Nutrition (also called nourishment or aliment) is the provision, to cells and organisms, of the materials necessary (in the form of food) to support life. Many common health problems can be prevented or alleviated with a healthy diet.
The diet of an organism is what it eats, which is largely determined by the perceived palatability of foods. Dietitians are health professionals who specialize in human nutrition, meal planning, economics, and preparation. They are trained to provide safe, evidence-based dietary advice and management to individuals (in health and disease), as well as to institutions. Clinicalnutritionists are health professionals who focus more specifically on the role of nutrition in chronic disease, including possible prevention or remediation by addressing nutritional deficiencies before resorting to drugs. While government regulation of the use of this professional title is less universal than for “dietician”, the field is supported by many high-level academic programs, up to and including the Doctoral level, and has its own voluntary certificationboard, professional associations, and peer-reviewed journals, e.g. the American Society for Nutrition and the American Journal of Clinical Nutrition.
A poor diet may have an injurious impact on health, causing deficiency diseases such as scurvy andkwashiorkor; health-threatening conditions like obesity and metabolic syndrome; and such common chronic systemic diseases as cardiovascular disease, diabetes, andosteoporosis.
Nutritional science investigates the metabolic and physiological responses of the body to diet. With advances in the fields of molecular biology, biochemistry, nutritional immunology, molecular medicineand genetics, the study of nutrition is increasingly concerned with metabolism and metabolic pathways: the sequences of biochemical steps through which substances in living things change from one form to another.
The human body contains chemical compounds, such as water, carbohydrates (sugar, starch, andfiber), amino acids (in proteins), fatty acids (in lipids), and nucleic acids (DNA and RNA). These compounds in turn consist of elements such as carbon, hydrogen, oxygen, nitrogen, phosphorus,calcium, iron, zinc, magnesium, manganese, and so on. 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 the plant and animal organisms that humans eat.
The human body consists of elements and compounds ingested, digested, absorbed, and circulated through the bloodstream to feed the cells of the body. Except in the unborn fetus, the digestive systemis the first system involved[vague]. In a typical adult, about seven liters of digestive juices enter thelumen of the digestive tract.[clarification needed] These digestive juices break chemical bonds in ingested molecules, and modify their conformations and energy states. Though some molecules are absorbed into the bloodstream unchanged, digestive processes release them from the matrix of foods. Unabsorbed matter, along with some waste products of metabolism, is eliminated from the body in the feces.
Studies of nutritional status must take into account the state of the body before and after experiments, as well as the chemical composition of the whole diet and of all material excreted and eliminated from the body (in urine and feces). Comparing the food to the waste can help determine the specific compounds and elements absorbed and metabolized in the body. The effects of nutrients may only be discernible over an extended period, during which all food and waste must be analyzed. The number ofvariables involved in such experiments is high, making nutritional studies time-consuming and expensive, which explains why the science of human nutrition is still slowly evolving.
In general, eating a wide variety of fresh, whole (unprocessed), foods has proven favorable for one’s health compared to monotonous diets based on processed foods. In particular, the consumption of whole-plant foods slows digestion and allows better absorption, and a more favorable balance of essential nutrients per Calorie, resulting in better management of cell growth, maintenance, and mitosis (cell division), as well as better regulation of appetite and blood sugar. Regularly scheduled meals (every few hours) have also proven more wholesome than infrequent or haphazard ones, although a recent study has also linked more frequent meals with a higher risk of colon cancer in men.
There are six major classes of nutrients: carbohydrates, fats, minerals, protein, vitamins, and water. These nutrient classes can be categorized as either macronutrients (needed in relatively large amounts) or micronutrients (needed in smaller quantities). The macronutrients include carbohydrates (including fiber), fats, protein, and water. The micronutrients are minerals and vitamins. The macronutrients (excluding fiber and water) provide structural material (amino acids from which proteins are built, and lipids from which cell membranes and some signaling molecules are built) and energy. Some of the structural material can be used to generate energy internally, and in either case it is measured in Joules or kilocalories (often called “Calories” and written with a capital C to distinguish them from little ‘c’ calories). Carbohydrates and proteins provide 17 kJ approximately (4 kcal) of energy per gram, while fats provide 37 kJ (9 kcal) per gram., though the net energy from either depends on such factors as absorption and digestive effort, which vary substantially from instance to instance. Vitamins, minerals, fiber, and water do not provide energy, but are required for other reasons. A third class of dietary material, fiber (i.e., non-digestible material such as cellulose), is also required, for both mechanical and biochemical reasons, although the exact reasons remain unclear.
Molecules of carbohydrates and fats consist of carbon, hydrogen, and oxygen atoms. Carbohydrates range from simple monosaccharides (glucose, fructose, galactose) to complex polysaccharides(starch). Fats are triglycerides, made of assorted fatty acid monomers bound to a glycerol backbone. Some fatty acids, but not all, are essential in the diet: they cannot be synthesized in the body. Protein molecules contain nitrogen atoms in addition to carbon, oxygen, and hydrogen. The fundamental components of protein are nitrogen-containing amino acids, some of which are essential in the sense that humans cannot make them internally. Some of the amino acids are convertible (with the expenditure of energy) to glucose and can be used for energy production, just as ordinary glucose, in a process known as gluconeogenesis. By breaking down existing protein, some glucose can be produced internally; the remaining amino acids are discarded, primarily as urea in urine. This occurs normally only during prolonged starvation.
Other micronutrients include antioxidants and phytochemicals, which are said to influence (or protect) some body systems. Their necessity is not as well established as in the case of, for instance, vitamins.
Most foods contain a mix of some or all of the nutrient classes, together with other substances, such as toxins of various sorts. Some nutrients can be stored internally (e.g., the fat soluble vitamins), while others are required more or less continuously. Poor health can be caused by a lack of required nutrients or, in extreme cases, too much of a required nutrient. For example, both salt and water (both absolutely required) will cause illness or even death in excessive amounts.
Carbohydrates may be classified as monosaccharides, disaccharides, or polysaccharides depending on the number of monomer (sugar) units they contain. They constitute a large part of foods such as rice, noodles, bread, and other grain-based products. Monosaccharides, disaccharides, and polysaccharides contain one, two, and three or more sugar units, respectively. Polysaccharides are often referred to as complex carbohydrates because they are typically long, multiple branched chains of sugar units.
Traditionally, simple carbohydrates were believed to be absorbed quickly and therefore to raise blood-glucose levels more rapidly than complex carbohydrates. This, however, is not accurate.Some simple carbohydrates (e.g. fructose) follow different metabolic pathways (e.g. fructolysis) which result in only a partial catabolism to glucose, while many complex carbohydrates may be digested at essentially the same rate as simple carbohydrates. Glucose stimulates the production of insulin through food entering the bloodstream, which is grasped by the beta cells in the pancreas. .
