Human nutrition

Foods high in magnesium (an example of a nutrient)

Human nutrition deals with the provision of essential nutrients in food that are necessary to support human life and good health.<ref>"human nutrition | Importance, Essential Nutrients, Food Groups, & Facts". Encyclopedia Britannica. Archived from the original on 11 July 2022. Retrieved 29 December 2020.</ref> Poor nutrition is a chronic problem often linked to poverty, food security, or a poor understanding of nutritional requirements.<ref name="Progress for Children">Progress for Children: A Report Card on Nutrition (No. 4), UNICEF, May 2006, ISBN 978-92-806-3988-9</ref> Malnutrition and its consequences are large contributors to deaths, physical deformities, and disabilities worldwide.<ref name="Essential Nutrition Actions">"Essential Nutrition Actions: Improving maternal, newborn, infant and young child health and nutrition". Washington, DC: World Health Organization. 2013. Archived from the original on 2013-06-12.</ref> Good nutrition is necessary for children to grow physically and mentally, and for normal human biological development.<ref name="Progress for Children" />

Overview

The human body contains chemical compounds such as water, carbohydrates, amino acids (found in proteins), fatty acids (found in lipids), and nucleic acids (DNA and RNA). These compounds are composed of elements such as carbon, hydrogen, oxygen, nitrogen, and phosphorus. Any study done to determine 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 the materials excreted and eliminated from the body (including urine and feces).

Nutrients

The seven major classes of nutrients are carbohydrates, fats, fiber, minerals, proteins, vitamins, and water.<ref name=WHO2004/> Nutrients can be grouped as either macronutrients or micronutrients (needed in small quantities). Carbohydrates, fats, and proteins are macronutrients, and provide energy.<ref name=WHO2004/> Water and fiber are macronutrients, but do not provide energy. The micronutrients are minerals and vitamins.<ref name=WHO2004>World Health Organization, Food and Agricultural Organization of the United Nations (2004). Vitamin and mineral requirements in human nutrition (2. ed.). Geneva [u.a.]: World Health Organization. ISBN 978-9241546126. Archived from the original on 12 December 2012.</ref>

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 also 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,<ref name=Stryer>Berg J, Tymoczko JL, Stryer L (2002). Biochemistry (5th ed.). San Francisco: W.H. Freeman. p. 603. ISBN 978-0-7167-4684-3.</ref> 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,<ref>"Get the Facts on Fiber". webmd.com. Archived from the original on 2022-05-19. Retrieved 2020-01-04.</ref> and water do not provide energy, but are required for other reasons. A third class of dietary material, fiber (i.e., nondigestible material such as cellulose), seems also to be required, for both mechanical and biochemical reasons, though the exact reasons remain unclear. For all age groups, males on average need to consume higher amounts of macronutrients than females. In general, intakes increase with age until the second or third decade of life.<ref>"National Nutrition Survey: Nutrient Intakes and Physical Measurements". Australian Bureau of Statistics. 1995. Archived from the original on 2023-01-09. Retrieved 2015-04-02.</ref>

Some nutrients can be stored – the fat-soluble vitamins – while others are required more or less continuously. Poor health can be caused by a lack of required nutrients, or for some vitamins and minerals, too much of a required nutrient. Essential nutrients cannot be synthesized by the body, and must be obtained from food.

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.<ref name=Nelson2005>Nelson DL, Cox MM (2005). Lehninger's Principles of Biochemistry (4th ed.). New York, New York: W. H. Freeman and Company.</ref> 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 naturally when atrophy takes place, or during periods of starvation.^{[citation needed]}

The list of nutrients that people are known to require is, in the words of Marion Nestle, "almost certainly incomplete".<ref>Nestle, Marion (2013) [2002]. Food Politics: How the Food Industry Influences Nutrition and Health. University of California Press. p. 413. ISBN 978-0-520-27596-6.</ref>

Carbohydrates

Carbohydrates may be classified as monosaccharides, disaccharides or polysaccharides depending on the number of monomer (sugar) units they contain. They are a diverse group of substances, with a range of chemical, physical and physiological properties.<ref>Cummings JH, Stephen AM (December 2007). "Carbohydrate terminology and classification" (PDF). European Journal of Clinical Nutrition. 61 (Suppl 1): S5-18. doi:10.1038/sj.ejcn.1602936. PMID 17992187. S2CID 3330936.^{[permanent dead link]}</ref> They make up a large part of foods such as rice, noodles, bread, and other grain-based products,<ref>"Grams of Carbohydrates in White Bread - Carb Counter". www.carb-counter.net. Archived from the original on 31 May 2016. Retrieved 18 March 2016.</ref><ref>"American Rice, Inc". www.amrice.com. Archived from the original on 19 March 2016. Retrieved 18 March 2016.</ref> but they are not an essential nutrient, meaning a human does not need to eat carbohydrates.<ref>Westman EC (May 2002). "Is dietary carbohydrate essential for human nutrition?". The American Journal of Clinical Nutrition. 75 (5): 951–3, author reply 953–4. doi:10.1093/ajcn/75.5.951a. PMID 11976176.</ref>

Monosaccharides contain one sugar unit, disaccharides two, and polysaccharides three or more. Monosaccharides include glucose, fructose and galactose.<ref>"Carbohydrates That Contain Monosaccharides". Healthy eating. 22 May 2012. Archived from the original on 2022-10-04. Retrieved 2015-04-17.</ref> Disaccharides include sucrose, lactose, and maltose; purified sucrose, for instance, is used as table sugar.<ref>Lean, Michael E.J. (2015). "Principles of human nutrition". Medicine. 43 (2): 61–65. doi:10.1016/j.mpmed.2014.11.009. S2CID 220865321.</ref> Polysaccharides, which include starch and glycogen, 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 raise blood-glucose levels more rapidly than complex carbohydrates. This is inaccurate.<ref>Otto, H (1973). Diabetik Bei Diabetus Mellitus. Bern: Verlag Hans Huber.</ref><ref>Crapo, P; Reaven, Olefsky (1977). "Postprandial plasma-glucose and -insulin responses to different complex carbohydrates". Diabetes. 26 (12): 1178–83. doi:10.2337/diabetes.26.12.1178. PMID 590639.</ref><ref>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): 1723–28. doi:10.1093/ajcn/33.8.1723. PMID 6996472.</ref><ref>Jenkins, David; Jenkins, Alexandra L.; Wolever, Thomas M.S.; Thompson, Lilian H.; Rao, A. Venkat (February 1986). "Simple and complex carbohydrates". Nutrition Reviews. 44 (2): 44–49. doi:10.1111/j.1753-4887.1986.tb07585.x. PMID 3703387.</ref> Some simple carbohydrates (e.g., fructose) follow different metabolic pathways (e.g., fructolysis) that result in only a partial catabolism to glucose, while, in essence, many complex carbohydrates may be digested at the same rate as simple carbohydrates.<ref>"The Nutrition Source: Carbohydrates". Harvard School of Public Health. Archived from the original on 7 July 2011. Retrieved 7 July 2011.</ref> The World Health Organization recommends that added sugars should represent no more than 10% of total energy intake.<ref>"WHO Technical Report Series. Diet, nutrition and the prevention of chronic diseases." Report of a Joint WHO/FAO Expert Consultation; Geneva 2003. Retrieved 7 March 2011</ref>

The most common plant carbohydrate nutrient – starch – varies in its absorption. Starches have been classified as rapidly digestible starch, slowly digestible starch and resistant starch.<ref>Englyst, K.N.; Liu, S.; Englyst, H.N. (2007). "Nutritional characterization and measurement of dietary carbohydrates". Eur J Clin Nutr. 61 (Suppl 1): S19-39. doi:10.1038/sj.ejcn.1602937. PMID 17992185. S2CID 4218364.</ref> Starches in plants are resistant to digestion (resistant starch), but cooking the starch in the presence of water can break down the starch granule and releases the glucose chains, making them more easily digestible by human digestive enzymes.<ref>Wang, Yi; Chen, Long; Yang, Tianyi; Ma, Yun; McClements, David Julian; Ren, Fei; Tian, Yaoqi; Jin, Zhengyu (2020). "A review of structural transformations and properties changes in starches during thermal processing of foods". Food Hydrocolloids. 113: 106543. doi:10.1016/j.foodhyd.2020.106543. S2CID 230574900.</ref> Historically, food was less processed and starches were contained within the food matrix, making them less digestible.<ref>Chen, Lying; Liu, Ruining; Qin, Chengyong; Meng, Yan; Zhang, Jie; Wang, Yun; Xu, Guifa (2010). "Sources and intake of resistant starch in the Chinese diet". Asia Pac J Clin Nutr. 19 (2): 274–282. doi:10.6133/apjcn.2010.19.2.18. PMID 20460244. Archived from the original on 2023-01-24. Retrieved 2021-02-26.</ref> Modern food processing has shifted carbohydrate consumption from less digestible and resistant starch to much more rapidly digestible starch.<ref name="Lockyer RS Review">Lockyer, S.; Nugent, A.P. (2017). "Health effects of resistant starch". Nutrition Bulletin. 42 (1): 10–41. doi:10.1111/nbu.12244. S2CID 89991088.</ref><ref>Birkett, A.M.; Brown, I.L. (2008). Chapter 4: Resistant Starch and Health. In Technology of Functional Cereal Products. Boca Raton, FL: Woodhead Publishing Ltd - CRC Press LLC. pp. 63–85. ISBN 978-1-84569-177-6.</ref> For instance, the resistant starch content of a traditional African diet was 38 grams/day.<ref>O'Keefe, Stephen J.D.; et, al. (2015). "Fat, fibre and cancer risk in African Americans and rural Africans". Nat Commun. 6: 6342. Bibcode:2015NatCo...6.6342O. doi:10.1038/ncomms7342. PMC 4415091. PMID 25919227.</ref> The resistant starch consumption from countries with high starch intakes has been estimated to be 30-40 grams/day.<ref name="Baghurst Review">Baghurst, P.A.; Baghurst, K.I.; Record, S.J. (1996). "Dietary fibre, non-starch polysaccharides and resistant starch - a review". Food Australia. 48 (3): S1-S35. Archived from the original on 2022-01-19. Retrieved 2021-02-26.</ref> In contrast, the average consumption of resistant starch in the United States was estimated to be 4.9 grams/day (range 2.8-7.9 grams of resistant starch/day).<ref name="Murphy RS Review">Murphy, M.M.; Douglass, J.S.; Birkett, A. (2008). "Resistant starch intakes in the United States". J Am Diet Assoc. 108 (1): 67–78. doi:10.1016/j.jada.2007.10.012. PMID 18155991.</ref>

Fat

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 chemical 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.<ref>Klonoff, David C. (24 June 2016). "Replacements for Trans Fats—Will There Be an Oil Shortage?". Journal of Diabetes Science and Technology. 1 (3): 415–22. doi:10.1177/193229680700100316. PMC 2769584. PMID 19885099.</ref>

Essential fatty acids

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 are substrates for a class of eicosanoids known as prostaglandins, which have roles throughout the human body.

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. 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). 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).

Fiber

Dietary fiber is a carbohydrate, specifically a polysaccharide, which 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, but in most circumstances, it accounts for less than that because of its limited absorption and digestibility.

The two subcategories are insoluble and soluble fiber.

Insoluble dietary fiber: Includes cellulose, a large carbohydrate polymer that is indigestible by humans, because humans do not have the required enzymes to break it down, and the human digestive system does not harbor enough of the types of microbes that can do so.; Includes resistant starch, an insoluble starch that resists digestion either because it is protected by a shell or food matrix (Type 1 resistant starch, RS1), maintains the natural starch granule (Type 2 resistant starch, RS2), is retrograded and partially crystallized (Type 3 resistant starch, RS3), has been chemically modified (Type 4 resistant starch, RS4) or has complexed with a lipid (Type 5 resistant starch, RS5).<ref name="Lockyer RS Review"/> Natural sources of resistant starch (RS1, RS2 and RS3) are fermented by the microbes in the human digestive system to produce short-chain fatty acids which are utilized as food for the colonic cells or absorbed.<ref name="Lockyer RS Review"/>

Soluble dietary fiber: Comprises a variety of oligosaccharides, waxes, esters, and other carbohydrates that dissolve or gelatinize in water. Many of these soluble fibers can be fermented or partially fermented by microbes in the human digestive system to produce short-chain fatty acids which are absorbed and therefore introduce some caloric content.<ref>Hervik, Astrid Kolderup; Svihus, Birger (2019). "The role of fiber in energy balance". Journal of Nutrition and Metabolism. 2019: 4983657. doi:10.1155/2019/4983657. ISSN 2090-0724. PMC 6360548. PMID 30805214.</ref>

Whole grains, beans, and other legumes, fruits (especially plums, prunes, and figs), and vegetables are good sources of dietary fiber. Fiber has three primary mechanisms, which in general determine their health impact: bulking, viscosity and fermentation.<ref name="Gallaher Fiber Review">Gallaher, Daniel D. (2006). Chapter 8 - Dietary Fiber in Present Knowledge in Nutrition (Ninth Edition, Volume I ed.). Washington DC: ILSI Press. pp. 102–110. ISBN 978-1-57881-199-1.</ref> Fiber provides bulk to the intestinal contents, and insoluble fiber facilitates peristalsis – the rhythmic muscular contractions of the intestines which move contents along the digestive tract. Some soluble and insoluble fibers produce a solution of high viscosity; this is essentially a gel, which slows the movement of food through the intestines. Fermentable fibers are used as food by the microbiome, mildly increasing bulk, and producing short-chain fatty acids and other metabolites, including vitamins, hormones, and glucose. One of these metabolites, butyrate, is important as an energy source for colon cells, and may improve metabolic syndrome.<ref>Bridgeman, Stephanie C.; Northrop, Wendy; Melton, Phillip E.; Ellison, Gaewyn C.; Newsholme, Philip; Mamotte, Cyril D.S. (1 October 2020). "Butyrate generated by gut microbiota and its therapeutic role in metabolic syndrome". Pharmacological Research. 160: 105174. doi:10.1016/j.phrs.2020.105174. PMID 32860943. S2CID 221373075.</ref><ref>Wang, Yong; Chen, Jing; Song, Ying-Han; Zhao, Rui; Xia, Lin; Chen, Yi; Cui, Ya-Ping; Rao, Zhi-Yong; Zhou, Yong; Zhuang, Wen; Wu, Xiao-Ting (5 June 2019). "Effects of the resistant starch on glucose, insulin, insulin resistance, and lipid parameters in overweight or obese adults: a systemic review and meta-analysis". Nutrition and Diabetes. 9 (1): 19. doi:10.1038/s41387-019-0086-9. PMC 6551340. PMID 31168050. Archived from the original on 24 January 2023. Retrieved 22 February 2021.</ref>

In 2016, the U.S. FDA approved a qualified health claim stating that resistant starch might reduce the risk of type 2 diabetes, but with qualifying language for product labels that only limited scientific evidence exists to support this claim. The FDA requires specific labeling language, such as the guideline concerning resistant starch: "High-amylose maize resistant starch may reduce the risk of type 2 diabetes. FDA has concluded that there is limited scientific evidence for this claim."<ref name="FDA approved health claim RS2 resistant starch">Balentine, Douglas. "Letter announcing decision for a health claim for high-amylose maize starch (containing type-2 resistant starch) and reduced risk of type 2 diabetes mellitus". www.regulations.gov. U.S. Food and Drug Administration. Archived from the original on 20 December 2016. Retrieved 16 December 2016.</ref>

Amino acids

Proteins are the basis of many animal body structures (e.g. muscles, skin, and hair) and form the enzymes that control chemical reactions throughout the body. Each protein molecule is composed of amino acids which contain 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). Amino acids are soluble in the digestive juices within the small intestine, where they are absorbed into the blood. Once absorbed, they cannot be stored in the body, so they are either metabolized as required or excreted in the urine.^{[medical citation needed]} Proteins consist of amino acids in different proportions. The most important aspect and defining characteristic of protein from a nutritional standpoint is its amino acid composition.<ref name="DRI">Dietary Reference Intakes: The Essential Guide to Nutrient Requirements, published by the Institute of Medicine's Food and Nutrition Board, currently available online at "DRI Reports | Food and Nutrition Information Center". Archived from the original on 5 July 2014. Retrieved 14 July 2014.</ref>

For all animals, some amino acids are essential (an animal cannot produce them internally so they must be eaten) 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. The synthesis of some amino acids can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress, and those are called conditionally essential.<ref name="DRI" />

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 incomplete protein source lacks one or more of the essential amino acids. It is possible with protein combinations of 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 do not need to be eaten at the same meal to be used together by the body.<ref>American Dietetic Association; Dietitians Of, Canada (2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dental Association. 103 (6): 748–65. doi:10.1053/jada.2003.50142. PMID 12778049.</ref> Excess amino acids from protein can be converted into glucose and used for fuel through a process called gluconeogenesis.

