A vitamin is an organic molecule (or related set of molecules) which is an essential micronutrient that an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet. Vitamin C can be synthesized by some species but not by others; it is not a vitamin in the first instance but is in the second. The term vitamin does not include the three other groups of essential nutrients: minerals, essential fatty acids, and essential amino acids. Most vitamins are not single molecules, but groups of related molecules called vitamers. For example, vitamin E consists of four tocopherols and four tocotrienols. The thirteen vitamins required by human metabolism are: vitamin A (retinols and carotenoids), vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B7 (biotin), vitamin B9 (folic acid or folate), vitamin B12 (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols), and vitamin K (quinones).
A bottle of B-complex vitamin pills
Vitamins have diverse biochemical functions. Some forms of vitamin A function as regulators of cell and tissue growth and differentiation. The B complex vitamins function as enzyme cofactors (coenzymes) or the precursors for them. Vitamin D has a hormone-like function as a regulator of mineral metabolism for bones and other organs. Vitamins C and E function as antioxidants. Both deficient and excess intake of a vitamin can potentially cause clinically significant illness; although excess intake of water-soluble vitamins is less likely to do so.
Before 1935, the only source of vitamins was from food. If intake of vitamins was lacking, the result was vitamin deficiency and consequent deficiency diseases. Then, commercially produced tablets of yeast-extract vitamin B complex and semi-synthetic vitamin C became available. This was followed in the 1950s by the mass production and marketing of vitamin supplements, including multivitamins, to prevent vitamin deficiencies in the general population. Governments mandated addition of vitamins to staple foods such as flour or milk, referred to as food fortification, to prevent deficiencies. Recommendations for folic acid supplementation during pregnancy reduced risk of infant neural tube defects. Although reducing incidence of vitamin deficiencies clearly has benefits, supplementation is thought to be of little value for healthy people who are consuming a vitamin-adequate diet.
The term vitamin is derived from the word vitamine, coined in 1912 by biochemist Casimir Funk, who isolated a complex of micronutrients essential to life, all of which he presumed to be amines. When this presumption was later determined not to be true, the "e" was dropped from the name. All vitamins were discovered (identified) between 1913 and 1948.
|Vitamer chemical name(s) (list not complete)||Solubility||US Recommended dietary allowances
(male/female, age 19–70)
|Deficiency disease||Overdose syndrome/symptoms||Food sources|
|Vitamin A||Retinol, Retinal, and
|Fat||900 µg/700 µg||Night blindness, hyperkeratosis, and keratomalacia||Hypervitaminosis A||Liver, orange, ripe yellow fruits, leafy vegetables, carrots, pumpkin, squash, spinach, fish, soy milk, milk|
|Vitamin B1||Thiamine||Water||1.2 mg/1.1 mg||Beriberi, Wernicke-Korsakoff syndrome||Drowsiness and muscle relaxation||Pork, oatmeal, brown rice, vegetables, potatoes, liver, eggs|
|Vitamin B2||Riboflavin||Water||1.3 mg/1.1 mg||Ariboflavinosis, glossitis, angular stomatitis||Dairy products, bananas, popcorn, green beans, asparagus|
|Vitamin B3||Niacin, Niacinamide, Nicotinamide riboside||Water||16 mg/14 mg||Pellagra||Liver damage (doses > 2g/day) and other problems||Meat, fish, eggs, many vegetables, mushrooms, tree nuts|
|Vitamin B5||Pantothenic acid||Water||5 mg/5 mg||Paresthesia||Diarrhea; possibly nausea and heartburn.||Meat, broccoli, avocados|
|Vitamin B6||Pyridoxine, Pyridoxamine, Pyridoxal||Water||1.3–1.7 mg/1.2–1.5 mg||Anemia, Peripheral neuropathy||Impairment of proprioception, nerve damage (doses > 100 mg/day)||Meat, vegetables, tree nuts, bananas|
|Vitamin B7||Biotin||Water||AI: 30 µg/30 µg||Dermatitis, enteritis||Raw egg yolk, liver, peanuts, leafy green vegetables|
|Vitamin B9||Folates, Folic acid||Water||400 µg/400 µg||Megaloblastic anemia and deficiency during pregnancy is associated with birth defects, such as neural tube defects||May mask symptoms of vitamin B12 deficiency; other effects.||Leafy vegetables, pasta, bread, cereal, liver|
|Vitamin B12||Cyanocobalamin, Hydroxocobalamin, Methylcobalamin, Adenosylcobalamin||Water||2.4 µg/2.4 µg||Pernicious anemia||None proven||Meat, poultry, fish, eggs, milk|
|Vitamin C||Ascorbic acid||Water||90 mg/75 mg||Scurvy||None known||Many fruits and vegetables, liver|