Dietary fiber is a carbohydrate (or a polysaccharide) that is incompletely absorbed in humans and in some animals. Like all carbohydrates, when it is metabolized it can produce four Calories (kilocalories) of energy per gram. However, in most circumstances it accounts for less than that because of its limited absorption and digestibility. Dietary fiber consists mainly of cellulose, a large carbohydrate polymer that is indigestible because humans do not have the required enzymes to disassemble it. There are two subcategories: soluble and insoluble fiber. Whole grains, fruits (especially plums, prunes, and figs), and vegetables are good sources of dietary fiber. There are many health benefits of a high-fiber diet. Dietary fiber helps reduce the chance of gastrointestinal problems such as constipation and diarrhea by increasing the weight and size of stool and softening it. Insoluble fiber, found in whole wheat flour, nuts and vegetables, especially stimulates peristalsis – the rhythmic muscular contractions of the intestines which move food along the digestive tract. Soluble fiber, found in oats, peas, beans, and many fruits, dissolves in water in the intestinal tract to produce a gel which slows the movement of food through the intestines. This may help lower blood glucose levels because it can slow the absorption of sugar. Additionally, fiber, perhaps especially that from whole grains, is thought to possibly help lessen insulin spikes, and therefore reduce the risk of type 2 diabetes. The link between increased fiber consumption and a decreased risk of colorectal cancer is still uncertain. 
A molecule of dietary fat typically consists of several fatty acids (containing long chains of carbon and hydrogen atoms), bonded to a glycerol. They are typically found as triglycerides (three fatty acids attached to one glycerol backbone). Fats may be classified as saturated or unsaturated depending on the detailed structure of the fatty acids involved. Saturated fats have all of the carbon atoms in their fatty acid chains bonded to hydrogen atoms, whereas unsaturated fats have some of these carbon atoms double-bonded, so their molecules have relatively fewer hydrogen atoms than a saturated fatty acid of the same length. Unsaturated fats may be further classified as monounsaturated (one double-bond) or polyunsaturated (many double-bonds). Furthermore, depending on the location of the double-bond in the fatty acid chain, unsaturated fatty acids are classified as omega-3 or omega-6 fatty acids.Trans fats are a type of unsaturated fat with trans-isomer bonds; these are rare in nature and in foods from natural sources; they are typically created in an industrial process called (partial) hydrogenation. There are nine kilocalories in each gram of fat. Fatty acids such as conjugated linoleic acid, catalpic acid, eleostearic acid and punicic acid, in addition to providing energy, represent potent immune modulatory molecules.
Saturated fats (typically from animal sources) have been a staple in many world cultures for millennia. Unsaturated fats (e. g., vegetable oil) are considered healthier, while trans fats are to be avoided. Saturated and some trans fats are typically solid at room temperature (such as butter or lard), while unsaturated fats are typically liquids (such as olive oil or flaxseed oil). Trans fats are very rare in nature, and have been shown to be highly detrimental to human health, but have properties useful in the food processing industry, such as rancidity resistance.
Most fatty acids are non-essential, meaning the body can produce them as needed, generally from other fatty acids and always by expending energy to do so. However, in humans, at least two fatty acids are essential and must be included in the diet. An appropriate balance of essential fatty acids—omega-3 and omega-6 fatty acids—seems also important for health, although definitive experimental demonstration has been elusive. Both of these “omega” long-chain polyunsaturated fatty acids aresubstrates for a class of eicosanoids known as prostaglandins, which have roles throughout the human body. They are hormones, in some respects. The omega-3 eicosapentaenoic acid (EPA), which can be made in the human body from the omega-3 essential fatty acid alpha-linolenic acid(ALA), or taken in through marine food sources, serves as a building block for series 3 prostaglandins (e.g. weakly inflammatory PGE3). The omega-6 dihomo-gamma-linolenic acid (DGLA) serves as a building block for series 1 prostaglandins (e.g. anti-inflammatory PGE1), whereas arachidonic acid (AA) serves as a building block for series 2 prostaglandins (e.g. pro-inflammatory PGE 2). Both DGLA and AA can be made from the omega-6 linoleic acid (LA) in the human 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 is one reason why a balance between omega-3 and omega-6 is believed important for cardiovascular health. In industrialized societies, people typically consume large amounts of processed vegetable oils, which have reduced amounts of the essential fatty acids along with too much of omega-6 fatty acids relative to omega-3 fatty acids.
The conversion rate of omega-6 DGLA to AA largely determines the production of the 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). The amount and type of carbohydrates consumed, along with some types of amino acid, can influence processes involving insulin, glucagon, and other hormones; therefore the ratio of omega-3 versus omega-6 has wide effects on general health, and specific effects on immune function and inflammation, and mitosis (i.e. cell division).
Proteins are the basis of many animal body structures (e.g. muscles, skin, and hair). They also form the enzymes that control chemical reactions throughout the body. Each molecule is composed of amino acids, which are characterized by inclusion of nitrogen and sometimes sulphur (these components are responsible for the distinctive smell of burning protein, such as the keratin in hair). The body requires amino acids to produce new proteins (protein retention) and to replace damaged proteins (maintenance). As there is no protein or amino acid storage provision, amino acids must be present in the diet. Excess amino acids are discarded, typically in the urine. For all animals, some amino acids are essential (an animal cannot produce them internally) and some are non-essential (the animal can produce them from other nitrogen-containing compounds). About twenty amino acids are found in the human body, and about ten of these are essential and, therefore, must be included in the diet. A diet that contains adequate amounts of amino acids (especially those that are essential) is particularly important in some situations: during early development and maturation, pregnancy, lactation, or injury (a burn, for instance). A complete protein source contains all the essential amino acids; an incompleteprotein source lacks one or more of the essential amino acids.
It is possible to combine two incomplete protein sources (e.g. rice and beans) to make a complete protein source, and characteristic combinations are the basis of distinct cultural cooking traditions. However, complementary sources of protein don’t need to be eaten at the same meal to be used together by the body. Sources of dietary protein include meats, tofu and other soy-products, eggs,legumes, and dairy products such as milk and cheese. Excess amino acids from protein can be converted into glucose and used for fuel through a process called gluconeogenesis. The amino acids remaining after such conversion are discarded.
Dietary minerals are the chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen that are present in nearly all organic molecules. The term “mineral” is archaic, since the intent is to describe simply the less common elements in the diet. Some are heavier than the four just mentioned, including several metals, which often occur as ions in the body. Some dietitians recommend that these be supplied from foods in which they occur naturally or at least as complex compounds, or sometimes even from natural inorganic sources (such as calcium carbonate from ground oyster shells). Some minerals are absorbed much more readily in the ionic forms found in such sources. On the other hand, minerals are often artificially added to the diet as supplements; the most famous is likely iodine in iodized salt which prevents goiter.
Many elements are essential in relative quantity; they are usually called “bulk minerals”. Some are structural, but many play a role as electrolytes. Elements with recommended dietary allowance (RDA) greater than 200 mg/day are, in alphabetical order (with informal or folk-medicine perspectives in parentheses):
- Calcium, a common electrolyte, but also needed structurally (for muscle and digestive system health, bone strength, some forms neutralize acidity, may help clear toxins, provides signaling ions for nerve and membrane functions)
- Chlorine as chloride ions; very common electrolyte; see sodium, below
- Magnesium, required for processing ATP and related reactions (builds bone, causes strong peristalsis, increases flexibility, increases alkalinity)
- Phosphorus, required component of bones; essential for energy processing
- Potassium, a very common electrolyte (heart and nerve health)
- Sodium, a very common electrolyte; not generally found in dietary supplements, despite being needed in large quantities, because the ion is very common in food: typically as sodium chloride, or common salt. Excessive sodium consumption can deplete calcium andmagnesium,[verification needed] leading to high blood pressure and osteoporosis.