There is an ongoing debate about the differences in nutritional quality and adequacy of protein from vegan, vegetarian and animal sources, though many studies and institutions have found that a well-planned vegan or vegetarian diet contains enough high-quality protein to support the protein requirements of both sedentary and active people at all stages of life.<ref>Alexandrov NV, Eelderink C, Singh-Povel CM, Navis GJ, Bakker SJ, Corpeleijn E (October 2018). "Dietary Protein Sources and Muscle Mass over the Life Course: The Lifelines Cohort Study". Nutrients. 10 (10): 1471. doi:10.3390/nu10101471. PMC 6212815. PMID 30308987.</ref><ref>"Protein". The Nutrition Source. 18 September 2012. Archived from the original on 27 October 2019. Retrieved 31 October 2019.</ref><ref>Rogerson D (13 September 2017). "Vegan diets: practical advice for athletes and exercisers". Journal of the International Society of Sports Nutrition. 14: 36. doi:10.1186/s12970-017-0192-9. PMC 5598028. PMID 28924423.</ref><ref name="dinu">Dinu M, Abbate R, Gensini GF, Casini A, Sofi F (November 2017). "Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies" (PDF). Critical Reviews in Food Science and Nutrition. 57 (17): 3640–3649. doi:10.1080/10408398.2016.1138447. hdl:2158/1079985. PMID 26853923. S2CID 10073754. Archived from the original on 2023-01-24. Retrieved 2018-08-02.</ref>

Water

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 six to eight glasses of water daily is the minimum to maintain proper hydration.<ref>"Healthy Water Living". BBC. Retrieved 1 February 2007. Archived from the original on 1 January 2007.</ref> However, the notion that a person should consume eight glasses of water per day cannot be traced to a credible scientific source.<ref>Valtin, Heinz (2002). ""Drink at least eight glasses of water a day." Really? Is there scientific evidence for "8 × 8"?". American Journal of Physiology. Regulatory, Integrative and Comparative Physiology. 283 (5): R993–R1004. doi:10.1152/ajpregu.00365.2002. PMID 12376390.</ref> 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."<ref>Food and Nutrition Board, National Academy of Sciences. Recommended Dietary Allowances, revised 1945. National Research Council, Reprint and Circular Series, No. 122, 1945 (Aug), pp. 3–18.</ref> 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.<ref name="Le Bellego">Le Bellego L, Jean C, Jiménez L, Magnani C, Tang W, Boutrolle I (2010). "Understanding fluid consumption patterns to improve healthy hydration". Nutr Today. 45 (6): S22–S26. doi:10.1097/NT.0b013e3181fe4314. S2CID 76128311.</ref> 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).<ref name="Scientific Opinion on Dietary Reference Values for water">EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) (2010). "Scientific Opinion on Dietary Reference Values for Water" (PDF). EFSA Journal. 8 (3): 1459. doi:10.2903/j.efsa.2010.1459. S2CID 79245852. Archived (PDF) from the original on 2017-09-22.</ref> 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."<ref name="Scientific Opinion on Dietary Reference Values for water" />

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.<ref>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. doi:10.1123/ijsnem.15.3.252. PMID 16131696.</ref> Water content varies depending on the type of food consumed, with fruit and vegetables containing more than cereals, for example.<ref name="FAO">"FAO Corporate Document Repository. Food Balance Sheets- A Handbook." Archived 2019-02-17 at the Wayback Machine Retrieved 7 March 2011</ref> These values are estimated using country-specific food balance sheets published by the Food and Agriculture Organisation of the United Nations.<ref name="FAO" />

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.<ref name="Scientific Opinion on Dietary Reference Values for water" /> Pregnant and breastfeeding 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.<ref name="Scientific Opinion on Dietary Reference Values for water" /> To compensate for additional fluid output, breastfeeding women require an additional 700 mL/day above the recommended intake values for non-lactating women. Dehydration and over-hydration – too little and too much water, respectively – can have harmful consequences. Drinking too much water is one of the possible causes of hyponatremia, i.e., low serum sodium.<ref name="Scientific Opinion on Dietary Reference Values for water" /><ref>Farrell DJ, Bower L (October 2003). "Fatal water intoxication". Journal of Clinical Pathology. 56 (10): 803–04. doi:10.1136/jcp.56.10.803-a. PMC 1770067. PMID 14514793.</ref>

Minerals

Essential elements for higher organisms (eucarya).<ref>Ultratrace minerals. Authors: Nielsen, Forrest H. USDA, ARS Source: Modern nutrition in health and disease / editors, Maurice E. Shils ... et al. Baltimore: Williams & Wilkins, c1999., p. 283-303. Issue Date: 1999 URI: [1]</ref><ref name="Szklarska2019">Szklarska D, Rzymski P (May 2019). "Is Lithium a Micronutrient? From Biological Activity and Epidemiological Observation to Food Fortification". Biol Trace Elem Res. 189 (1): 18–27. doi:10.1007/s12011-018-1455-2. PMC 6443601. PMID 30066063.</ref><ref name="Enderle2020">Enderle J, Klink U, di Giuseppe R, Koch M, Seidel U, Weber K, Birringer M, Ratjen I, Rimbach G, Lieb W (August 2020). "Plasma Lithium Levels in a General Population: A Cross-Sectional Analysis of Metabolic and Dietary Correlates". Nutrients. 12 (8): 2489. doi:10.3390/nu12082489. PMC 7468710. PMID 32824874.</ref><ref name=bromine>McCall AS, Cummings CF, Bhave G, Vanacore R, Page-McCaw A, Hudson BG (June 2014). "Bromine is an essential trace element for assembly of collagen IV scaffolds in tissue development and architecture". Cell. 157 (6): 1380–92. doi:10.1016/j.cell.2014.05.009. PMC 4144415. PMID 24906154.</ref><ref name=essentialmetals>Zoroddu, Maria Antonietta; Aaseth, Jan; Crisponi, Guido; Medici, Serenella; Peana, Massimiliano; Nurchi, Valeria Marina (2019). "The essential metals for humans: a brief overview". Journal of Inorganic Biochemistry. 195: 120–129. doi:10.1016/j.jinorgbio.2019.03.013.</ref> v t e
H																	He
Li	Be											B	C	N	O	F	Ne
Na	Mg											Al	Si	P	S	Cl	Ar
K	Ca	Sc	Ti	V	Cr	Mn	Fe	Co	Ni	Cu	Zn	Ga	Ge	As	Se	Br	Kr
Rb	Sr	Y	Zr	Nb	Mo	Tc	Ru	Rh	Pd	Ag	Cd	In	Sn	Sb	Te	I	Xe

Legend:

The four basic organic elements

Quantity elements

Essential trace elements

Essentiality or function debated

Dietary minerals are inorganic chemical elements required by living organisms,<ref name="Mitchell, Dakota and Haroun, Lee 2012 279">Mitchell, Dakota; Haroun, Lee (2012). Introduction to Health Care (3 ed.). Delmar Cengage. p. 279. ISBN 978-1-4354-8755-0.</ref> other than the four elements carbon, hydrogen, nitrogen, and oxygen that are present in nearly all organic molecules. Some have roles as cofactors, while others are electrolytes.<ref>Nelson, D.L.; Cox, M.M. (2000). Lehninger Principles of Biochemistry (3rd ed.). New York: Worth Publishing. ISBN 978-1-57259-153-0.</ref> 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 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 well-known is likely iodine in iodized salt which prevents goiter.^{[medical citation needed]}

Macrominerals

Elements with recommended dietary allowance (RDA) greater than 150 mg/day are, in alphabetical order:

Calcium (Ca²⁺) is vital to the health of the muscular, circulatory, and digestive systems; is indispensable to the building of bone; and supports the synthesis and function of blood cells. For example, calcium is used to regulate the contraction of muscles, nerve conduction, and the clotting of blood. It can play this role because the Ca²⁺ ion forms stable coordination complexes with many organic compounds, especially proteins; it also forms compounds with a wide range of solubility, enabling the formation of the skeleton.<ref>"Office of Dietary Supplements - Calcium". ods.od.nih.gov. Archived from the original on 17 March 2018. Retrieved 31 October 2019.</ref>
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). Approximately 50% is in bone, the remaining 50% is almost all inside body cells, with only about 1% located in extracellular fluid. Food sources include oats, buckwheat, tofu, nuts, caviar, green leafy vegetables, legumes, and chocolate.<ref name="mahan">L. Kathleen Mahan; Janice L. Raymond; Sylvia Escott-Stump (2012). Krausw's Food and the Nutrition Care Process (13th ed.). St. Louis: Elsevier. ISBN 978-1-4377-2233-8.</ref><ref name="USDA DB">"USDA National Nutrient Database for Standard Reference, SR26, 2013". Archived from the original on 2023-01-15. Retrieved 2022-10-19.</ref>
Phosphorus, required component of bones; essential for energy processing.<ref>D. E. C. Corbridge (1995). Phosphorus: An Outline of its Chemistry, Biochemistry, and Technology (5th ed.). Amsterdam: Elsevier. ISBN 978-0-444-89307-9.</ref> Approximately 80% is found in the inorganic portion of bones and teeth. Phosphorus is a component of every cell, as well as important metabolites, including DNA, RNA, ATP, and phospholipids. Also important in pH regulation. It is an important electrolyte in the form of phosphate.<ref>"Overview of Disorders of Phosphate Concentration - Endocrine and Metabolic Disorders". MSD Manual Professional Edition. Archived from the original on 5 August 2019. Retrieved 31 October 2019.</ref> Food sources include cheese, egg yolk, milk, meat, fish, poultry, whole-grain cereals, and many others.<ref name="mahan" />
Potassium, a common electrolyte (heart and nerve function). With sodium, potassium is involved in maintaining normal water balance, osmotic equilibrium, and acid-base balance. In addition to calcium, it is important in the regulation of neuromuscular activity. Food sources include bananas, avocados, nuts, vegetables, potatoes, legumes, fish, and mushrooms.<ref name="USDA DB" />
Sodium, a common food ingredient and electrolyte, found in most foods and manufactured consumer products, typically as sodium chloride (salt). Excessive sodium consumption can deplete calcium and magnesium.<ref>"Chapter 14. Magnesium". Food and Agriculture Organization of the United States. Archived from the original on 2019-11-01. Retrieved 2020-01-03.</ref> Sodium has a role in the etiology of hypertension demonstrated from studies showing that a reduction of table salt intake may reduce blood pressure.<ref>Ha, Sung Kyu (1 June 2014). "Dietary salt intake and hypertension". Electrolytes and Blood Pressure. 12 (1): 7–18. doi:10.5049/EBP.2014.12.1.7. ISSN 1738-5997. PMC 4105387. PMID 25061468.</ref><ref>Wang, Miao; Moran, Andrew E.; Liu, Jing; Qi, Yue; Xie, Wuxiang; Tzong, Keane; Zhao, Dong (1 December 2015). "A Meta-Analysis of Effect of Dietary Salt Restriction on Blood Pressure in Chinese Adults". Global Heart. 10 (4): 291–299.e6. doi:10.1016/j.gheart.2014.10.009. ISSN 2211-8179. PMC 4529389. PMID 26014655.</ref>

Trace minerals

Many elements are required in smaller amounts (microgram quantities), usually because they play a catalytic role in enzymes.<ref name=lipp>Lippard, S. J.; Berg, J. M. (1994). Principles of Bioinorganic Chemistry. Mill Valley, CA: University Science Books. ISBN 978-0-935702-73-6.</ref> Some trace mineral elements (RDA < 200 mg/day) are, in alphabetical order:^{[medical citation needed]}

Cobalt as a component of the vitamin B₁₂ family of coenzymes
Copper required component of many redox enzymes, including cytochrome c oxidase (see Copper in health)
Chromium required for sugar metabolism
Iodine required not only for the biosynthesis of thyroxin, but probably, for other important organs as breast, stomach, salivary glands, thymus etc. (see Iodine deficiency); for this reason iodine is needed in larger quantities than others in this list, and sometimes classified with the macrominerals;<ref>Kapil U (December 2007). "Health consequences of iodine deficiency". Sultan Qaboos University Medical Journal. 7 (3): 267–72. PMC 3074887. PMID 21748117.</ref> Nowadays it is most easily found in iodized salt, but there are also natural sources such as Kombu.<ref>Zava TT, Zava DT (October 2011). "Assessment of Japanese iodine intake based on seaweed consumption in Japan: A literature-based analysis". Thyroid Research. 4 (1): 14. doi:10.1186/1756-6614-4-14. PMC 3204293. PMID 21975053.</ref><ref>Yeh TS, Hung NH, Lin TC (1 June 2014). "Analysis of iodine content in seaweed by GC-ECD and estimation of iodine intake". Journal of Food and Drug Analysis. 22 (2): 189–196. doi:10.1016/j.jfda.2014.01.014. ISSN 1021-9498. PMC 9359334.</ref>
Iron required for many enzymes, and for hemoglobin and some other proteins
Manganese (processing of oxygen)
Molybdenum required for xanthine oxidase and related oxidases
Selenium required for peroxidase (antioxidant proteins)
Zinc required for several enzymes such as carboxypeptidase, liver alcohol dehydrogenase, carbonic anhydrase

