The Nutritional Health Alliance is an industry lobby group which lobbies
The Nutritional Health Alliance was formed in 1992 by the supplement industry "to mount a forceful campaign to evade studies of their products." Gerald Kessler, president of Nature's Plus, was the first head. Flyers were sent to health food stores with such titles as "The FDA wants to put you out of Business" and "Don't Let the FDA Take Your Vitamins Away"
The Nutritional Health Alliance is best known for its involvement in the Nutritional Health Alliance vs. Shalala case. In this case Nutritional Health Alliance argued to the second circuit that the U.S. Food and Drug Administration (FDA) mandating health claims on dietary supplements violated manufacturer's First Amendment rights.
The National Health and Nutrition Examination Survey (NHANES) is a survey research program conducted by the
The first NHANES was conducted in 1971. Findings from the survey are used to determine the prevalence of major diseases and risk factors for diseases. Information is used to assess nutritional status and its association with health promotion and disease prevention. NHANES findings are also the basis for national standards for such measurements as height, weight, and blood pressure. Data from this survey are used in epidemiological studies and health sciences research, which help develop sound public health policy, direct and design health programs and services, and expand the health knowledge.
Child Health and Nutrition Research Initiative (CHNRI)
Founded in 2001, the Child Health Nutrition Research Initiative (CHNRI) is a network of interested partners supported by the Global Forum for Health Research, based in
Eradicating extreme poverty and hunger,
Reducing child mortality, and
Combating HIV/AIDS, malaria and diseases in children.
CHNRI is helping to set research priorities in child health, development and nutrition, and resolve related methodological issues. It also sponsors research into priority child health and nutrition problems, especially in low- and middle-income countries, with a focus on research to inform policies for scaling up effective interventions.
CHNRI aims at increasing the level of communication and discussion amongst players working on research on child health and nutrition, such as nutritionists, child health specialists, and child development specialists. It provides a platform to initiate and maintain debate on the importance and direction of the research, bringing together scientists and implementing bodies to discuss issues relevant to the current status of knowledge and the requirements for the future.The secretariat of CHNRI is now located in ICDDR,B. The board is chaired by Dr Robert E. Black, Professor and Chair, Department of International Health, Johns Hopkins Bloomberg School of Public Health, USA.
Vegetarian nutrition
Vegetarian nutrition is the set of health-related challenges and advantages of vegetarian diets.
Evidence suggests that vegetarians are generally healthier and live longer than non-vegetarians. They have lower rates of coronary heart disease, obesity, hypertension, type 2 diabetes,osteoporosis, dementia and some forms of cancer. Vegetarian diets tend to be rich in carbohydrates, omega-6 fatty acids, dietary fibre, carotenoids, folic acid, vitamin C, vitamin E, potassium and magnesium. They are generally low in saturated fat, cholesterol, and animal protein.
However, vegetarian diets can sometimes be relatively low in protein, iron, zinc, vitamin B12, calcium and other nutrients. Nonetheless, well-planned vegetarian and vegan diets can meet all these nutrient requirements and are appropriate for all stages of the life cycle, including during pregnancy, lactation, infancy, childhood, and adolescence.
Benefits of a vegetarian diet
Vegetarian diets are usually rich in carbohydrates, omega-6 fatty acids, dietary fibre, carotenoids, folic acid, vitamin C, vitamin E, potassium and magnesium. They contain lower levels of saturated fat, cholesterol, and animal protein.
Studies show that the health of vegetarians compares favourably with that of non-vegetarians. British vegetarians have lower death rates than non-vegetarians,although this is at least partly due to non-dietary lifestyle factors, such as a low prevalence of smoking and the generally high socioeconomic status of vegetarians, or to aspects of the diet other than the avoidance of meat and fish.