- Sulfur, for three essential amino acids and therefore many proteins (skin, hair, nails, liver, and pancreas). Sulfur is not consumed alone, but in the form of sulfur-containing amino acids
- Cobalt required for biosynthesis of vitamin B12 family of coenzymes. Animals cannot biosynthesize B12, and must obtain this cobalt-containing vitamin in the diet
- Copper required component of many redox enzymes, including cytochrome c oxidase
- Chromium required for sugar metabolism
- Iodine required not only for the biosynthesis of thyroxine, but probably, for other important organs as breast, stomach, salivary glands, thymus etc. (see Extrathyroidal iodine); for this reason iodine is needed in larger quantities than others in this list, and sometimes classified with the macrominerals
- Iron required for many enzymes, and for hemoglobin and some other proteins
- Manganese (processing of oxygen)
- Molybdenum required for xanthine oxidase and related oxidases
- Nickel present in urease
- Selenium required for peroxidase (antioxidant proteins)
- Vanadium (Speculative: there is no established RDA for vanadium. No specific biochemical function has been identified for it in humans, although vanadium is required for some lower organisms.)
- Zinc required for several enzymes such as carboxypeptidase, liver alcohol dehydrogenase, andcarbonic anhydrase
As with the minerals discussed above, some vitamins are recognized as essential nutrients, necessary in the diet for good health. (Vitamin D is the exception: it can be synthesized in the skin, in the presence of UVB radiation.) Certain vitamin-like compounds that are recommended in the diet, such as carnitine, are thought useful for survival and health, but these are not “essential” dietary nutrients because the human body has some capacity to produce them from other compounds. Moreover, thousands of different phytochemicals have recently been discovered in food (particularly in fresh vegetables), which may have desirable properties including antioxidant activity (see below); however, experimental demonstration has been suggestive but inconclusive. Other essential nutrients that are not classified as vitamins include essential amino acids (see above), choline, essential fatty acids (see above), and the minerals discussed in the preceding section.
Vitamin deficiencies may result in disease conditions, including goitre, scurvy, osteoporosis, impairedimmune system, disorders of cell metabolism, certain forms of cancer, symptoms of premature aging, and poor psychological health (including eating disorders), among many others. Excess levels of some vitamins are also dangerous to health (notably vitamin A), and for at least one vitamin, B6, toxicity begins at levels not far above the required amount. Deficient or excess levels of minerals can also have serious health consequences.
Water is excreted from the body in multiple forms; including urine and feces, sweating, and by water vapour in the exhaled breath. Therefore it is necessary to adequately rehydrate to replace lost fluids.
Early recommendations for the quantity of water required for maintenance of good health suggested that 6–8 glasses of water daily is the minimum to maintain proper hydration. However the notion that a person should consume eight glasses of water per day cannot be traced to a credible scientific source. The original water intake recommendation in 1945 by the Food and Nutrition Board of the National Research Council read: “An ordinary standard for diverse persons is 1 milliliter for each calorie of food. Most of this quantity is contained in prepared foods.” More recent comparisons of well-known recommendations on fluid intake have revealed large discrepancies in the volumes of water we need to consume for good health.Therefore, to help standardize guidelines, recommendations for water consumption are included in two recent European Food Safety Authority (EFSA) documents (2010): (i) Food-based dietary guidelines and (ii) Dietary reference values for water or adequate daily intakes (ADI). These specifications were provided by calculating adequate intakes from measured intakes in populations of individuals with “desirable osmolarity values of urine and desirable water volumes per energy unit consumed.” For healthful hydration, the current EFSA guidelines recommend total water intakes of 2.0 L/day for adult females and 2.5 L/day for adult males. These reference values include water from drinking water, other beverages, and from food. About 80% of our daily water requirement comes from the beverages we drink, with the remaining 20% coming from food. Water content varies depending on the type of food consumed, with fruit and vegetables containing more than cereals, for example. These values are estimated using country-specific food balance sheets published by the Food and Agriculture Organisation of the United Nations. Other guidelines for nutrition also have implications for the beverages we consume for healthy hydration- for example, the World Health Organization (WHO) recommend that added sugars should represent no more than 10% of total energy intake.
The EFSA panel also determined intakes for different populations. Recommended intake volumes in the elderly are the same as for adults as despite lower energy consumption, the water requirement of this group is increased due to a reduction in renal concentrating capacity. Pregnant andbreastfeeding women require additional fluids to stay hydrated. The EFSA panel proposes that pregnant women should consume the same volume of water as non-pregnant women, plus an increase in proportion to the higher energy requirement, equal to 300 mL/day. To compensate for additional fluid output, breastfeeding women require an additional 700 mL/day above the recommended intake values for non-lactating women.
For those who have healthy kidneys, it is somewhat difficult to drink too much water, but (especially in warm humid weather and while exercising) it is dangerous to drink too little. While overhydration is much less common than dehydration, it is also possible to drink far more water than necessary which can result in water intoxication, a serious and potentially fatal condition. In particular, large amounts of de-ionized water are dangerous.
Other micronutrients include antioxidants and phytochemicals. These substances are generally more recent discoveries that have not yet been recognized as vitamins or as required. Phytochemicals may act as antioxidants, but not all phytochemicals are antioxidants.
As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as free radicals can form. Most of these are oxidizers (i.e. acceptors of electrons) and some react very strongly. For the continued normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds. Recently, some researchers suggested an interesting theory of evolution of dietary antioxidants. Some are produced by the human body with adequate precursors (glutathione, Vitamin C), and those the body cannot produce may only be obtained in the diet via 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). Phytochemicals (Section Below) and their subgroup, polyphenols, make up the majority of antioxidants; about 4,000 are known. Different antioxidants are now known to function in a cooperative network. For example, Vitamin C can reactivate free radical-containing glutathione or Vitamin E by accepting the free radical itself. 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.
Although initial studies suggested that antioxidant supplements might promote health, later large clinical trials did not detect any benefit and suggested instead that excess supplementation may be harmful. Blackberries are a source of polyphenol antioxidants
A growing area of interest is the effect upon human health of trace chemicals, collectively called phytochemicals. These nutrients are typically found in edible plants, especially colorful fruits and vegetables, but also other organisms including seafood, algae, and fungi. The effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. One of the principal classes of phytochemicals are polyphenol antioxidants, chemicals that 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 incardiovascular 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).[better source needed] Less rigorous studies have proposed a correlation between zeaxanthin intake and cataracts.[better source needed] 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 carotenoid, 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.
As indicated above, some of the correlations between the ingestion of certain phytochemicals and the prevention of disease are, in some cases, enormous in magnitude. Yet, 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. Yet, such sauces tend to have high amounts of salt, sugar, other substances a person may wish or even need to avoid.
