do dose. A ciência do nutrition tenta compreender como e porque os aspectos dietéticos específicos influenciam a saúde.
A ciência
do Nutrition da vista geral procura explicar respostas metabolic e physiological do corpo à dieta. Com avanços na biologia, no biochemistry, e em genetics molecular, a ciência do nutrition está tornando-se adicionalmente o estudo do metabolism integrative, que as buscas para conectar a dieta e a saúde através da lente de processos biochemical.
O corpo humano é composto de compostos químicos tais como a água, os aminos-ácido (proteínas), ácidos fatty (lipids), os ácidos nucleic (DNA/RNA), e os hidratos de carbono (por exemplo. açúcares e fibra). Estes compostos consistem por sua vez em elementos tais como o carbono, o hidrogênio, o oxigênio, o nitrogênio, e o phosphorus, e podem ou não podem conter minerais tais como o cálcio, o ferro, ou o zinco. Os minerais ocorrem ubiquitously no formulário dos sais e dos eletrólitos. Todos estes compostos e elementos químicos ocorrem em vários formulários e combinações (por exemplo. hormones/vitaminas, phospholipids, hydroxyapatite), no corpo humano e nos organismos (por exemplo. as plantas, os animais) esses seres humanos comem. O corpo humano compreende necessariamente os elementos que come e absorve no bloodstream. O sistema digestivo, exceto no fetus do unborn, participa na primeira etapa que faz os compostos e os elementos químicos diferentes no alimento disponível para os trillions das pilhas do corpo. Ao processo digestivo de um adulto médio, aproximadamente sete litros do líquido, sabidos como sucos digestivos, retiram o corpo interno e incorporam o lúmen do intervalo digestivo.
Os sucos digestivos ajudam quebrar ligações químicas entre compostos ingested assim como module o conformation e/ou o estado energético dos compostos/elementos. Entretanto, muitos elementos dos compostos são absorvidos no bloodstream unchanged, embora o processo digestivo ajuda os liberar da matriz dos alimentos onde ocorrem. Alguns unabsorbed a matéria excreted nos feces. Mas somente uma quantidade mínima de suco digestivo é eliminada por este processo; os intestines reabsorb a maioria dele; se não o corpo desidratar-se-ia ràpidamente; (daqui os efeitos devastating do diarrhea persistente).
O estudo neste campo deve fazer exame com cuidado no cliente do estado do corpo antes do ingestion e após a digestão as well as a composição química do alimento e do desperdício. Comparar o desperdício ao alimento pode determinar os tipos específicos de compostos e os elementos absorvidos pelo corpo. O efeito que a matéria absorvida tem no corpo pode ser determinado encontrando a diferença entre o estado do pre-ingestion e o estado da borne-digestão. O efeito pode somente ser discernible após um período de tempo prolongado em que todo o alimento e ingestion devem exatamente ser regulados e todo o desperdício deve ser analisado. O número das variáveis (por exemplo. da “os fatores confusão”) envolvidos neste tipo de experimentação são muito elevados. Isto faz scientifically o estudo nutritivo válido muito time-consuming e caro, e explica porque uma ciência apropriada do nutrition humano é rather nova.
No general, comer uma variedade de alimentos de planta (unprocessed) frescos, inteiros provou hormonally e metabolically favorável comparado a comer uma dieta monotonous baseada em alimentos processados. No detalhe, o consumo de alimentos de planta inteiros retarda a digestão e fornece umas quantidades mais elevadas e um contrapeso mais favorável de nutrientes essenciais e vitais por a unidade da energia; tendo por resultado a gerência melhor do crescimento, da manutenção, e do mitosis da pilha (divisão de pilha) as well as o regulamento do glucose e do apetite do sangue. Um teste padrão geralmente mais regular comer (por exemplo. comendo refeições de tamanho médio cada 3 a 4 horas) provaram também mais hormonally e metabolically favorável do que a entrada de alimento infrequënte, haphazard.
Os seres humanos
da história evoluíram como caçador-gatherers omnivorous sobre os 250.000 anos passados. As dietas adiantadas eram primeiramente vegetarian com carnes e os peixes infrequëntes do jogo onde disponíveis. A agricultura tornou-se aproximadamente 10.000 anos há em posições múltiplas durante todo o mundo, fornecendo grões tais como o trigo, arroz, e maize, com os grampos tais como o pão e o pasta. Cultivando o leite e produtos de leiteria também fornecidos, e aumentado agudamente a disponibilidade das carnes e a diversidade dos vegetais. A importância do purity do alimento foi reconhecida quando o armazenamento de maioria conduziu aos riscos do infestation e da contaminação. Cozinhar desenvolvido como uma atividade frequentemente ritualistic, devido à eficiência e à confiabilidade concerne reque o adherence às receitas e aos procedimentos estritos, e em resposta às demandas para o purity e a consistência do alimento.
Antiquity com o Enlightenment
c. 475 BC: Anaxagoras indica que o alimento está absorvido pelo corpo humano e pelo “homeomerics conseqüentemente contido” (componentes generative), deduzindo desse modo a existência dos nutrientes.
c. 400 BC: Hippocrates diz, “deixe o alimento seja sua medicina e a medicina seja seu alimento.”
A experiência nutritiva primeiramente gravada é encontrada no livro do Bible de Daniel. Daniel e seus amigos foram capturados pelo rei de Babylon durante uma invasão de Israel. Selecionado como empregados da corte, eram compartilhar nos alimentos finos e no vinho do rei. Mas objetaram, preferindo vegetais (pulsos) e água de acordo com suas limitações dietéticas Jewish. O steward principal do rei concordou relutantemente a uma experimentação. Daniel e seus amigos receberam sua dieta por 10 dias e foram comparados então aos homens do rei. Parecendo mais saudáveis, foram permitidos continuar com sua dieta.
1500s: O da Vinci de Leonardo do cientista e do artista comparou o metabolism a uma vela ardente.
1747: Dr. James Lind, um médico na marinha britânica, executou a primeira experiência científica do nutrition, descobrindo que o suco de cal conservou os sailors que tinham estado no mar por anos do scurvy, de um disorder mortal e doloroso do sangramento. A descoberta foi ignorada por quarenta anos, depois do qual os sailors britânicos tornaram-se sabidos como “limeys.” A vitamina C essencial dentro do suco de cal não seria reconhecida por cientistas até os 1930s.
1770: Antoine Lavoisier, “pai do Nutrition e do Chemistry” descobriu os detalhes do metabolism, demonstrando que a oxidação do alimento é a fonte do calor do corpo.
1790: George Fordyce reconheceu o cálcio necessário para a sobrevivência do fowl.
Era moderna com 1941
1800s adiantado: Os elementos carbono, nitrogênio, hidrogênio e oxigênio foram reconhecidos como os componentes preliminares do alimento, e os métodos para medir suas proporções foram desenvolvidos.
1816: François Magendie descobre que os cães alimentaram somente hidratos de carbono e a gordura perdeu sua proteína do corpo e morreu em algumas semanas, mas os cães alimentaram também a proteína sobreviveram, identificando a proteína como um componente dietético essencial.
1840: Justus Liebig descobre a composição química dos hidratos de carbono (açúcares), das gorduras (ácidos fatty) e das proteínas (os aminos-ácido.)
1860s: Claus Bernard descobre que a gordura de corpo pode synthesized do hidrato de carbono e da proteína, mostrando que a energia no glucose do sangue pode ser armazenada como gorda ou como o glycogen.
1880s adiantado: Kanehiro Takaki observou que os sailors japoneses desenvolveram o beriberi (ou o neuritis endemic, uma doença que causa problemas e paralysis do coração) mas os sailors britânicos não. Adicionar o leite e a carne às dietas do japonês impediu a doença.
1896: Iodo observado Baumann nas glândulas de thyroid.
1897: Christiaan Eijkman trabalhou com os nativos de Java, que sofreram também do beriberi. Eijkman observou que as galinhas alimentaram a dieta nativa do arroz branco desenvolveram os sintomas do beriberi, mas remanesceram saudáveis quando arroz marrom unprocessed do fed com o farelo exterior intato. Eijkman curou os nativos alimentando lhes o arroz marrom, descobrindo que o alimento pode curar a doença. Sobre duas décadas mais tarde, os nutritionists aprenderam que o farelo de arroz exterior contem a vitamina B1, sabida também como o thiamine.
1900s adiantados: Carl Von Voit e máximo Rubner mede independentemente a despesa de energia caloric na espécie diferente dos animais, aplicando princípios da física no nutrition.
1906: Wilcock e Hopkins mostraram que o tryptophan do amino-ácido era necessário para a sobrevivência dos ratos. Gowland Hopkins reconheceu “fatores acessórios do alimento” à excepção dos calories, proteína e minerais, como os materiais orgânicos essenciais à saúde mas que o corpo não pode synthesise.
1907: Stephen M. Babcock e Edwin B. Conduta do cervo a experiência da Único-grão. Esta experiência funciona com 1911.
1912: O Funk de Casmir inventou a vitamina do termo, um fator vital na dieta, das palavras “vitais” e do “amine,” porque estas substâncias desconhecidas que impedem o scurvy, o beriberi, e o pellagra, foram pensadas então para ser derivadas da amônia.
1913: Elmer V. McCollum descobriu as primeiras vitaminas, a vitamina soluble gorda A, e a água - vitamina soluble B (em 1915; sabido agora para ser um complexo de diversas vitaminas water-soluble) e de vitamina C dos nomes como a substância então-desconhecida que impede o scurvy.
1919: O senhor Edward Mellanby identificou incorretamente rickets como uma deficiência da vitamina A, porque poderia a curar nos cães com óleo do fígado de bacalhau.
1922: McCollum destrói a vitamina A no óleo mas nos achados que do fígado de bacalhau cura ainda os rickets, nomeando a vitamina D.
1922: H.M. Evans e L.S. O Bishop descobre a vitamina E como essencial para a gravidez do rato, originalmente chamando a do “o fator X alimento” até 1925.
1925: O cervo descobre que quantidades de traço de cobre é necessário para o absorption do ferro.
1927: Adolf Otto Reinhold Windaus synthesizes a vitamina D, para que ganhou o prêmio de Nobel no Chemistry em 1928.
1928: Albert Szent-Gyorgyi isola o ácido ascorbic, e em 1932 prova que é a vitamina C impedindo o scurvy. Em 1935 synthesizes o, e em 1937 ganha um prêmio de Nobel para seus esforços. Szent-Gyorgyi elucidates simultaneamente muito do ciclo do ácido citric.
1930s: William Cumming Rosa identifica aminos-ácido essenciais, as proteínas necessárias que o corpo não pode synthesize.
1935: Underwood e Marston descobrem independentemente a necessidade do cobalt.
1936: Eugene Floyd Dubois mostra que o desempenho do trabalho e da escola está relacionado à entrada caloric.
1938: A estrutura química da vitamina E é descoberta por Erhard Fernholz, e synthesized por Paul Karrer.
1941: As permissões dietéticas primeiramente recomendadas (RDAs) foram estabelecidas pelo conselho de pesquisa nacional.
Recente
1992 os ESTADOS UNIDOS. O departamento de agricultura introduz a pirâmide da guia do alimento.
Relação de 2002 mostras do estudo entre o nutrition e o comportamento violento.
O Obesity 2005 pode ser causado pelo adenovírus além ao nutrition mau.
O Nutrition e a saúde
lá são seis nutrientes principais em que o corpo necessita receber. Estes nutrientes incluem hidratos de carbono, proteínas, gorduras, vitaminas, minerais, e água. É importante consumir estes seis nutrientes em uma base diária para construir e manter sistemas saudáveis do corpo.
A saúde doente pode ser causada por um desequilíbrio dos nutrientes, produzindo um excesso ou a deficiência, que afetem por sua vez o corpo que funciona cumulativa. Além disso, porque a maioria de nutrientes estão, em alguma maneira ou em outra, envolvido em sinalizar da pilha-à-pilha (por exemplo. como o bloco de edifício ou a parte de um hormone ou de sinalizar “é conectado em cascata”), deficiência ou o excesso de vários nutrientes afeta a função hormonal indiretamente. Assim, porque regulam pela maior parte a expressão dos genes, os hormones representam uma ligação entre o nutrition e como nossos genes são expressados, isto é. nosso phenotype.
A força e a natureza desta ligação estão continuamente sob a investigação, mas as observações especialmente em anos recentes demonstraram um papel pivotal para o nutrition na atividade e na função hormonal e conseqüentemente na saúde. Uma fonte dos artigos no nutrition e na saúde é o boletim de notícias trimestral do Nutrition para a associação Optimal da saúde (NOHA). Artigos desde que 1984 são posicionados pelo assunto, pelo nome, e pelo chronology.
Os aminos-ácido essenciais e non-essential
o corpo requerem aminos-ácido produzir a proteína nova do corpo (retenção da proteína) e substituir as proteínas danificadas (manutenção) que são perdidas no urine. Nos animais as exigências do amino-ácido são classificadas nos termos (o animal pode os produzir do outro nitrogênio que contem compostos) de aminos-ácido essenciais (um animal não pode os produzir) e non-essential.
Consumir uma dieta que contenha quantidades adequadas de aminos-ácido essenciais (mas também non-essential) é particularmente importante para os animais crescentes, que têm uma exigência particularmente elevada.
Os ácidos Fatty
além à entrada suficiente, um contrapeso apropriado de ácidos fatty essenciais - os ácidos omega-3 e omega-6 fatty - foram descobertos para ser cruciais para a saúde mantendo. Ambos estes ácidos fatty polyunsaturated long-chain originais de “omega” são carcaças para uma classe dos eicosanoids sabidos como os prostaglandins que funcionam como hormones. O ácido omega-3 eicosapentaenoic (EPA) (que pode ser feito no corpo do ácido alfa-linolenic essencial do ácido omega-3 fatty (LNA), ou feito exame dentro com as fontes marinhas do alimento), saques como o bloco de edifício para a série 3 prostaglandins (por exemplo. fraco-inflammation PGE3). O ácido omega-6 dihomo-gamma-linolenic (DGLA) serve como o bloco de edifício para prostaglandins da série 1 (por exemplo. PGE1 anti-inflammatory), visto que o ácido arachidonic (AA) serve como o bloco de edifício para a série a 2 prostaglandins (por exemplo. PGE pro-inflammatory 2). DGLA e o AA são feitos do ácido omega-6 linoleic (LA) no corpo, ou podem ser feitos exame dentro diretamente através do alimento. Uma entrada apropriadamente equilibrada de omega-3 e de omega-6 determina em parte a produção relativa de prostaglandins diferentes, que explica em parte a importância do contrapeso de omega-3/omega-6 para a saúde cardiovascular. Em sociedades industrialized, povoe consomem geralmente quantidades grandes de óleos vegetais processados que reduziram quantidades de ácidos fatty essenciais junto com uma quantidade excessiva de omega-6 omega-3 relative to.
A taxa de conversões de omega-6 DGLA ao AA determina pela maior parte a produção dos prostaglandins respectivos PGE1 e PGE2. Omega-3 EPA impede que o AA esteja liberado das membranas, enviesando desse modo o contrapeso do prostaglandin longe de PGE2 pro-inflammatory feito do AA para PGE1 anti-inflammatory feito de DGLA. Além disso, a conversão (desaturation) de DGLA ao AA é controlada pelo enzyme delta-5-desaturase, que é controlado por sua vez por hormones tais como o insulin (acima-regulamento) e o glucagon (para baixo-regulamento). Porque os tipos diferentes e as quantidades de alimento comidos/absorvidos afetam o insulin, o glucagon e os outros hormones aos graus variando, não somente a quantidade de omega-3 contra omega-6 comida mas também a composição geral da dieta determina conseqüentemente implicações com relação aos ácidos fatty essenciais, inflammation da saúde (por exemplo. função imune) e mitosis (isto é. divisão de pilha).