Notably, vegetarians avoid the negative health effects of animal protein including red meat. One review found that mortality from coronary heart disease was 24% lower in vegetarians than in nonvegetarians.Studies of cancer have not shown clear differences in cancer rates between vegetarians and non-vegetarians. There is evidence that vegetarians tend to have a lower body mass index, lower risk of obesity,lower blood cholesterol levels, lower homocysteine levels,, lower risk of high blood pressure, and lower risk of type 2 diabetes.One large prospective study found that non-meat-eaters had only half the risk of meat eaters of requiring an emergency appendectomy.
Vegetarians are less likely to die by choking on food since the most common food to obstruct the airway is fish, which caused about 4,500 accidents a year in the
Potential nutrient deficiencies
Vegetarian diets can be relatively low in protein, iron, zinc, vitamin B12, calcium, omega-3 fatty acids, retinol (vitamin A), vitamin D, riboflavin (vitamin B2) and iodine. Poorly planned vegetarian diets may sometimes fall short in vitamin B12, calcium, omega-3 fatty acids, vitamin D, iron and zinc, and some vegans may have particularly low intakes of vitamin B12 and calcium.Nonetheless, well-balanced vegetarian and vegan diets can meet all these nutrient requirements and are appropriate for all stages of the life cycle, including during pregnancy, lactation, infancy, childhood, and adolescence.
Protein
The typical vegetarian gets adequate protein as long as caloric intake is adequate and a variety of foods is eaten. Vegetarian diets are usually relatively low in protein, which may be beneficial.
Combining proteins
“ Virtually all plant foods have all of the essential amino acids; and not only are the amino acids there, they are present in more than enough quantity to meet the needs of normal adults, if you are on a calorically adequate diet.
— Keith Akers
”
Despite a widespread belief that vegetarians must eat grains and beans within a few hours of each other in order to make a 'complete' protein which contains all 9 "essential amino acids", this has never been substantiated by research. The protein-combining theory was brought to popular attention in Frances Moore Lappé's 1971 bestseller Diet for a Small Planet.In later editions of the book, as early as 1981, Lappé withdrew her contention that protein 'combining' is necessary.
Iron
In several studies, vegans and other vegetarians were not found to suffer from iron-deficiency more than non-vegetarians. However, while one study agreed that iron-deficiency anemia is not more common among vegetarians, they found "vegetarian children had ... reduced levels of haemoglobin and iron compared to omnivores" due "to the absence of animal iron sources with high utilizability".
Tofu can be a valuable source of protein, iron, zinc and calcium for vegetarians and vegans
The recommended iron intake for vegetarians is 1.8 times that of nonvegetarians, due to the fact that plants, dairy, and eggs contain only non-heme iron, and this is absorbed less efficiently than heme iron. Although a lower percentage of non-heme iron is absorbed, greater amounts of non-heme iron are concentrated in many non-meat sources of iron (than the amount of iron per serving in meats), and therefore, cereals, eggs, nuts, seeds, and legumes (including soy foods, peas, beans, chickpeas, and lentils) are significant sources of iron,and a well-planned vegetarian diet should not lead to iron deficiency, but fruitarianism and raw foods diets should not be pursued for infants or children.Meat, fish, and poultry (not dairy or eggs) are the only sources of heme iron; intake of heme iron is associated with colon cancer.Non-heme iron is more sensitive to both inhibitors and enhancers of iron absorption. Vitamin C is an iron absorption enhancer. The main inhibitors for most people are phytates (e.g. legumes and grains), but other inhibitors include tannins (tea, wine), calcium and polyphenols.
Iron is an integral part of many proteins and enzymes which maintain good health. In humans, iron is an essential component of proteins involved in red blood cells' oxygen transport. Iron also helps regulate cell growth and differentiation.
Zinc
Western vegetarians and vegans have not been found to suffer from overt zinc deficiencies any more than meat-eaters. However, phytates in many whole-grains and fiber in many foods may interfere with zinc absorption and marginal zinc intake has poorly understood effects. Vegetarians may need more than the US RDA (15 mg) of zinc daily if their diet is high in phytates.