The following table presents phytochemical groups and common sources, arranged by family:
|Flavonoids||Berries, herbs, vegetables,wine, grapes, tea||General antioxidant, oxidation of LDLs, prevention ofarteriosclerosis and heart disease|
|Isoflavones(phytoestrogens)||Soy, red clover, kudzu root||General antioxidant, prevention of arteriosclerosisand heart disease, easing symptoms of menopause,cancer prevention |
|Isothiocyanates||Cruciferous vegetables||cancer prevention|
|Monoterpenes||Citrus peels, essential oils,herbs, spices, green plants,atmosphere||Cancer prevention, treating gallstones|
|Organosulfur compounds||Chives, garlic, onions||cancer prevention, lowered LDLs, assistance to theimmune system|
|Saponins||Beans, cereals, herbs||Hypercholesterolemia, Hyperglycemia, Antioxidant,cancer prevention, Anti-inflammatory|
|Capsaicinoids||Chili peppers||Topical pain relief, cancer prevention, cancer cellapoptosis|
It is now also known that animal intestines contain a large population of gut flora. In humans, these include species such as Bacteroides, L. acidophilus and E. coli, among many others. They are essential to digestion, and are also affected by the food we eat. Bacteria in the gut perform many important functions for humans, including breaking down and aiding in the absorption of otherwise indigestible food; stimulating cell growth; repressing the growth of harmful bacteria, training the immune system to respond only to pathogens; producing vitamin B12, and defending against some infectious diseases.
In the US, dietitians are registered (RD) or licensed (LD) with the Commission for Dietetic Registration and the American Dietetic Association, and are only able to use the title “dietitian,” as described by the business and professions codes of each respective state, when they have met specific educational and experiential prerequisites and passed a national registration or licensure examination, respectively. In California, registered dietitians must abide by the “Business and Professions Code of Section 2585-2586.8”.Anyone may call themselves a nutritionist, including unqualified dietitians, as this term is unregulated. Some states, such as the State of Florida, have begun to include the title “nutritionist” in state licensure requirements. Most governments provide guidance on nutrition, and some also impose mandatory disclosure/labeling requirements for processed food manufacturers and restaurants to assist consumers in complying with such guidance.
In the US, nutritional standards and recommendations are established jointly by the US Department of Agriculture and US Department of Health and Human Services. Dietary and physical activity guidelines from the USDA are presented in the concept of a food pyramid, which superseded the Four Food Groups. The Senate committee currently responsible for oversight of the USDA is the Agriculture, Nutrition and Forestry Committee. Committee hearings are often televised on C-SPAN as seen here.
The U.S. Department of Health and Human Services provides a sample week-long menu which fulfills the nutritional recommendations of the government. Canada’s Food Guide is another governmental recommendation.
Federal and state governmental organizations have been working on nutrition literacy interventions in non-primary health care settings to address the nutrition information problem in the U.S. Some programs include:
The Family Nutrition Program (FNP) is a free nutrition education program serving low-income adults around the U.S. This program is funded by the Food Nutrition Service’s (FNS) branch of the United States Department of Agriculture (USDA) usually through a local state academic institution which runs the program. The FNP has developed a series of tools to help families participating in the Food Stamp Program stretch their food dollar and form healthful eating habits including nutrition education.
Expanded Food and Nutrition Education Program (ENFEP) is a unique program that currently operates in all 50 states and in American Samoa, Guam, Micronesia, Northern Marianas, Puerto Rico, and the Virgin Islands. It is designed to assist limited-resource audiences in acquiring the knowledge, skills, attitudes, and changed behavior necessary for nutritionally sound diets, and to contribute to their personal development and the improvement of the total family diet and nutritional well-being.
An example of a state initiative to promote nutrition literacy is Smart Bodies, a public-private partnership between the state’s largest university system and largest health insurer, Louisiana State Agricultural Center and Blue Cross and Blue Shield of Louisiana Foundation. Launched in 2005, this program promotes lifelong healthful eating patterns and physically active lifestyles for children and their families. It is an interactive educational program designed to help prevent childhood obesity through classroom activities that teach children healthful eating habits and physical exercise.
Nutrition is taught in schools in many countries. In England and Wales the Personal and Social Education and Food Technology curricula include nutrition, stressing the importance of a balanced diet and teaching how to read nutrition labels on packaging. In many schools a Nutrition class will fall within the Family and Consumer Science or Health departments. In some American schools, students are required to take a certain number of FCS or Health related classes. Nutrition is offered at many schools, and if it is not a class of its own, nutrition is included in other FCS or Health classes such as: Life Skills, Independent Living, Single Survival, Freshmen Connection, Health etc. In many Nutrition classes, students learn about the food groups, the food pyramid, Daily Recommended Allowances, calories, vitamins, minerals, malnutrition, physical activity, healthful food choices and how to live a healthy life.
A 1985 US National Research Council report entitled Nutrition Education in US Medical Schoolsconcluded that nutrition education in medical schools was inadequate. Only 20% of the schools surveyed taught nutrition as a separate, required course. A 2006 survey found that this number had risen to 30%.
Heart disease, cancer, obesity, and diabetes are commonly called “Western” diseases because these maladies were once rarely seen in developing countries. An international study in China found some regions had essentially no cancer or heart disease, while in other areas they reflected “up to a 100-fold increase” coincident with shifts from diets that were found to be entirely plant-based to heavily animal-based, respectively. In contrast, diseases of affluence like cancer and heart disease are common throughout the developed world, including the United States. Adjusted for age and exercise, large regional clusters of people in China rarely suffered from these “Western” diseases possibly because their diets are rich in vegetables, fruits and whole grains, and have little dairy and meat products.Some studies show these to be, in high quantities, possible causes of some cancers. There are arguments for and against this controversial issue.
The United Healthcare/Pacific are nutrition guideline recommends a whole plant food diet, and recommends using protein only as a condiment with meals. A National Geographic cover article from November 2005, entitled The Secrets of Living Longer, also recommends a whole plant food diet. The article is a lifestyle survey of three populations, Sardinians, Okinawans, and Adventists, who generally display longevity and “suffer a fraction of the diseases that commonly kill people in other parts of the developed world, and enjoy more healthy years of life.” In sum, they offer three sets of ‘best practices’ to emulate. The rest is up to you. In common with all three groups is to “Eat fruits, vegetables, and whole grains.”
The National Geographic article noted that an NIH funded study of 34,000 Seventh-day Adventists between 1976 and 1988 “…found that the Adventists’ habit of consuming beans, soy milk, tomatoes, and other fruits lowered their risk of developing certain cancers. It also suggested that eating whole grain bread, drinking five glasses of water a day, and, most surprisingly, consuming four servings of nuts a week reduced their risk of heart disease.”
The French paradox is the observation that the French suffer a relatively low incidence of coronary heart disease, despite having a diet relatively rich in saturated fats. A number of explanations have been suggested:
- Saturated fat consumption does not cause heart disease
- Reduced consumption of processed carbohydrate and other junk foods.
- Regular consumption of red wine.
- More active lifestyles involving plenty of daily exercise, especially walking; the French are much less dependent on cars than Americans are.
- Higher consumption of artificially produced trans-fats by Americans, which has been shown to have greater lipoprotein effects per gram than saturated fat.