Ultratrace minerals

Ultratrace minerals are an as yet unproven aspect of human nutrition, and may be required at amounts measured in very low ranges of μg/day. Many ultratrace elements have been suggested as essential, but such claims have usually not been confirmed. Definitive evidence for efficacy comes from the characterization of a biomolecule containing the element with an identifiable and testable function. These include:<ref>Nielsen, Forrest H. (1998). "Ultratrace elements in nutrition: Current knowledge and speculation". The Journal of Trace Elements in Experimental Medicine. 11 (2–3): 251–274. doi:10.1002/(SICI)1520-670X(1998)11:2/3<251::AID-JTRA15>3.0.CO;2-Q. ISSN 1520-670X.</ref><ref>Nielsen FH (September 1996). "How should dietary guidance be given for mineral elements with beneficial actions or suspected of being essential?". The Journal of Nutrition. 126 (9 Suppl): 2377S–2385S. doi:10.1093/jn/126.suppl_9.2377S. PMID 8811801.</ref>

Bromine
Arsenic
Nickel
Fluorine
Boron
Lithium
Strontium
Silicon
Vanadium

Vitamins

Except for vitamin D, vitamins are essential nutrients,<ref name="Mitchell, Dakota and Haroun, Lee 2012 279"/> necessary in the diet for good health. Vitamin D can be synthesized in the skin in the presence of UVB radiation. (Many animal species can synthesize vitamin C, but humans cannot.) 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); experimental demonstration has been suggestive but inconclusive. Other essential nutrients not classed as vitamins include essential amino acids (see above), essential fatty acids (see above), and the minerals discussed in the preceding section.^{[medical citation needed]}

Vitamin deficiencies may result in disease conditions: goiter, 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.<ref>Shils (2005). Modern Nutrition in Health and Disease. Lippincott Williams and Wilkins. ISBN 978-0-7817-4133-0.</ref>

Excess levels of some vitamins are also dangerous to health. The Food and Nutrition Board of the Institute of Medicine has established Tolerable Upper Intake Levels (ULs) for seven vitamins.<ref>Dietary Reference Intakes (DRIs): Tolerable Upper Intake Levels, Vitamins, 2011, archived from the original on 2022-06-29, retrieved 2020-01-03</ref>

Malnutrition

The term malnutrition addresses 3 broad groups of conditions:

Undernutrition, which includes wasting (low weight-for-height), stunting (low height-for-age) and underweight (low weight-for-age)
Micronutrient-related malnutrition, which includes micronutrient deficiencies or insufficiencies (a lack of important vitamins and minerals) or micronutrient excess
Overweight, obesity and diet-related noncommunicable diseases (such as heart disease, stroke, diabetes and some cancers).<ref>"Malnutrition". www.who.int. Archived from the original on 2022-07-16. Retrieved 2020-01-03.</ref>

In developed countries, the diseases of malnutrition are most often associated with nutritional imbalances or excessive consumption; there are more people in the world who are malnourished due to excessive consumption. According to the United Nations World Health Organization, the greatest challenge in developing nations today is not starvation, but insufficient nutrition – the lack of nutrients necessary for the growth and maintenance of vital functions. The causes of malnutrition are directly linked to inadequate macronutrient consumption and disease, and are indirectly linked to factors like "household food security, maternal and child care, health services, and the environment."<ref name="Essential Nutrition Actions" />

Insufficient

The U.S. Food and Nutrition Board sets Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for vitamins and minerals. EARs and RDAs are part of Dietary Reference Intakes.<ref name="ods.od.nih.gov">[2] Archived 2020-07-02 at the Wayback Machine Nutrient recommendations: Dietary Reference Intakes (DRI).</ref> The DRI documents describe nutrient deficiency signs and symptoms.

Excessive

The U.S. Food and Nutrition Board sets Tolerable Upper Intake Levels (known as ULs) for vitamins and minerals when evidence is sufficient. ULs are set a safe fraction below amounts shown to cause health problems. ULs are part of Dietary Reference Intakes.<ref name="ods.od.nih.gov"/> The European Food Safety Authority also reviews the same safety questions and set its own ULs.<ref>Tolerable Upper Intake Levels For Vitamins And Minerals (PDF), European Food Safety Authority, 2006, archived (PDF) from the original on 2016-03-16, retrieved 2020-01-03</ref>

Unbalanced

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. High calorie food ingredients such as vegetable oils, sugar and alcohol are referred to as "empty calories" because they displace from the diet foods that also contain protein, vitamins, minerals and fiber.<ref>"What are empty calories?". USDA MyPlate 2011. 27 March 2015. Archived from the original on 30 January 2014. Retrieved 20 October 2017.</ref>

Illnesses caused by underconsumption and overconsumption

Nutrients	Deficiency	Excess
Macronutrients
Food energy	Starvation, marasmus	Obesity, diabetes mellitus, cardiovascular disease
Simple carbohydrates	None	Obesity, diabetes mellitus, cardiovascular disease
Complex carbohydrates	None	Obesity, cardiovascular disease (high glycemic index foods)
Protein	Kwashiorkor	Protein poisoning
Saturated fat	Low testosterone levels,<ref>Berardi, John. "The Big T: How Your Lifestyle Influences Your Testosterone Levels". Deepfitness.com. Archived from the original on 30 May 2012. Retrieved 8 October 2013.</ref> vitamin deficiencies^{[citation needed]}	Obesity, cardiovascular disease<ref name="ESC">Graham I, Atar D, Borch-Johnsen K, Boysen G, Burell G, Cifkova R, et al. (October 2007). "European guidelines on cardiovascular disease prevention in clinical practice: executive summary: Fourth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular Disease Prevention in Clinical Practice (Constituted by representatives of nine societies and by invited experts)". European Heart Journal. 28 (19): 2375–414. doi:10.1093/eurheartj/ehm316. hdl:2066/52036. PMID 17726041.</ref>
Trans fat	None	Obesity, cardiovascular disease
Unsaturated fat	Fat-soluble vitamin deficiency	Obesity, cardiovascular disease
Micronutrients
Vitamin A	Xerophthalmia, night blindness, and low testosterone levels^{[citation needed]}	Hypervitaminosis A (cirrhosis, hair loss)
Vitamin B₁	Beri-Beri
Vitamin B₂	Skin and corneal lesions, cracking of skin and corneal unclearation
Niacin	Pellagra	Dyspepsia, cardiac arrhythmias, birth defects
Biotin	Biotin deficiency	Reproductive and teratogenic effects
Folate	Anemia	Masks B₁₂ deficiency, which can lead to permanent neurological damage
Vitamin B₁₂	Pernicious anemia, nerve cell damage
Vitamin C	Scurvy	Diarrhea causing dehydration
Vitamin D	Rickets, osteomalacia	Hypervitaminosis D (dehydration, vomiting, constipation)
Vitamin E	Neurological disease	Hypervitaminosis E (anticoagulant: excessive bleeding)
Vitamin K	Hemorrhage
Omega-3 fats	Cardiovascular Disease	Bleeding, hemorrhages, hemorrhagic stroke, reduced glycemic control among diabetics
Omega-6 fats	None	Cardiovascular disease, Cancer
Cholesterol		Cardiovascular disease:<ref name=ESC/> atherosclerotic plaques, heart attack, stroke
Macrominerals
Calcium	Osteoporosis, tetany, carpopedal spasm, laryngospasm, cardiac arrhythmias	Fatigue, depression, confusion, nausea, vomiting, constipation, pancreatitis, increased urination, kidney stones, anorexia^{[citation needed]}
Magnesium	Hypertension	Weakness, nausea, vomiting, impaired breathing, and hypotension
Potassium	Hypokalemia, cardiac arrhythmias	Hyperkalemia, palpitations
Sodium	Hyponatremia	Hypernatremia, hypertension
Trace minerals
Iron	Anemia	Cirrhosis, hereditary hemochromatosis, heart disease, cardiovascular disease
Iodine	Goiter, hypothyroidism	Iodine toxicity (goiter, hypothyroidism)

Other substances

Alcohol (ethanol)

Pure ethanol provides 7 calories per gram. For distilled spirits, a standard serving in the United States is 1.5 fluid ounces, which at 40% ethanol (80 proof), would be 14 grams and 98 calories.<ref>"Appendix 9. Alcohol". health.gov. Archived from the original on 2020-02-01. Retrieved 2020-01-03.</ref> Wine and beer contain a similar range of ethanol for servings of 5 ounces and 12 ounces, respectively, but these beverages also contain non-ethanol calories. A 5-ounce serving of wine contains 100 to 130 calories. A 12-ounce serving of beer contains 95 to 200 calories.<ref>"Alcohol and Nutrition: The Calorie and Carb Breakdown!". The Catholic University of America. Archived from the original on 2019-10-01. Retrieved 2020-01-03.</ref> According to the U.S. Department of Agriculture, based on NHANES 2013-2014 surveys, women ages 20 and up consume on average 6.8 grams/day and men consume on average 15.5 grams/day.<ref>"What We Eat in America, NHANES 2013-2014" (PDF). Archived (PDF) from the original on 2017-02-12.</ref> Ignoring the non-alcohol contribution of those beverages, the average ethanol calorie contributions are 48 and 108 cal/day. Alcoholic beverages are considered empty calorie foods because other than calories, these contribute no essential nutrients.

Phytochemicals

Phytochemicals such as polyphenols are compounds produced naturally in plants (phyto means "plant" in Greek). In general, the term identifies compounds that are prevalent in plant foods, but are not proven to be essential for human nutrition, as of 2018. There is no conclusive evidence in humans that polyphenols or other non-nutrient compounds from plants confer health benefits, mainly because these compounds have poor bioavailability, i.e., following ingestion, they are digested into smaller metabolites with unknown functions, then are rapidly eliminated from the body.<ref>d'Archivio, M.; Filesi, C.; Varì, R.; Scazzocchio, B.; Masella, R. (2010). "Bioavailability of the polyphenols: status and controversies". International Journal of Molecular Sciences. 11 (4): 1321–42. doi:10.3390/ijms11041321. PMC 2871118. PMID 20480022.</ref><ref name="acs">"Common questions about diet and cancer". American Cancer Society. 5 February 2016. Archived from the original on 23 November 2018. Retrieved 23 November 2018.</ref>

While initial studies sought to reveal if dietary supplements might promote health, one meta-analysis concluded that supplementation with antioxidant vitamins A and E and beta-carotene did not convey any benefits, and may increase risk of death.<ref>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". JAMA. 297 (8): 842–57. doi:10.1001/jama.297.8.842. PMID 17327526.</ref> Vitamin C and selenium supplements did not impact mortality rate. Health effect of non-nutrient phytochemicals such as polyphenols were not assessed in this review.<ref>Sepkowitz, Kent (3 August 2011). "The Doctor and the Pomegranate". Slate. Archived from the original on 14 September 2011. Retrieved 3 January 2020.</ref>

Colorful fruits and vegetables may be components of a healthy diet.

Intestinal microbiome

The intestines contain a large population of gut flora. In humans, the four dominant phyla are Bacillota, Bacteroidota, Actinomycetota, and Pseudomonadota.<ref name="pmid24388028">Khanna S, Tosh PK (January 2014). "A clinician's primer on the role of the microbiome in human health and disease". Mayo Clin. Proc. 89 (1): 107–14. doi:10.1016/j.mayocp.2013.10.011. PMID 24388028.</ref> They are essential to digestion and are also affected by food that is consumed. Bacteria are essential for metabolizing food substrates and thereby increasing energy output, and produce a great variety of metabolites, including vitamins and short-chain fatty acids that contribute to the metabolism in a wide variety of ways.<ref>Kolmeder, Carolin A.; de Vos, Willem M. (29 October 2020). "Roadmap to functional characterization of the human intestinal microbiota in its interaction with the host". Journal of Pharmaceutical and Biomedical Analysis. 194: 113751. doi:10.1016/j.jpba.2020.113751. PMID 33328144. S2CID 229300476.</ref> These metabolites are responsible for stimulating cell growth, repressing the growth of harmful bacteria, priming the immune system to respond only to pathogens, helping to maintain a healthy gut barrier, control gene expression by epigenetic regulation<ref>Gu, Bon-Hee; Kim, Myunghoo; Yun, Cheol-Heui (7 January 2021). "Regulation of gastrointestinal immunity by metabolites". Nutrients. 13 (1): 167. doi:10.3390/nu13010167. PMC 7826526. PMID 33430497.</ref> and defending against some infectious diseases.<ref name="Guarner and Malagelada 2003b">Guarner, F; Malagelada, J (2003). "Gut flora in health and disease". The Lancet. 361 (9356): 512–19. doi:10.1016/S0140-6736(03)12489-0. PMID 12583961. S2CID 38767655.</ref>

Global nutrition challenges

The challenges facing global nutrition are disease, child malnutrition, obesity, and vitamin deficiency.^{[medical citation needed]}

Disease

The most common non-infectious diseases worldwide, that contribute most to the global mortality rate, are cardiovascular diseases, various cancers, diabetes, and chronic respiratory problems, all of which are linked to poor nutrition. Nutrition and diet are closely associated with the leading causes of death, including cardiovascular disease and cancer. Obesity and high sodium intake can contribute to ischemic heart disease, while consumption of fruits and vegetables can decrease the risk of developing cancer.<ref name="GNP"/>

Food-borne and infectious diseases can result in malnutrition, and malnutrition exacerbates infectious disease. Poor nutrition leaves children and adults more susceptible to contracting life-threatening diseases such as diarrheal infections and respiratory infections.<ref name="Progress for Children" /> According to the WHO, in 2011, 6.9 million children died of infectious diseases like pneumonia, diarrhea, malaria, and neonatal conditions, of which at least one third were associated with undernutrition.<ref>"UNICEF 2012 Progress Report: Rapid progress in child survival". World Health Organization. 18 September 2012. Archived from the original on 17 June 2016. Retrieved 28 May 2016.</ref><ref name="ENA4">WHO. World health statistics 2013: a wealth of information on global public health. Geneva, WHO, 2013. pp. 5-7</ref><ref name="ENA6">Liu L, Johnson HL, Cousens S, Perin J, Scott S, Lawn JE, et al. (June 2012). "Global, regional, and national causes of child mortality: an updated systematic analysis for 2010 with time trends since 2000". Lancet. 379 (9832): 2151–61. doi:10.1016/S0140-6736(12)60560-1. PMID 22579125. S2CID 43866899.</ref>