|Vitamin D||Cholecalciferol (D3), Ergocalciferol (D2)||Fat||15 µg/15 µg||Rickets and osteomalacia||Hypervitaminosis D||Lichen, eggs, liver, certain fish species such as sardines, certain mushroom species such as shiitake|
|Vitamin E||Tocopherols, Tocotrienols||Fat||15 mg/15 mg||Deficiency is very rare; mild hemolytic anemia in newborn infants||Possible increased incidence of congestive heart failure.||Many fruits and vegetables, nuts and seeds, and seed oils|
|Vitamin K||Phylloquinone, Menaquinones||Fat||AI: 110 µg/120 µg||Bleeding diathesis||Decreased anticoagulation effect of warfarin.||Leafy green vegetables such as spinach; egg yolks; liver|
For the most part, vitamins are obtained from the diet, but some are acquired by other means: for example, microorganisms in the gut flora produce vitamin K and biotin; and one form of vitamin D is synthesized in skin cells when they are exposed to a certain wavelength of ultraviolet light present in sunlight. Humans can produce some vitamins from precursors they consume: for example, vitamin A is synthesized from beta carotene; and niacin is synthesized from the amino acid tryptophan. The Food Fortification Initiative lists countries which have mandatory fortification programs for vitamins folic acid, niacin, vitamin A and vitamins B1, B2 and B12.
Classification by solubilityEdit
Vitamins are classified as either water-soluble or fat-soluble. In humans there are 13 vitamins: 4 fat-soluble (A, D, E, and K) and 9 water-soluble (8 B vitamins and vitamin C). Water-soluble vitamins dissolve easily in water and, in general, are readily excreted from the body, to the degree that urinary output is a strong predictor of vitamin consumption. Because they are not as readily stored, more consistent intake is important. Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids (fats). Vitamins A and D can accumulate in the body, which can result in dangerous hypervitaminosis. Fat-soluble vitamin deficiency due to malabsorption is of particular significance in cystic fibrosis.
Each vitamin is typically used in multiple reactions, and therefore most have multiple functions.
On fetal growth and childhood developmentEdit
Vitamins are essential for the normal growth and development of a multicellular organism. Using the genetic blueprint inherited from its parents, a fetus begins to develop from the nutrients it absorbs. It requires certain vitamins and minerals to be present at certain times. These nutrients facilitate the chemical reactions that produce among other things, skin, bone, and muscle. If there is serious deficiency in one or more of these nutrients, a child may develop a deficiency disease. Even minor deficiencies may cause permanent damage.
On adult health maintenanceEdit
Once growth and development are completed, vitamins remain essential nutrients for the healthy maintenance of the cells, tissues, and organs that make up a multicellular organism; they also enable a multicellular life form to efficiently use chemical energy provided by food it eats, and to help process the proteins, carbohydrates, and fats required for cellular respiration.
Effects of cookingEdit
The USDA has conducted extensive studies on the percentage losses of various nutrients from different food types and cooking methods. Some vitamins may become more "bio-available" – that is, usable by the body – when foods are cooked. The table below shows whether various vitamins are susceptible to loss from heat—such as heat from boiling, steaming, frying, etc. The effect of cutting vegetables can be seen from exposure to air and light. Water-soluble vitamins such as B and C dissolve into the water when a vegetable is boiled, and are then lost when the water is discarded.
|Vitamin||Soluble in Water||Stable to Air Exposure||Stable to Light Exposure||Stable to Heat Exposure|
|Vitamin A||no||partially||partially||relatively stable|
|Vitamin C||very unstable||yes||no||no|
|Thiamine (B1)||highly||no||?||> 100 °C|
|Riboflavin (B2)||slightly||no||in solution||no|
|Pantothenic Acid (B5)||quite stable||?||no||yes|
|Folic Acid (B9)||yes||?||when dry||at high temp|
The body's stores for different vitamins vary widely; vitamins A, D, and B12 are stored in significant amounts, mainly in the liver, and an adult's diet may be deficient in vitamins A and D for many months and B12 in some cases for years, before developing a deficiency condition. However, vitamin B3 (niacin and niacinamide) is not stored in significant amounts, so stores may last only a couple of weeks. For vitamin C, the first symptoms of scurvy in experimental studies of complete vitamin C deprivation in humans have varied widely, from a month to more than six months, depending on previous dietary history that determined body stores.