However, statistics collected by the World Health Organization from 1990–2000 show that the incidence of heart disease in France may have been underestimated and, in fact, may be similar to that of neighboring countries.
Protein milkshakes, made from protein powder (center) and milk (left), are a common bodybuilding supplement.
Protein is an important component of every cell in the body. Hair and nails are mostly made of protein. The body uses protein to build and repair tissues. In addition, protein is used to make hormones and other chemicals in the body. Protein is also an important building block of bones, muscles, cartilage, skin, and blood.
The protein requirement for each individual differs, as do opinions about whether and to what extent physically active people require more protein. The 2005 Recommended Dietary Allowances (RDA), aimed at the general healthy adult population, provide for an intake of 0.8 – 1 grams of protein per kilogram of body weight (according to the BMI formula), with the review panel stating that “no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise”. Conversely, Di Pasquale (2008), citing recent studies, recommends a minimum protein intake of 2.2 g/kg “for anyone involved in competitive or intense recreational sports who wants to maximize lean body mass but does not wish to gain weight”.
Water and salts
Water is one of the most important nutrients in the sports diet. It helps eliminate food waste products in the body, regulates body temperature during activity and helps with digestion. Maintaining hydration during periods of physical exertion is key to peak performance. While drinking too much water during activities can lead to physical discomfort, dehydration in excess of 2% of body mass (by weight) markedly hinders athletic performance. Additional carbohydrates and protein before, during, and after exercise increase time to exhaustion as well as speed recovery. The amount of water needed is based on work performed, lean body mass, and environmental factors, especially ambient temperature and humidity. Maintaining the right amount is key.[vague]
The main fuel used by the body during exercise is carbohydrates, which are stored in muscle as glycogen—a form of sugar. During exercise, muscle glycogen reserves can be used up, especially when activities last longer than 90 min. Because the amount of glycogen stored in the body is limited, it is important for athletes to replace glycogen by consuming a diet high in carbohydrates. Meeting energy needs can help improve performance during the sport, as well as improve overall strength and endurance.
At the time of this entry, we were not able to identify any specific nutrition literacy studies in the U.S. at a national level. However, the findings of the 2003 National Assessment of Adult Literacy (NAAL) provide a basis upon which to frame the nutrition literacy problem in the U.S. NAAL introduced the first ever measure of “the degree to which individuals have the capacity to obtain, process and understand basic health information and services needed to make appropriate health decisions,” – an objective of Healthy People 2010  and of which nutrition literacy might be considered an important subset. On a scale of below basic, basic, intermediate and proficient, NAAL found 13 percent of adult Americans have proficient health literacy, 44% have intermediate literacy, 29 percent have basic literacy and 14 percent have below basic health literacy. The study found that health literacy increases with education and people living below the level of poverty have lower health literacy then those above it.
Another study examining the health and nutrition literacy status of residents of the lower Mississippi Delta found that 52 percent of participants had a high likelihood of limited literacy skills. While a precise comparison between the NAAL and Delta studies is difficult, primarily because of methodological differences, Zoellner et al. suggest that health literacy rates in the Mississippi Delta region are different from the U.S. general population and that they help establish the scope of the problem of health literacy among adults in the Delta region. For example, only 12 percent of study participants identified the My Pyramid graphic two years after it had been launched by the USDA. The study also found significant relationships between nutrition literacy and income level and nutrition literacy and educational attainment further delineating priorities for the region.
These statistics point to the complexities surrounding the lack of health/nutrition literacy and reveal the degree to which they are embedded in the social structure and interconnected with other problems. Among these problems are the lack of information about food choices, the lack of understanding nutritional information and its application to individual circumstances, limited or difficult access to healthful foods, and a range of cultural influences and socioeconomic constraints such as low levels of education and high levels of poverty that decrease opportunities for healthful eating and living.
The links between low health literacy and poor health outcomes has been widely documented and there is evidence that some interventions to improve health literacy have produced successful results in the primary care setting. More must be done to further our understanding of nutrition literacy specific interventions in non-primary care settings in order to achieve better health outcomes.
Malnutrition refers to insufficient, excessive, or imbalanced consumption of nutrients by an organism. In developed countries, the diseases of malnutrition are most often associated with nutritional imbalances or excessive consumption.
Although there are more organisms in the world who are malnourished due to insufficient consumption, increasingly more organisms suffer from excessive over-nutrition; a problem caused by an over abundance of sustenance coupled with the instinctual desire (by animals in particular) to consume all that it can.
Nutritionism is the view that excessive reliance on food science and the study of nutrition can, paradoxically, lead to poor nutrition and to ill health. It was originally credited to Gyorgy Scrinis,and was popularized by Michael Pollan. Since nutrients are invisible, policy makers rely on nutrition experts to advise on food choices. Because science has an incomplete understanding of how food affects the human body, Pollan argues, nutritionism can be blamed for many of the health problems relating to diet in the Western World today.
Under consumption generally refers to the long-term consumption of insufficient sustenance in relation to the energy that an organism expends or expels, leading to poor health.
Over consumption generally refers to the long-term consumption of excess sustenance in relation to the energy that an organism expends or expels, leading to poor health and, in animals, obesity. It can cause excessive hair loss, brittle nails, and irregular premenstrual cycles for females
When too much of one or more nutrients is present in the diet to the exclusion of the proper amount of other nutrients, the diet is said to be unbalanced.
Illnesses caused by improper nutrient consumption
Research indicates that improving the awareness of nutritious meal choices and establishing long-term habits of healthful eating have a positive effect on cognitive and spatial memory capacity, potentially increasing a student’s potential to process and retain academic information.
Some organizations have begun working with teachers, policymakers, and managed foodservice contractors to mandate improved nutritional content and increased nutritional resources in school cafeterias from primary to university level institutions. Health and nutrition have been proven to have close links with overall educational success. Currently, less than 10% of American college students report that they eat the recommended five servings of fruit and vegetables daily. Better nutrition has been shown to have an impact on both cognitive and spatial memory performance; a study showed those with higher blood sugar levels performed better on certain memory tests. In another study, those who consumed yogurt performed better on thinking tasks when compared to those who consumed caffeine free diet soda or confections. Nutritional deficiencies have been shown to have a negative effect on learning behavior in mice as far back as 1951.
“Better learning performance is associated with diet induced effects on learning and memory ability”.
The “nutrition-learning nexus” demonstrates the correlation between diet and learning and has application in a higher education setting.
“We find that better nourished children perform significantly better in school, partly because they enter school earlier and thus have more time to learn but mostly because of greater learning productivity per year of schooling.”
91% of college students feel that they are in good health while only 7% eat their recommended daily allowance of fruits and vegetables.
More “engaged” learning models that encompass nutrition is an idea that is picking up steam at all levels of the learning cycle.
There is limited research available that directly links a student’s Grade Point Average (G.P.A.) to their overall nutritional health. Additional substantive data is needed to prove that overall intellectual health is closely linked to a person’s diet, rather than just another correlation fallacy.
Nutritional supplement treatment may be appropriate for major depression, bipolar disorder,schizophrenia, and obsessive compulsive disorder, the four most common mental disorders in developed countries. Supplements that have been studied most for mood elevation and stabilization include eicosapentaenoic acid and docosahexaenoic acid (each of which are an omega-3 fatty acidcontained in fish oil, but not in flaxseed oil), vitamin B12, folic acid, and inositol.