Child malnutrition

According to UNICEF, in 2011, 101 million children across the globe were underweight and one in four children, 165 million, were stunted in growth.<ref name="ENA1">UNICEF, WHO, World Bank. UNICEF-WHO-World Bank Joint child malnutrition estimates. New York, Geneva & Washington DC, UNICEF, WHO & World Bank, 2012 ([3], accessed 27 March 2013)</ref> Simultaneously, there are 43 million children under five who are overweight or obese.<ref name="Essential Nutrition Actions" /> Nearly 20 million children under five suffer from severe acute malnutrition, a life-threatening condition requiring urgent treatment.<ref name="Essential Nutrition Actions" /> According to estimations at UNICEF, hunger will be responsible for 5.6 million deaths of children under the age of five this year.<ref name="Progress for Children"/> These all represent significant public health emergencies.<ref name="GNP">WHO (2013). Global Nutrition Policy. Report of a WHO Expert Committee. Geneva, World Health Organization. http://apps.who.int/iris/bitstream/10665/84408/1/9789241505529_eng.pdf Archived 2013-12-25 at the Wayback Machine</ref> This is because proper maternal and child nutrition has immense consequences for survival, acute and chronic disease incidence, normal growth, and economic productivity of individuals.<ref name="Maternal undernutrition">Black RE, Victora CG, Walker SP, Bhutta ZA, Christian P, de Onis M, et al. (August 2013). "Maternal and child undernutrition and overweight in low-income and middle-income countries". Lancet. 382 (9890): 427–451. doi:10.1016/S0140-6736(13)60937-X. PMID 23746772. S2CID 12237910.</ref>

Childhood malnutrition is common and contributes to the global burden of disease.<ref>Murray CJ, Lopez AD (May 1997). "Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study". Lancet. 349 (9063): 1436–42. doi:10.1016/S0140-6736(96)07495-8. PMID 9164317. S2CID 2569153.</ref> Childhood is a particularly important time to achieve good nutrition status, because poor nutrition has the capability to lock a child in a vicious cycle of disease susceptibility and recurring sickness, which threatens cognitive and social development.<ref name="Progress for Children" /> Undernutrition and bias in access to food and health services leaves children less likely to attend or perform well in school.<ref name="Progress for Children" />

Undernutrition

UNICEF defines undernutrition "as the outcome of insufficient food intake (hunger) and repeated infectious diseases. Under nutrition includes being underweight for one's age, too short for one's age (stunted), dangerously thin (wasted), and deficient in vitamins and minerals (micronutrient malnutrient).<ref name="Progress for Children" /> Under nutrition causes 53% of deaths of children under five across the world.<ref name="Progress for Children" /> It has been estimated that undernutrition is the underlying cause for 35% of child deaths.<ref name="Black">Black RE, Allen LH, Bhutta ZA, Caulfield LE, de Onis M, Ezzati M, et al. (January 2008). "Maternal and child undernutrition: global and regional exposures and health consequences". Lancet. 371 (9608): 243–60. doi:10.1016/s0140-6736(07)61690-0. PMID 18207566. S2CID 3910132.</ref> The Maternal and Child Nutrition Study Group estimate that under nutrition, "including fetal growth restriction, stunting, wasting, deficiencies of vitamin A and zinc along with suboptimum breastfeeding—is a cause of 3.1 million child deaths and infant mortality, or 45% of all child deaths in 2011".<ref name="Maternal undernutrition" />

When humans are undernourished, they no longer maintain normal bodily functions, such as growth, resistance to infection, or have satisfactory performance in school or work.<ref name="Progress for Children" /> Major causes of under nutrition in young children include lack of proper breast feeding for infants and illnesses such as diarrhea, pneumonia, malaria, and HIV/AIDS.<ref name="Progress for Children" /> According to UNICEF 146 million children across the globe, that one out of four under the age of five, are underweight.<ref name="Progress for Children" /> The number of underweight children has decreased since 1990, from 33 percent to 28 percent between 1990 and 2004.<ref name="Progress for Children" /> Underweight and stunted children are more susceptible to infection, more likely to fall behind in school, more likely to become overweight and develop non-infectious diseases, and ultimately earn less than their non-stunted coworkers.<ref name="IMPROVING CHILD NUTRITION">IMPROVING CHILD NUTRITION > UNICEF. (April 2013). IMPROVING CHILD NUTRITION: The achievable imperative for global progress. http://www.unicef.org/publications/index_68661.html Archived 2013-05-13 at the Wayback Machine</ref> Therefore, undernutrition can accumulate deficiencies in health which results in less productive individuals and societies<ref name="Progress for Children" />

Many children are born with the inherent disadvantage of low birth weight, often caused by intrauterine growth restriction and poor maternal nutrition, which results in worse growth, development, and health throughout the course of their lifetime.<ref name="GNP" /> Children born at low birthweight (less than 5.5 pounds or 2.5 kg), are less likely to be healthy and are more susceptible to disease and early death.<ref name="Progress for Children" /> Those born at low birthweight also are likely to have a depressed immune system, which can increase their chances of heart disease and diabetes later on in life.<ref name="Progress for Children" /> Because 96% of low birthweight occurs in the developing world, low birthweight is associated with being born to a mother in poverty with poor nutritional status that has had to perform demanding labor.<ref name="Progress for Children" />

Stunting and other forms of undernutrition reduces a child's chance of survival and hinders their optimal growth and health.<ref name="IMPROVING CHILD NUTRITION" /> Stunting has demonstrated association with poor brain development, which reduces cognitive ability, academic performance, and eventually earning potential.<ref name="IMPROVING CHILD NUTRITION" /> Important determinants of stunting include the quality and frequency of infant and child feeding, infectious disease susceptibility, and the mother's nutrition and health status.<ref name="IMPROVING CHILD NUTRITION" /> Undernourished mothers are more likely to birth stunted children, perpetuating a cycle of undernutrition and poverty.<ref name="IMPROVING CHILD NUTRITION" /> Stunted children are more likely to develop obesity and chronic diseases upon reaching adulthood.<ref name="IMPROVING CHILD NUTRITION" /> Therefore, malnutrition resulting in stunting can further worsen the obesity epidemic, especially in low and middle income countries.<ref name="IMPROVING CHILD NUTRITION" /> This creates even new economic and social challenges for vulnerable impoverished groups.<ref name="IMPROVING CHILD NUTRITION" />

Data on global and regional food supply shows that consumption rose from 2011 to 2012 in all regions. Diets became more diverse, with a decrease in consumption of cereals and roots and an increase in fruits, vegetables, and meat products.<ref name="FAO2012">FAO (2012). The state of food insecurity in the world 2012: Economic growth is necessary but not sufficient to accelerate reduction of hunger and malnutrition. Rome, Food and Agricultural Organization of the United Nations. http://www.fao.org/publications/sofi/en/ Archived 2021-02-14 at the Wayback Machine (Accessed 7 December 2012.).</ref> However, this increase masks the discrepancies between nations, where Africa, in particular, saw a decrease in food consumption over the same years.<ref name="FAO2012" /> This information is derived from food balance sheets that reflect national food supplies, however, this does not necessarily reflect the distribution of micro and macronutrients.<ref name="FAO2012" /> Often inequality in food access leaves distribution which uneven, resulting in undernourishment for some and obesity for others.<ref name="FAO2012" />

Undernourishment, or hunger, according to the FAO, is dietary intake below the minimum daily energy requirement.<ref name="FAO" /> The amount of undernourishment is calculated utilizing the average amount of food available for consumption, the size of the population, the relative disparities in access to the food, and the minimum calories required for each individual.<ref name="FAO" /> According to FAO, 868 million people (12% of the global population) were undernourished in 2012.<ref name="FAO" /> This has decreased across the world since 1990, in all regions except for Africa, where undernourishment has steadily increased.<ref name="FAO" /> However, the rates of decrease are not sufficient to meet the first Millennium Development Goal of halving hunger between 1990 and 2015.<ref name="FAO" /> The global financial, economic, and food price crisis in 2008 drove many people to hunger, especially women and children. The spike in food prices prevented many people from escaping poverty, because the poor spend a larger proportion of their income on food and farmers are net consumers of food.<ref name="UNSCN09">UNSCN (2009). Global financial and economic crisis – The most vulnerable are at increased risk of hunger and malnutrition. United Nations Standing Committee on Nutrition. http://www.unscn.org/en/publications/nutrition_briefs/#Nutrition_impacts_of_global_food_and_financial_crises Archived 3 December 2013 at the Wayback Machine.</ref> High food prices cause consumers to have less purchasing power and to substitute more-nutritious foods with low-cost alternatives.<ref name="IBRD">IBRD, World Bank (2012). Global Monitoring Report 2012: Food prices, nutrition, and the Millennium Development Goals. International Bank for Reconstruction and Development (IBRD)/World Bank, Washington, DC.</ref>

Adult overweight and obesity

Malnutrition in industrialized nations is primarily due to excess calories and non-nutritious carbohydrates, which has contributed to the obesity epidemic affecting both developed and some developing nations.<ref name=P4C48>Darnton-Hill I, Nishida C, James WP (2004). "A life course approach to diet, nutrition and the prevention of chronic diseases". Public Health Nutrition. 7 (1A): 101–121. doi:10.1079/phn2003584. PMID 14972056.</ref> In 2008, 35% of adults above the age of 20 years were overweight (BMI ≥ 25 kg/m²), a prevalence that has doubled worldwide between 1980 and 2008.<ref name="ENA25">Finucane MM, Stevens GA, Cowan MJ, Danaei G, Lin JK, Paciorek CJ, et al. (February 2011). "National, regional, and global trends in body-mass index since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 country-years and 9·1 million participants". Lancet. 377 (9765): 557–67. doi:10.1016/S0140-6736(10)62037-5. PMC 4472365. PMID 21295846.</ref> Also 10% of men and 14% of women were obese, with a BMI greater than 30.<ref name="WHOglobe" /> Rates of overweight and obesity vary across the globe, with the highest prevalence in the Americas, followed by European nations, where over 50% of the population is overweight or obese.<ref name="WHOglobe" />

Obesity is more prevalent amongst high income and higher middle income groups than lower divisions of income.<ref name="WHOglobe" /> Women are more likely than men to be obese, where the rate of obesity in women doubled from 8% to 14% between 1980 and 2008.<ref name="WHOglobe" /> Being overweight as a child has become an increasingly important indicator for later development of obesity and non-infectious diseases such as heart disease.<ref name="Maternal undernutrition" /> In several western European nations, the prevalence of overweight and obese children rose by 10% from 1980 to 1990, a rate that has begun to accelerate recently.<ref name="Progress for Children" />

Vitamin and mineral malnutrition

Vitamins and minerals are essential to the proper functioning and maintenance of the human body.<ref name=":0">Stein, A. J. (2010). "Global Impacts of Human Mineral Malnutrition". Plant and Soil. 335 (1/2): 133–154. Bibcode:2010PlSoi.335..133S. doi:10.1007/s11104-009-0228-2. S2CID 23959785.</ref> There are 20 trace elements and minerals that are essential in small quantities to body function and overall human health.<ref name=":0" />

Iron deficiency is the most common inadequate nutrient worldwide, affecting approximately 2 billion people.<ref name="ENA12">WHO. Iron deficiency anemia: assessment, prevention, and control. A guide for program managers. Geneva, WHO, 2001^{[page needed]}</ref> Globally, anemia affects 1.6 billion people, and represents a public health emergency in mothers and children under five.<ref name="Iron">WHO (2001). Iron deficiency anemia: Assessment, prevention, and control. A guide for program managers. Geneva, World Health Organization.</ref> The World Health Organization estimates that there exists 469 million women of reproductive age and approximately 600 million preschool and school-age children worldwide who are anemic.<ref name="ENA13">WHO, Centers for Disease Control. Worldwide prevalence of anemia 1993–2005: WHO global database of anemia. Geneva, WHO, 2008.^{[page needed]}</ref> Anemia, especially iron-deficient anemia, is a critical problem for cognitive developments in children, and its presence leads to maternal deaths and poor brain and motor development in children.<ref name="Progress for Children" /> The development of anemia affects mothers and children more because infants and children have higher iron requirements for growth.<ref name="ENA14">W Institute of Medicine. Dietary reference intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. Washington DC, National Academy Press, 2001^{[page needed]}</ref> Health consequences for iron deficiency in young children include increased perinatal mortality, delayed mental and physical development, negative behavioral consequences, reduced auditory and visual function, and impaired physical performance.<ref name="ENA16">Algarín C, Peirano P, Garrido M, Pizarro F, Lozoff B (February 2003). "Iron deficiency anemia in infancy: long-lasting effects on auditory and visual system functioning". Pediatric Research. 53 (2): 217–23. doi:10.1203/01.PDR.0000047657.23156.55. PMID 12538778.</ref> The harm caused by iron deficiency during child development cannot be reversed and result in reduced academic performance, poor physical work capacity, and decreased productivity in adulthood.<ref name="Essential Nutrition Actions" /> Mothers are also very susceptible to iron-deficient anemia because women lose iron during menstruation, and rarely supplement it in their diet.<ref name="Essential Nutrition Actions" /> Maternal iron deficiency anemia increases the chances of maternal mortality, contributing to at least 18% of maternal deaths in low and middle income countries.<ref name="ENA20">"Global health risks - Mortality and burden of disease attributable to selected major risks". Geneva, WHO, 2009 (http://www.who.int/healthinfo/global_burden_disease/GlobalHealthRisks_report_full.pdf Archived 2013-08-10 at the Wayback Machine accessed 31 July 2017).^{[page needed]}</ref>

Vitamin A plays an essential role in developing the immune system in children, therefore, it is considered an essential micronutrient that can greatly affect health.<ref name="Progress for Children" /> However, because of the expense of testing for deficiencies, many developing nations have not been able to fully detect and address vitamin A deficiency, leaving vitamin A deficiency considered a silent hunger.<ref name="Progress for Children" /> According to estimates, subclinical vitamin A deficiency, characterized by low retinol levels, affects 190 million pre-school children and 19 million mothers worldwide.<ref name="VitAWHO">WHO (2009). Global prevalence of vitamin A deficiency in populations at risk 1995–2005. WHO Global Database on Vitamin A Deficiency. Geneva, World Health Organization. "Archived copy" (PDF). Archived from the original (PDF) on 23 September 2015. Retrieved 1 March 2014.{{cite web}}: CS1 maint: archived copy as title (link)</ref>