Sugars
diversas linhas da evidência indicam o hyperinsulinemia lifestyle-induzido e a função reduzida do insulin (isto é. resistência de insulin) como um fator decisive em muitos estados da doença. Por exemplo, a resistência do hyperinsulinemia e de insulin é ligada fortemente ao inflammation crônico, que é ligado por sua vez fortemente a uma variedade de desenvolvimentos adversos tais como microinjuries e a formação arterial do clot (isto é. doença de coração) e divisão de pilha exaggerated (isto é. cancer).
Hyperinsulinemia e a resistência de insulin (o syndrome metabolic so-called) são caracterizados por uma combinação do obesity abdominal, do açúcar de sangue elevated, da pressão de sangue elevated, de triglycerides elevated do sangue, e do cholesterol reduzido de HDL. O impacto negativo do hyperinsulinemia no contrapeso do prostaglandin PGE1/PGE2 pode ser significativo.
O estado do obesity contribui claramente à resistência de insulin, que por sua vez pode causar o tipo 2 diabetes. Virtualmente todos os obese e a maioria de tipo 2 indivíduos diabetic marcaram a resistência de insulin. Embora a associação entre o overfatness e a resistência de insulin esteja desobstruída, (as causas exatas multifarious provável) da resistência de insulin remanescem mais menos desobstruídas. Importante, demonstrou-se que o exercício apropriado, uma entrada de alimento mais regular e reduzir a carga glycemic (veja abaixo) toda podem inverter a resistência de insulin em indivíduos do overfat (e para abaixar desse modo níveis de açúcar de sangue naqueles que têm o tipo 2 diabetes).
Obesity can unfavourably alter hormonal and metabolic status via resistance to the hormone leptin, and a vicious cycle may occur in which insulin/leptin resistance and obesity aggravate one another. The vicious cycle is putatively fuelled by continuously high insulin/leptin stimulation and fat storage, as a result of high intake of strongly insulin/leptin stimulating foods and energy.
Both insulin and leptin normally function as satiety signals to the hypothalamus in the brain; however, insulin/leptin resistance may reduce this signal and therefore allow continued overfeeding despite large body fat stores. In addition, reduced leptin signalling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate.
There is debate about how and to what extent different dietary factors -- e.g. intake of processed carbohydrates, total protein, fat, and carbohydrate intake, intake of saturated and trans fatty acids, and low intake of vitamins/minerals -- contribute to the development of insulin- and leptin resistance. In any case, analogous to the way modern man-made pollution may potentially overwhelm the environment's ability to maintain 'homeostasis', the recent explosive introduction of high Glycemic Index- and processed foods into the human diet may potentially overwhelm the body's ability to maintain homeostasis and health (as evidenced by the metabolic syndrome epidemic).
Antioxidants are another recent discovery. As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as radical oxygen species or free radicals form as a result. For normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds, some produced by the body with adequate precursors (glutathione, Vitamin C in most animals) and those that the body cannot produce may only be obtained through the diet through direct sources (Vitamin C in humans, Vitamin A, Vitamin K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight). Different antioxidants are now known to function in a cooperative network, e.g. vitamin C can reactivate free radical-containing glutathione or vitamin E by accepting the free radical itself, and so on. Some antioxidants are more effective than others at neutralizing different free radicals.
Some cannot neutralize certain free radicals. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas). When interacting with a free radical, some antioxidants produce a different free radical compound that is less dangerous or more dangerous than the previous compound. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect.
Intestinal bacterial flora
Some information in this article or section has not been verified and may not be reliable. Please check for any inaccuracies, and modify and cite sources as needed. It is now also known that the human digestion system contains a population of a range of bacteria which are essential to digestion, and which are also affected by the food we eat. The role and significance of the intestinal bacterial flora is under investigation. Both good and bad bacteria inhabit the digestive system. It is estimated that in the Western world, most people are no longer in a homeostatic balance. It is ideal to have 80% good to 20% bad, typically differentiated by gram negative and gram positive staining, respectively; however, in western diets it is more likely to be the other way around. Consuming processed food that are low in nutrients and high in sugar will allow bad bacteria to flourish.
Phytochemicals
Blackberries are a source of polyphenol antioxidants. A growing area of interest is the effect upon human health of trace chemicals, collectively called phytochemicals, nutrients typically found in edible plants, especially colorful fruits and vegetables (see Whole Foods Diet, below). Unlike the anecdotal and sometimes specious nutritional claims of medicinal herbs and compounds, the effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. One of the principal classes of phytochemicals are polyphenol antioxidants, chemicals which are known to provide certain health benefits to the cardiovascular system and immune system. These chemicals are known to down-regulate the formation of reactive oxygen species, key chemicals in cardiovascular disease.
Perhaps the most rigorously tested phytochemical is zeaxanthin, a yellow- pigmented carotenoid present in many yellow and orange fruits and vegetables. Repeated studies have shown a strong correlation between ingestion of zeaxanthin and the prevention and treatment of age-related macular degeneration (AMD). Less rigorous studies have proposed a correlation between zeaxanthin intake and cataracts. A second carotenoid, lutein, has also been shown to lower the risk of contracting AMD. Both compounds have been observed to collect in the retina when ingested orally, and they serve to protect the rods and cones against the destructive effects of light.
Another caretenoid, beta-cryptoxanthin, appears to protect against chronic joint inflammatory diseases, such as arthritis. While the association between serum blood levels of beta-cryptoxanthin and substantially decreased joint disease has been established, neither a convincing mechanism for such protection nor a cause-and-effect have been rigorously studied. Similarly, a red phytochemical, lycopene, has substantial credible evidence of negative association with development of prostate cancer.
The correlations between the ingestion of some phytochemicals and the prevention of disease are, in some cases, enormous in magnitude. For example, several studies have correlated high levels of zeaxanthin intake with roughly a 50% reduction in AMD. The difficulties in demonstrating causative properties and in applying the findings to human diet, however, are similarly enormous.
The standard for rigorous proof of causation in medicine is the double-blind study, a time-consuming, difficult and expensive process, especially in the case of preventative medicine. While new drugs must undergo such rigorous testing, pharmaceutical companies have a financial interest in funding rigorous testing and may recover the cost if the drug goes to market. No such commercial interest exists in studying chemicals that exist in orange juice and spinach, making funding for medical research difficult to obtain.
Even when the evidence is obtained, translating it to practical dietary advice can be difficult and counter-intuitive. Lutein, for example, occurs in many yellow and orange fruits and vegetables and protects the eyes against various diseases. However, it does not protect the eye nearly as well as zeaxanthin, and the presence of lutein in the retina will prevent zeaxanthin uptake.
Additionally, evidence has shown that the lutein present in egg yolk is more readily absorbed than the lutein from vegetable sources, possibly because of fat solubility. At the most basic level, the question "should you eat eggs?" is complex to the point of dismay, including misperceptions about the health effects of cholesterol in egg yolk, and its saturated fat content.
As another example, lycopene is prevalent in tomatoes (and actually is the chemical that gives tomatoes their red color). It is more highly concentrated, however, in processed tomato products such as commercial pasta sauce, or tomato soup, than in fresh "healthy" tomatoes. Such sauces, however, tend to have high amounts of salt, sugar, other substances a person may wish or even need to avoid.
for more details go to
http://www.consumersresearchcncl.org/Healthcare/Ophthalmologists/ophth_nutrition.html
Obetitlat
Automatically translated into Swedish thanks to WorldLingo
Näring och ditt vård-
från studier
för Wikipedia näringvetenskap som förhållandet between bantar och påstår av vård- och sjukdom. Dietister är vård- professionell som specialiseras i detta område av sakkunskap som utbildas högt för att ge kassaskåp, bevisa-baserad dietary rådgivning och ingripanden. Det finns en spectrum som vanligt spänner från malnutrition till optimal vård-, inklusive många tecken och sjukdomar som kan ofta förhindras eller lättas med bättre näring.
Brister, överskotts och obalanser bantar in kan jordbruksprodukternegationen får effekt på vård-, som kan leda till sjukdomar liksom scurvy, fetma eller osteoporosis, as well as psykologiska och beteende- problem. Dessutom överdriven intagande av föda av beståndsdelar, som har ingen påtaglig roll i vård-, (e.g. bly- kvicksilver, PCBs, dioxins), kan åsamka sig gift, och potentiellt dödligt verkställer, beroende av dosen. Vetenskapen av näringförsök att förstå hur och varför specifik dietary vård- aspektpåverkan.
Sökanden
för överblicknäringvetenskap att förklara metabolic och fysiologiska svar av förkroppsliga som bantar. Med framflyttningar i molekylär biologi, biochemistry och genetik framkallar näringvetenskap dessutom in i studien av integrative ämnesomsättning, som sökanden att förbinda bantar, och vård- till och med linsen av biochemical bearbetar.
Människokroppen göras upp av kemiska sammansättningar liksom bevattnar, amino syror (proteiner), fettsyror (lipids), nucleic syror (DNA/RNA) och kolhydrat (e.g. sockrar och fiber). Dessa sammansättningar består i sin tur av beståndsdelar liksom kol, väten, syre, ett gasformigt grundämne och phosphorus, och kan eller kan inte innehålla mineraler liksom calcium, att stryka eller zinc. Mineraler uppstår ubiquitously i form av saltar och electrolytes. Alla dessa kemiska sammansättningar och beståndsdelar uppstår i olikt bildar och kombinationer (e.g. hormon/vitaminer, phospholipids, hydroxyapatite), både i människokroppen och i organismer (e.g. de växter, djur) människor äter. Människokroppen består av nödvändigtvis beståndsdelarna som hon äter och absorberar in i bloodstreamen. Digestivkexsystemet, undantar i det ofödda foster, deltar i första steg som gör de olika kemiska sammansättningarna och beståndsdelarna i mat som är tillgänglig för triljonerna av celler av förkroppsliga. I digestivkexen som är processaa av en genomsnittlig vuxen människa, går ut omkring sju liter av flytande, bekant som digestivkexfruktsaftar, det inre förkroppsligar och skriver in lumenen av digestivkexområdet.
Digestivkexfruktsaftarna hjälper att bryta kemiska förbindelser mellan tog in föda sammansättningar as well as modulerar gestaltningen, och/eller driftigt påstå av sammansättningarna/beståndsdelarna. Emellertid absorberas många compounds/beståndsdelar in i den oförändrade bloodstreamen, fast den processaa hjälpen för digestivkexen för att frigöra dem från matrisen av matarna var de uppstår. Några unabsorbed materien utsöndras i avföringen. Men endast avlägsnas ett minsta belopp av digestivkexfruktsaft av detta processaa; inälvorna reabsorb mest av det; annorlunda torkar förkroppsliga som snabbt skulle; (skövla verkställer hence av ihärdig diarré).
Studien i denna sätter in måste ta försiktigt in i konto det statligt av förkroppsliga för intagande av föda och efter matsmältning as well as den kemiska sammansättningen av maten och det förloradt. När du jämför det förloradt till maten kan bestämma de specifika typerna av sammansättningar och beståndsdelar som absorberas av förkroppsliga. Verkställa, som den absorberade materien har på förkroppsliga kan vara beslutsam, genom att finna skillnaden mellan den statliga pre-intagande av föda, och den statliga posta-matsmältningen. Verkställa kan endast vara urskiljbar efter en extended tidsperiod som all mat och intagande av föda måste exakt regleras i, och all förloradt måste analyseras. Numrera av variabler (e.g. ”dela upp i faktorer att blanda ihop”) involverat i denna typ av experimenterandet är mycket kicken. Detta gör scientifically den giltiga näringsrika studien mycket tidskrävande och dyr och förklarar varför en riktig vetenskap av människanäring är ganska ny.
I allmänhet har att äta en variation av nya hela (outredda) växtmatar bevisat hormonally, och metabolically bantar gynnsamt som jämförs till att äta ett monotont, baserat på bearbetade matar. I synnerhet saktar ger förbrukning av hela växtmatar matsmältning och högre belopp, och ett mer gynnsam balanserar av nödvändiga och livsviktiga nutrients per enhet av energi; resultera i bättre ledning av den celltillväxt, underhåll och mitosen (celluppdelning) as well as reglering av blodglukos och aptit. Mer äta för stamgäst mönstrar allmänt (e.g. äta medelstora mål har varje 3 till 4 timmar) bevisat också hormonally och metabolically gynnsamt än infrequent slumpmässigt matintag.
Historie
människor har evolved som allätande jägare-ihopsamlarear över förflutnan 250.000 år. Tidig sort bantar var i första hand vegetarian med infrequent modiga meats och fisken, var tillgänglig. Jordbruk framkallade omkring 10.000 år sedan i multipellägealltigenom världen som ger korn liksom vete, rice och maize, med häftklamrar liksom bröd och pasta. Bruka också förutsatt att mjölka och mejeriprodukter och ökade skarpt tillgängligheten av meats och mångfalden av grönsaker. Betydelsen av matrenhet kändes igen, då bulk lagring ledde till infestationen, och förorening riskerar. Matlagning som framkallas som en ofta ritualistic aktivitet, tack vare effektivitets- och pålitlighetsbekymmer som kräver adherence till strikt recept och tillvägagångssätt och som svar på begärningar för matrenhet och konsistens.
Forntid till och med insikt
c. 475 BC: Anaxagoras påstår att mat absorberas av människokroppen och den därför innehållna ”homeomericsen” (generativa delar) som sluta sig till därmed existensen av nutrients.
c. 400 BC: Hippocrates något att säga, ”låter mat vara din medicin, och medicinen är din mat.”,
Det först antecknade näringsrika experiment finnas i bibeln bokar av Daniel. Daniel och hans vänner fångades av konungen av Babylon under en invasion av Israel. Utvalt som domstoltjänare, var de att dela i konung fina matar och wine. Men de anmärkte och att föredra grönsaker (pulserar) och bevattnar i överensstämmelse med deras judiska dietary begränsningar. Konung högsta marskalk instämmde motvilligt till ett försök. Daniel och hans vänner mottog deras bantar för 10 dagar och jämfördes därefter till konung manar. Verka mer sund, var de tillåtna att fortsätta med deras bantar.
1500s: Den forskare- och konstnärLeonardo daen Vinci jämförde ämnesomsättning till ett brinna stearinljus.
1747: Dr. James Lind, en läkare i den brittiska marinen, utförde det första vetenskapliga näringexperiment som upptäcker att limefruktfruktsaft sparade sjömän som hade varit på havet för år från scurvy, en dödlig och smärtsam blöda oordning. Upptäckten ignorerades för forty år, som brittiska sjömän blev bekant efter som ”limeys.”, Det nödvändiga vitaminet C inom limefruktfruktsaft skulle för att inte kännas igen av forskare till 30-tal.
1770: Antoine Lavoisier, ”fadern av näring och kemi” upptäckte att specificerar av ämnesomsättning och att visa att oxidationen av mat är källan av förkroppsligar värmer.
1790: George Fordyce kände igen calcium som var nödvändig för fjäderfä överlevnad.
Modern era till och med 1941
Tidig sort 1800s: Beståndsdelarna kol, ett gasformigt grundämne, väten och syre kändes igen som de primära delarna av mat, och metoder som mäter deras, proportionerar framkallades.
1816: François Magendie upptäcker att hundkapplöpningen matade endast kolhydrat och feta borttappada deras förkroppsligar protein och som dör i några veckor, men hundkapplöpningen matade också fortlevt protein och att identifiera protein som ett nödvändigt dietary del-.
1840: Justus Liebig upptäcker den kemiska makeupen av kolhydrat (sockrar), fett (fettsyror) och proteiner (amino syror.)