Cancer is now common in developing countries. According to a study by the International Agency for Research on Cancer, “In the developing world, cancers of the liver, stomach and esophagus were more common, often linked to consumption of carcinogenic preserved foods, such as smoked or salted food, and parasitic infections that attack organs.” Lung cancer rates are rising rapidly in poorer nations because of increased use of tobacco. Developed countries “tended to have cancers linked to affluence or a ‘Western lifestyle’ — cancers of the colon, rectum, breast and prostate — that can be caused by obesity, lack of exercise, diet and age.”
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-calledmetabolic 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 overweight 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 overweight 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 a debate about how and to what extent different dietary factors— such as 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 indexand 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).
Excess water intake, without replenishment of sodium and potassium salts, leads to hyponatremia, which can further lead to water intoxication at more dangerous levels. A well-publicized case occurred in 2007, when Jennifer Strange died while participating in a water-drinking contest. More usually, the condition occurs in long-distance endurance events (such as marathon or triathlon competition and training) and causes gradual mental dulling, headache, drowsiness, weakness, and confusion; extreme cases may result in coma, convulsions, and death. The primary damage comes from swelling of the brain, caused by increased osmosis as blood salinity decreases. Effective fluid replacement techniques include water aid stations during running/cycling races, trainers providing water during team games, such as soccer, and devices such as Camel Baks, which can provide water for a person without making it too hard to drink the water.
Antinutrients are natural or synthetic compounds that interfere with the absorption of nutrients. Nutrition studies focus on antinutrients commonly found in food sources and beverages.
Since the Industrial Revolution some two hundred years ago, the food processing industry has invented many technologies that both help keep foods fresh longer and alter the fresh state of food as they appear in nature. Cooling is the primary technology used to maintain freshness, whereas many more technologies have been invented to allow foods to last longer without becoming spoiled. These latter technologies include pasteurisation, autoclavation, drying, salting, and separation of various components, all of which appear to alter the original nutritional contents of food. Pasteurisation and autoclavation (heating techniques) have no doubt improved the safety of many common foods, preventing epidemics of bacterial infection. But some of the (new) food processing technologies undoubtedly have downfalls as well.
Modern separation techniques such as milling, centrifugation, and pressing have enabled concentration of particular components of food, yielding flour, oils, juices and so on, and even separate fatty acids, amino acids, vitamins, and minerals. Inevitably, such large scale concentration changes the nutritional content of food, saving certain nutrients while removing others. Heating techniques may also reduce food’s content of many heat-labile nutrients such as certain vitamins and phytochemicals, and possibly other yet to be discovered substances. Because of reduced nutritional value, processed foods are often ‘enriched’ or ‘fortified’ with some of the most critical nutrients (usually certain vitamins) that were lost during processing. Nonetheless, processed foods tend to have an inferior nutritional profile compared to whole, fresh foods, regarding content of both sugar and high GI starches, potassium/sodium, vitamins, fiber, and of intact, unoxidized (essential) fatty acids. In addition, processed foods often contain potentially harmful substances such as oxidized fats and trans fatty acids.
A dramatic example of the effect of food processing on a population’s health is the history of epidemics of beri-beri in people subsisting on polished rice. Removing the outer layer of rice by polishing it removes with it the essential vitamin thiamine, causing beri-beri. Another example is the development of scurvy among infants in the late 19th century in the United States. It turned out that the vast majority of sufferers were being fed milk that had been heat-treated (as suggested by Pasteur) to control bacterial disease. Pasteurisation was effective against bacteria, but it destroyed the vitamin C.
As mentioned, lifestyle- and obesity-related diseases are becoming increasingly prevalent all around the world. There is little doubt that the increasingly widespread application of some modern food processing technologies has contributed to this development. The food processing industry is a major part of modern economy, and as such it is influential in political decisions (e.g. nutritional recommendations, agricultural subsidising). In any known profit-driven economy, health considerations are hardly a priority; effective production of cheap foods with a long shelf-life is more the trend. In general, whole, fresh foods have a relatively short shelf-life and are less profitable to produce and sell than are more processed foods. Thus, the consumer is left with the choice between more expensive, but nutritionally superior, whole, fresh foods, and cheap, usually nutritionally inferior, processed foods. Because processed foods are often cheaper, more convenient (in both purchasing, storage, and preparation), and more available, the consumption of nutritionally inferior foods has been increasing throughout the world along with many nutrition-related health complications.
- ^ Clinical Nutrition Certification Board. Cncb.org. Retrieved on 2011-10-17.
- ^ Linus Pauling Institute at Oregon State University. Lpi.oregonstate.edu (2001-06-15). Retrieved on 2011-10-17.
- ^ Kwashiorkor: MedlinePlus Medical Encyclopedia. Nlm.nih.gov (2011-10-13). Retrieved on 2011-10-17.
- ^ Obesity, Weight Linked to Prostate Cancer Deaths – National Cancer Institute. Cancer.gov. Retrieved on 2011-10-17.
- ^ Obesity and Overweight for Professionals: Causes | DNPAO | CDC. Cdc.gov (2011-05-16). Retrieved on 2011-10-17.
- ^ Metabolic syndrome – PubMed Health. Ncbi.nlm.nih.gov. Retrieved on 2011-10-17.
- ^ Omega 3 Fatty Acid Deficiency – 11 Signs of Omega 3 Fatty Acid Deficiency. Bodybuildingforyou.com. Retrieved on 2011-10-17.
- ^ Omega-3 fatty acids. Umm.edu (2011-10-05). Retrieved on 2011-10-17.
- ^ What I need to know about Eating and Diabetes – National Diabetes Information Clearinghouse. Diabetes.niddk.nih.gov. Retrieved on 2011-10-17.
- ^ Diabetes Diet and Food Tips: Eating to Prevent and Control Diabetes. Helpguide.org. Retrieved on 2011-10-17.
- ^ Osteoporosis & Vitamin D: Deficiency, How Much, Benefits, and More. Webmd.com (2005-07-07). Retrieved on 2011-10-17.
- ^ Dietary Supplement Fact Sheet: Vitamin D. Ods.od.nih.gov. Retrieved on 2011-10-17.
- ^ “Osteoporosis Linked to Vitamin D Deficiency”. The New York Times.
- ^ “Making the Transition to Whole Foods”[dead link]
- ^ Researchers Look at How Frequency of Meals May Affect Health / February 15, 2008 / News from the USDA Agricultural Research Service. Ars.usda.gov. Retrieved on 2011-10-17.
- ^ More Meals Per Day May Up Men’s Colon Cancer Risk. Prevent Disease.com. Retrieved on 2011-10-17.
- ^ Berg J, Tymoczko JL, Stryer L (2002).Biochemistry (5th ed.). San Francisco: W.H. Freeman. p. 603. ISBN 0-7167-4684-0.
- ^ “Strange but True: Drinking Too Much Water Can Kill”. Scientific American. June 21, 2007.
- ^ “Can shipwrecked men survive if they drink sea water?”. Natural History Magazine.