The WHO estimates that 5.2 million of these children under five are affected by night blindness, which is considered clinical vitamin A deficiency.<ref name="ENA9">WHO. Global prevalence of vitamin A deficiency in populations at risk 1995–2005: WHO Global database of vitamin A deficiency. Geneva, WHO, 2009.</ref> Severe vitamin A deficiency (VAD) for developing children can result in visual impairments, anemia and weakened immunity, and increase their risk of morbidity and mortality from infectious disease.<ref name="ENA10">Sommer A, West KP Jr. Vitamin A deficiency: health, survival, and vision. New York, Oxford University Press, 1996 p. 19 ISBN 0195088247</ref> This also presents a problem for women, with WHO estimating that 9.8 million women are affected by night blindness.<ref name="ENA11">Lozoff B, Jimenez E, Wolf AW (September 1991). "Long-term developmental outcome of infants with iron deficiency". The New England Journal of Medicine. 325 (10): 687–94. doi:10.1056/NEJM199109053251004. PMID 1870641.</ref> Clinical vitamin A deficiency is particularly common among pregnant women, with prevalence rates as high as 9.8% in South-East Asia.<ref name="VitAWHO"/>

Estimates say that 28.5% of the global population is iodine deficient, representing 1.88 billion individuals.<ref name="Iodine">Andersson M, Karumbunathan V, Zimmermann MB (April 2012). "Global iodine status in 2011 and trends over the past decade". The Journal of Nutrition. 142 (4): 744–50. doi:10.3945/jn.111.149393. PMID 22378324.</ref> Although salt iodization programs have reduced the prevalence of iodine deficiency, this is still a public health concern in 32 nations. Moderate deficiencies are common in Europe and Africa, and over consumption is common in the Americas.<ref name="GNP" /> Iodine-deficient diets can interfere with adequate thyroid hormone production, which is responsible for normal growth in the brain and nervous system. This ultimately leads to poor school performance and impaired intellectual capabilities.<ref name="Progress for Children" />

Infant and young child feeding

Improvement of breast feeding practices, like early initiation and exclusive breast feeding for the first two years of life, could save the lives of 1.5 million children annually.<ref name=ENA7>Jones G, Steketee RW, Black RE, Bhutta ZA, Morris SS (July 2003). "How many child deaths can we prevent this year?". Lancet. 362 (9377): 65–71. doi:10.1016/S0140-6736(03)13811-1. PMID 12853204. S2CID 17908665.</ref> Nutrition interventions targeted at infants aged 0–5 months first encourages early initiation of breastfeeding.<ref name="Essential Nutrition Actions" /> Though the relationship between early initiation of breast feeding and improved health outcomes has not been formally established, a recent study in Ghana suggests a causal relationship between early initiation and reduced infection-caused neo-natal deaths.<ref name="Essential Nutrition Actions" /> Also, experts promote exclusive breastfeeding, rather than using formula, which has shown to promote optimal growth, development, and health of infants.<ref name=ENA2P7>WHO. Report of the expert consultation on the optimal duration of exclusive breastfeeding. Geneva, WHO, 2001.^{[page needed]}</ref> Exclusive breastfeeding often indicates nutritional status because infants that consume breast milk are more likely to receive all adequate nourishment and nutrients that will aid their developing body and immune system. This leaves children less likely to contract diarrheal diseases and respiratory infections.<ref name="Progress for Children" />

Besides the quality and frequency of breastfeeding, the nutritional status of mothers affects infant health. When mothers do not receive proper nutrition, it threatens the wellness and potential of their children.<ref name="Progress for Children" /> Well-nourished women are less likely to experience risks of birth and are more likely to deliver children who will develop well physically and mentally.<ref name="Progress for Children" /> Maternal undernutrition increases the chances of low-birth weight, which can increase the risk of infections and asphyxia in fetuses, increasing the probability of neonatal deaths.<ref name=ENA23>Ramakrishnan U, Yip R (April 2002). "Experiences and challenges in industrialized countries: control of iron deficiency in industrialized countries". The Journal of Nutrition. 132 (4 Suppl): 820S–4S. doi:10.1093/jn/132.4.820S. PMID 11925488.</ref> Growth failure during intrauterine conditions, associated with improper mother nutrition, can contribute to lifelong health complications.<ref name="Essential Nutrition Actions" /> Approximately 13 million children are born with intrauterine growth restriction annually.<ref name=ENA2>Black RE, Allen LH, Bhutta ZA, Caulfield LE, de Onis M, Ezzati M, et al. (January 2008). "Maternal and child undernutrition: global and regional exposures and health consequences". Lancet. 371 (9608): 243–60. doi:10.1016/S0140-6736(07)61690-0. PMID 18207566. S2CID 3910132.</ref>

Anorexia nervosa

The lifetime prevalence of anorexia nervosa in women is 0.9%, with 19 years as the average age of onset.^{[citation needed]} Although relatively uncommon, eating disorders can negatively affect menstruation, fertility, and maternal and fetal well-being. Among infertile women with amenorrhea or oligomenorrhea due to eating disorders, 58% had menstrual irregularities, according to preliminary research in 1990.<ref>Stewart, D. E.; Robinson, E.; Goldbloom, D. S.; Wright, C. (1990). "Infertility and eating disorders". American Journal of Obstetrics and Gynecology. 163 (4): 1196–1199. doi:10.1016/0002-9378(90)90688-4. ISSN 0002-9378. PMID 2220927.</ref>^{[citation needed]}

Nutrition literacy

The findings of the 2003 National Assessment of Adult Literacy (NAAL), conducted by the US Department of Education, 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<ref>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) Archived 2022-05-27 at the Wayback Machine. U.S. Department of Education, National Center for Education Statistics. Washington, DC: U.S. Government Printing Office.</ref> 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 than 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.<ref name="cdc.gov">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. 6 (4): A128. PMC 2774642. PMID 19755004. Archived from the original on 2022-08-07. Retrieved 2020-01-03.</ref> 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<ref name="cdc.gov"/> 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, a lack of understanding of 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<ref>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 Archived 2022-04-01 at the Wayback Machine. Prepared by RTI International – University of North Carolina Evidence-based Practice Center. Publication Number 11-E006. Rockville, MD. Agency for Healthcare Research and Quality.</ref> 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<ref name="cdc.gov"/> in order to achieve better health outcomes.

International food insecurity and malnutrition

According to UNICEF, South Asia has the highest levels of underweight children under five, followed by sub-Saharan Africans nations, with Industrialized countries and Latin nations having the lowest rates.<ref name="Progress for Children" />

United States

In the United States, 2% of children are underweight, with under 1% stunted and 6% are wasting.<ref name="Progress for Children" />

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. Anyone may call themselves a nutritionist, including unqualified dietitians, as this term is unregulated.^{[citation needed]} 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.^{[citation needed]}

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 plate of food which in 2011 superseded the MyPyramid food pyramid that had replaced 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. The U.S. Department of Health and Human Services provides a sample week-long menu which fulfills the nutritional recommendations of the government.<ref>"Archived copy" (PDF). Archived from the original (PDF) on 8 March 2008. Retrieved 8 March 2008.{{cite web}}: CS1 maint: archived copy as title (link)</ref> Canada's Food Guide is another governmental recommendation.^{[citation needed]}

Industrialized countries

According to UNICEF, the Commonwealth of Independent States has the lowest rates of stunting and wasting, at 14 percent and 3 percent.<ref name="Progress for Children" /> The nations of Estonia, Finland, Iceland, Lithuania and Sweden have the lowest prevalence of low birthweight children in the world- at 4%.<ref name="Progress for Children" /> Proper prenatal nutrition is responsible for this small prevalence of low birthweight infants.<ref name="Progress for Children" /> However, low birthweight rates are increasing, due to the use of fertility drugs, resulting in multiple births, women bearing children at an older age, and the advancement of technology allowing more pre-term infants to survive.<ref name="Progress for Children" /> Industrialized nations more often face malnutrition in the form of over-nutrition from excess calories and non-nutritious carbohydrates, which has contributed greatly to the public health epidemic of obesity.<ref name="P4C48"/> Disparities, according to gender, geographic location and socio-economic position, both within and between countries, represent the biggest threat to child nutrition in industrialized countries. These disparities are a direct product of social inequalities and social inequalities are rising throughout the industrialized world, particularly in Europe.<ref name="Progress for Children" />

South Asia

South Asia has the highest percentage and number of underweight children under five in the world, at approximately 78 million children.<ref name="Progress for Children" /> Patterns of stunting and wasting are similar, where 44% have not reached optimal height and 15% are wasted, rates much higher than any other regions.<ref name="Progress for Children" /> This region of the world has extremely high rates of underweight children. According to a 2006 UNICEF study, 46% of its child population under five is underweight.<ref name="Progress for Children" /> The same study indicates India, Bangladesh, and Pakistan combined account for half the globe's underweight child population.<ref name="Progress for Children" /> South Asian nations have made progress towards the MDGs, considering the rate has decreased from 53% since 1990, however, a 1.7% decrease of underweight prevalence per year will not be sufficient to meet the 2015 goal.<ref name="Progress for Children" /> Some nations, such as Afghanistan, Bangladesh, and Sri Lanka, on the other hand, have made significant improvements, all decreasing their prevalence by half in ten years.<ref name="Progress for Children" /> While India and Pakistan have made modest improvements, Nepal has made no significant improvement in underweight child prevalence.<ref name="Progress for Children" /> Other forms of undernutrition have continued to persist with high resistance to improvement, such as the prevalence of stunting and wasting, which has not changed significantly in the past 10 years.<ref name="Progress for Children" /> Causes of this poor nutrition include energy-insufficient diets, poor sanitation conditions, and the gender disparities in educational and social status.<ref name="Progress for Children" /> Girls and women face discrimination especially in nutrition status, where South Asia is the only region in the world where girls are more likely to be underweight than boys.<ref name="Progress for Children" /> In South Asia, 60% of children in the lowest quintile are underweight, compared to only 26% in the highest quintile, and the rate of reduction of underweight is slower amongst the poorest.<ref name="UNMDG2011">UN (2011b). The Millennium Development Goals report 2011. New York, United Nations. http://www.un.org/en/development/desa/news/statistics/mdg-report-2011.html Archived 2022-10-06 at the Wayback Machine.</ref>

Eastern and Southern Africa

The Eastern and Southern African nations have shown no improvement since 1990 in the rate of underweight children under five.<ref name="Progress for Children" /> They have also made no progress in halving hunger by 2015, the most prevalent Millennium Development Goal.<ref name="Progress for Children" /> This is due primarily to the prevalence of famine, declined agricultural productivity, food emergencies, drought, conflict, and increased poverty.<ref name="Progress for Children" /> This, along with HIV/AIDS, has inhibited the nutrition development of nations such as Lesotho, Malawi, Mozambique, Swaziland, Zambia and Zimbabwe.<ref name="Progress for Children" /> Botswana has made remarkable achievements in reducing underweight prevalence, dropping 4% in 4 years, despite its place as the second leader in HIV prevalence amongst adults in the globe.<ref name="Progress for Children" /> South Africa, the wealthiest nation in this region, has the second-lowest proportion of underweight children at 12%, but has been steadily increasing in underweight prevalence since 1995.<ref name="Progress for Children" /> Almost half of Ethiopian children are underweight, and along with Nigeria, they account for almost one-third of the underweight under five in all of Sub-Saharan Africa.<ref name="Progress for Children" />

West and Central Africa

West and Central Africa has the highest rate of children under five underweight in the world.<ref name="Progress for Children" /> Of the countries in this region, the Congo has the lowest rate at 14%, while the nations of Democratic Republic of the Congo, Ghana, Guinea, Mali, Nigeria, Senegal and Togo are improving slowly.<ref name="Progress for Children" /> In Gambia, rates decreased from 26% to 17% in four years, and their coverage of vitamin A supplementation reaches 91% of vulnerable populations.<ref name="Progress for Children" /> This region has the next highest proportion of wasted children, with 10% of the population under five not at optimal weight.<ref name="Progress for Children" /> Little improvement has been made between the years of 1990 and 2004 in reducing the rates of underweight children under five, whose rate stayed approximately the same.<ref name="Progress for Children" /> Sierra Leone has the highest child under five mortality rate in the world, due predominantly to its extreme infant mortality rate, at 238 deaths per 1000 live births.<ref name="Progress for Children" /> Other contributing factors include the high rate of low birthweight children (23%) and low levels of exclusive breast feeding (4%).<ref name="Progress for Children" /> Anemia is prevalent in these nations, with unacceptable rates of iron deficient anemia.<ref name="Progress for Children" /> The nutritional status of children is further indicated by its high (10%) rate of child wasting.<ref name="Progress for Children" /> Wasting is a significant problem in Sahelian countries – Burkina Faso, Chad, Mali, Mauritania and Niger – where rates fall between 11% and 19% of under fives, affecting more than 1 million children.<ref name="Progress for Children" />

In Mali, the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and the Aga Khan Foundation trained women's groups to make equinut, a healthy and nutritional version of the traditional recipe di-dèguè (comprising peanut paste, honey and millet or rice flour). The aim was to boost nutrition and livelihoods by producing a product that women could make and sell, and which would be accepted by the local community because of its local heritage.<ref>Nourishing communities through holistic farming Archived 6 October 2018 at the Wayback Machine, Impatient optimists, Bill & Melinda Gates Foundation. 30 April 2013.</ref>

Middle East and North Africa

Six countries in the Middle East and North Africa region are on target to meet goals for reducing underweight children by 2015, and 12 countries have prevalence rates below 10%.<ref name="Progress for Children" /> However, the nutrition of children in the region as a whole has degraded for the past ten years due to the increasing portion of underweight children in three populous nations – Iraq, Sudan, and Yemen.<ref name="Progress for Children" /> Forty six percent of all children in Yemen are underweight, a percentage that has worsened by 4% since 1990.<ref name="Progress for Children" /> In Yemen, 53% of children under five are stunted and 32% are born at low birth weight.<ref name="Progress for Children" /> Sudan has an underweight prevalence of 41%, and the highest proportion of wasted children in the region at 16%.<ref name="Progress for Children" /> One percent of households in Sudan consume iodized salt.<ref name="Progress for Children" /> Iraq has also seen an increase in child underweight since 1990.<ref name="Progress for Children" /> Djibouti, Jordan, the Occupied Palestinian Territory (OPT), Oman, the Syrian Arab Republic and Tunisia are all projected to meet minimum nutrition goals, with OPT, Syrian AR, and Tunisia the fastest improving regions.<ref name="Progress for Children" /> This region demonstrates that undernutrition does not always improve with economic prosperity, where the United Arab Emirates, for example, despite being a wealthy nation, has similar child death rates due to malnutrition to those seen in Yemen.<ref name="Progress for Children" />