1860s: Claus Bernard upptäcker förkroppsligar att som, kan fett synthesizeds från kolhydratet och protein, visning att energin i blodglukos kan lagras som fett eller som glykogen.
Tidig sort 1880s: Kanehiro Takaki observerade att japanska sjömän framkallade beriberi (eller endemic nervinflammationar, en sjukdom orsaka hjärtaproblem och förlamning), men brittiska sjömän inte. Att tillfoga mjölkar, och meat till japanen bantar förhindrade sjukdomen.
1896: Baumann observerad jod i thyroidkörtlar.
1897: Christiaan Eijkman fungerade med infödingar av Java, som led också från beriberi. Eijkman observerade att hönor matade infödingen bantar av vitrice framkallade tecknen av beriberien, men återstod sunda då outredda rårisar för feden med den intakt yttre klin. Eijkman kurerade infödingarna genom att mata dem rårisar som upptäcker att mat kan kurera sjukdomen. Över två mer sistnämnda årtionden, lärda näringsfysiologer, som den yttre riceklin innehåller vitaminet B1, också bekant som thiamine.
Tidig sort1900s: Carl Von Voit och maximal Rubner mäter självständigt caloric energiförbrukning i olik art av djur som applicerar principer av fysik i näring.
1906: Wilcock och Hopkins visade att den amino syrliga tryptophanen var nödvändig för överlevnaden av möss. Gowland dela upp i faktorer Hopkins igenkänd ”åtfölja mat” annan än kalorier, protein och mineraler, som organiska material som är nödvändiga till vård-, men som förkroppsliga kan inte synthesise.
1907: Stephen M. Babcock och Edwin B. Hartuppförande detkorn experiment. Detta experiment kör till och med 1911.
1912: Casmir Funk myntade benämnavitaminet, ett livsviktigt dela upp i faktorer i banta, från uttrycker ”livsviktigt” och ”aminen,”, därför att dessa okända vikter som förhindrar scurvy, beriberi och pellagra, tänktes därefter för att härledas från ammoniak.
1913: Elmer V. McCollum upptäckte de första vitaminerna, fett lösligt vitamin A och bevattnar - lösligt vitamin B (i 1915; nu bekant att vara ett komplex av flera water-soluble vitaminer) och namnger vitamin C som denokända vikten som förhindrar scurvy.
1919: Herrnen Edward Mellanby identifierade felaktigt rickets som en brist för vitamin A, därför att han kunde kurera den i hundkapplöpning med torskleverolja.
1922: McCollum förstör vitaminet A i torskleverolja men fynd det stillbildbotrickets som namnger vitaminet D.
1922: H.M. Evans och L.S. Biskopen upptäcker att vitamin E som nödvändigt för tjaller havandeskap som kallar ursprungligen det ”mat dela upp i faktorer X” till 1925.
1925: Harten upptäcker att tracebelopp av förkopprar är nödvändig för stryker absorbering.
1927: Adolf Otto Reinhold Windaus synthesizes vitamin D, som han segrade för den Nobel prisen i kemi i 1928.
1928: Bevisar ascorbic syra för Albert Szent-Gyorgyi isolater, och i 1932 att det är vitamin C genom att förhindra scurvy. I 1935 synthesizes han det, och i 1937 segrar han en Nobel pris för hans försök. Szent-Gyorgyi belyser samtidigt mycket av citronsyran cyklar.
30-tal: Den William Cumming ron identifierar nödvändiga amino syror, nödvändiga proteiner som förkroppsliga kan inte synthesize.
1935: Underwood och Marston upptäcker självständigt nödvändigheten av kobolt.
1936: Eugene Floyd Dubois visar det arbete och skolar kapacitet förbinds till caloric intag.
1938: Det kemiskt strukturerar av vitamin E upptäcks av Erhard Fernholz, och det synthesizeds av Paul Karrer.
1941: De först rekommenderade Dietary avdragen (RDAs) var etablerade vid medborgareforskningrådet.
Nytt
1992 U.S.NA. Jordbruksavdelningen introducerar mat vägleder pyramiden.
Studien 2002 visar förhållande mellan näring och våldsamt uppförande.
Fetma 2005 kan orsakas av adenovirusen förutom dåliganäring.
Näring och vård-
där är sex huvudsakliga nutrients i som förkroppsligabehoven att motta. Dessa nutrients inkluderar kolhydrat, proteiner, fett, vitaminer, mineraler och bevattnar. Det är viktigt att konsumera dessa sex nutrients på en dagstidningbas för att bygga, och att underhålla sunt förkroppsliga system.
Sjuk vård- kan orsakas av en obalans av nutrients och att producera endera en överskotts eller bristen, som affekter förkroppsligar i sin tur att fungera kumulativt. Dessutom, därför att mest nutrients är, i något långt eller another, involverat, i cell-till-cell att signalera (e.g. som byggnadskvarter eller del av ett hormon eller att signalera ”kaskader), påverkar bristen eller överskottsen av olika nutrients hormonal fungerar indirekt. Således därför att de reglerar i hög grad uttryckt av gener, föreställer hormon en anknyta mellan näring och hur våra gener uttrycks, dvs. vår fenotyp.
Styrkan och naturen av denna anknyter är ständigt under utredning, men observationer speciellt har visat en svängbar roll för näring i hormonal aktivitet och fungerar under senare år och därför i vård-. Ett källa av artiklar på näring och vård- är det quarterly informationsbladet av näringen för den optimala vård- anslutningen (NOHA). Artiklar, sedan 1984 indexeras by, betvingar, känt och kronologi.
Nödvändiga och oväsentliga amino syror som
förkroppsliga kräver amino syror till den nya jordbruksprodukter, förkroppsligar protein (proteinkvarhållande) och att byta ut skadada proteiner (underhåll) som är borttappada i urinen. I djur klassificeras amino syrliga krav in benämner av nödvändiga (ett djur kan inte jordbruksprodukter dem) och oväsentliga (djurcanjordbruksprodukter dem från annan ett gasformigt grundämne som innehåller sammansättningar) amino syror.
Det är bestämt viktigt att konsumera en banta, som innehåller adekvat belopp av nödvändiga (men också oväsentligheten) amino syror, för växande djur, som har bestämt ett kickkrav.
Fettsyror
förutom tillräckligt intag, en anslå balanserar av nödvändiga fettsyror - fettsyror omega-3 och omega-6 - har upptäckts för att vara avgörande för att underhålla som är vård-. Båda av dessa unika ”omega” long-chain polyunsaturated fettsyror är substrates för en klassificera av eicosanoids som är bekant som prostaglandins som fungerar som hormon. Den eicosapentaenoic syran omega-3 (EPA) (som kan göras i förkroppsliga från denlinolenic syran för nödvändig fettsyra omega-3 (LNA), eller taget in till och med marin- matkällor), servar som byggnadskvarteret för serie 3 prostaglandins (e.g. svag-inflammation PGE3). Omega-6 delinolenic syrliga servarna (DGLA) som byggnadskvarteret för prostaglandins för serie 1 (e.g. anti-inflammatory PGE1), eftersom arachidonic syrliga servar (AA) som byggnadskvarteret för serie 2 prostaglandins (e.g. pro-upphetsa PGE 2). Både DGLA och AA göras från den linoleic syran omega-6 (LA) i förkroppsliga eller kan tas in direkt till och med mat. Ett lämpligt allsidigt intag av omega-3 och omega-6 bestämmer delvis släktingproduktionen av olika prostaglandins, som förklarar delvis betydelsen av omega-3/omega-6 balanserar för kardiovaskulärt vård-. Bemanna konsumerar allmänt stora belopp av bearbetade grönsakoljor som har förminskat belopp av nödvändiga fettsyror tillsammans med ett överdrivet belopp av släktingen omega-6 till omega-3 i industrialized samhällen.
Klassa av omvandlingar av omega-6 DGLA till AA bestämmer i hög grad produktionen av de respektive prostaglandinsna PGE1 och PGE2. Omega-3 EPA förhindrar AA från att vara utsläppt från membran som kör därmed prostaglandinen skevt, balanserar i väg från pro-upphetsa PGE2 som göras från AA in mot anti-inflammatory PGE1 som göras från DGLA. Dessutom kontrolleras omvandlingen (desaturation) av DGLA till AA av enzymet delta-5-desaturase, som kontrolleras i sin tur av hormon liksom insulin (upp-reglering) och glucagon (besegra-reglering). Därför att olika åt typer och belopp av mat/absorberade affektinsulin, glucagon och andra hormon till varierande grader, inte endast bestämmer beloppet av äten omega-3 kontra omega-6 men också den allmänna sammansättningen av banta därför vård- implikationer i förhållande till nödvändiga fettsyror, inflammation (e.g. immunt fungera) och mitosen (dvs. celluppdelning).
Sockrar
flera fodrar av bevisar indikerar att denframkallade hyperinsulinemiaen och förminskad insulin fungerar (dvs. insulinmotstånd) som ett avgörande dela upp i faktorer i många sjukdomen påstår. Till exempel anknytas hyperinsulinemia- och insulinmotstånd starkt till kronisk inflammation, som i sin tur anknytas starkt till en variation av motsatt utvecklingar liksom arterial microinjuries och koaguleringbildande (dvs. hjärtsjukdom) och överdriven celluppdelning (dvs. cancer).
Hyperinsulinemia och insulinmotstånd (det so-called metabolic syndromet) karakteriseras av en kombination av buk- fetma, höjt blodsocker, högstämt blodtryck, höjde blodtriglycerides och förminskad HDL-cholesterol. Negationen får effekt av hyperinsulinemia på prostaglandinen PGE1/PGE2 balanserar kan vara viktig.
Det statligt av fetma bidrar klart till insulinmotstånd, som i sin tur kan orsaka typ 2 sockersjuka. Faktiskt alla obese och mest skrivar 2 diabetiska individer har markerat insulinmotstånd. Även om anslutningen mellan overfatnessen och insulinmotstånd är frikänden, orsakar avkräva (rimligt multifarious) av insulinmotstånd återstår mindre frikänd. Huvudsakligen har det visats att anslå övar, alla laddar mer stamgästmatintag och förminskande glycemic (se nedanfört), kan vända om insulinmotstånd i overfatindivider (och därmed att fälla ned blodsocker jämnar i de som har sockersjuka för typ 2).
Obesity can unfavourably alter hormonal and metabolic status via resistance to the hormone leptin, and a vicious cycle may occur in which insulin/leptin resistance and obesity aggravate one another. The vicious cycle is putatively fuelled by continuously high insulin/leptin stimulation and fat storage, as a result of high intake of strongly insulin/leptin stimulating foods and energy.
Both insulin and leptin normally function as satiety signals to the hypothalamus in the brain; however, insulin/leptin resistance may reduce this signal and therefore allow continued overfeeding despite large body fat stores. In addition, reduced leptin signalling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate.
There is debate about how and to what extent different dietary factors -- e.g. intake of processed carbohydrates, total protein, fat, and carbohydrate intake, intake of saturated and trans fatty acids, and low intake of vitamins/minerals -- contribute to the development of insulin- and leptin resistance. In any case, analogous to the way modern man-made pollution may potentially overwhelm the environment's ability to maintain 'homeostasis', the recent explosive introduction of high Glycemic Index- and processed foods into the human diet may potentially overwhelm the body's ability to maintain homeostasis and health (as evidenced by the metabolic syndrome epidemic).
Antioxidants are another recent discovery. As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as radical oxygen species or free radicals form as a result. For normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds, some produced by the body with adequate precursors (glutathione, Vitamin C in most animals) and those that the body cannot produce may only be obtained through the diet through direct sources (Vitamin C in humans, Vitamin A, Vitamin K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight). Different antioxidants are now known to function in a cooperative network, e.g. vitamin C can reactivate free radical-containing glutathione or vitamin E by accepting the free radical itself, and so on. Some antioxidants are more effective than others at neutralizing different free radicals.
Some cannot neutralize certain free radicals. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas). When interacting with a free radical, some antioxidants produce a different free radical compound that is less dangerous or more dangerous than the previous compound. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect.
Intestinal bacterial flora
Some information in this article or section has not been verified and may not be reliable. Please check for any inaccuracies, and modify and cite sources as needed. It is now also known that the human digestion system contains a population of a range of bacteria which are essential to digestion, and which are also affected by the food we eat. The role and significance of the intestinal bacterial flora is under investigation. Both good and bad bacteria inhabit the digestive system. It is estimated that in the Western world, most people are no longer in a homeostatic balance. It is ideal to have 80% good to 20% bad, typically differentiated by gram negative and gram positive staining, respectively; however, in western diets it is more likely to be the other way around. Consuming processed food that are low in nutrients and high in sugar will allow bad bacteria to flourish.
Phytochemicals
Blackberries are a source of polyphenol antioxidants. A growing area of interest is the effect upon human health of trace chemicals, collectively called phytochemicals, nutrients typically found in edible plants, especially colorful fruits and vegetables (see Whole Foods Diet, below). Unlike the anecdotal and sometimes specious nutritional claims of medicinal herbs and compounds, the effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. One of the principal classes of phytochemicals are polyphenol antioxidants, chemicals which are known to provide certain health benefits to the cardiovascular system and immune system. These chemicals are known to down-regulate the formation of reactive oxygen species, key chemicals in cardiovascular disease.
Perhaps the most rigorously tested phytochemical is zeaxanthin, a yellow- pigmented carotenoid present in many yellow and orange fruits and vegetables. Repeated studies have shown a strong correlation between ingestion of zeaxanthin and the prevention and treatment of age-related macular degeneration (AMD). Less rigorous studies have proposed a correlation between zeaxanthin intake and cataracts. A second carotenoid, lutein, has also been shown to lower the risk of contracting AMD. Both compounds have been observed to collect in the retina when ingested orally, and they serve to protect the rods and cones against the destructive effects of light.
Another caretenoid, beta-cryptoxanthin, appears to protect against chronic joint inflammatory diseases, such as arthritis. While the association between serum blood levels of beta-cryptoxanthin and substantially decreased joint disease has been established, neither a convincing mechanism for such protection nor a cause-and-effect have been rigorously studied. Similarly, a red phytochemical, lycopene, has substantial credible evidence of negative association with development of prostate cancer.
The correlations between the ingestion of some phytochemicals and the prevention of disease are, in some cases, enormous in magnitude. For example, several studies have correlated high levels of zeaxanthin intake with roughly a 50% reduction in AMD. The difficulties in demonstrating causative properties and in applying the findings to human diet, however, are similarly enormous.
The standard for rigorous proof of causation in medicine is the double-blind study, a time-consuming, difficult and expensive process, especially in the case of preventative medicine. While new drugs must undergo such rigorous testing, pharmaceutical companies have a financial interest in funding rigorous testing and may recover the cost if the drug goes to market. No such commercial interest exists in studying chemicals that exist in orange juice and spinach, making funding for medical research difficult to obtain.
Even when the evidence is obtained, translating it to practical dietary advice can be difficult and counter-intuitive. Lutein, for example, occurs in many yellow and orange fruits and vegetables and protects the eyes against various diseases. However, it does not protect the eye nearly as well as zeaxanthin, and the presence of lutein in the retina will prevent zeaxanthin uptake.
Additionally, evidence has shown that the lutein present in egg yolk is more readily absorbed than the lutein from vegetable sources, possibly because of fat solubility. At the most basic level, the question "should you eat eggs?" is complex to the point of dismay, including misperceptions about the health effects of cholesterol in egg yolk, and its saturated fat content.