- ^ Otto, H (1973). Diabetik Bei Diabetus Mellitus. Bern: Verlag Hans Huber.
- ^ Crapo, P; Reaven, Olefsky (1977). “Postprandial plasma-glucose and -insulin responses to different complex carbohydrates”. Diabetes 26 (12): 1178–1183.doi:10.2337/diabetes.26.12.1178.PMID 590639.
- ^ Crapo, P; Kolterman, Waldeck, Reaven, Olefsky (1980). “Postprandial hormonal responses to different types of complex carbohydrate in individuals with impaired glucose tolerance”. Am J Clin Nutr 33 (8): 1723–1728. PMID 6996472.
- ^ Jenkins, David; Alexandra L. Jenkins, Thomas M.S. Wolever, MD, Lilian H. Thompson, PhD, and A. Venkat Rao, PhD (February 1986). “Simple and complex carbohydrates”. Nutritional Reviews 44 (2): 44–49.
- ^ “The Nutrition Source: Carbohydrates”. Harvard School of Public Health. Retrieved 2011-07-07.
- ^ Anonymous,  ,“forecast: NUTRITION” ,
- ^ “Dietary fiber: Essential for a healthy diet – MayoClinic.com”. MayoClinic.com. Retrieved 2010-05-02.
- ^ Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets. JADA, 2003; 103(6) 748 – 765.
- ^ Nelson, D. L.; Cox, M. M. (2000). Lehninger Principles of Biochemistry (3rd ed.). New York: Worth Publishing. ISBN 1-57259-153-6.
- ^ D. E. C. Corbridge (1995). Phosphorus: An Outline of its Chemistry, Biochemistry, and Technology (5th ed.). Amsterdam: Elsevier.ISBN 0-444-89307-5.
- ^ Lippard, S. J. and Berg, J. M. (1994).Principles of Bioinorganic Chemistry. Mill Valley, CA: University Science Books.
- ^ Shils et al. (2005). Modern Nutrition in Health and Disease. Lippincott Williams and Wilkins. ISBN 0-7817-4133-5.
- ^ “Healthy Water Living”. BBC. Retrieved 2007-02-01. Archived from the original on 2007-01-01.
- ^ “Drink at least eight glasses of water a day.” Really? Is there scientific evidence for “8 × 8”? by Heinz Valdin, Department of Physiology, Dartmouth Medical School, Lebanon, New Hampshire
- ^ Food and Nutrition Board, National Academy of Sciences. Recommended Dietary Allowances, revised 1945. National Research Council, Reprint and Circular Series, No. 122, 1945 (Aug), p. 3-18.
- ^ Le Bellego L, Jean C, Jiménez L, Magnani C, Tang W, Boutrolle I. Understanding fluid consumption patterns to improve healthy hydration. Nutr Today. 2010;45(S6):S22-S26.
- ^ a b c d e f g “Scientific Opinion on Dietary Reference Values for Water” EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA). EFSA Journal 2010;8(3):1459. Retrieved 2011-02-21.
- ^ Armstrong LE, Pumerantz AC, Roti MW, Judelson DA, Watson G, Dias JC, Sokmen B, Casa DJ, Maresh CM et al. (2005). “Fluid, electrolyte, and renal indices of hydration during 11 days of controlled caffeine consumption”. Int J Sport Nutr Exerc Metab 15(3): 252–65. PMID 16131696.
- ^ a b “FAO Corporate Document Repository. Food Balance Sheets- A Handbook.”Retrieved 2011-03-07
- ^ “WHO Technical Report Series. Diet, nutrition and the prevention of chronic diseases.” Report of a Joint WHO/FAO Expert Consultation; Geneva 2003. Retrieved 2011-03-07
- ^ Farrell DJ, Bower L (2003-10). “Fatal water intoxication”. J. Clin. Pathol. (Journal of Clinical Pathology) 56 (10): 803–4.PMC 1770067. PMID 14514793.
- ^ Bjelakovic G; Nikolova, D; Gluud, LL; Simonetti, RG; Gluud, C (2007). “Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis”. JAMA297 (8): 842–57.doi:10.1001/jama.297.8.842.PMID 17327526.
- ^ “The Doctor and the Pomegranate”. Slate. Retrieved 2011-08-18.
- ^ Seddon JM, Ajani UA, Sperduto RD, et al.(November 1994). “Dietary carotenoids, vitamins A, C, and E, and advanced age-related macular degeneration. Eye Disease Case-Control Study Group”. JAMA 272 (18): 1413–20. doi:10.1001/jama.272.18.1413.PMID 7933422. Seehttp://www.mdsupport.org/library/zeaxanthin.html.
- ^ Lyle BJ, Mares-Perlman JA, Klein BE, Klein R, Greger JL (May 1999). “Antioxidant intake and risk of incident age-related nuclear cataracts in the Beaver Dam Eye Study”. Am. J. Epidemiol. 149 (9): 801–9.PMID 10221316.
Yeum KJ, Taylor A, Tang G, Russell RM (December 1995). “Measurement of carotenoids, retinoids, and tocopherols in human lenses”. Invest. Ophthalmol. Vis. Sci.36 (13): 2756–61. PMID 7499098.
Chasan-Taber L, Willett WC, Seddon JM, et al.(October 1999). “A prospective study of carotenoid and vitamin A intakes and risk of cataract extraction in US women”. Am. J. Clin. Nutr. 70 (4): 509–16. PMID 10500020.
Brown L, Rimm EB, Seddon JM, et al.(October 1999). “A prospective study of carotenoid intake and risk of cataract extraction in US men”. Am. J. Clin. Nutr. 70 (4): 517–24. PMID 10500021.
- ^ Pattison DJ, Symmons DP, Lunt M, et al.(August 2005). “Dietary beta-cryptoxanthin and inflammatory polyarthritis: results from a population-based prospective study”. Am. J. Clin. Nutr. 82 (2): 451–5. PMID 16087992.
Am J Epidemiology 2006 163(1).
- ^ Handelman GJ, Nightingale ZD, Lichtenstein AH, Schaefer EJ, Blumberg JB (August 1999). “Lutein and zeaxanthin concentrations in plasma after dietary supplementation with egg yolk”. Am. J. Clin. Nutr. 70 (2): 247–51. PMID 10426702.
- ^ Note that some isoflavone studies have linked isoflavones to increased cancer risk.
- ^ Monoterpenes are enormously widespread among green plant life (including algae). Many plants, notably coniferous trees, emit beneficial monoterpenes into the atmosphere.
- ^ [dead link]
- ^ Commission on Life Sciences. (1985).Nutrition Education in US Medical Schools, p. 4. National Academies Press.
- ^ Adams KM, Lindell KC, Kohlmeier M, Zeisel SH (April 2006). “Status of nutrition education in medical schools”. Am. J. Clin. Nutr. 83(4): 941S–4S. PMC 2430660.PMID 16600952.
- ^ a b Campbell T., Campbell T. (2005). The China Study. Dallas: Benella Books.