Major plant sources of zinc include cooked dried beans, sea vegetables, fortified cereals, soyfoods, nuts, peas, and seeds.
Vitamin B12
Eggs are an excellent source of vitamin B12 for vegetarians.
Vitamin B12 deficiency is potentially extremely serious, leading to pernicious anemia, nerve degeneration and irreversible neurological damage.
Lacto-ovo vegetarians may get vitamin B12 from eggs and dairy products; for some this is adequate but some may remain B12-deficient.The world's largest group of professional dietitians says the form of vitamin B12 sourced from animal-products is protein-bound and not as easily digested, especially as people age, and therefore recommends B12 supplementation for everyone over the age of 50. Pregnant and lactating vegetarians (and breastfed infants if the mother's diet is not supplemented) should also use supplements, whether pills, injections, or B12-fortified foods, if they don't get adequate B12 from animal-products like eggs or dairy.
Evidence suggests that vegetarians and vegans who are not taking vitamin B12 supplements do not consume sufficient servings of B12 and often have abnormally low blood concentrations of vitamin B12. This is because, unless fortified, plant foods do not contain reliable amounts of active vitamin B12.
It is essential, therefore, that vegetarians consume adequate amounts of dietary supplements or foods that have been fortified with B12 (such as nutritional yeast or other yeast extracts, vegetable stock, veggie burger mixes, textured vegetable protein, soy milks, vegetable and sunflower margarines, and breakfast cereals).B12 that is to be used in these supplements is typically grown from vegan sources (such as bacteria). Another bacterial source happens to be that plants and edible fungi (like mushrooms) on farms or in the wild may absorb vitamin B12 from bacteria in soil, but since modern pesticides kill most B12 in the soil (including on organic farms to some degree, as the pesticides spread, via hydrology, from non-organic farms to organic ones), the B12 in these plants is not considered a reliable dietary source,whereas B12 supplements from bacteria grown under controlled conditions are considered reliable amounts of B12. There is a patent for a cultivating vitamin B12 from plants.
Nori (seaweed) contains B12 very abundantly. However, while the one included in Nori is effective it does not contain reliable or significant amounts of active B12; instead, seaweeds tend to be high in inactive B12 which actually may inhibit uptake of active B12.
Omega-3 fatty acids
Vegetarian diets that lack eggs or generous amounts of sea vegetables (seaweed) can be low in omega-3 fatty acids (O3FA). This and a high ratio of O6FA to O3FA in the diet may raise risk of heart disease in some vegetarians. Major vegetarian sources of O3FA include walnuts, flaxseeds and flaxseed oil, olive oil, canola (rapeseed) oil, and avocado. DHA supplements derived from DHA-rich microalgae are also available.
Common flax seed contains more omega-3 fatty acids than fish.
Walnuts are a source of omega-3 fatty acids
A well-known source of O3FA for non-vegetarians is fish, and to get the same amount of O3FA, one needs to only consume 1/3 the weight of walnuts compared to a given weight of salmon; and flax seeds have even more highly-concentrated O3FA than walnuts. However, vegetarian sources of O3FA are primarily the short chain variety and likely to have lower concentrations of the particular essential fatty acids (EFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The body can synthesize small quantities of EPA and DHA from other omega-3 fatty acids, such as alpha-linolenic acids, which are present in vegetarian sources of O3FA's. The human body can also convert DHA into EPA.Whilst the human body can in theory do this conversion, in practice modern diets and lifestyles reduce the effectiveness of the conversion systems. Roughly ten times[citation needed] more of the short chain omega-3s must be consumed to have the same effect as the long chain form from fish oil.
While there is no scientific consensus on the role of omega-3 fatty acids, it is generally believed that they may reduce the risk of coronary heart disease, lower triglycerides, stabilize mood and help prevent depression, help reduce symptoms of ADD, reduce joint pain and other rheumatoid problems and reduce the risk of dementia in older age.