As another example, lycopene is prevalent in tomatoes (and actually is the chemical that gives tomatoes their red color). It is more highly concentrated, however, in processed tomato products such as commercial pasta sauce, or tomato soup, than in fresh "healthy" tomatoes. Such sauces, however, tend to have high amounts of salt, sugar, other substances a person may wish or even need to avoid.
for more details go to
http://www.consumersresearchcncl.org/Healthcare/Ophthalmologists/ophth_nutrition.html
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Питание и ваше здоровье
от науки
питания Wikipedia изучают отношение между диетпитанием и положениями здоровья и заболевания. Dieticians будут специалистами в области здравоохранения специализируют в этой сфере экспертизы, высоки натренированной для того чтобы обеспечить сейф, доказательств-основанную диетическую консультацию и интервенции. Будет спектр колебаясь от недоедания к оптимальному здоровью, включая много общих симптомы и заболеваний которые можно часто предотвращать или разрешать с более лучшим питанием.
Дефициты, избытки и разницы в диетпитании могут произвести отрицательные удары на здоровье, которое может вести к заболеваниям such as скорбут, тучность или osteoporosis, также, как психологические и поведенческие проблемы. Сверх того, чрезмерно заглатывание элементов которые не имеют никакую явно роль в здоровье, (например. руководство, ртуть, PCBs, dioxins), могут произвести токсические и потенциальн летальные влияния, в зависимости от дозы. Наука питания пытает понять как и почему специфически диетические аспекты влияют на здоровье.
Наука
питания обзора изыскивает объяснить метаболически и физиологические реакции тела к диетпитанию. С выдвижениями в молекулярные биологию, биохимию, и генетик, наука питания дополнительн превращается в изучение интегративного метаболизма, которое seeks для того чтобы соединить диетпитание и здоровье через объектив биохимических процессов.
Человеческое тело составлено химически смесей such as вода, amino acid (протеины), наварные кислоты (липиды), нуклеиновые кислоты (DNA/RNA), и углеводы (например. сахары и волокно). Эти смеси в свою очередь consist of элементы such as углерод, водопод, кислород, азот, и фосфор, и may or may not содержать минералы such as кальций, утюг, или цинк. Минералы ubiquitously происходят in the form of соли и электролиты. Весь из этих химически смесей и элементов происходят в различных формах и комбинациях (например. инкрети/витамины, фосфолипиды, hydroxyapatite), и в человеческом теле и в организмах (например. заводы, животные) те люди едят. Человеческое тело обязательно состоит из природная стихия оно ест и поглощает в bloodstream. Пищеварительная система, за исключением в fetus unborn, участвует в первом шаге которое делает по-разному химически смеси и элементы в еде имеющейся для триллионов клеток тела. В пищеварительный процесс среднего взрослого, около 7 литров жидкости, известно как пищеварительные соки, выходят внутренне тело и вписывают люмен пищеварительного тракта.
Пищеварительные соки помогают сломать химическые соединения между ingested смесями так же, как модулируйте конформацию and/or напористое положение смесей/элементов. Однако, много элементов смесей поглощены в bloodstream неизменно, хотя пищеварительный процесс помогает выпустить их от матрицы еды где они происходят. Любые unabsorbed дело выделяны в фекалиях. Но только минимальное количество пищеварительного сока исключено этим процессом; intestines реабсорбируют большое часть из его; в противном случае тело быстро обезводило бы; (следовательно опустошительные влияния упорнейшего поноса).
Изучение в этом поле должно принять тщательно into account положение тела перед заглатыванием и после пищеварения также, как химический состав еды и отхода. Сравнивающ отход к консервной банке обусловьте специфически типы смесей и элементы поглощенные телом. Влияние поглощенное дело имеет на теле может быть обусловлено путем находить разницу между положением pre-заглатывания и положением столб-пищеварения. Влияние может только быть discernible после выдвинутого периода времени в все еду и заглатывание необходимо точно отрегулировать и весь отход необходимо проанализировать. Число перемеююых (например. «факторы confounding»), котор включили в этот тип экспериментации очень высоки. Это делает научно действительное питательное изучение очень time-consuming и дороге, и объясняет почему правильная наука людского питания довольно нова.
In general, есть разнообразие свежей, всей (unprocessed) еды завода доказывал гормонально и метаболически благоприятная сравненная к еде однозвучного диетпитания основанного на обрабатываемой еде. В частности, потребление всей еды завода замедляет пищеварение и обеспечивает более высокое количество и более благоприятный баланс необходимых и существенных питательных веществ в блок энергии; resulting in более лучшее управление роста, обслуживания, и митоза клетки (разделения клетки) также, как регулировка глюкозы и аппетита крови. Вообще более регулярно картина еды (например. ел medium-sized еды каждые от 3 до 4 часа) также доказывали гормонально и метаболически благоприятно чем нечастого, haphazard входа еды.
Люди
истории эволюционировали как omnivorous охотник-gatherers над прошлыми 250.000 летами. Предыдущие диетпитания были главным образом вегетариански с нечастыми мяс и рыбами игры где имеющеся. Земледелие превратилось около 10.000 лет тому назад в множественных положениях повсеместно в мир, обеспечивая зерна such as пшеница, рис, и маис, с штапелями such as хлеб и pasta. Также обеспеченные молоко и молочные продучты, и остро увеличено наличию мяс и разнообразности овощей. Важность очищенности еды когда навальное хранение водить к рискам infestation и загрязнения. Варить начатый как часто ritualistic деятельность, из-за забот эффективности и надежности требуя придерживания к только recipes и процедурам, и in response to требования для очищенности и последовательности еды.
Древность через прозрение
C. 475 BC: Anaxagoras заявляет что еда поглощена человеческим телом и поэтому, котор содержат «homeomerics» (генеративные компоненты), таким образом дедуцируя существование питательных веществ.
C. 400 BC: Hippocrates говорит, «препятствуйте еде будьте вашей микстурой и микстурой была ваша еда.»
Сперва записанный питательный эксперимент найден в книге библии Даниель. Даниель и его друзья были захващены королем Вавилона во время нашествия Израиля. Я выбрано как холопки суда, они должны было делить в еде и вине короля точной. Но они возразили, предпочитающ овощи (ИМПы ульс) и воду в соответствии с их еврейскими диетическими ограничениями. Steward короля главный неохотн согласовал проба. Даниель и его друзья получили их диетпитание на 10 дней и после этого были сравнены к людям короля. Кажущся здорове, они были позволены продолжать с их диетпитанием.
1500s: Da Vinci Leonardo научного работника и художника сравнило метаболизм к горящей свечке.
1747: Др. Джеймс Lind, врач в великобританском военно-морском флоте, выполнило первый научный эксперимент по питания, открывая что сок известки сохранил матросов которые находились на море на леты от скорбута, deadly и тягостного разлада кровотечения. Открытие было проигнорировано на 40 лет, after which великобританские матросы стали известный как «limeys.» Необходимое vitamin c внутри сок известки научными работниками до 1930s.
1770: Antoine Lavoisier, «отец питания и химии» открыло детали метаболизма, демонстрируя что оксидацией еды будет источник жары тела.
1790: Джордж Fordyce узнало кальций обязательно для выживания пулярки.
Самомоднейшая эра через 1941
Предыдущее 1800s: Природная стихия углерод, азот, водопод и кислород как главным образом компоненты еды, и были начаты методы для того чтобы измерить их пропорции.
1816: François Magendie открывает что собаки поданные только углеводы и сало потеряли их протеин тела и умерли в немного неделей, но выслеживает также поданный протеин выдержало, определяющ протеин как необходимый диетический компонент.
1840: Justus Liebig открывает химически состав углеводов (сахаров), сал (наварных кислот) и протеинов (amino acid.)
1860s: Claus Бернард открывает что жировые отложения можно синтезировать от углевода и протеина, показывая что энергия в глюкозе крови можно хранить как тучно или как гликоген.
Предыдущее 1880s: Kanehiro Takaki наблюдало что японские матросы начали beriberi (или эндемичный неврит, заболевание причиняя проблемы и парализованность сердца) но великобританские матросы не сделали. Добавлять молоко и мясо к диетпитаниям японца предотвратил заболевание.
1896: Иод наблюдаемый Baumann в тироидных железах.
1897: Christiaan Eijkman работало с уроженцами Java, которые также вытерпели от beriberi. Eijkman наблюдало что цыплята подали родное диетпитание белого риса начали симптомы beriberi, но остали здоровыми когда поданный unprocessed коричневый рис с наружными отрубями неповрежденными. Eijkman вылечило уроженцев путем подавать им коричневый рис, открывая что заболевание лечения консервной банки. Над 2 декадами более поздно, nutritionists выучили что наружные рисовые отруби содержат витамин B1, также известно как тиамин.
Предыдущие 1900s: Карл Von Voit и Макс Rubner независимо измеряют калорийное расходование энергии в по-разному виде животных, прикладывая принципы физики в питании.
1906: Wilcock и Hopkins показали что триптофан amino acid был обязательно для выживания мышей. Gowland Hopkins узнало «вспомогательные факторы еды» за исключением калорий, протеина и минералов, как органические материалы необходимые к здоровью но которое тело не может синтезировать.
1907: Стефан M. B. Babcock и Эдвин. Проведение Hart эксперимент по Одиночн-зерна. Этот эксперимент бежит через 1911.
1912: Funk Casmir чеканил витамин термине, существенный фактор в диетпитании, от слов «существенных» и «амина,» потому что были подуманы, что после этого были выведены эти неизвестные вещества предотвращая скорбут, beriberi, и pellagra, от амиака.
1913: Элмер v. McCollum открыло первые витамины, тучное soluble vitamin a, и водорастворимый витамин b (в 1915; теперь известно быть комплексом нескольких водорастворимых витаминов) и vitamin c имен как скорбут после этого-неизвестного вещества предотвращая.
1919: Господин Эдвард Mellanby неправильно определил rickets как дефицит vitamin a, потому что он смог вылечить его в собаках с маслом печенки cod.
1922: McCollum разрушает vitamin a в масле но находках печенки cod, котор оно все еще лечит rickets, называя D. витамина.
1922: H.M. Evans и L.S. Епископ не открыть витамин e как необходимо для стельности крысы, первоначально вызывающ ее «фактором x еды» до 1925.
1925: Hart открывает итоги трассировки меди обязательно для абсорбциы утюга.
1927: Adolf Otto Reinhold Windaus синтезирует витамин d, для которого он выиграл Нобелевскую премию в химии в 1928.
1928: Альберт Szent-Gyorgyi изолирует аскорбиновую кислоту, и в 1932 доказывает что это будет vitamin c путем предотвращать скорбут. В 1935 он синтезирует его, и в 1937 он выигрывает Нобелевскую премию для его усилий. Szent-Gyorgyi одновременно разъясняет много из цикла лимонной кислоты.
1930s: William Cumming Роза определяет необходимые amino acid, обязательно протеины которые тело не может синтезирует.
1935: Underwood и Marston независимо открывают необходимость кобальта.
1936: Евгений Флойд Dubois показывает что проведение работы и школы отнесено к калорийному входу.
1938: Химическая структура витамина e открына Erhard Fernholz, и она синтезирована Пол Karrer.
1941: Сперва порекомендованные диетические стипендии (RDAs) были установлены национальным научным советом.
Недавн
1992 США. Министерство сельского хозяйства вводит пирамидку направляющего выступа еды.
Отношение 2002 выставок изучения между питанием и яростным поведением.
Тучность 2005 может быть причинена аденовирусом в дополнение к плохому питанию.
Питание и здоровье
там 6 GLAVNых питательных веществ в телу нужно получить. Эти питательные вещества вклюают углеводы, протеины, сала, витамины, минералы, и воду. Важно уничтожить эти 6 питательных веществ на ежедневное основание для того чтобы построить и поддержать здоровые системы тела.
Плохое здоровье может быть причинено разницей питательных веществ, производящ или избыток или дефицит, который в свою очередь влияют на тело действуя кумулятивно. Сверх того, потому что большинств питательные вещества, in some way или другие, включили в сигнализировать клетк-к-клетки (например. как блок здания или часть инкрети или сигнализировать «каскадирует»), дефицит или избыток различных питательных веществ влияет на гормональную функцию косвенно. Таким образом, потому что они больш регулируют выражение генов, инкрети представляют соединение между питанием и как наши гены выражены, т.е. наш фенотип.
Прочность и природа этого соединения находятся постоянно под исследованием, но замечания специально in recent years продемонстрировали стержневую роль для питания в гормональных деятельности и функции и поэтому в здоровье. Одним источником статьей на питании и здоровье будет ежеквартальный информационый бюллетень питания для оптимальной ассоциации здоровья (NOHA). Статьи в виду того что 1984 индексированы вопросом, именем, и хронологией.
Необходимые и non-essential amino acid
тело требуют, что amino acid производят новый протеин тела (удерживание протеина) и заменяют ть поврежденные протеины (обслуживание) потеряны в моче. В животных требования к amino acid расклассифицированы in terms of необходимые (животное не может произвести их) и non-essential (животное может произвести их от другого азота содержа смеси) amino acid.
Уничтожать диетпитание содержит подходящее количество необходимых (но также non-essential) amino acid определенно важн для животных, которые имеют определенно высокое требование.
Были открыны, что
будут наварные кислоты в дополнение к достаточно входу, соотвествующий баланс необходимых наварных кислот - наварные кислоты omega-3 и omega-6 - критическими для поддерживая здоровья. Both of these уникально кислоты «омеги» long-chain polyunsaturated наварные будут субстратами для типа eicosanoids известных как простагландины действуют как инкрети. Eicosapentaenoic кислота omega-3 (EPA) (можно сделать в теле от необходимой кислоты наварной кислоты omega-3 альфа-линоленовой (LNA), или принято внутри через морские источники еды), подачи как блок здания на серия 3 простагландина (например. слаб-воспаление PGE3). Dihomo-гамм-линоленовая кислота omega-6 (DGLA) служит как блок здания для простагландинов серии 1 (например. anti-inflammatory PGE1), тогда как арахидоновая кислота (AA) служит как блок здания на серия 2 простагландина (например. pro-воспалительное PGE 2). И DGLA и AA сделаны от линолевой кислоты omega-6 (LA) в теле, или могут быть приняты внутри сразу через еду. Соотвествующе balanced вход omega-3 и omega-6 отчасти обусловливает относительную продукцию по-разному простагландинов, которая отчасти объясняет важность баланса omega-3/omega-6 для сердечнососудистого здоровья. В индустриализированных обществах, населите вообще уничтожайте большое количество обрабатываемых овощных масел которые уменьшали количество необходимых наварных кислот вместе с чрезмерно количеством omega-6 relative to omega-3.
Коэффициент перевода omega-6 DGLA к AA больш обусловливает продукцию соответственно простагландинов PGE1 и PGE2. Omega-3 EPA предотвращает AA от быть выпущенным от мембран, таким образом уклоняя баланс простагландина далеко от pro-воспалительного PGE2 сделанного от AA к anti-inflammatory PGE1 сделанному от DGLA. Сверх того, преобразование (десатурация) DGLA к AA проконтролировано энзимом delta-5-desaturase, который в свою очередь проконтролирован инкретями such as инсулин (вверх-регулировка) и глюкагон (вниз-регулировка). Потому что по-разному поглощенные типы и количество еды съеденные/влияют на инсулин, глюкагон и другие инкрети к меняя градусам, not only съеденное количество omega-3 против omega-6 но также вообще состав диетпитания поэтому обусловливает прикосновенности по отношению к необходимым наварным кислотам, воспаление здоровья (например. иммунная функция) и митоз (т.е. разделение клетки).
Засахаривает
несколько линий доказательства покажите lifestyle-наведенное hyperinsulinemia и уменьшенную функцию инсулина (т.е. сопротивление инсулина) как решающий фактор в много положений заболеванием. Например, сопротивление hyperinsulinemia и инсулина сильно соединено к хроническому воспалению, которое в свою очередь сильно соединено к разнообразию неблагоприятных развитий such as артериальные microinjuries и образование сгустка крови (т.е. заболевание сердца) и утрированное разделение клетки (т.е. рак).