Deficiencies of vitamins are classified as either primary or secondary. A primary deficiency occurs when an organism does not get enough of the vitamin in its food. A secondary deficiency may be due to an underlying disorder that prevents or limits the absorption or use of the vitamin, due to a "lifestyle factor", such as smoking, excessive alcohol consumption, or the use of medications that interfere with the absorption or use of the vitamin. People who eat a varied diet are unlikely to develop a severe primary vitamin deficiency. In contrast, restrictive diets have the potential to cause prolonged vitamin deficits, which may result in often painful and potentially deadly diseases.
Well-known human vitamin deficiencies involve thiamine (beriberi), niacin (pellagra), vitamin C (scurvy), and vitamin D (rickets). In much of the developed world, such deficiencies are rare; this is due to (1) an adequate supply of food and (2) the addition of vitamins and minerals to common foods (fortification). In addition to these classical vitamin deficiency diseases, some evidence has also suggested links between vitamin deficiency and a number of different disorders.
Some vitamins have documented acute or chronic toxicity at larger intakes. The European Union and the governments of several countries have established Tolerable upper intake levels (ULs) for those vitamins which have documented toxicity (see table). The likelihood of consuming too much of any vitamin from food is remote, but excessive intake (vitamin poisoning) from dietary supplements does occur. In 2016, overdose exposure to all formulations of vitamins and multi-vitamin/mineral formulations was reported by 63,931 individuals to the American Association of Poison Control Centers with 72% of these exposures in children under the age of five.
In setting human nutrient guidelines, government organizations do not necessarily agree on amounts needed to avoid deficiency or maximum amounts to avoid the risk of toxicity. For example, for vitamin C, recommended intakes range from 40 mg/day in India to 155 mg/day for the European Union. The table below shows U.S. Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for vitamins, PRIs for the European Union (same concept as RDAs), followed by what three government organizations deem to be the safe upper intake. RDAs are set higher than EARs to cover people with higher than average needs. Adequate Intakes (AIs) are set when there is not sufficient information to establish EARs and RDAs. Governments are slow to revise information of this nature. For the U.S. values, with the exception of calcium and vitamin D, all of the data date to 1997-2004.
|Nutrient||U.S. EAR||Highest U.S.
RDA or AI
PRI or AI
|α-tocopherol (Vit E)||12||15||13||1000||300||650-900||mg|
|Thiamin (Vit B1)||1.0||1.2||0.1 mg/MJ||ND||ND||ND||mg|
|Riboflavin (Vit B2)||1.1||1.3||2.0||ND||ND||ND||mg|
|Niacin (Vit B3)||12||16||1.6 mg/MJ||35||10||60-85||mg|
|Pantothenic acid (Vit B5)||NE||5||7||ND||ND||ND||mg|
|Biotin (Vit B7)||NE||30||45||ND||ND||ND||µg|
|Folate (Vit B9)||320||400||600||1000||1000||900-1000||µg|
|Cyanocobalamin (Vit B12)||2.0||2.4||5.0||ND||ND||ND||µg|
EAR US Estimated Average Requirements.
RDA US Recommended Dietary Allowances; higher for adults than for children, and may be even higher for women who are pregnant or lactating.
AI US and EFSA Adequate Intake; AIs established when there is not sufficient information to set EARs and RDAs.
PRI Population Reference Intake is European Union equivalent of RDA; higher for adults than for children, and may be even higher for women who are pregnant or lactating. For Thiamin and Niacin the PRIs are expressed as amounts per MJ of calories consumed. MJ = megajoule = 239 food calories.
Upper Limit Tolerable upper intake levels.
ND ULs have not been determined.
NE EARs have not been established.
In those who are otherwise healthy, there is little evidence that supplements have any benefits with respect to cancer or heart disease. Vitamin A and E supplements not only provide no health benefits for generally healthy individuals, but they may increase mortality, though the two large studies that support this conclusion included smokers for whom it was already known that beta-carotene supplements can be harmful. A 2018 meta-analysis found no evidence that intake of vitamin D or calcium for community-dwelling elderly people reduced bone fractures.
In Europe are regulations that define limits of vitamin (and mineral) dosages for their safe use as dietary supplements. Most vitamins that are sold as dietary supplements are not supposed to exceed a maximum daily dosage referred to as the tolerable upper intake level (UL). Vitamin products above these regulatory limits are not considered supplements and should be registered as prescription or non-prescription (over-the-counter drugs) due to their potential side effects. The European Union, United States, Japan establish recommended upper intake levels.