East Asia and the Pacific

The East Asia and Pacific region has reached its goals on nutrition, in part due to the improvements contributed by China, the region's most populous country.<ref name="Progress for Children" /> China has reduced its underweight prevalence from 19 percent to 8 percent between 1990 and 2002.<ref name="Progress for Children" /> China played the largest role in the world in decreasing the rate of children under five underweight between 1990 and 2004, halving the prevalence.<ref name="Progress for Children" /> This reduction of underweight prevalence has aided in the lowering of the under 5 mortality rate from 49 to 31 of 1000. They also have a low birthweight rate at 4%, a rate comparable to industrialized countries, and over 90% of households receive adequate iodized salts.<ref name="Progress for Children" /> However, large disparities exist between children in rural and urban areas, where 5 provinces in China leave 1.5 million children iodine deficient and susceptible to diseases.<ref name="Progress for Children" /> Singapore, Vietnam, Malaysia, and Indonesia are all projected to reach nutrition MDGs.<ref name="Progress for Children" /> Singapore has the lowest under five mortality rate of any nation, besides Iceland, in the world, at 3%.<ref name="Progress for Children" /> Cambodia has the highest rate of child mortality in the region (141 per 1,000 live births), while still its proportion of underweight children increased by 5 percent to 45% in 2000. Further nutrient indicators show that only 12 per cent of Cambodian babies are exclusively breastfed and only 14 per cent of households consume iodized salt.<ref name="Progress for Children" />

Latin America and the Caribbean

This region has undergone the fastest progress in decreasing poor nutrition status of children in the world.<ref name="Progress for Children" /> The Latin American region has reduced underweight children prevalence by 3.8% every year between 1990 and 2004, with a current rate of 7% underweight.<ref name="Progress for Children" /> They also have the lowest rate of child mortality in the developing world, with only 31 per 1000 deaths, and the highest iodine consumption.<ref name="Progress for Children" /> Cuba has seen improvement from 9 to 4 percent underweight under 5 between 1996 and 2004.<ref name="Progress for Children" /> The prevalence has also decreased in the Dominican Republic, Jamaica, Peru, and Chile.<ref name="Progress for Children" /> Chile has a rate of underweight under 5, at merely 1%.<ref name="Progress for Children" /> The most populous nations, Brazil and Mexico, mostly have relatively low rates of underweight under 5, with only 6% and 8%.<ref name="Progress for Children" /> Guatemala has the highest percentage of underweight and stunted children in the region, with rates above 45%.<ref name="Progress for Children" /> There are disparities amongst different populations in this region. For example, children in rural areas have twice the prevalence of underweight at 13%, compared to urban areas at 5%.<ref name="Progress for Children" />

Nutrition access disparities

Occurring throughout the world, lack of proper nutrition is both a consequence and cause of poverty.<ref name="Progress for Children" /> Impoverished individuals are less likely to have access to nutritious food and to escape from poverty than those who have healthy diets.<ref name="Progress for Children" /> Disparities in socioeconomic status, both between and within nations, provide the largest threat to child nutrition in industrialized nations, where social inequality is on the rise.<ref name=P4C43>"World Health Organization, European Health Report 2005: Public health action for healthier children and populations" (PDF). WHO Regional Office for Europe, Copenhagen. 2005. Archived (PDF) from the original on 2016-03-04. Retrieved 2014-12-15.</ref> According to UNICEF, children living in the poorest households are twice as likely to be underweight as those in the richest.<ref name="Progress for Children" /> Those in the lowest wealth quintile and whose mothers have the least education demonstrate the highest rates of child mortality and stunting.<ref name="WHOstats">"WHO (2013b)" (PDF). World health statistics. Geneva, World Health Organization. Archived (PDF) from the original on 2013-06-16.</ref> Throughout the developing world, socioeconomic inequality in childhood malnutrition is more severe than in upper income brackets, regardless of the general rate of malnutrition.<ref name="VanP">Van de Poel E, Hosseinpoor AR, Speybroeck N, Van Ourti T, Vega J (April 2008). "Socioeconomic inequality in malnutrition in developing countries". Bulletin of the World Health Organization. 86 (4): 282–91. doi:10.2471/blt.07.044800. PMC 2647414. PMID 18438517.</ref> According to UNICEF, children in rural locations are more than twice as likely to be underweight as compared to children under five in urban areas.<ref name="Progress for Children" /> In Latin American/Caribbean nations, "Children living in rural areas in Bolivia, Honduras, Mexico and Nicaragua are more than twice as likely to be underweight as children living in urban areas. That likelihood doubles to four times in Peru." Concurrently, the greatest increase in childhood obesity has been seen in the lower middle income bracket.<ref name="WHOglobe">"WHO (2011a). Global status report on noncommunicable diseases 2010". Geneva, World Health Organization. Archived from the original on 2 May 2011.</ref>

In the United States, the incidence of low birthweight is on the rise among all populations, but particularly among minorities.<ref name=P4C45>Polhamus B, et al. (2004). "Pediatric Nutrition Surveillance 2003 Report, Table 18D" (PDF). U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, Atlanta. Archived (PDF) from the original on 2004-11-17.</ref>

According to UNICEF, boys and girls have almost identical rates as underweight children under age 5 across the world, except in South Asia.<ref name="Progress for Children" />

Nutrition policy

Nutrition interventions

Nutrition directly influences progress towards meeting the Millennium Goals of eradicating hunger and poverty through health and education.<ref name="Progress for Children" /> Therefore, nutrition interventions take a multi-faceted approach to improve the nutrition status of various populations. Policy and programming must target both individual behavioral changes and policy approaches to public health. While most nutrition interventions focus on delivery through the health-sector, non-health sector interventions targeting agriculture, water and sanitation, and education are important as well.<ref name="Essential Nutrition Actions" /> Global nutrition micro-nutrient deficiencies often receive large-scale solution approaches by deploying large governmental and non-governmental organizations. For example, in 1990, iodine deficiency was particularly prevalent, with one in five households, or 1.7 billion people, not consuming adequate iodine, leaving them at risk to develop associated diseases.<ref name="Progress for Children" /> Therefore, a global campaign to iodize salt to eliminate iodine deficiency successfully boosted the rate to 69% of households in the world consuming adequate amounts of iodine.<ref name="Progress for Children" />

Emergencies and crises often exacerbate undernutrition, due to the aftermath of crises that include food insecurity, poor health resources, unhealthy environments, and poor healthcare practices.<ref name="Progress for Children" /> Therefore, the repercussions of natural disasters and other emergencies can exponentially increase the rates of macro and micronutrient deficiencies in populations.<ref name="Progress for Children" /> Disaster relief interventions often take a multi-faceted public health approach. UNICEF's programming targeting nutrition services amongst disaster settings include nutrition assessments, measles immunization, vitamin A supplementation, provision of fortified foods and micronutrient supplements, support for breastfeeding and complementary feeding for infants and young children, and therapeutic and supplementary feeding.<ref name="Progress for Children" /> For example, during Nigeria's food crisis of 2005, 300,000 children received therapeutic nutrition feeding programs through the collaboration of UNICEF, the Niger government, the World Food Programme, and 24 NGOs utilizing community and facility based feeding schemes.<ref name="Progress for Children" />

Interventions aimed at pregnant women, infants, and children take a behavioral and program-based approach. Behavioral intervention objectives include promoting proper breast-feeding, the immediate initiation of breastfeeding, and its continuation through 2 years and beyond.<ref name="Essential Nutrition Actions" /> UNICEF recognizes that to promote these behaviors, healthful environments must be established conducive to promoting these behaviors, like healthy hospital environments, skilled health workers, support in the public and workplace, and removing negative influences.<ref name="Essential Nutrition Actions" /> Finally, other interventions include provisions of adequate micro and macro nutrients such as iron, anemia, and vitamin A supplements and vitamin-fortified foods and ready-to-use products.<ref name="Essential Nutrition Actions" /> Programs addressing micro-nutrient deficiencies, such as those aimed at anemia, have attempted to provide iron supplementation to pregnant and lactating women. However, because supplementation often occurs too late, these programs have had little effect.<ref name="Progress for Children" /> Interventions such as women's nutrition, early and exclusive breastfeeding, appropriate complementary food and micronutrient supplementation have proven to reduce stunting and other manifestations of undernutrition.<ref name="IMPROVING CHILD NUTRITION" /> A Cochrane review of community-based maternal health packages showed that this community-based approach improved the initiation of breastfeeding within one hour of birth.<ref>Lassi ZS, Bhutta ZA (March 2015). "Community-based intervention packages for reducing maternal and neonatal morbidity and mortality and improving neonatal outcomes". The Cochrane Database of Systematic Reviews. 2015 (3): CD007754. doi:10.1002/14651858.CD007754.pub3. PMC 8498021. PMID 25803792. Archived from the original on 2022-03-09. Retrieved 2019-09-24.</ref> Some programs have had adverse effects. One example is the "Formula for Oil" relief program in Iraq, which resulted in the replacement of breastfeeding for formula, which has negatively affected infant nutrition.<ref name="Progress for Children" />

Implementation and delivery platforms

In April 2010, the World Bank and the IMF released a policy briefing entitled "Scaling up Nutrition (SUN): A Framework for action" that represented a partnered effort to address the Lancet's Series on under nutrition, and the goals it set out for improving under nutrition.<ref name="SUN">Nabarro D (August 2013). "Global child and maternal nutrition--the SUN rises". Lancet. 382 (9893): 666–7. doi:10.1016/S0140-6736(13)61086-7. PMID 23746773. S2CID 34484370.</ref> They emphasized the 1000 days after birth as the prime window for effective nutrition intervention, encouraging programming that was cost-effective and showed significant cognitive improvement in populations, as well as enhanced productivity and economic growth.<ref name="SUN" /> This document was labeled the SUN framework, and was launched by the UN General Assembly in 2010 as a road map encouraging the coherence of stakeholders like governments, academia, UN system organizations and foundations in working towards reducing under nutrition.<ref name="SUN" /> The SUN framework has initiated a transformation in global nutrition- calling for country-based nutrition programs, increasing evidence based and cost–effective interventions, and "integrating nutrition within national strategies for gender equality, agriculture, food security, social protection, education, water supply, sanitation, and health care".<ref name="SUN" /> Government often plays a role in implementing nutrition programs through policy. For instance, several East Asian nations have enacted legislation to increase iodization of salt to increase household consumption.<ref name="Progress for Children" /> Political commitment in the form of evidence-based effective national policies and programs, trained skilled community nutrition workers, and effective communication and advocacy can all work to decrease malnutrition.<ref name="IMPROVING CHILD NUTRITION" /> Market and industrial production can play a role as well. For example, in the Philippines, improved production and market availability of iodized salt increased household consumption.<ref name="Progress for Children" /> While most nutrition interventions are delivered directly through governments and health services, other sectors, such as agriculture, water and sanitation, and education, are vital for nutrition promotion as well.<ref name="Essential Nutrition Actions" />

Advice and guidance

Government policies

Canada's Food Guide is an example of a government-run nutrition program. Produced by Health Canada, the guide advises food quantities, provides education on balanced nutrition, and promotes physical activity in accordance with government-mandated nutrient needs. Like other nutrition programs around the world, Canada's Food Guide divides nutrition into four main food groups: vegetables and fruit, grain products, milk and alternatives, and meat and alternatives.<ref>Canada's Food Guide. Health Canada</ref> Unlike its American counterpart, the Canadian guide references and provides alternative to meat and dairy, which can be attributed to the growing vegan and vegetarian movements.

In the US, nutritional standards and recommendations are established jointly by the US Department of Agriculture and US Department of Health and Human Services (HHS) and these recommendations are published as the Dietary Guidelines for Americans. Dietary and physical activity guidelines from the USDA are presented in the concept of MyPlate, which superseded the food pyramid, which replaced 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. The U.S. HHS provides a sample week-long menu that fulfills the nutritional recommendations of the government.<ref>Sample Menus for a 2000 Calorie Food Pattern. mypyramid.gov</ref>

Government programs

Governmental organisations 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 that 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.<ref>Guthrie, Joanne F.; Stommes, Eileen; Voichick, Jane (January–February 2006). "Evaluating Food Stamp Nutrition Education: Issues and Opportunities". Journal of Nutrition Education and Behavior. 38 (1): 6–11. doi:10.1016/j.jneb.2005.11.001. PMID 16595272. Archived from the original on 2022-01-25. Retrieved 2020-01-03.</ref>

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.

Education

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 (FCS) 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, portion sizes, and how to live a healthy life.^{[medical citation needed]}

A 1985 US National Research Council report entitled Nutrition Education in US Medical Schools concluded that nutrition education in medical schools was inadequate.<ref name="p. 4">Commission on Life Sciences. (1985). Nutrition Education in US Medical Schools, p. 4 Archived 2011-06-07 at the Wayback Machine. National Academies Press.</ref> Only 20% of the schools surveyed taught nutrition as a separate, required course. A 2006 survey found that this number had risen to 30%.<ref>Adams KM, Lindell KC, Kohlmeier M, Zeisel SH (2006). "Status of nutrition education in medical schools". Am. J. Clin. Nutr. 83 (4): 941S–14S. doi:10.1093/ajcn/83.4.941S. PMC 2430660. PMID 16600952.</ref> Membership by physicians in leading professional nutrition societies such as the American Society for Nutrition has generally declined from the 1990s.<ref>McClave, Stephen A.; Mechanick, Jeffrey I.; Bistrian, Bruce; Graham, Toby; Hegazi, Refaat; Jensen, Gordon L.; Kushner, Robert F.; Merritt, Russell (1 December 2016). "What is the significance of a physician shortage in nutrition medicine?". Journal of Parenteral and Enteral Nutrition. 34 (6 Suppl): 7S–20S. doi:10.1177/0148607110375429. PMID 21149831.</ref>

Professional organizations

In the US, Registered dietitian nutritionists (RDs or RDNs)<ref>"What is an RDN and DTR?". Academy of Nutrition and Dietetics. Archived from the original on 23 December 2017. Retrieved 9 May 2015.</ref> are health professionals qualified to provide safe, evidence-based dietary advice which includes a review of what is eaten, a thorough review of nutritional health, and a personalized nutritional treatment plan through dieting. They also provide preventive and therapeutic programs at work places, schools and similar institutions. Certified Clinical Nutritionists or CCNs, are trained health professionals who also offer dietary advice on the role of nutrition in chronic disease, including possible prevention or remediation by addressing nutritional deficiencies before resorting to drugs.<ref>http://www.iaacn.org/ Archived 2022-12-04 at the Wayback Machine The International & American Associations of Clinical Nutritionist, 2014, Retrieved 14 December 2014</ref> Government regulation especially in terms of licensing, is currently less universal for the CCN than that of RD or RDN. Another advanced Nutrition Professional is a Certified Nutrition Specialist or CNS. These Board Certified Nutritionists typically specialize in obesity and chronic disease. In order to become board certified, potential CNS candidate must pass an examination, much like Registered Dieticians. This exam covers specific domains within the health sphere including; Clinical Intervention and Human Health.<ref>"FAQs about CNS Certification – Certification Board for Nutrition Specialists". Archived from the original on 11 August 2014. Retrieved 24 September 2015.</ref> The National Board of Physician Nutrition Specialists offers board certification for physicians practicing nutrition medicine.<ref>Van Horn, L; Lenders, CM; Pratt, CA; et al. (1 November 2019). "Advancing Nutrition Education, Training, and Research for Medical Students, Residents, Fellows, Attending Physicians, and Other Clinicians: Building Competencies and Interdisciplinary Coordination". Advances in Nutrition. 10 (6): 1181–1200. doi:10.1093/advances/nmz083. PMC 6855992. PMID 31728505.</ref>