Hyperinsulinemia и сопротивление инсулина (so-called метаболически синдром) охарактеризованы комбинацией подбрюшной тучности, повышенного сахара крови, повышенного кровяного давления, повышенных триглицеридов крови, и уменьшенного холестерола HDL. Отрицательный удар hyperinsulinemia на балансе простагландина PGE1/PGE2 может быть значительно.
Положение тучности ясно способствует к сопротивлению инсулина, которое в свою очередь может причинить мочеизнурение типа 2. Фактически все большинств типа 2 диабетические индивидуалы брюзглых и маркировали сопротивление инсулина. Хотя ассоциация между overfatness и сопротивлением инсулина ясна, точно (причины правоподобное multifarious) сопротивления инсулина остают более менее ясными. Важно, было продемонстрировано что соотвествующая тренировка, более регулярно вход еды и уменьшение гликемической нагрузки (см. ниже) всего могут обратить сопротивление инсулина в индивидуалах overfat (и таким образом понизить уровни сахара крови в тех которые имеют мочеизнурение типа 2).
Obesity can unfavourably alter hormonal and metabolic status via resistance to the hormone leptin, and a vicious cycle may occur in which insulin/leptin resistance and obesity aggravate one another. The vicious cycle is putatively fuelled by continuously high insulin/leptin stimulation and fat storage, as a result of high intake of strongly insulin/leptin stimulating foods and energy.
Both insulin and leptin normally function as satiety signals to the hypothalamus in the brain; however, insulin/leptin resistance may reduce this signal and therefore allow continued overfeeding despite large body fat stores. In addition, reduced leptin signalling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate.
There is debate about how and to what extent different dietary factors -- e.g. intake of processed carbohydrates, total protein, fat, and carbohydrate intake, intake of saturated and trans fatty acids, and low intake of vitamins/minerals -- contribute to the development of insulin- and leptin resistance. In any case, analogous to the way modern man-made pollution may potentially overwhelm the environment's ability to maintain 'homeostasis', the recent explosive introduction of high Glycemic Index- and processed foods into the human diet may potentially overwhelm the body's ability to maintain homeostasis and health (as evidenced by the metabolic syndrome epidemic).
Antioxidants are another recent discovery. As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as radical oxygen species or free radicals form as a result. For normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds, some produced by the body with adequate precursors (glutathione, Vitamin C in most animals) and those that the body cannot produce may only be obtained through the diet through direct sources (Vitamin C in humans, Vitamin A, Vitamin K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight). Different antioxidants are now known to function in a cooperative network, e.g. vitamin C can reactivate free radical-containing glutathione or vitamin E by accepting the free radical itself, and so on. Some antioxidants are more effective than others at neutralizing different free radicals.
Some cannot neutralize certain free radicals. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas). When interacting with a free radical, some antioxidants produce a different free radical compound that is less dangerous or more dangerous than the previous compound. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect.
Intestinal bacterial flora
Some information in this article or section has not been verified and may not be reliable. Please check for any inaccuracies, and modify and cite sources as needed. It is now also known that the human digestion system contains a population of a range of bacteria which are essential to digestion, and which are also affected by the food we eat. The role and significance of the intestinal bacterial flora is under investigation. Both good and bad bacteria inhabit the digestive system. It is estimated that in the Western world, most people are no longer in a homeostatic balance. It is ideal to have 80% good to 20% bad, typically differentiated by gram negative and gram positive staining, respectively; however, in western diets it is more likely to be the other way around. Consuming processed food that are low in nutrients and high in sugar will allow bad bacteria to flourish.
Phytochemicals
Blackberries are a source of polyphenol antioxidants. A growing area of interest is the effect upon human health of trace chemicals, collectively called phytochemicals, nutrients typically found in edible plants, especially colorful fruits and vegetables (see Whole Foods Diet, below). Unlike the anecdotal and sometimes specious nutritional claims of medicinal herbs and compounds, the effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. One of the principal classes of phytochemicals are polyphenol antioxidants, chemicals which are known to provide certain health benefits to the cardiovascular system and immune system. These chemicals are known to down-regulate the formation of reactive oxygen species, key chemicals in cardiovascular disease.
Perhaps the most rigorously tested phytochemical is zeaxanthin, a yellow- pigmented carotenoid present in many yellow and orange fruits and vegetables. Repeated studies have shown a strong correlation between ingestion of zeaxanthin and the prevention and treatment of age-related macular degeneration (AMD). Less rigorous studies have proposed a correlation between zeaxanthin intake and cataracts. A second carotenoid, lutein, has also been shown to lower the risk of contracting AMD. Both compounds have been observed to collect in the retina when ingested orally, and they serve to protect the rods and cones against the destructive effects of light.
Another caretenoid, beta-cryptoxanthin, appears to protect against chronic joint inflammatory diseases, such as arthritis. While the association between serum blood levels of beta-cryptoxanthin and substantially decreased joint disease has been established, neither a convincing mechanism for such protection nor a cause-and-effect have been rigorously studied. Similarly, a red phytochemical, lycopene, has substantial credible evidence of negative association with development of prostate cancer.
The correlations between the ingestion of some phytochemicals and the prevention of disease are, in some cases, enormous in magnitude. For example, several studies have correlated high levels of zeaxanthin intake with roughly a 50% reduction in AMD. The difficulties in demonstrating causative properties and in applying the findings to human diet, however, are similarly enormous.
The standard for rigorous proof of causation in medicine is the double-blind study, a time-consuming, difficult and expensive process, especially in the case of preventative medicine. While new drugs must undergo such rigorous testing, pharmaceutical companies have a financial interest in funding rigorous testing and may recover the cost if the drug goes to market. No such commercial interest exists in studying chemicals that exist in orange juice and spinach, making funding for medical research difficult to obtain.
Even when the evidence is obtained, translating it to practical dietary advice can be difficult and counter-intuitive. Lutein, for example, occurs in many yellow and orange fruits and vegetables and protects the eyes against various diseases. However, it does not protect the eye nearly as well as zeaxanthin, and the presence of lutein in the retina will prevent zeaxanthin uptake.
Additionally, evidence has shown that the lutein present in egg yolk is more readily absorbed than the lutein from vegetable sources, possibly because of fat solubility. At the most basic level, the question "should you eat eggs?" is complex to the point of dismay, including misperceptions about the health effects of cholesterol in egg yolk, and its saturated fat content.
As another example, lycopene is prevalent in tomatoes (and actually is the chemical that gives tomatoes their red color). It is more highly concentrated, however, in processed tomato products such as commercial pasta sauce, or tomato soup, than in fresh "healthy" tomatoes. Such sauces, however, tend to have high amounts of salt, sugar, other substances a person may wish or even need to avoid.
for more details go to
http://www.consumersresearchcncl.org/Healthcare/Ophthalmologists/ophth_nutrition.html
Zonder titel
Automatically translated into Dutch thanks to WorldLingo
De voeding en Uw Gezondheid
van de wetenschap
van de Voeding Wikipedia bestuderen het verband tussen dieet en staten van gezondheid en ziekte. De diëtisten zijn de beroeps van de Gezondheid die in dit gebied van deskundigheid gespecialiseerd zijn, dat hoogst wordt opgeleid om veilige, op bewijsmateriaal-gebaseerde dieetraad en acties te geven. Er is een spectrum dat van ondervoeding tot optimale gezondheid, met inbegrip van vele gemeenschappelijke symptomen en ziekten gaat die vaak kunnen met betere voeding worden verhinderd of worden verminderd.
De deficiënties, de overmaat en de onevenwichtigheid in dieet kunnen negatieve effecten op gezondheid veroorzaken, die tot ziekten zoals scheurbuik, zwaarlijvigheid of osteoporose, evenals psychologische en gedragsproblemen kan leiden. Voorts bovenmatige opname van elementen die geen duidelijke rol in gezondheid hebben, (b.v. het lood, het kwik, PCBs, dioxins), kunnen giftige en potentieel dodelijke gevolgen, afhankelijk van de dosis oplopen. De wetenschap van voeding probeert om te begrijpen hoe en waarom de specifieke dieetaspecten gezondheid beïnvloeden.
De wetenschap
van de Voeding van het overzicht heeft tot doel om metabolische en fysiologische reacties te verklaren van het lichaam op dieet. Met vooruitgang in moleculaire biologie, biochemie, en genetica, ontwikkelt de voedingswetenschap zich bovendien tot de studie van integratiemetabolisme, dat tot doel heeft om dieet en gezondheid door de lens van biochemische processen te verbinden.
Het menselijke lichaam wordt samengesteld uit chemische samenstellingen zoals water, aminozuren (proteïnen), vetzuren (lipiden), nucleic zuren (DNA/RNA), en koolhydraten (b.v. suikers en vezel). Deze samenstellingen bestaan beurtelings uit elementen zoals koolstof, waterstof, zuurstof, stikstof, en fosfor, en kunnen of kunnen mineralen zoals calcium, ijzer, of zink niet bevatten. De mineralen komen ubiquitously in de vorm van zouten en elektrolyten voor. Elk van deze chemische samenstellingen en elementen komen in diverse vormen en combinaties voor (b.v. hormonen/vitaminen, phospholipids, hydroxyapatite), zowel in het menselijke lichaam als in organismen (b.v. planten, dieren) dat de mensen eten. Het menselijke lichaam bestaat noodzakelijk uit de elementen die het eet en in de bloedsomloop absorbeert. Het spijsverteringssysteem, behalve in het ongeboren foetus, neemt aan de eerste stap deel die de verschillende chemische samenstellingen en de elementen in voedsel beschikbaar voor de triljoenen cellen van het lichaam maakt. In het spijsverteringsproces van een gemiddelde volwassene, gaat ongeveer zeven liter vloeistof, die als spijsverteringssappen wordt bekend, het interne lichaam weg en gaat het lumen van het spijsverteringskanaal in.
De spijsverteringssappen helpen chemische banden tussen opgenomen samenstellingen breken evenals de bouw en/of de energieke staat van de samenstellingen/de elementen moduleren. Nochtans, worden vele samenstellingenelementen geabsorbeerd in de onveranderde bloedsomloop, hoewel het spijsverteringsproces helpt om hen van de matrijs van het voedsel vrij te geven waar zij voorkomen. Om het even welk unabsorbed kwestie worden afgescheiden in de faecaliën. Maar slechts wordt een minimale hoeveelheid spijsverteringssap geëlimineerda door dit proces; de darmen absorberen het grootste deel weer; anders zou het lichaam snel ontwateren; (vandaar de verwoestende gevolgen van blijvende diarree).
De studie op dit gebied moet met de staat van het lichaam vóór opname en na spijsvertering evenals de chemische samenstelling van het voedsel en het afval zorgvuldig rekening houden. Het vergelijken van het afval bij het voedsel kan de specifieke types van samenstellingen en elementen bepalen die door het lichaam worden geabsorbeerd. Het effect dat de geabsorbeerde kwestie op het lichaam heeft kan worden bepaald door het verschil tussen de pre-opnamestaat en de post-spijsverteringsstaat te vinden. Het effect kan slechts na een uitgebreide tijdspanne waarneembaar zijn waarin al voedsel en de opname precies moeten worden geregeld en al afval moet worden geanalyseerd. Het aantal variabelen (b.v. „verwarren van factoren“) betrokken bij dit type van proefneming is zeer hoog. Dit maakt wetenschappelijk geldige voedingsstudie tijdrovend en duur zeer, en verklaart waarom een juiste wetenschap van menselijke voeding eerder nieuw is.
In het algemeen, is het eten van een verscheidenheid van vers, geheel (onverwerkt) installatievoedsel hormonaal en metabolisch gunstig in vergelijking met het eten van een monotoon dieet gebleken dat op verwerkt voedsel wordt gebaseerd. In het bijzonder, vertraagt de consumptie van geheel installatievoedsel spijsvertering en verstrekt hogere hoeveelheden en een gunstiger saldo van essentiële en essentiële voedingsmiddelen per eenheid van energie; resulterend in beter beheer van de celgroei, onderhoud, en mitose (celafdeling) evenals regelgeving van bloedglucose en eetlust. Een over het algemeen regelmatiger het eten patroon (b.v. etend middelgrote maaltijd om de 3 tot 4 uren) ook meer hormonaal en metabolisch gunstig dan zeldzame, toevallige voedselopname heeft bewezen.
De Mensen
van de geschiedenis hebben als omnivorous jager-gatherers in de loop van de afgelopen 250.000 jaar geëvolueerdo. De vroege diëten waren hoofdzakelijk vegetarisch met zeldzame wild en vissen waar beschikbaar. De landbouw ontwikkelde zich ongeveer 10.000 jaar geleden over de hele wereld in veelvoudige plaatsen die, korrels zoals tarwe, rijst, en maïs voorzien, van nietjes zoals brood en deegwaren. De landbouw verstrekte ook melk en zuivelproducten, en verhoogde scherp de beschikbaarheid van vlees en de diversiteit van groenten. Het belang van voedselzuiverheid werd erkend toen de bulkopslag tot teistering en verontreinigingsrisico's leidde. Koken ontwikkeld als vaak ritualistische activiteit, wegens efficiency en betrouwbaarheid betreft het vereisen van aanhankelijkheid aan strikte recepten en procedures, en in antwoord op vraag naar voedselzuiverheid en consistentie.
Antiquiteit door Verlichting
c. 475 V.CHR.: Anaxagoras verklaart dat het voedsel door het menselijke lichaam daarom „homeomerics“ (generatieve componenten) wordt geabsorbeerd en geabsorbeerd, daardoor afleidend het bestaan van voedingsmiddelen.
c. 400 V.CHR.: Hippocrates zegt, „laat voedsel uw geneeskunde zijn en de geneeskunde is uw voedsel.“
Het eerste geregistreerde voedingsexperiment wordt gevonden in het Boek van de Bijbel van Daniel. Daniel en zijn vrienden werden gevangen door de koning van Babylon tijdens een invasie van Israël. Geselecteerd als hofbedienden, moesten zij in het fijne voedsel en de wijn van de koning delen. Maar zij hadden bezwaar, verkiezend groenten (impulsen) en water overeenkomstig hun Joodse dieetbeperkingen. De belangrijkste beheerder van de koning ging met tegenzin met een proef akkoord. Daniel en zijn vrienden ontvingen hun dieet 10 dagen en werden toen vergeleken bij de mensen van de koning. Lijkend gezonder, werden zij toegestaan om met hun dieet verder te gaan.
1500s: Het vergeleken metabolisme van de wetenschapper en van de kunstenaar Leonardo da Vinci aan een brandende kaars.
1747: Dr. James Lind, een arts in de Britse marine, voerde het eerste wetenschappelijke voedingsexperiment uit, ontdekkend dat citroensap geredde zeelieden die jarenlang van scheurbuik, een dodelijke en pijnlijke het aftappen wanorde op zee waren geweest. De ontdekking werd genegeerd veertig jaar, waarna werden de Britse zeelieden genoemd geworden „limeys.“ De essentiële vitamine C binnen citroensap zou niet erkend worden door wetenschappers tot de jaren '30.
1770: Antoine Lavoisier, de „Vader van Voeding en Chemie“ ontdekte de details die van metabolisme aantonen, dat de oxydatie van voedsel de bron van lichaamshitte is.
1790: George Fordyce erkende calcium noodzakelijk voor kipoverleving.
Moderne era door 1941
Vroege 1800s: De de de de elementenkoolstof, stikstof, waterstof en zuurstof werden gezien als de primaire componenten van voedsel, en de methodes werden om hun aandelen te meten ontwikkeld.
1816: François Magendie ontdekt dat de honden slechts koolhydraten voedden en het vet hun lichaamsproteïne verloor en in een paar weken stierf, maar de honden voedden overleefde ook proteïne, identificeert proteïne als essentiële dieetcomponent.