Vitamin D
The human body can synthesize vitamin D when skin is exposed to ultraviolet radiation from the sun. Vegans who do not eat foods or pills fortified with synthetic vitamin D and with little exposure to the sun's ultraviolet radiation (e.g., those who don't expose their extremities for at least 15-30 minutes per day or those living at latitudes close to the poles) are vulnerable to Vitamin D deficiencies.
Vitamin D acts as a hormone, sending a message to the intestines to increase the absorption of calcium and phosphorus, which produces strong bones. Vitamin D also works in concert with a number of other vitamins, minerals, and hormones to promote bone mineralization. Research also suggests that vitamin D may help maintain a healthy immune system and help regulate cell growth and differentiation.
Iodine
One study reported a "potential danger of [iodine] deficiency disorders due to strict forms of vegetarian nutrition, especially when fruits and vegetables grown in soils with low [iodine] levels are ingested." Iodine, however, is usually supplied by iodized salt and other sources in first world countries. Other significant sources of iodine include sea vegetables (seaweed) and bread made with dough conditioners.
Riboflavin
According to the American Dietetic Association, “Some studies have shown vegans to have lower intakes of riboflavin, compared with nonvegetarians; however, clinical riboflavin deficiency has not been observed.”
Nutrition
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 refers to what it eats. Dietitians are health professionals who specialize in human nutrition, meal planning, economics, preparation, and so on. They are trained to provide safe, evidence-based dietary advice and management to individuals (in health and disease), as well as to institutions.
Poor diet can have an injurious impact on health, causing deficiency diseases such as scurvy, beriberi, and kwashiorkor; health-threatening conditions like obesity and metabolic syndrome, and such common chronic systemic diseases as cardiovascular disease, diabetes, and osteoporosis.
Nutrients
There are seven major classes of nutrients: carbohydrates, fats, fiber, 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 are carbohydrates, fats, fiber, proteins, and water. The micronutrients are minerals and vitamins.
The macronutrients (excluding fiber and water) provide energy, which is measured in Joules or kilocalories (often called "Calories" and written with a capital C to distinguish them from gram calories). Carbohydrates and proteins provide 17 kJ (4 kcal) of energy per gram, while fats provide 37 kJ (9 kcal) per gram.Vitamins, minerals, fiber, and water do not provide energy, but are necessary for other reasons.
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 various fatty acid monomers bound to glycerol. 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 the elements of carbohydrates and fats. The nitrogen-containing monomers of protein are amino acids, and they include some essential amino acids. They fulfill many roles other than energy metabolism; and when they are used as fuel, getting rid of the nitrogen places a burden on the kidneys.
Other micronutrients include antioxidants and phytochemicals.
Most foods contain a mix of some or all of the nutrient classes. Some nutrients are required regularly, while others are needed only occasionally. Poor health can be caused by an imbalance of nutrients, whether an excess or a deficiency.
Carbohydrates
A pack of toasted bread is a cheap, high calorie nutrient (usually unbalanced, i.e., deficient in essential minerals and vitamins, because of removal of grain bran) food source with a long shelf-life.
Carbohydrates may be classified as monosaccharides, disaccharides, or polysaccharides by the number of monomer (sugar) units they contain. They constitute a large proportion of foods such as rice, noodles, bread, and other grain-based products. Monosaccharides contain one sugar unit, disaccharides two, and polysaccharides three or more. Polysaccharides are often referred to as complex carbohydrates because they are long chains of sugar units, whereas monosaccharides and disaccharides are simpler. The difference is important: complex carbohydrates take longer to digest and absorb since their sugar units are processed one-by-one off the ends of the chains. The spike in blood-sugar levels after ingestion of simple sugars is thought to be involved in causing heart and vascular disease. Simple sugars form a greater part of modern diets, leading to more cardiovascular disease in populations. Simple carbohydrates are absorbed quickly, and therefore raise blood-sugar levels more rapidly.