Nutrition for special populations

Sports nutrition

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 grams of protein per kilogram of body weight.<ref name="DRI" /> A review panel stating that "no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise."<ref>Di Pasquale, Mauro G. (2008). "Utilization of Proteins in Energy Metabolism". In Ira Wolinsky, Judy A. Driskell (ed.). Sports Nutrition: Energy metabolism and exercise. CRC Press. p. 73. ISBN 978-0-8493-7950-5.</ref>

The main fuel used by the body during exercise is carbohydrates, which is 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.<ref>"Iowa State University: Extension and outreach". Archived from the original on 2015-04-19. Retrieved 2015-04-16.</ref>

Maternal nutrition

Paediatric nutrition

Adequate nutrition is essential for the growth of children from infancy right through until adolescence. Some nutrients are specifically required for growth on top of nutrients required for normal body maintenance, in particular calcium and iron.<ref>Wahlqvist, M. L. (2011). Food and Nutrition: Food and Health Systems in Australia and New Zealand (3rd ed.). NSW, Australia: Allen & Unwin. pp. 429–441. ISBN 978-1-74175-897-9.</ref>

Elderly nutrition

Malnutrition in general is higher among the elderly, but has different aspects in developed and undeveloped countries.<ref name="Chwang">Chwang, Leh-Chii (September 2012). "Nutrition and dietics in aged care". Nutrition and Dietics. 69 (3): 203–207. doi:10.1111/j.1747-0080.2012.01617.x.</ref>

Clinical nutrition

On admission to intensive care unit, energy and protein requirements are calculated to determine the targets of nutritional therapy. Enteral nutrition (administering nutrition using a feeding tube) is started within 24 to 48 hours of admission with feeding targets increased every week. The risk of aspiration (inhalation of fluid or food particles while drinking or eating) can be reduced by elevating the head, using prokinetic agent, and using a chlorhexidine mouthwash. Although the presence of bowel sounds and the amount of gastric residual volume aspirated after feeding can be used to monitor the functionality of the gastrointestinal tract before feeding is started; starting nutritional therapy at this stage regardless of the functional status is feasible and safe within 36 to 48 hours of admission. Parenteral nutrition (administering of nutrition intravenously) should be started when enteral nutrition is not possible or sufficient or in high-risk subjects.<ref>McClave, Stephen A.; Taylor, Beth E.; Martindale, Robert G.; Warren, Malissa M.; Johnson, Debbie R.; Braunschweig, Carol; McCarthy, Mary S.; Davanos, Evangelia; Rice, Todd W.; Cresci, Gail A.; Gervasio, Jane M.; Sacks, Gordon S.; Roberts, Pamela R.; Compher, Charlene; the Society of Critical Care Medicine (February 2016). "Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.)". Journal of Parenteral and Enteral Nutrition. 40 (2): 159–211. doi:10.1177/0148607115621863. ISSN 0148-6071. PMID 26773077. S2CID 3772578.</ref>

Before undergoing surgery, a subject should avoid long periods of fasting. Oral feeding should be established as soon as possible after surgery. Other aspects of nutrition such as control of glucose, reduction in risk factors that causes stress-related catabolism or impairment of gastrointestinal functions, and encourage early physical activity to encourage protein synthesis and muscle functions.<ref>Weimann, Arved; Braga, Marco; Carli, Franco; Higashiguchi, Takashi; Hübner, Martin; Klek, Stanislaw; Laviano, Alessandro; Ljungqvist, Olle; Lobo, Dileep N.; Martindale, Robert; Waitzberg, Dan L.; Bischoff, Stephan C.; Singer, Pierre (June 2017). "ESPEN guideline: Clinical nutrition in surgery". Clinical Nutrition. 36 (3): 623–650. doi:10.1016/j.clnu.2017.02.013. PMID 28385477. S2CID 4235396.</ref>

History of human nutrition

Early human nutrition was largely determined by the availability and palatability of foods.<ref>Ralph M. Trüeb (23. November 2020): Brief History of Human Nutrition. In: Nutrition for Healthy Hair, pp. 3–15. Springer, Cham. doi: [4] Archived 2023-01-24 at the Wayback Machine</ref> Humans evolved as omnivorous hunter-gatherers, though the diet of humans has varied significantly depending on location and climate. The diet in the tropics tended^[when?] to depend more heavily on plant foods, while the diet at higher latitudes tended more towards animal products. Analyses of postcranial and cranial remains of humans and animals from the Neolithic, along with detailed bone-modification studies, have shown that cannibalism also occurred among prehistoric humans.<ref>Villa P, Bouville C, Courtin J, Helmer D, Mahieu E, Shipman P, et al. (July 1986). "Cannibalism in the neolithic". Science. 233 (4762): 431–7. Bibcode:1986Sci...233..431V. doi:10.1126/science.233.4762.431. PMID 17794567. S2CID 30617302.</ref>

Agriculture developed at different times in different places, starting about 11,500 years ago, providing some cultures with a more abundant supply of grains (such as wheat, rice and maize) and potatoes; and originating staples such as bread, pasta dough,<ref> Guzzardi, Sergio (27 July 2014). Buona Pasta. Sergio Guzzardi (published 2014). p. 19. ISBN 9786050314915. Retrieved 21 November 2014. The first two certain dates in the history of pasta in Italy are: 1154, when in a sort of tour guide ahead of its [time] Arab geographer Al-Idrin mentions 'a food of flour in the form of wires,' called Triyah [...], which is packaged in Palermo and was exported in barrels throughout the peninsula [...]; [...] and 1279 [...]. </ref> and tortillas. The domestication of animals provided some cultures with milk and dairy products.

In 2020, archeological research discovered a frescoed thermopolium (a fast-food counter) in an exceptional state of preservation from 79 in Pompeii, including 2,000-year-old foods available in some of the deep terra cotta jars.<ref>The Guardian (26 December 2020): Exceptionally well-preserved snack bar unearthed in Pompeii Archived 2022-09-26 at the Wayback Machine (via Agence France-Presse).</ref>

Nutrition in antiquity

During classical antiquity, diets consisted of simple fresh or preserved whole foods that were either locally grown or transported from neighboring areas during times of crisis.<ref>Garnsey, P. (1999). Food and society in classical antiquity (Key themes in ancient history; Key themes in ancient history). Cambridge, U.K.: Cambridge University Press.</ref><ref>Skiadas, P., & Lascaratos, J. (2001). Dietetics in ancient Greek philosophy: Plato's concepts of healthy diet. Published Online: 14 June 2001; | doi:10.1038/sj.ejcn.1601179, 55(7).</ref>

18th century until today: food processing and nutrition

Since the Industrial Revolution in the 18th and 19th century, 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 and freezing are primary technologies 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 appearing 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.

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 the content of many heat-labile nutrients such as certain vitamins and phytochemicals, and possibly other yet-to-be-discovered substances.<ref>Morris, Audrey; Audia Barnett; Olive-Jean Burrows (2004). "Effect of Processing on Nutrient Content of Foods" (PDF). Cajanus. 37 (3): 160–64. Archived (PDF) from the original on 2007-06-04. Retrieved 26 October 2006.</ref>

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 those affected 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.

Research of nutrition and nutritional science

Antiquity: Start of scientific research on nutrition

Around 3000 BC the Vedic texts made mention of scientific research on nutrition.^{[citation needed]}^{[example needed]} The first^{[citation needed]} recorded dietary advice, carved into a Babylonian stone tablet in about 2500 BC, cautioned those with pain inside to avoid eating onions for three days. Scurvy, later found to be a vitamin C deficiency, was first described in 1500 BC in the Ebers Papyrus.<ref>Payne-Palacio, June R.; Canter, Deborah D. (2014). The Profession of Dietetics. Jones & Bartlett Learning. pp. 3–4. ISBN 978-1-284-02608-5.</ref>

According to Walter Gratzer, the study of nutrition probably began during the 6th century BC. In China, the concept of qi developed, a spirit or "wind" similar to what Western Europeans later called pneuma.<ref name=Gratzer40>Gratzer 2005, p. 40.</ref> Food was classified into "hot" (for example, meats, blood, ginger, and hot spices) and "cold" (green vegetables) in China, India, Malaya, and Persia.<ref name=Gratzer41 /> Humours developed perhaps first in China alongside qi.<ref name=Gratzer40 /> Ho the Physician concluded that diseases are caused by deficiencies of elements (Wu Xing: fire, water, earth, wood, and metal), and he classified diseases as well as prescribed diets.<ref name=Gratzer41>Gratzer 2005, p. 41.</ref> About the same time in Italy, Alcmaeon of Croton (a Greek) wrote of the importance of equilibrium between what goes in and what goes out, and warned that imbalance would result in disease marked by obesity or emaciation.<ref name=Gratzer36>Gratzer 2005, p. 36.</ref>

Around 475 BC, Anaxagoras wrote that food is absorbed by the human body and, therefore, contains "homeomerics" (generative components), suggesting the existence of nutrients.<ref name=history>History of the Study of Nutrition in Western Culture (Rai University lecture notes for General Nutrition course, 2004)</ref> Around 400 BC, Hippocrates, who recognized and was concerned with obesity, which may have been common in southern Europe at the time,<ref name=Gratzer36 /> said, "Let food be your medicine and medicine be your food."<ref name="Smith">Smith, Richard (24 January 2004). "Let food by thy medicine…". BMJ. 328 (7433): 0–g–0. doi:10.1136/bmj.328.7433.0-g. PMC 318470.</ref> The works that are still attributed to him, Corpus Hippocraticum, called for moderation and emphasized exercise.<ref name=Gratzer36 />

Salt, pepper and other spices were prescribed for various ailments in various preparations for example mixed with vinegar. In the 2nd century BC, Cato the Elder believed that cabbage (or the urine of cabbage-eaters) could cure digestive diseases, ulcers, warts, and intoxication. Living about the turn of the millennium, Aulus Celsus, an ancient Roman doctor, believed in "strong" and "weak" foods (bread for example was strong, as were older animals and vegetables).<ref name=Gratzer37 />

The Book of Daniel, dated to the second century BC, contains a description of a comparison in health of captured people following Jewish dietary laws versus the diet of the soldiers of the king of Babylon.<ref>Daniel 1:5–16 Archived 2022-07-14 at the Wayback Machine. Biblegateway.com. Retrieved on 17 October 2011.</ref><ref>McCollum, Elmer V. (1957). A History of Nutrition. Cambridge, Mass.: The Riverside Press (Houghton Mifflin). pp. 8–9.</ref> (The story may be legendary rather than historical.)

1st to 17th century

Galen was physician to gladiators in Pergamon, and in Rome, physician to Marcus Aurelius and the three emperors who succeeded him.<ref name=Gratzer38>Gratzer 2005, p. 38.</ref> In use from his life in the 1st century AD until the 17th century, it was heresy^{[clarification needed]} to disagree with the teachings of Galen for 1500 years.<ref name=Gratzer>Gratzer 2005, pp. 38, 39, 41.</ref> Most of Galen's teachings were gathered and enhanced in the late 11th century by Benedictine monks at the School of Salerno in Regimen sanitatis Salernitanum, which still had users in the 17th century.<ref name=Gratzer39>Gratzer 2005, p. 39.</ref> Galen believed in the bodily humours of Hippocrates, and he taught that pneuma is the source of life. Four elements (earth, air, fire and water) combine into "complexion", which combines into states (the four temperaments: sanguine, phlegmatic, choleric, and melancholic). The states are made up of pairs of attributes (hot and moist, cold and moist, hot and dry, and cold and dry), which are made of four humours: blood, phlegm, green (or yellow) bile, and black bile (the bodily form of the elements). Galen thought that for a person to have gout, kidney stones, or arthritis was scandalous, which Gratzer likens to Samuel Butler's Erehwon (1872) where sickness is a crime.<ref name=Gratzer />

In the 1500s, Paracelsus was probably the first to criticize Galen publicly.<ref name=Gratzer /> Also in the 16th century, scientist and artist Leonardo da Vinci compared metabolism to a burning candle. Leonardo did not publish his works on this subject, but he was not afraid of thinking for himself and he definitely disagreed with Galen.<ref name=Gratzer41 /> Ultimately, 16th century works of Andreas Vesalius, sometimes called the father of modern human anatomy, overturned Galen's ideas.<ref>Gratzer 2005, p. 48.</ref> He was followed by piercing thought amalgamated with the era's mysticism and religion sometimes fueled by the mechanics of Newton and Galileo. Jan Baptist van Helmont, who discovered several gases such as carbon dioxide, performed the first quantitative experiment. Robert Boyle advanced chemistry. Sanctorius measured body weight. Physician Herman Boerhaave modeled the digestive process. Physiologist Albrecht von Haller worked out the difference between nerves and muscles.<ref>Gratzer 2005, pp. 48–50, 52–54.</ref>

18th and 19th century: Lind, Lavoisier and modern science

Sometimes forgotten during his life, James Lind, a physician in the British navy, performed the first scientific nutrition experiment in 1747. Lind discovered that lime juice saved sailors that had been at sea for years from scurvy, a deadly and painful bleeding disorder. Between 1500 and 1800, an estimated two million sailors had died of scurvy.<ref name=Willett-scurvy>Willett, Walter C.; Skerrett, Patrick J. (2005) [2001]. Eat, Drink, and be Healthy: The Harvard Medical School Guide To Healthy Eating. Free Press (Simon & Schuster). p. 183. ISBN 978-0-684-86337-5.</ref> The discovery was ignored^{[by whom?]} for forty years, but after about 1850, British sailors became known as "limeys".<ref>Gratzer 2005, pp. 21–24, 32.</ref> The essential vitamin C within citrus fruits would not be identified by scientists until 1932.<ref name=Willett-scurvy />

Around 1770, Antoine Lavoisier discovered the details of metabolism, demonstrating that the oxidation of food is the source of body heat. Called the most fundamental chemical discovery of the 18th century,<ref>Silberberg, Martin S. (2009). Chemistry: The Molecular Nature of Matter and Change (5 ed.). McGraw-Hill. p. 44. ISBN 978-0-07-304859-8.</ref> Lavoisier discovered the principle of conservation of mass. His ideas made the phlogiston theory of combustion obsolete.<ref>Gratzer 2005, p. 56.</ref>