- ^ Andrew Mente; Lawrence de Koning; Harry S. Shannon; Sonia S. Anand (2009). “A Systematic Review of the Evidence Supporting a Causal Link Between Dietary Factors and Coronary Heart Disease”. Arch Intern Med169 (7): 659–669.doi:10.1001/archinternmed.2009.38.PMID 19364995.
- ^ Eckel RH, Borra S, Lichtenstein AH, Yin-Piazza SY (April 2007). “Understanding the complexity of trans fatty acid reduction in the American diet: American Heart Association Trans Fat Conference 2006: report of the Trans Fat Conference Planning Group”.Circulation 115 (16): 2231–46.doi:10.1161/CIRCULATIONAHA.106.181947. PMID 17426064.
- ^ Ducimetière P, Lang T, Amouyel P, Arveiler D, Ferrières J (January 2000). “Why mortality from heart disease is low in France. Rates of coronary events are similar in France and Southern Europe”. BMJ 320 (7229): 249–50. doi:10.1136/bmj.320.7229.249/a (inactive 2010-03-17). PMC 1117444.PMID 10642245.
- ^ Di Pasquale, Mauro G. (2008). “Utilization of Proteins in Energy Metabolism”. In Ira Wolinsky, Judy A. Driskell. Sports Nutrition: Energy metabolism and exercise. CRC Press. p. 73. ISBN 978-0-8493-7950-5.
- ^ Di Pasquale, Mauro G. (2008). “Utilization of Proteins in Energy Metabolism”. In Ira Wolinsky, Judy A. Driskell. Sports Nutrition: Energy metabolism and exercise. CRC Press. p. 79. ISBN 978-0-8493-7950-5.
- ^ Wnforum Sports Nutrition Game Plan. (PDF). page 19. winforum.org. Retrieved on 2011-10-17.
- ^ Baldi, S. (ED.) et al. (2009). Technical Report and Data File User’s Manual for the 2003 National Assessment of Adult Literacy (NCES 2009-47). U.S. Department of Education, National Center for Education Statistics. Washington, D.C.: U.S. Government Printing Office.
- ^ a b c Zoellner, J., Connell, C., Bounds, W., Crook, L., Yadrick, K. (2009). Nutrition Literacy Status and Preferred Nutrition Communications Channels Among Adults in the Lower Mississippi Delta. Preventing Chronic Disease, Public Health Research, Practice and Policy, 6(4):A128. Retrieved from http://www.cdc.gov/pcd/issues/2009/oct/08_0016.htm
- ^ Berkman N. D., Sheridan, S.L., Donahue, K. E., Halpern, D.J., Viera, A., Crotty, K., … Viswanathan, M. (2011). Health and Literacy Intervention Outcomes: an Updated Systematic Review. Evidence Report/Technology Assessment no. 199. Prepared by RTI International – University of North Carolina Evidence-based Practice Center. Publication Number 11-E006. Rockville, MD. Agency for Healthcare Research and Quality.
- ^ “Gyorgy Scrinis’ Web Page”. Retrieved 2009-01-14.
- ^ Pollan, Michael (2007-01-28). “Unhappy Meals”. The New York Times.
- ^ Pollan, Michael (2008). In Defense of Food: An Eater’s Manifesto. New York, USA: Penguin Press. ISBN 978-1594201455.
- ^ Jere R. Behrman (1996). “The impact of health and nutrition on education”. World Bank Research Observer 11 (1): 23–37.
- ^ a b American College Health Association (2007). “American College Health Association National College Health Assessment Spring 2006 Reference Group data report (abridged)”. J Am Coll Health 55 (4): 195–206.doi:10.3200/JACH.55.4.195-206.PMID 17319325.
- ^ Benton D, Sargent J (July 1992). “Breakfast, blood glucose and memory”. Biol Psychol 33(2–3): 207–10. doi:10.1016/0301-0511(92)90032-P. PMID 1525295.
- ^ Kanarek RB, Swinney D (February 1990). “Effects of food snacks on cognitive performance in male college students”.Appetite 14 (1): 15–27. doi:10.1016/0195-6663(90)90051-9. PMID 2310175.
- ^ Whitley JR, O’Dell BL, Hogan AG (September 1951). “Effect of diet on maze learning in second generation rats; folic acid deficiency”. J. Nutr. 45 (1): 153–60.PMID 14880969.
- ^ Umezawa M, Kogishi K, Tojo H, et al.(February 1999). “High-linoleate and high-alpha-linolenate diets affect learning ability and natural behavior in SAMR1 mice”. J. Nutr.129 (2): 431–7. PMID 10024623.
- ^ Glewwe P, Jacoby H, King E (2001). “Early childhood nutrition and academic achievement: A longitudinal analysis”. Journal of Public Economics 81 (3): 345–68.doi:10.1016/S0047-2727(00)00118-3.
- ^ “Managed food service contractors react quickly to the demands of their clients achievement: A longitudinal analysis”. Journal of Public Economics 81 (3): 345–368.
- ^ Guernsey L (1993). “Many colleges clear their tables of steak, substitute fruit and pasta”. Chronicle of Higher Education 39 (26): A30.
- ^ Duster T, Waters A (2006). “Engaged learning across the curriculum: The vertical integration of food for thought”. Liberal Education 92 (2): 42.
- ^ Lakhan SE, Vieira KF (2008). “Nutritional therapies for mental disorders”. Nutr J 7 (1): 2. doi:10.1186/1475-2891-7-2.PMC 2248201. PMID 18208598.
- ^ Coren, Michael (2005-03-10). “Study: Cancer no longer rare in poorer countries”. CNN. Retrieved 2007-01-01.
- ^ “Why is too much water dangerous?”. BBC News. 2007-01-15. Retrieved 2008-11-09.
- ^ Morris, Audrey; Audia Barnett, Olive-Jean Burrows (2004). “Effect of Processing on Nutrient Content of Foods” (PDF). Cajanus37 (3): 160–164. Retrieved 2006-10-26.
- ^ Villa P, Bouville C, Courtin J, et al. (July 1986). “Cannibalism in the Neolithic”. Science233 (4762): 431–7.doi:10.1126/science.233.4762.431.PMID 17794567.
- ^ a b History of the Study of Nutrition in Western Culture (Rai University lecture notes for General Nutrition course, 2004)
- ^ Daniel 1:5–16. Biblegateway.com. Retrieved on 2011-10-17.
- ^ Richard Smith (24 January 2004). “Let food by thy medicine…”. BMJ 328 (7433): 0-g.doi:10.1136/bmj.328.7433.0-g. Retrieved 2008-11-09.
- ^ Heinemann 2e Biology Activity Manual by Judith Brotherton and Kate Mundie
- ^ Unraveling the Enigma of Vitamin D – a paper funded by the United States National Academy of Sciences
- ^ “Can a virus make you fat?” at BBC News;“Contagious obesity? Identifying the human adenoviruses that may make us fat” at Science Blog
- ^ Montouri,Paulo (2012). Food Quality and preference. Retrieved fromhttp://journals1.scholarsportal.info.myaccess.library.utoronto.ca/tmp/13163608955942835523.pdf
- ^ http://aces.nmsu.edu/pubs/_a/a-129.pdfLINDEMANN,W.C., C.R. GLOVER, C.R. Nitrogen Fixation by Legumes New Mexico State University, May200