1840: Justus Liebig ontdekt chemische makeup van koolhydraten (suikers), vetten (vetzuren) en proteïnen (aminozuren.)
1860s: Claus Bernard ontdekt dat het lichaamsvet van koolhydraat en proteïne kan worden samengesteld aantonen, die dat de energie in bloedglucose als vet of als glycogeen kan worden opgeslagen.
Vroege 1880s: Kanehiro Takaki merkte op dat de Japanse zeelieden beriberi ontwikkelden (of endemisch neuritis, een ziekte die hartproblemen en verlamming veroorzaken) maar de Britse zeelieden niet. Het toevoegen van melk en vlees aan Japanse diëten verhinderde de ziekte.
1896: Baumann waargenomen jodium in schildklieren.
1897: Christiaan Eijkman werkte met inwoners van Java, die ook aan beriberi leden. Eijkman merkte op dat de kippen het inheemse dieet van witte rijst ontwikkeld de symptomen van beriberi voedden, maar bleef gezond wanneer gevoede onverwerkte ongepelde rijst met de buiten intacte zemelen. Eijkman genas de inwoners door hen ongepelde rijst te voeden, ontdekkend dat het voedsel ziekte kan genezen. Meer dan twee later decennia, leerden de voedingsdeskundigen dat de buitenrijstzemelen vitamine B1 bevatten, die ook als thiamine wordt bekend.
De vroege jaren 1900: Carl Von Voit en Maximum Rubner meten onafhankelijk warmteenergieuitgaven die in verschillende soorten dieren, principes van fysica in voeding toepast.
1906: Wilcock en Hopkins toonden aan dat het aminozuurtryptofaan voor de overleving van muizen noodzakelijk was. Gowland Hopkins zag „bijkomende voedselfactoren“ buiten calorieën, proteïne en mineralen, als organische materialen essentieel aan gezondheid maar die het lichaam niet kan samenstellen.
1907: Stephen M. Babcock en Edwin B. Het hert leidt het experiment van de enig-Korrel. Dit experiment neemt 1911 door.
1912: Funk van Casmir muntte de term vitamine, een essentiële factor in het dieet, van de „essentiële“ woorden en „amine,“ omdat deze onbekende substanties die scheurbuik, beriberi, en pellagra verhinderen, toen om uit ammoniak werden verondersteld worden afgeleid.
1913: Elmer V. McCollum ontdekte de eerste vitaminen, de in vet oplosbare vitamine A, en de in water oplosbare vitamine B (in 1915; nu het geweten om een complex van verscheidene in water oplosbare vitaminen) en namenvitamine C te zijn als toen-onbekende substantie die scheurbuik verhindert.
1919: De heer Edward Mellanby identificeerde verkeerd rachitis als vitamine Adeficiëntie, omdat hij het bij honden met de olie van de kabeljauwlever kon genezen.
1922: McCollum vernietigt de vitamine A in de olie van de kabeljauwlever maar vindt het rachitis geneest, die vitamine D. nog noemen.
1922: H.M. Evans en L.S. De bischop ontdekt vitamine E essentieel voor rattenzwangerschap, oorspronkelijk roepend het „voedselfactor X“ tot 1925.
1925: Het hert ontdekt de spoorhoeveelheden koper voor ijzerabsorptie noodzakelijk zijn.
1927: Adolf Otto Reinhold Windaus stelt vitamine D samen, waarvoor hij de Prijs van Nobel in Chemie in 1928 won.
1928: Albert Szent-Gyorgyi isoleert ascorbinezuur, en in 1932 bewijst dat het vitamine C door scheurbuik te verhinderen is. In 1935 stelt hij het samen, en in 1937 wint hij een Prijs van Nobel voor zijn inspanningen. Szent-Gyorgyi licht gelijktijdig veel van de citroenzuurcyclus nader toe.
jaren '30: William Cumming Rose identificeert essentiële aminozuren, noodzakelijke proteïnen die het lichaam niet kan samenstellen.
1935: Underwood en Marston ontdekken onafhankelijk de noodzaak van kobalt.
1936: Eugene Floyd Dubois toont aan dat het werk en de schoolprestaties met warmteopname verwant zijn.
1938: De chemische structuur van vitamine E wordt ontdekt door Erhard Fernholz, en het wordt samengesteld door Paul Karrer.
1941: De eerste adviseerde de DieetToelagen (RDAs) door de Nationale Raad voor Onderzoek werden gevestigd.
Recent
1992 de V.S. Het Ministerie van Landbouw introduceert de Piramide van de Gids van het Voedsel.
2002 toont de Studie relatie tussen voeding en hevig gedrag.
2005 kan de Zwaarlijvigheid door adenovirus naast slechte voeding worden veroorzaakt.
Voeding en Gezondheid
zijn Er zes belangrijke voedingsmiddelen waarin het lichaam moet ontvangen. Deze voedingsmiddelen omvatten koolhydraten, proteïnen, vetten, vitaminen, mineralen, en water. Het is belangrijk om deze zes voedingsmiddelen op een dagelijkse basis te verbruiken om gezonde lichaamssystemen op te bouwen en te handhaven.
De slechte gezondheid kan door een onevenwichtigheid van voedingsmiddelen worden veroorzaakt, veroorzakend of een overmaat of deficiëntie, die beurtelings lichaam cumulatief het functioneren beïnvloeden. Voorts omdat de meeste voedingsmiddelen, op één of andere manier betrokken of een andere zijn, bij cel-aan-cel het signaleren (b.v. als bouwsteen of deel van een hormoon of signalerende „cascades“), onrechtstreeks beïnvloeden de deficiëntie of de overmaat van diverse voedingsmiddelen hormonale functie. Aldus, omdat zij grotendeels de uitdrukking van genen regelen, vertegenwoordigen de hormonen een verband tussen voeding en hoe onze genen, d.w.z. worden uitgedrukt. ons fenotype.
De sterkte en de aard van deze verbinding zijn voortdurend in onderzoek, maar de observaties hebben vooral de laatste jaren een centrale rol voor voeding in hormonale activiteit en functie en daarom in gezondheid aangetoond. Één bron van artikelen op voeding en gezondheid is het driemaandelijkse bulletin van de Voeding voor de Optimale Vereniging van de Gezondheid (NOHA). De artikelen sinds 1984 worden geïndexeerdn door onderwerp, naam, en chronologie.
De essentiële en niet-essentiële aminozuren
het lichaam vereist aminozuren om nieuwe lichaamsproteïne (eiwitbehoud) te produceren en beschadigde proteïnen (onderhoud) te vervangen die in de urine worden verloren. In dieren zijn de aminozuurvereisten geclassificeerd in termen van essentieel (een dier kan hen produceren niet) en niet-essentieel (het dier kan hen uit andere stikstofhoudende samenstellingen produceren) aminozuren.
Verbruiken van een dieet dat adequate hoeveelheden essentiële (maar ook niet-essentiële) aminozuren bevat is bijzonder belangrijk voor groeiende dieren, die een bijzonder hoog vereiste hebben.
De vetzuren
naast voldoende opname, een aangewezen evenwicht van essentiële vetzuren - omega-3 en omega-6 vetzuren - is ontdekt essentieel om te zijn voor het handhaven van gezondheid. Beide unieke „omega“ lange-keten meervoudig onverzadigde vetzuren zijn substraten voor een klasse van eicosanoids die als prostaglandines wordt bekend die als hormonen functioneren. Eicosapentaenoic zuur omega-3 (EPA) (wat in het lichaam van het omega-3 essentiële vetzuur alpha--linolenic zuur (LNA) kan worden gemaakt, of binnen genomen door mariene voedselbronnen), dient als bouwsteen voor reeks 3 prostaglandines (b.v. zwak-ontsteking PGE3). Dihomo-gamma-linolenic zuur omega-6 (DGLA) dient als bouwsteen voor reeks 1 prostaglandines (b.v. anti-inflammatory PGE1), terwijl arachidonic zuur (aa) als bouwsteen voor reeks 2 prostaglandines dient (b.v. pro-ontstekings PGE 2). Zowel worden DGLA als aa gemaakt van linoleic zuur omega-6 (La) in het lichaam, of kunnen binnen direct door voedsel worden genomen. Een geschikt evenwichtige opname van omega-3 en omega-6 bepaalt gedeeltelijk de relatieve productie van verschillende prostaglandines, die gedeeltelijk het belang van saldo omega-3 omega-6 voor cardiovasculaire gezondheid verklaart. In de geïndustrialiseerdek maatschappijen, verbruiken de mensen over het algemeen grote hoeveelheden verwerkte plantaardige oliën die hoeveelheden essentiële vetzuren samen met een bovenmatig bedrag van omega-6 met betrekking tot omega-3 hebben verminderd.
Het tarief omzettingen van omega-6 DGLA aan aa bepaalt grotendeels de productie van de respectieve prostaglandines PGE1 en PGE2. Omega-3 EPA verhindert aa van membranen worden bevrijd, daardoor afschuinend prostaglandinesaldo vanaf pro-ontstekingsPGE2 dat van aa naar anti-inflammatory PGE1 wordt gemaakt dat van DGLA wordt gemaakt. Voorts wordt de omzetting (desaturatie) van DGLA aan aa gecontroleerd door het enzym delta-5-desaturase, die beurtelings door hormonen zoals insuline (omhoog-verordening) en glucagon (beneden-verordening) wordt gecontroleerd. Omdat de verschillende types en de hoeveelheden gegeten/geabsorbeerd voedsel insuline, glucagon en andere hormonen in verschillende mate beïnvloeden, niet alleen bepalen het bedrag van omega-3 tegenover gegeten omega-6 maar ook de algemene samenstelling van het dieet daarom gezondheidsimplicaties met betrekking tot essentiële vetzuren, ontsteking (b.v. immune functie) en mitose (d.w.z. cel afdeling).
De suikers
Verscheidene lijnen van bewijsmateriaal wijzen op levensstijl-veroorzaakte hyperinsulinemia en verminderde insulinefunctie (d.w.z. insuline weerstand) als beslissende factor in vele ziektestaten. Bijvoorbeeld, hyperinsulinemia en insuline is de weerstand sterk verbonden met chronische ontsteking, die beurtelings met een verscheidenheid van ongunstige ontwikkelingen zoals slagaderlijke microinjuries en klontervorming sterk verbonden is (d.w.z. hartkwaal) en overdreven celafdeling (d.w.z. kanker).
De weerstand van Hyperinsulinemia en van de insuline (het zogenaamde metabolische syndroom) wordt gekenmerkt door een combinatie van buikzwaarlijvigheid, opgeheven bloedsuiker, opgeheven bloeddruk, opgeheven bloedtriglyceride, en verminderde cholesterol HDL. Het negatieve effect van hyperinsulinemia op prostaglandinePGE1/PGE2 saldo kan significant zijn.
De staat van zwaarlijvigheid draagt duidelijk tot insulineweerstand bij, die beurtelings type 2 diabetes kan veroorzaken. Vrijwel alle zwaarlijvig en meesten typt 2 diabetesindividuen heeft gemerkt insulineweerstand. Hoewel de vereniging tussen overfatness en insulineweerstand duidelijk is, blijven de nauwkeurige (waarschijnlijke multifarious) oorzaken van insulineweerstand minder duidelijk. Belangrijk, heeft men aangetoond dat de aangewezen oefening, de regelmatigere voedselopname en het verminderen van glycemic lading (zie verder) allen insulineweerstand in overfatindividuen (en daardoor de lagere niveaus van de bloedsuiker in hen die type 2 diabetes hebben) kunnen omkeren.
Obesity can unfavourably alter hormonal and metabolic status via resistance to the hormone leptin, and a vicious cycle may occur in which insulin/leptin resistance and obesity aggravate one another. The vicious cycle is putatively fuelled by continuously high insulin/leptin stimulation and fat storage, as a result of high intake of strongly insulin/leptin stimulating foods and energy.
Both insulin and leptin normally function as satiety signals to the hypothalamus in the brain; however, insulin/leptin resistance may reduce this signal and therefore allow continued overfeeding despite large body fat stores. In addition, reduced leptin signalling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate.
There is debate about how and to what extent different dietary factors -- e.g. intake of processed carbohydrates, total protein, fat, and carbohydrate intake, intake of saturated and trans fatty acids, and low intake of vitamins/minerals -- contribute to the development of insulin- and leptin resistance. In any case, analogous to the way modern man-made pollution may potentially overwhelm the environment's ability to maintain 'homeostasis', the recent explosive introduction of high Glycemic Index- and processed foods into the human diet may potentially overwhelm the body's ability to maintain homeostasis and health (as evidenced by the metabolic syndrome epidemic).
Antioxidants are another recent discovery. As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as radical oxygen species or free radicals form as a result. For normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds, some produced by the body with adequate precursors (glutathione, Vitamin C in most animals) and those that the body cannot produce may only be obtained through the diet through direct sources (Vitamin C in humans, Vitamin A, Vitamin K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight). Different antioxidants are now known to function in a cooperative network, e.g. vitamin C can reactivate free radical-containing glutathione or vitamin E by accepting the free radical itself, and so on. Some antioxidants are more effective than others at neutralizing different free radicals.
Some cannot neutralize certain free radicals. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas). When interacting with a free radical, some antioxidants produce a different free radical compound that is less dangerous or more dangerous than the previous compound. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect.
Intestinal bacterial flora
Some information in this article or section has not been verified and may not be reliable. Please check for any inaccuracies, and modify and cite sources as needed. It is now also known that the human digestion system contains a population of a range of bacteria which are essential to digestion, and which are also affected by the food we eat. The role and significance of the intestinal bacterial flora is under investigation. Both good and bad bacteria inhabit the digestive system. It is estimated that in the Western world, most people are no longer in a homeostatic balance. It is ideal to have 80% good to 20% bad, typically differentiated by gram negative and gram positive staining, respectively; however, in western diets it is more likely to be the other way around. Consuming processed food that are low in nutrients and high in sugar will allow bad bacteria to flourish.
Phytochemicals
Blackberries are a source of polyphenol antioxidants. A growing area of interest is the effect upon human health of trace chemicals, collectively called phytochemicals, nutrients typically found in edible plants, especially colorful fruits and vegetables (see Whole Foods Diet, below). Unlike the anecdotal and sometimes specious nutritional claims of medicinal herbs and compounds, the effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. One of the principal classes of phytochemicals are polyphenol antioxidants, chemicals which are known to provide certain health benefits to the cardiovascular system and immune system. These chemicals are known to down-regulate the formation of reactive oxygen species, key chemicals in cardiovascular disease.
Perhaps the most rigorously tested phytochemical is zeaxanthin, a yellow- pigmented carotenoid present in many yellow and orange fruits and vegetables. Repeated studies have shown a strong correlation between ingestion of zeaxanthin and the prevention and treatment of age-related macular degeneration (AMD). Less rigorous studies have proposed a correlation between zeaxanthin intake and cataracts. A second carotenoid, lutein, has also been shown to lower the risk of contracting AMD. Both compounds have been observed to collect in the retina when ingested orally, and they serve to protect the rods and cones against the destructive effects of light.
Another caretenoid, beta-cryptoxanthin, appears to protect against chronic joint inflammatory diseases, such as arthritis. While the association between serum blood levels of beta-cryptoxanthin and substantially decreased joint disease has been established, neither a convincing mechanism for such protection nor a cause-and-effect have been rigorously studied. Similarly, a red phytochemical, lycopene, has substantial credible evidence of negative association with development of prostate cancer.
The correlations between the ingestion of some phytochemicals and the prevention of disease are, in some cases, enormous in magnitude. For example, several studies have correlated high levels of zeaxanthin intake with roughly a 50% reduction in AMD. The difficulties in demonstrating causative properties and in applying the findings to human diet, however, are similarly enormous.