In 1790, George Fordyce recognized calcium as necessary for the survival of fowl. In the early 19th century, the elements carbon, nitrogen, hydrogen, and oxygen were recognized^{[by whom?]} as the primary components of food, and methods to measure their proportions were developed.<ref name="Paul Muljadi">Muljadi, Paul. Health. Paul Muljadi. p. 42.^{[permanent dead link]}</ref>

In 1816, François Magendie discovered that dogs fed only carbohydrates (sugar), fat (olive oil), and water died evidently of starvation, but dogs also fed protein survived – identifying protein as an essential dietary component.<ref>Gratzer 2005, pp. 73–74.</ref> William Prout in 1827 was the first person to divide foods into carbohydrates, fat, and protein.<ref>Ahrens, Richard (1 January 1977). "William Prout (1785–1850): A Biographical Sketch" (PDF). The Journal of Nutrition. 107 (1): 17–23. doi:10.1093/jn/107.1.15. PMID 319206. Archived from the original on 17 October 2015. Retrieved 3 January 2020.</ref> In 1840, Justus von Liebig discovered the chemical makeup of carbohydrates (sugars), fats (fatty acids) and proteins (amino acids). During the 19th century, Jean-Baptiste Dumas and von Liebig quarrelled over their shared belief that animals get their protein directly from plants (animal and plant protein are the same and that humans do not create organic compounds).<ref>Gratzer 2005, p. 82.</ref> With a reputation as the leading organic chemist of his day but with no credentials in animal physiology,<ref>Carpenter 1994, p. 224.</ref> von Liebig grew rich making food extracts like beef bouillon and infant formula that were later found to be of questionable nutritious value.<ref>Gratzer 2005, pp. 86, 92, 95, 115.</ref>

In the early 1880s, Kanehiro Takaki observed that Japanese sailors (whose diets consisted almost entirely of white rice) developed beriberi (or endemic neuritis, a disease causing heart problems and paralysis), but British sailors and Japanese naval officers did not. Adding various types of vegetables and meats to the diets of Japanese sailors prevented the disease. (This was not because of the increased protein as Takaki supposed, but because it introduced a few parts per million of thiamine to the diet.)<ref>Carpenter 1994, p. 220.</ref>). In the 1860s, Claude Bernard discovered that body fat can be synthesized from carbohydrate and protein, showing that the energy in blood glucose can be stored as fat or as glycogen.<ref>Gratzer 2005, pp. 98–99.</ref>

In 1896, Eugen Baumann observed iodine in thyroid glands. In 1897, Christiaan Eijkman worked with natives of Java, who also had beriberi. Eijkman observed that chickens fed the native diet of white rice developed the symptoms of beriberi but remained healthy when fed unprocessed brown rice with the outer bran intact. His assistant, Gerrit Grijns correctly identified and described the anti-beriberi substance in rice. Eijkman cured the natives by feeding them brown rice, discovering that food can cure disease. Over two decades later, nutritionists learned that the outer rice bran contains vitamin B1, also known as thiamine.^{[medical citation needed]}

Early 20th century

Vitamin	Isolated in...<ref>Carpenter's table gives the year each vitamin was proposed, the year isolated (shown here), the year the structure was determined, and the year that synthesis was achieved. Carpenter, Kenneth J. (1 October 2003). "A Short History of Nutritional Science: Part 3 (1912–1944)". The Journal of Nutrition. 133 (10): 3023–32. doi:10.1093/jn/133.10.3023. PMID 14519779. Archived from the original on 2 November 2017. Retrieved 3 January 2020. from Combs, G.F., Jr (1992). The Vitamins: Fundamental Aspects in Nutrition and Health. Academic Press. ISBN 978-0-12-381980-2.</ref>
B₁: thiamin	1926
C: ascorbic acid	1926
D: calciferol	1931
B₂: riboflavin	1933
B₆: pyridoxine, pyridoxal, pyridoxamine	1936
E: tocopherol	1936
B₃: niacin	1937
B₈: biotin	1939
B₉: folate	1939
B₅: pantothenic acid	1939
A :retinol	1939
K :phylloquinone	1939
B₁₂: cynocobalamin	1948

In the early 20th century, Carl von Voit and Max Rubner independently measured caloric energy expenditure in different species of animals, applying principles of physics in nutrition. In 1906, Edith G. Willcock and Frederick Hopkins showed that the amino acid tryptophan aids the well-being of mice but it did not assure their growth.<ref>Willcock, Edith G.; F. Gowland Hopkins (1906). "The importance of individual amino-acids in metabolism: Observations on the effect of adding tryptophane to a dietary in which zein is the sole nitrogenous constituent". The Journal of Physiology. 35 (1–2): 88–102. doi:10.1113/jphysiol.1906.sp001181. PMC 1465819. PMID 16992872.</ref> In the middle of twelve years of attempts to isolate them,<ref>Semenza, G., ed. (2012). Comprehensive Biochemistry: Selected Topics in the History of Biochemistry: Personal Recollections, Part 1. Vol. 35. Elsevier. p. 117. ISBN 978-0-444-59820-2. Archived from the original on 24 January 2023. Retrieved 15 March 2016.</ref> Hopkins said in a 1906 lecture that "unsuspected dietetic factors", other than calories, protein, and minerals, are needed to prevent deficiency diseases.<ref>Hopkins, F. Gowland (1912). "Feeding Experiments Illustrating the Importance of Accessory Factors in Normal Dietaries". The Journal of Physiology. 44 (5–6): 425–60. doi:10.1113/jphysiol.1912.sp001524. PMC 1512834. PMID 16993143.</ref> In 1907, Stephen M. Babcock and Edwin B. Hart started the cow feeding, single-grain experiment, which took nearly four years to complete.

In 1912 Casimir Funk coined the term vitamin to label a vital factor in the diet: from the words "vital" and "amine", because these unknown substances preventing scurvy, beriberi, and pellagra, and were thought then to derive from ammonia. In 1913 Elmer McCollum discovered the first vitamins, fat-soluble vitamin A and water-soluble vitamin B (in 1915; later identified as a complex of several water-soluble vitamins) and named vitamin C as the then-unknown substance preventing scurvy. Lafayette Mendel (1872-1935) and Thomas Osborne (1859–1929) also performed pioneering work on vitamins A and B.

In 1919, Sir Edward Mellanby incorrectly identified rickets as a vitamin A deficiency because he could cure it in dogs with cod liver oil.<ref name=NAS-D>Conlan, Roberta; Elizabeth Sherman (October 2000). "Unraveling the Enigma of Vitamin D" (PDF). National Academy of Sciences. Archived (PDF) from the original on 2015-03-17. Retrieved 13 June 2016.</ref> In 1922, McCollum destroyed the vitamin A in cod liver oil, but found that it still cured rickets.<ref name=NAS-D /> Also in 1922, H.M. Evans and L.S. Bishop discover vitamin E as essential for rat pregnancy, originally calling it "food factor X" until 1925.

In 1925 Hart discovered that iron absorption requires trace amounts of copper. In 1927 Adolf Otto Reinhold Windaus synthesized vitamin D, for which he won the Nobel Prize in Chemistry in 1928. In 1928 Albert Szent-Györgyi isolated ascorbic acid, and in 1932 proved that it is vitamin C by preventing scurvy. In 1935 he synthesized it, and in 1937 won a Nobel Prize for his efforts. Szent-Györgyi concurrently elucidated much of the citric acid cycle.

In the 1930s, William Cumming Rose identified essential amino acids, necessary protein components that the body cannot synthesize. In 1935 Eric Underwood and Hedley Marston independently discovered the necessity of cobalt. In 1936, Eugene Floyd DuBois showed that work and school performance are related to caloric intake. In 1938, Erhard Fernholz discovered the chemical structure of vitamin E.<ref name=NAS>Subcommittee on Vitamin Tolerance, Committee on Animal Nutrition, National Research Council (1987). Vitamin E, in Vitamin Tolerance of Animals. National Academy of Sciences. doi:10.17226/949. ISBN 978-0-309-03728-0. Archived from the original on 24 December 2013. Retrieved 22 December 2013.</ref><ref>"F.B.I. Joins Hunt for Young German Chemist". San Bernardino Daily Sun. 18 December 1940. Archived from the original on 24 December 2013. Retrieved 22 December 2013.</ref> It was synthesised the same year by Paul Karrer.<ref name=NAS />

Oxford University closed down its nutrition department after World War II because the subject seemed to have been completed between 1912 and 1944.<ref name=":1">Carpenter, Kenneth J. (1 November 2003). "A Short History of Nutritional Science: Part 4 (1945–1985)". The Journal of Nutrition. 133 (11): 3331–42. doi:10.1093/jn/133.11.3331. PMID 14608041. Archived from the original on 23 January 2018. Retrieved 3 January 2020.</ref>

Institutionalization of nutritional science in the 1950s

Nutritional science as a separate, independent science discipline was institutionalized in the 1950s. At the instigation of the British physiologist John Yudkin at the University of London, the degrees Bachelor of Science and Master of Science in nutritional science were established. The first students were admitted in 1953, and in 1954 the Department of Nutrition was officially opened.<ref name=Davies24July1995>Davies, Louise (24 July 1995). "Obituary: John Yudkin" Archived 2019-12-18 at the Wayback Machine, The Independent.</ref> In Germany, institutionalization followed in November 1956, when Hans-Diedrich Cremer was appointed to the chair for human nutrition in Giessen. Over time, seven other universities with similar institutions followed in Germany.<ref>Gertrud Rehner (1 June 2007): 50 Jahre Institut für Ernährungswissenschaft in Gießen – Ein Rückblick Archived 2022-03-14 at the Wayback Machine. In: Der Präsident der Justus-Liebig-Universität Gießen (Hrsg.): Spiegel der Forschung, pp. 26–30 (German only)</ref> From the 1950s to 1970s, a focus of nutritional science was on dietary fat and sugar. From the 1970s to the 1990s, attention was put on diet-related chronic diseases and supplementation.<ref>Dariush Mozaffarian, Irwin Rosenberg Ricardo Uauy (13 June 2018): History of modern nutrition science—implications for current research, dietary guidelines, and food policy. In: BMJ 2018; 361 doi: https://doi.org/10.1136/bmj.k2392 Archived 2023-01-24 at the Wayback Machine</ref>

References

External links

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Essential elements for higher organisms (eucarya).<ref>Ultratrace minerals. Authors: Nielsen, Forrest H. USDA, ARS Source: Modern nutrition in health and disease / editors, Maurice E. Shils ... et al. Baltimore: Williams & Wilkins, c1999., p. 283-303. Issue Date: 1999 URI: [1]</ref><ref name="Szklarska2019">Szklarska D, Rzymski P (May 2019). "Is Lithium a Micronutrient? From Biological Activity and Epidemiological Observation to Food Fortification". Biol Trace Elem Res. 189 (1): 18–27. doi:10.1007/s12011-018-1455-2. PMC 6443601. PMID 30066063.</ref><ref name="Enderle2020">Enderle J, Klink U, di Giuseppe R, Koch M, Seidel U, Weber K, Birringer M, Ratjen I, Rimbach G, Lieb W (August 2020). "Plasma Lithium Levels in a General Population: A Cross-Sectional Analysis of Metabolic and Dietary Correlates". Nutrients. 12 (8): 2489. doi:10.3390/nu12082489. PMC 7468710. PMID 32824874.</ref><ref name=bromine>McCall AS, Cummings CF, Bhave G, Vanacore R, Page-McCaw A, Hudson BG (June 2014). "Bromine is an essential trace element for assembly of collagen IV scaffolds in tissue development and architecture". Cell. 157 (6): 1380–92. doi:10.1016/j.cell.2014.05.009. PMC 4144415. PMID 24906154.</ref><ref name=essentialmetals>Zoroddu, Maria Antonietta; Aaseth, Jan; Crisponi, Guido; Medici, Serenella; Peana, Massimiliano; Nurchi, Valeria Marina (2019). "The essential metals for humans: a brief overview". Journal of Inorganic Biochemistry. 195: 120–129. doi:10.1016/j.jinorgbio.2019.03.013.</ref> v t e
H																	He
Li	Be											B	C	N	O	F	Ne
Na	Mg											Al	Si	P	S	Cl	Ar
K	Ca	Sc	Ti	V	Cr	Mn	Fe	Co	Ni	Cu	Zn	Ga	Ge	As	Se	Br	Kr
Rb	Sr	Y	Zr	Nb	Mo	Tc	Ru	Rh	Pd	Ag	Cd	In	Sn	Sb	Te	I	Xe

Essential elements for higher organisms (eucarya).<ref>Ultratrace minerals. Authors: Nielsen, Forrest H. USDA, ARS Source: Modern nutrition in health and disease / editors, Maurice E. Shils ... et al. Baltimore: Williams & Wilkins, c1999., p. 283-303. Issue Date: 1999 URI: [1]</ref><ref name="Szklarska2019">Szklarska D, Rzymski P (May 2019). "Is Lithium a Micronutrient? From Biological Activity and Epidemiological Observation to Food Fortification". Biol Trace Elem Res. 189 (1): 18–27. doi:10.1007/s12011-018-1455-2. PMC 6443601. PMID 30066063.</ref><ref name="Enderle2020">Enderle J, Klink U, di Giuseppe R, Koch M, Seidel U, Weber K, Birringer M, Ratjen I, Rimbach G, Lieb W (August 2020). "Plasma Lithium Levels in a General Population: A Cross-Sectional Analysis of Metabolic and Dietary Correlates". Nutrients. 12 (8): 2489. doi:10.3390/nu12082489. PMC 7468710. PMID 32824874.</ref><ref name=bromine>McCall AS, Cummings CF, Bhave G, Vanacore R, Page-McCaw A, Hudson BG (June 2014). "Bromine is an essential trace element for assembly of collagen IV scaffolds in tissue development and architecture". Cell. 157 (6): 1380–92. doi:10.1016/j.cell.2014.05.009. PMC 4144415. PMID 24906154.</ref><ref name=essentialmetals>Zoroddu, Maria Antonietta; Aaseth, Jan; Crisponi, Guido; Medici, Serenella; Peana, Massimiliano; Nurchi, Valeria Marina (2019). "The essential metals for humans: a brief overview". Journal of Inorganic Biochemistry. 195: 120–129. doi:10.1016/j.jinorgbio.2019.03.013.</ref> v t e
H																	He
Li	Be											B	C	N	O	F	Ne
Na	Mg											Al	Si	P	S	Cl	Ar
K	Ca	Sc	Ti	V	Cr	Mn	Fe	Co	Ni	Cu	Zn	Ga	Ge	As	Se	Br	Kr
Rb	Sr	Y	Zr	Nb	Mo	Tc	Ru	Rh	Pd	Ag	Cd	In	Sn	Sb	Te	I	Xe

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