Fat
A molecule of fat 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. 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 few hydrogen atoms. Unsaturated fats may be further classified as monounsaturated (one double-bond) or polyunsaturated (many double-bonds). Trans fats are a type of unsaturated fat with trans-isomer fatty acid, typically created in an industrial process called (partial) hydrogenation.
Many studies have shown that unsaturated fats, particularly monounsaturated fats, are best in the human diet. Saturated fats, typically from animal sources, are next, while trans fats are to be avoided. Saturated and 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, but have properties useful in the food processing industry.
Essential fatty acids
Most fatty acids are non-essential, meaning the body can produce them as needed. 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—is important for health. Both of these "omega" long-chain polyunsaturated fatty acids are substrates 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 (LNA), 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: one reason a balance between omega-3 and omega-6 is 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).
Good sources of essential fatty acids include most vegetables, nuts, seeds, and marine oils, Some of the best sources are fish, flax seed oils, soy beans, pumpkin seeds, sunflower seeds, and walnuts.
Fiber
Fiber is a carbohydrate (or a polysaccharide) that is incompletely absorbed in humans and in some other animals. Like all carbohydrates, when it is metabolized it can produce four Calories (kilocalories) of energy per gram. But in most circumstances it accounts for less than that because of its limited absorption. Dietary fiber consists mainly of cellulose, a large carbohydrate polymer that is indigestible because humans do not have the required enzymes. There are two subcategories: soluble and insoluble fiber. Whole grains, fruits (especially plums, prunes, and figs), and vegetables are rich in dietary fiber. Fiber is important to digestive health and is thought to reduce the risk of colon cancer.It can help in alleviating both constipation and diarrhea. Fiber provides bulk to the intestinal contents, and insoluble fiber stimulates peristalsis: the rhythmic muscular contractions passing along the digestive tract. Some soluble fibers produce a solution of high viscosity: a gel, which slows the movement of food through the intestines. Fiber, especially from whole grains, may help lessen insulin spikes and reduce the risk of diabetes [type 2].
Protein
Most meats such as chicken contain all the essential amino acids needed for humans
Main article: Protein in nutrition
Proteins are the basis of many animal body structures (e.g. muscles, skin, and hair). Each molecule is composed of amino acids which are characterized by inclusion of nitrogen and sometimes sulphur. The body requires amino acids to produce new proteins (protein retention) and to replace damaged proteins (maintenance). 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 when there is greater need: in early development and maturation, pregnancy, lactation, or injury. A complete protein source contains all the essential amino acids; an incomplete protein 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. Sources of dietary protein include meats, tofu and other soy-products, eggs, grains, legumes, and dairy products such as milk and cheese. A few 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.
Minerals
Dietary minerals are the chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen that are present in common organic molecules. The term "mineral" is archaic, since the intent is to describe simply the less common elements in the diet: heavier than the four just mentioned; including several metals; and often occurring 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). On the other hand, minerals are often artificially added to the diet as supplements, the most famous being iodine in iodized salt.
Macrominerals
Many elements are essential in quantity; also 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 the following, in alphabetical order (with informal or folk-medicine perspectives in parentheses):
Calcium, a common electrolyte, but also structural (for muscle and digestive system health, builds bone, neutralizes acidity, clears toxins, helps blood stream)
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
Sulfur for three essential amino acids and therefore many proteins (skin, hair, nails, liver, and pancreas)
Trace minerals
Many elements are required in trace amounts, usually because they play a catalytic role in enzymes. Some trace mineral elements (RDA <>
Cobalt required for biosynthesis of vitamin B12 family of coenzymes
Copper required component of many redox enzymes, including cytochrome c oxidase
Chromium required for sugar metabolism
Iodine required for the biosynthesis of thyroxin; 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 found in lower organisms.)