The standard for rigorous proof of causation in medicine is the double-blind study, a time-consuming, difficult and expensive process, especially in the case of preventative medicine. While new drugs must undergo such rigorous testing, pharmaceutical companies have a financial interest in funding rigorous testing and may recover the cost if the drug goes to market. No such commercial interest exists in studying chemicals that exist in orange juice and spinach, making funding for medical research difficult to obtain.
Even when the evidence is obtained, translating it to practical dietary advice can be difficult and counter-intuitive. Lutein, for example, occurs in many yellow and orange fruits and vegetables and protects the eyes against various diseases. However, it does not protect the eye nearly as well as zeaxanthin, and the presence of lutein in the retina will prevent zeaxanthin uptake.
Additionally, evidence has shown that the lutein present in egg yolk is more readily absorbed than the lutein from vegetable sources, possibly because of fat solubility. At the most basic level, the question "should you eat eggs?" is complex to the point of dismay, including misperceptions about the health effects of cholesterol in egg yolk, and its saturated fat content.
As another example, lycopene is prevalent in tomatoes (and actually is the chemical that gives tomatoes their red color). It is more highly concentrated, however, in processed tomato products such as commercial pasta sauce, or tomato soup, than in fresh "healthy" tomatoes. Such sauces, however, tend to have high amounts of salt, sugar, other substances a person may wish or even need to avoid.
for more details go to
http://www.consumersresearchcncl.org/Healthcare/Ophthalmologists/ophth_nutrition.html
[أونتيتلد]
Automatically translated into Arabic thanks to WorldLingo
يدرس تغذية وصحتك
من [ويكيبديا]
تغذية علم العلاقة بين حمية و [ستت وف هلث] ومرض. [ديتيسن] [هلث بروفسّيونل] الذي يكون اختصّت في هذا [أرا وف إكسبرتيس], جدّا يدرّب أن يزوّد خزينة, [إفيدنس-بسد] إشعار حمييّة وتدخلات. هناك طيف يتراوح من حالة سوء تغذية إلى صحة أفضل, بما في ذلك كثير عاديّة أعراض وأمراض أيّ يستطيع غالبا كنت منعت أو خفّفت مع تغذية جيّدة.
أعجاز, تجاوزات وإختلالات في حمية يستطيع أنتجت تأثير صدمة سلبيّة على صحة, أيّ يمكن قدت إلى أمراض مثل مرض حفر, بدانة أو [أستيوبوروسس], [أس ولّ س] نفسانيّة ومشاكل [بهفيورل]. فضلا عن ذلك, ابتلاع مفرّطة عناصر أنّ يتلقّى ما من دور ظاهرة في صحة, ([إ.غ.]. رصاص, زئبق, [بكبس], [ديوإكسين]), يمكن تكبّدت مسمّة وتأثيرات قاتلة احتماليّا, [دبندينغ ون] الجرعة. يحاول العلم التغذية أن يفهم كيف ولما مظاهر خاصّة حمييّة يأثرون صحة.
نظرة عامّة
تغذية يبحث علم أن يفسّر أيضيّة وإستجابات [فسولوجكل] من الجسم إلى حمية. مع تقدمات في جزيئيّة علم الأحياء, كيمياء حيويّة, وعلم وراثة, تغذية يطوّر علم إضافة إلى ذلك داخل الدراسة من أيض [إينتغرتيف], أيّ [سك] أن يربط حمية وصحة من خلال العدسة من عمليات كيميائيّ حيويّ.
اصطلحت ال [هومن بودي] من مركبات كيميائيّ مثل ماء, [أمينو سد] (بروتين), [فتّي سد] (أدهان), [نوكليك سد] ([دن/رنا]), وكربوهيدر ([إ.غ.]. [سوغرس] وليف). يتألّف هذا مركبات بالتّالي عناصر مثل كربون, هيدروجين, أكسجين, نيتروجين, وفسفور, ويمكن أو يمكن لا يحتوي معدنات مثل كالسيوم, حديد, أو زنك. يقع معدنات بالوجود الكلّيّ [إين ث فورم وف] ملاح و [إلكترولت]. يقع كلّ من هذا كيميائيّة مركبات وعناصر في مختلفة أشكال وإدماجات ([إ.غ.]. هرمونات/حيمينات, دهن فوسفات, [هدروإكسبتيت]), على حدّ سواء في ال [هومن بودي] وفي كائن حيّ ([إ.غ.]. يأكل معامل, حيوانات) أنّ أناس. [كمبريز] ال [هومن بودي] بالضّرورة العناصر أنّ هو يأكل ويمتصّ داخل الدورة دمويّة. يساهم ال [ديجستيف سستم], ماعدا في ال [أونبورن] جنين, في الخطوة أولى أيّ يجعل المختلفة كيميائيّة مركبات وعناصر في طعام يتوفّر للترليونات الخلايا من الجسم. في العملية هضمية من بالغ معدّلة, يخرج حوالي سبعة [ليتر] السائل, يعرف ك [ديجستيف جويس], الجسم داخليّة ويدخل التجويف صغير من المسلك منشور هضمية.
يساعد ال [ديجستيف جويس] كسرت روابط كيميائيّ بين يبتلع مركبات [أس ولّ س] ضمنت التكيف [أند/ور] دولة نشيطة من المركبات/عناصر. مهما, كثير [كمبووندس/] امتصّت عناصر داخل الدورة دمويّة [أونشنجد] [, ثوو] العملية هضمية يساعد أن يطلقهم من المادّة ترابط من الأطعمة حيث هم يقعون. أيّ [أونبسربد] أمر أفرزت في البراز. غير أنّ فقط أزلت مبلغة أدنى [ديجستيف جويس] ب هذا عملية; يعيد الأمعية أكثر من هو; خلاف ذلك نزع الجسم بسرعة; (بالتّالي التأثيرات مدمّرة من إسهال مستمرّة).
دراسة في هذا مجال ينبغي أخذت بعناية [إينتو كّوونت] الدولة من الجسم قبل ابتلاع وبعد هضم [أس ولّ س] ال [شميكل كمبوسأيشن] من الطعام والنفاية. يقارن النفاية إلى الطعام يستطيع حددت الأنواع خاصّة مركبات وعناصر يمتصّ بالجسم. التأثير أنّ ال يمتصّ أمر يتلقّى على الجسم يستطيع كنت حددت ب يجد الفرق بين ال [بر-ينجسأيشن] دولة وال [بوست-ديجسأيشن] دولة. التأثير يمكن فقط كنت سهل تمييز بعد فترة زمنيّة موسّعة في أيّ كلّ طعام وابتلاع ينبغي كنت تماما نظّمت وكلّ نفاية ينبغي كنت حللت. الرقم المتغيرات ([إ.غ.]. "يتيّه عاملات") يتضمّن في هذا نوع التجريب جدّا عال. هذا يجعل علميّا دراسة شرعيّة غذائيّة جدّا مستغرق وقتا طويلا وغالية, ويفسّر لما علم مناسبة [هومن نوتريأيشن] يكون بالأحرى جديدة.
[إين جنرل,] قد برهن يأكل تشكيل من طازجة, كاملة ([أونبروسسّد]) [بلنت فوود] هرمونيّا وأيضيّا مواتي يقارن إلى يأكل حمية رتيبة يؤسّس على يعالج أطعمة. [إين برتيكلر], يتمهّل إستهلاك من أطعمة [وهول بلنت] هضم ويزوّد مبلغات [هيغر] وأكثر [ففوربل بلنس] من أساسيّة ومغذيات حيويّة لكلّ وحدة الطاقة; [رسولتينغ ين] إدارة جيّدة من خلية حالة نموّ, صيانة, و [ميتوسس] (خلية تقسيم) [أس ولّ س] نظام تعديل من دم سكروز وشهية. عموما أكثر نظاميّة يأكل أسلوب ([إ.غ.]. يأكل وجبات [مديوم-سزد] كلّ 3 [تو] 4 يبرهن ساعات) يتلقّى أيضا أكثر هرمونيّا وأيضيّا مواتي من نادرة, [فوود ينتك] اتّفاقيّة.
تاريخ
قد تطوّر أناس ك [هونتر-غثررس] ملتهمة على السابقة 250,000 سنون. كان حمية مبكّرة أوّلا نباتيّة مع نادرة لعبة لحام وسمكة حيث يتوفّر. زراعة طوّر حوالي 10,000 سنون [أغو] في يتعدّد موقعات طوال العالم, يزوّد حبات مثل قمح, أرز, وحبّ ذرة, مع مشابك مثل خبز وباستا. يزرع أيضا يزوّد لبن و [ديري برودوكت], وبحدّة يزيد التوفر الألحاظ والتنوع الخضر. ميّزت الأهمية من طعام نقاوة كان عندما [بولك ستورج] قاد إلى عيث وتلوث أخطار. يتعلّق يطبخ يطوّر كنشاط [ريتثليستيك] غالبا, واجبة إلى فعالية وإعتمادية يتطلّب إلتزام إلى صارمة وصفات وإجراءات, و [إين رسبونس تو] طلبات لطعام نقاوة وتماسك.
العصور القديمة من خلال تنوير
[ك.]. 475 قبل المسيح: [أنإكسغرس] يفيد أنّ امتصّت طعام ب ال [هومن بودي] ولذلك يحتوى "[هوميومريكس]" (عناصر مولدة), بذلك يستنتج الوجود المغذيات.
[ك.]. 400 قبل المسيح: تركت [هيبّوكرتس] يقول, "طعام الطبّك والطبّ طعامك."
الأولى أسّست يسجّل تجربة غذائيّة في الكتاب مقدّس كتاب دانييل. على قبض دانييل وصديقاته كان بالملك بابل أثناء غزوة إسرائيل. ينتقي كمحكمة خادمات, كان هم أن يشارك في الملك أطعمة دقيقة وخمر. غير أنّ اعترض هم, يفضّل خضر (ذبذبات) وماء وفق حصورهم [جويش] حمييّة. الملك وافق مضيفة رئيسيّة على مضض إلى محاكمة. استلم دانييل وصديقاته حميتهم ل 10 أيام وكان بعد ذلك قارنت إلى الملك رجال. يظهر صحّ, سمحت هم كان أن يستمرّ مع حميتهم.
[1500س]: عالمة وفن ليوناردو قارن [دا] [فينس] أيض إلى شمعة مشتعلة.
1747: [در.]. أنجز جيمس [ليند], طبيبة في القوّة بحريّة بريطانيّة, الأولى علميّة تغذية تجربة, يكتشف أنّ [ليم جويس] أنقذ بحارات الذي كان قد كان في بحث لسنون من مرض حفر, مميتة ومؤلمة نزيف اضطراب. تجاهلت الإكتشاف كان ل [فورتي] سنون, [أفتر وهيش] بحارات بريطانيّة أصبحوا يعرف بما أنّ "[ليمس]." ميّزت ال [فيتمين ك] أساسيّة ضمن [ليم جويس] لم يكن بعالمات حتّى الثلاثينات.
1770: اكتشف [أنتوين] [لفويسر], ال "أب من تغذية وكيمياء" التفاصيل الأيض, يعرض أنّ التأكسد الطعام المصدر من جسم حرارة.
1790: ميّز جورج [فوردس] كالسيوم ضروريّة لطائر بقاء.
عصر حديثة من خلال 1941
[1800س] مبكّرة: ميّزت العناصر كربون, نيتروجين, هيدروجين وأكسجين كان كالعناصر أوّليّة طعام, وطرق أن يقيس نسبهم كان طوّرت.
1816: يكتشف [فرنويس] [مجندي] أنّ كلاب غذّوا فقط كربوهيدر ودهن خسر هم جسم بروتين ومات في [ا فو] أسابيع, غير أنّ كلاب أيضا غذّوا بروتين بقي, يعيّن بروتين كعنصر أساسيّة حمييّة.
1840: يكتشف [جوستثس] ليبج البنية كيميائيّ من كربوهيدر ([سوغرس]), أدهان ([فتّي سد]) وبروتين ([أمينو سد].)
[1860س]: يكتشف كلاوس برنارد أنّ جسم دهن يستطيع كنت اصطنعت من كربوهيدر وبروتين, يبدي أنّ الطاقة في دم سكروز يستطيع كنت خزّنت بما أنّ سمينة أو كسكاكرين.
[1880س] مبكّرة: لاحظ [كنهيرو] [تككي] أنّ بحارات يابانيّة طوّروا [بريبري] (أو [نيوريتيس] مستوطنة, مرض يسبّب قلب مشاكل وحالة شلل) غير أنّ بحارات بريطانيّة أتمّوا لم. منع يضيف لبن ولحظ إلى يابانية حمية المرض.
1896: [بومنّ] يلاحظ عنصر يود في [ثرويد غلند].
1897: عمل [كريستين] [إيجكمن] مع ساكن محلّيّ جاوة, الذي أيضا عانى من [بريبري]. [إيجكمن] لاحظ أنّ غذّى دجاج الحمية أهليّ طبيعيّ [وهيت ريس] طوّر الأعراض ال [بريبري], غير أنّ بقي يصحّ عندما مجلس نظام الاحتياطيّ الفيدراليّ [بروون ريس] [أونبروسسّد] مع النخالة خارجيّة مصونة. [إيجكمن] عالج الساكن محلّيّ ب يغذّيهم [بروون ريس], يكتشف أنّ طعام يستطيع عالجت مرض. على اثنان عقود فيما بعد, علم [نوتريأيشنيست] أنّ ال [ريس برن] خارجيّة يحتوي حيمين [ب1], أيضا يعرف كثيمين.
[1900س] مبكّرة: يقيس كارل [فون] [فويت] وحدّ أقصى [روبنر] بشكل مستقلّ [إنرج إكسبنديتثر] حراريّة في نوع مختلفة حيوانات, يطبّق مبادئ الفيزياء في تغذية.
1906: أبدى [ويلكك] و [هوبكينس] أنّ ال [أمينو سد] [تربتوفن] كان ضروريّة للبقاء الفؤوس. ميّز [غولند] [هوبكينس] "ثانويّة طعام عاملات" غير حريرة, بروتين ومعدنات, ك [متريلس] عضويّة أساسيّة إلى صحة غير أنّ أيّ الجسم يستطيع لا يصطنع.
1907: إسطفان [م.]. [ببكك] وأدوين [ب.]. أيّل تصرّف إداريّ ال [سنغل-غرين] تجربة. يركض هذا تجربة من خلال 1911.
1912: [كسمير] سكّ جبانة العبارة حيمين, عاملة حيويّة في الحمية, من الكلمات "حيويّة" و" أمينة," لأنّ هذا مواد مجهولة يمنع مرض حفر, [بريبري], وحصاف, كان فكّرت بعد ذلك أن يكون استنتجت من أمونيوم.
1913: [إلمر] [ف.]. [مكّولّوم] اكتشف الأولى حيمينات, [فت سلوبل] [فيتمين ا], وحيمين [وتر-سلوبل] [ب] (في 1915; الآن يعرف أن يكون مركبة من عدّة حيمينات [وتر-سلوبل]) واسم [فيتمين ك] كالمادة [ثن-وننوون] يمنع مرض حفر.
1919: عيّن سيد إدوارد [ملّنبي] بشكل غير لائق كساح الأطفال ك [فيتمين ا] عجز, لأنّ هو استطاع عالجت هو في كلاب مع [كد ليفر] زيت.
1922: [مكّولّوم] يدمّر ال [فيتمين ا] في [كد ليفر] زيت غير أنّ اكتشافات هو بعد يعالج كساح الأطفال, يعيّن حيمين [د.].
1922: [ه.م.]. [إفنس] و [ل.س.]. أسقف يكتشف حيمين [إ] بما أنّ أساسيّة لفأرة حالة حمل, أصلا يدعو هو "طعام عاملة [إكس]" حتّى 1925.