Zinc required for several enzymes such as carboxypeptidase, liver alcohol dehydrogenase, carbonic anhydrase
Vitamins
As with the minerals discussed above, twelve vitamins are recognized as essential nutrients, necessary in the diet for good health. (Vitamin D is the exception: it can alternatively 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 indispensable for survival and health; but these are not strictly "essential" 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). Other essential nutrients not classed 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: goitre, scurvy, osteoporosis, impaired immune system, disorders of cell metabolism, certain forms of cancer, symptoms of premature aging, and poor psychological health (including eating disorders), among many others.Excess of some vitamins is also dangerous to health (notably vitamin A); and deficiency or excess of minerals can also have serious health consequences.
Water
A manual water pump in
About 70% of the non-fat mass of the human body is made of water.To function properly, the body requires between one and seven liters of water per day to avoid dehydration; the precise amount depends on the level of activity, temperature, humidity, and other factors.With physical exertion and heat exposure, water loss will increase and daily fluid needs may increase as well.
It is not clear how much water intake is needed by healthy people, although some experts assert that 8–10 glasses of water (approximately 2 liters) daily is the minimum to maintain proper hydration. The notion that a person should consume eight glasses of water per day cannot be traced back to a scientific source.The effect of water intake on weight loss and on constipation is also still unclear. Original recommendation for water intake 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." The latest dietary reference intake report by the United States National Research Council in general recommended (including food sources): 2.7 liters of water total for women and 3.7 liters for men. Specifically, pregnant and breastfeeding women need additional fluids to stay hydrated. According to the Institute of Medicine—who recommend that, on average, women consume 2.2 litres and men 3.0 litres—this is recommended to be 2.4 litres (approx. 9 cups) for pregnant women and 3 litres (approx. 12.5 cups) for breastfeeding women since an especially large amount of fluid is lost during nursing.
For those who have healthy kidneys, it is rather difficult to drink too much water, but (especially in warm humid weather and while exercising) it is dangerous to drink too little. People can drink far more water than necessary while exercising, however, putting them at risk of water intoxication, which can be fatal. In particular large amounts of de-ionized water are dangerous.
Normally, about 20 percent of water intake comes in food, while the rest comes from drinking water and assorted beverages (caffeinated included). Water is excreted from the body in multiple forms; including urine and feces, sweating, and by water vapor in the exhaled breath.
Other nutrients
Other micronutrients include antioxidants and phytochemicals. These substances are generally more recent discoveries which: have not yet been recognized as vitamins; are still under investigation; or contribute to health but are not necessary for life. Phytochemicals may act as antioxidants, but not all phytochemicals are antioxidants.
Antioxidants
Antioxidants are a recent discovery. 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 normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds. Some are produced by the human body with adequate precursors (glutathione, Vitamin C) 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). Phytochemicals (Section Below) and their subgroup polyphenols are the majority of antioxidants; about 4,000 are known. 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.
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. 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 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 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.
The correlations between the ingestion of some phytochemicals and the prevention of disease are, in some cases, enormous in magnitude.
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:
Family Sources Possible Benefits
flavonoids berries, herbs, vegetables, wine, grapes, tea general antioxidant, oxidation of LDLs, prevention of arteriosclerosis and heart disease
isoflavones (phytoestrogens) soy, red clover, kudzu root general antioxidant, prevention of arteriosclerosis and 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 the immune system
saponins beans, cereals, herbs Hypercholesterolemia, Hyperglycemia, Antioxidant, cancer prevention,
Anti-inflammatory
capsaicinoids all capiscum (chile) peppers topical pain relief, cancer prevention, cancer cell apoptosis
Intestinal bacterial flora
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.
Advice and guidance
Governmental policies
The updated USDA food pyramid, published in 2005, is a general nutrition guide for recommended food consumption for humans.
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
In the
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.
Teaching
Nutrition is taught in schools in many countries. In
A 1985 US National Research Council report entitled Nutrition Education in US Medical Schools concluded 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%.
Healthy diets
Whole plant food diet
Heart disease, cancer, obesity, and diabetes are commonly called "Western" diseases because these maladies were once rarely seen in developing countries. One 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 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 United States. Adjusted for age and exercise, large regional clusters of people in
The United Healthcare/Pacificare 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."
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