1925: أيّل يكتشف [ترس موونت] النحاسة ضروريّة لحديد امتصاص.
1927: يصطنع أدولف أوتو [رينهولد] [ويندوس] [فيتمين د], ل أيّ هو ربح ال [نوبل بريز] في كيمياء في 1928.
1928: يعزل [ألبرت] [سزنت-جورجي] [أسكربيك سد], وفي 1932 يبرهن أنّ هو [فيتمين ك] ب يمنع مرض حفر. في 1935 يصطنع هو هو, وفي 1937 هو يربح [نوبل بريز] لجهوده. يوضح [سزنت-جورجي] بتزامن كثير من ال [ستريك سد] دورة.
ثلاثينات: يعيّن وليام [كمّينغ] [روس] [إسّنتيل مينو سد], بروتين ضروريّة أيّ الجسم يستطيع لا يصطنع.
1935: يكتشف [أوندرووود] و [مرستون] بشكل مستقلّ الحاجة الكوبلت.
1936: يبدي [إيوجن] [فلود] [دوبويس] أنّ عمل ومدرسة أداء ارتبطت إلى [كلوريك ينتك].
1938: اكتشفت ال [شميكل ستروكتثر] الحيمين [إ] ب [إرهرد] [فرنهولز], وهو اصطنعت ببول [كرّر].
1941: الأولى أسّست يوصى تسامحات حمييّة ([ردس]) كان ب ال [رسرش كونسل] وطنيّة.
أخيرة
1992 الولايات المتّحدة الأمريكيّة [دبرتمنت وف غريكلتثر] يقدّم طعام مرشدة هرم.
2002 دراسة أعراض علاقة بين تغذية وتصرف عنيفة.
2005 بدانة يمكن كنت سبّبت ب [أدنوفيروس] [إين دّيأيشن تو] تغذية سيّئة.
تغذية وصحة
هناك ستّة مغذيات رئيسيّة في أيّ الجسم يحتاج أن يستلم. يتضمّن هذا مغذيات كربوهيدر, بروتينات, أدهان, حيمينات, معدنات, وماء. هو مهمّة أن يستهلك هذا ستّة مغذيات على أساس يوميّة أن يبني وأبقيت يصحّ جسم نظامات.
[إيلّ هلث] يستطيع كنت سبّبت بإختلال المغذيات, ينتج إمّا تجاوز أو عجز, أيّ بالتّالي يأثر جسم يعمل تراكميّا. فضلا عن ذلك, لأنّ كثير مغذيات يكونون, [إين سم وي] أو آخر, يتضمّن في [سلّ-تو-سلّ] يشير ([إ.غ.]. يسقط كبناية قالب أو جزء من هرمون أو يشير ""), عجز أو تجاوز من مغذيات مختلفة يأثر عمل هرمونيّة بشكل غير مباشر. لذلك, لأنّ هم كثيرا ينظّمون التعبير المورثات, يمثّل هرمونات خطوة بين تغذية وكيف مورثاتنا يكون عبّر عن, [إي.]. نمط ظاهريّنا.
القوة وطبيعة من هذا خطوة باستمرار تحت تحقيق, غير أنّ قد عرض بطاقات خصوصا [إين رسنت رس] دور محورية لتغذية في هرمونيّة نشاط وعمل ولذلك في صحة. واحدة مصدر المواد على تغذية وصحة الالرسالة الإخباريّة فصليّة من التغذية لأفضل صحة جمعية ([نوها]). مواد بما أنّ 1984 يكون فهرست بموضوع, اسم, وجدول زمنيّ.
أساسيّة ويتطلّب [أمينو سد]
غير أساسيّ الجسم [أمينو سد] أن ينتج جديدة جسم بروتين (بروتين احتجاز) وأن يستبدل يضرّر بروتينات (صيانة) أنّ يكون خسرت في البول. في حيوانات [أمينو سد] صنّفت متطلبات بخصوص أساسيّة (حيوان يستطيع لا ينتجهم) وغير أساسيّ (الحيوان يستطيع أنتجتهم من أخرى [نيتروجن كنتينينغ] مركبات) [أمينو سد].
يستهلك حمية أنّ يحتوي مبلغات كافية من أساسيّة (غير أنّ أيضا غير أساسيّ) [أمينو سد] بشكل خاصّ مهمّة ل ينمو حيوانات, الذي يتلقّى متطلب عال بشكل خاصّ.
اكتشفت [فتّي سد]
[إين دّيأيشن تو] مدخل كاف, ميزان مناسبة من [فتّي سد] أساسيّة - [أمغ-3] و [أمغ-6] [فتّي سد] - يتلقّى يكون أن يكون حاسمة ل يبقي صحة. [بوث وف ثيس] فريدة "أوميغا" [فتّي سد] [لونغ-شين] [بولونستثرتد] طبقة سفليّة لصنف ال [إيكسنويدس] يعرف ك [بروستغلندين] أيّ يعمل كهرمونات. ال [أمغ-3] حامض [إيكسبنتنويك] ([إبا]) (أيّ يستطيع كنت جعلت في الجسم من ال [أمغ-3] أساسيّة [فتّي سد] حامض [ألف-لينولنيك] ([لنا]), أو يأخذ داخل من خلال بحريّة طعام مصادر), خدمات كبناية قالب ل [سري] 3 [بروستغلندين] ([إ.غ.]. [وكل-ينفلمّأيشن] [بج3]). ال [أمغ-6] يخدم حامض [ديهومو-غمّ-لينولنيك] ([دغلا]) كبناية قالب ل [سري] 1 [بروستغلندين] ([إ.غ.]. [بج1] [أنتي-ينفلمّتوري]), حيث أنّ [أرشدونيك سد] ([أا]) يخدم كبناية قالب ل [سري] 2 [بروستغلندين] ([إ.غ.]. [برو-ينفلمّتوري] [بج] 2). على حدّ سواء جعلت [دغلا] و [أا] من ال [أمغ-6] [لينوليك سد] (لا) في الجسم, أو يستطيع كنت أخذت داخل مباشرة من خلال طعام. يحدث مدخل متوازنة بشكل مناسب من [أمغ-3] و [أمغ-6] جزئيّا الإنتاج نسبيّة من [بروستغلندين] مختلفة, أيّ جزئيّا يفسّر الأهمية من [أمغ-3/] [أمغ-6] ميزان لصحة قلبيّ وعائيّ. عمّرت في يصنع مجتمعات, عموما يستهلك مبلغات كبيرة من يعالج [فجتبل ويل] أنّ قد قلّل مبلغات من [فتّي سد] أساسيّة مع مبلغة مفرّطة [أمغ-6] [أمغ-3] [رلتيف تو].
يحدّ ال [رت وف كنفرسون] من [أمغ-6] [دغلا] إلى [أا] كثيرا الإنتاج من ال [بروستغلندين] شخصيّة [بج1] و [بج2]. يمنع [أمغ-3] [إبا] [أا] من يكون يطلق من أغشية, بذلك يميل [بروستغلندين] ميزان بعيدا من [بج2] [برو-ينفلمّتوري] يجعل من [أا] نحو [بج1] [أنتي-ينفلمّتوري] يجعل من [دغلا]. فضلا عن ذلك, ضبطت التحويل (إزالة تشبّع) من [دغلا] إلى [أا] بالأنزيم [دلت-5-دستثرس], أيّ بالتّالي يكون ضبطت بهرمونات مثل أنسولين ([أوب-رغلأيشن]) ومضاعف سكّر ([دوون-رغلأيشن]). لأنّ أنواع مختلفة ومبلغات الطعام يؤكل/يمتصّ يأثرون أنسولين, مضاعف سكّر وأخرى هرمونات إلى يتغيّر درجات, ليس فحسب يحدّ المبلغة ال [أمغ-3] ضدّ [أمغ-6] يؤكل غير أنّ أيضا التركيب عامّة من الحمية لذلك صحة تضمنات [إين رلأيشن تو] [فتّي سد] أساسيّة, التهاب ([إ.غ.]. عمل محصّنة) و [ميتوسس] ([إي.]. خلية تقسيم).
يسكّر
عدّة خطوط البيّنة يشير [ليفستل-يندوسد] [هبرينسولينميا] ويقلّد أنسولين عمل ([إي.]. [إينسولين رسستنس]) كعاملة حاسمة في كثير مرض دول. مثلا, [هبرينسولينميا] واقترنت [إينسولين رسستنس] بقوّة إلى التهاب مزمنة, أيّ بالتّالي يكون بقوّة اقترنت إلى تشكيل من تطويرات عكسيّة مثل شريانيّة [ميكروينجوريس] وجلطة تشكيل ([إي.]. مرض القلب) ويبالغ خلية تقسيم ([إي.]. سرطان).
ميّزت [هبرينسولينميا] و [إينسولين رسستنس] (التناذر ما يسمّى أيضيّة) بإدماج من بدانة بطنيّة, يعزّز [بلوود سوغر], يعزّز [بلوود برسّور], يعزّز دم [تريغلسريد], ويقلّد [هدل] كوليستيرول. التأثير صدمة سلبيّة [هبرينسولينميا] على [بروستغلندين] [بج1/بج2] ميزان يمكن كنت هامّة.
يسهم الدولة البدانة بوضوح إلى [إينسولين رسستنس], أيّ بالتّالي يستطيع سبّبت نوع 2 داء سكّريّ. قد علم كلّ في الواقع بدينة وكثير نوع 2 فردات مصاب بالسّكّريّ [إينسولين رسستنس]. رغم أنّ الجمعية بين [أفرفتنسّ] و [إينسولين رسستنس] يكون واضحة, الدقيقة (مرجّحة متنوّعة) يبقى أسباب ال [إينسولين رسستنس] أقلّ واضحة. بأهمّيّة, عرضت هو يتلقّى يكون أنّ تمرين عمليّ مناسبة, أكثر [فوود ينتك] نظاميّة ويقلّد تحميل سكّريّ دمّ (يرى أدناه) كلّ يستطيع عكست [إينسولين رسستنس] في [أفرفت] فردات (وبذلك خفّضت [بلوود سوغر لفل] في أنّ الذي يتلقّى نوع 2 داء سكّريّ).
Obesity can unfavourably alter hormonal and metabolic status via resistance to the hormone leptin, and a vicious cycle may occur in which insulin/leptin resistance and obesity aggravate one another. The vicious cycle is putatively fuelled by continuously high insulin/leptin stimulation and fat storage, as a result of high intake of strongly insulin/leptin stimulating foods and energy.
Both insulin and leptin normally function as satiety signals to the hypothalamus in the brain; however, insulin/leptin resistance may reduce this signal and therefore allow continued overfeeding despite large body fat stores. In addition, reduced leptin signalling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate.
There is debate about how and to what extent different dietary factors -- e.g. intake of processed carbohydrates, total protein, fat, and carbohydrate intake, intake of saturated and trans fatty acids, and low intake of vitamins/minerals -- contribute to the development of insulin- and leptin resistance. In any case, analogous to the way modern man-made pollution may potentially overwhelm the environment's ability to maintain 'homeostasis', the recent explosive introduction of high Glycemic Index- and processed foods into the human diet may potentially overwhelm the body's ability to maintain homeostasis and health (as evidenced by the metabolic syndrome epidemic).
Antioxidants are another recent discovery. As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as radical oxygen species or free radicals form as a result. For normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds, some produced by the body with adequate precursors (glutathione, Vitamin C in most animals) and those that the body cannot produce may only be obtained through the diet through direct sources (Vitamin C in humans, Vitamin A, Vitamin K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight). Different antioxidants are now known to function in a cooperative network, e.g. vitamin C can reactivate free radical-containing glutathione or vitamin E by accepting the free radical itself, and so on. Some antioxidants are more effective than others at neutralizing different free radicals.
Some cannot neutralize certain free radicals. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas). When interacting with a free radical, some antioxidants produce a different free radical compound that is less dangerous or more dangerous than the previous compound. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect.
Intestinal bacterial flora
Some information in this article or section has not been verified and may not be reliable. Please check for any inaccuracies, and modify and cite sources as needed. It is now also known that the human digestion system contains a population of a range of bacteria which are essential to digestion, and which are also affected by the food we eat. The role and significance of the intestinal bacterial flora is under investigation. Both good and bad bacteria inhabit the digestive system. It is estimated that in the Western world, most people are no longer in a homeostatic balance. It is ideal to have 80% good to 20% bad, typically differentiated by gram negative and gram positive staining, respectively; however, in western diets it is more likely to be the other way around. Consuming processed food that are low in nutrients and high in sugar will allow bad bacteria to flourish.
Phytochemicals
Blackberries are a source of polyphenol antioxidants. A growing area of interest is the effect upon human health of trace chemicals, collectively called phytochemicals, nutrients typically found in edible plants, especially colorful fruits and vegetables (see Whole Foods Diet, below). Unlike the anecdotal and sometimes specious nutritional claims of medicinal herbs and compounds, the effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. One of the principal classes of phytochemicals are polyphenol antioxidants, chemicals which are known to provide certain health benefits to the cardiovascular system and immune system. These chemicals are known to down-regulate the formation of reactive oxygen species, key chemicals in cardiovascular disease.
Perhaps the most rigorously tested phytochemical is zeaxanthin, a yellow- pigmented carotenoid present in many yellow and orange fruits and vegetables. Repeated studies have shown a strong correlation between ingestion of zeaxanthin and the prevention and treatment of age-related macular degeneration (AMD). Less rigorous studies have proposed a correlation between zeaxanthin intake and cataracts. A second carotenoid, lutein, has also been shown to lower the risk of contracting AMD. Both compounds have been observed to collect in the retina when ingested orally, and they serve to protect the rods and cones against the destructive effects of light.
Another caretenoid, beta-cryptoxanthin, appears to protect against chronic joint inflammatory diseases, such as arthritis. While the association between serum blood levels of beta-cryptoxanthin and substantially decreased joint disease has been established, neither a convincing mechanism for such protection nor a cause-and-effect have been rigorously studied. Similarly, a red phytochemical, lycopene, has substantial credible evidence of negative association with development of prostate cancer.
The correlations between the ingestion of some phytochemicals and the prevention of disease are, in some cases, enormous in magnitude. For example, several studies have correlated high levels of zeaxanthin intake with roughly a 50% reduction in AMD. The difficulties in demonstrating causative properties and in applying the findings to human diet, however, are similarly enormous.
The standard for rigorous proof of causation in medicine is the double-blind study, a time-consuming, difficult and expensive process, especially in the case of preventative medicine. While new drugs must undergo such rigorous testing, pharmaceutical companies have a financial interest in funding rigorous testing and may recover the cost if the drug goes to market. No such commercial interest exists in studying chemicals that exist in orange juice and spinach, making funding for medical research difficult to obtain.
Even when the evidence is obtained, translating it to practical dietary advice can be difficult and counter-intuitive. Lutein, for example, occurs in many yellow and orange fruits and vegetables and protects the eyes against various diseases. However, it does not protect the eye nearly as well as zeaxanthin, and the presence of lutein in the retina will prevent zeaxanthin uptake.
Additionally, evidence has shown that the lutein present in egg yolk is more readily absorbed than the lutein from vegetable sources, possibly because of fat solubility. At the most basic level, the question "should you eat eggs?" is complex to the point of dismay, including misperceptions about the health effects of cholesterol in egg yolk, and its saturated fat content.
As another example, lycopene is prevalent in tomatoes (and actually is the chemical that gives tomatoes their red color). It is more highly concentrated, however, in processed tomato products such as commercial pasta sauce, or tomato soup, than in fresh "healthy" tomatoes. Such sauces, however, tend to have high amounts of salt, sugar, other substances a person may wish or even need to avoid.
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