Dietary supplements often contain vitamins, but may also include other ingredients, such as minerals, herbs, and botanicals. Scientific evidence supports the benefits of dietary supplements for persons with certain health conditions. In some cases, vitamin supplements may have unwanted effects, especially if taken before surgery, with other dietary supplements or medicines, or if the person taking them has certain health conditions. They may also contain levels of vitamins many times higher, and in different forms, than one may ingest through food.
Most countries place dietary supplements in a special category under the general umbrella of foods, not drugs. As a result, the manufacturer, and not the government, has the responsibility of ensuring that its dietary supplement products are safe before they are marketed. Regulation of supplements varies widely by country. In the United States, a dietary supplement is defined under the Dietary Supplement Health and Education Act of 1994. There is no FDA approval process for dietary supplements, and no requirement that manufacturers prove the safety or efficacy of supplements introduced before 1994. The Food and Drug Administration must rely on its Adverse Event Reporting System to monitor adverse events that occur with supplements. In 2007, the US Code of Federal Regulations (CFR) Title 21, part III took effect, regulating Good Manufacturing Practices (GMPs) in the manufacturing, packaging, labeling, or holding operations for dietary supplements. Even though product registration is not required, these regulations mandate production and quality control standards (including testing for identity, purity and adulterations) for dietary supplements. In the European Union, the Food Supplements Directive requires that only those supplements that have been proven safe can be sold without a prescription. For most vitamins, pharmacopoeial standards have been established. In the United States, the United States Pharmacopeia (USP) sets standards for the most commonly used vitamins and preparations thereof. Likewise, monographs of the European Pharmacopoeia (Ph.Eur.) regulate aspects of identity and purity for vitamins on the European market.
|Previous name||Chemical name||Reason for name change|
|Vitamin B4||Adenine||DNA metabolite; synthesized in body|
|Vitamin B8||Adenylic acid||DNA metabolite; synthesized in body|
|Vitamin BT||Carnitine||Synthesized in body|
|Vitamin F||Essential fatty acids||Needed in large quantities (does|
not fit the definition of a vitamin).
|Vitamin G||Riboflavin||Reclassified as Vitamin B2|
|Vitamin H||Biotin||Reclassified as Vitamin B7|
|Vitamin J||Catechol, Flavin||Catechol nonessential; flavin reclassified as Vitamin B2|
|Vitamin L1||Anthranilic acid||Non essential|
|Vitamin L2||Adenylthiomethylpentose||RNA metabolite; synthesized in body|
|Vitamin M||Folic acid||Reclassified as Vitamin B9|
|Vitamin P||Flavonoids||No longer classified as a vitamin|
|Vitamin PP||Niacin||Reclassified as Vitamin B3|
|Vitamin S||Salicylic acid||Proposed inclusion of salicylate as an essential micronutrient|
|Vitamin U||S-Methylmethionine||Protein metabolite; synthesized in body|
The reason that the set of vitamins skips directly from E to K is that the vitamins corresponding to letters F–J were either reclassified over time, discarded as false leads, or renamed because of their relationship to vitamin B, which became a complex of vitamins.
The German-speaking scientists who isolated and described vitamin K (in addition to naming it as such) did so because the vitamin is intimately involved in the coagulation of blood following wounding (from the German word Koagulation). At the time, most (but not all) of the letters from F through to J were already designated, so the use of the letter K was considered quite reasonable. The table nomenclature of reclassified vitamins lists chemicals that had previously been classified as vitamins, as well as the earlier names of vitamins that later became part of the B-complex.
There are other missing B vitamins which were reclassified or determined not to be vitamins. For example, B9 is folic acid and five of the folates are in the range B11 through B16, forms of other vitamins already discovered, not required as a nutrient by the entire population (like B10, PABA for internal use), biologically inactive, toxic, or with unclassifiable effects in humans, or not generally recognised as vitamins by science, such as the highest-numbered, which some naturopath practitioners call B21 and B22. There are also nine lettered B complex vitamins (e.g. Bm). There are other D vitamins now recognised as other substances, which some sources of the same type number up to D7. The controversial cancer treatment laetrile was at one point lettered as vitamin B17. There appears to be no consensus on any vitamins Q, R, T, V, W, X, Y or Z, nor are there substances officially designated as Vitamins N or I, although the latter may have been another form of one of the other vitamins or a known and named nutrient of another type.
Once discovered, vitamins were actively promoted in articles and advertisements in McCall's, Good Housekeeping, and other media outlets. Marketers enthusiastically promoted cod-liver oil, a source of Vitamin D, as "bottled sunshine", and bananas as a “natural vitality food". They promoted foods such as yeast cakes, a source of B vitamins, on the basis of scientifically-determined nutritional value, rather than taste or appearance. World War II researchers focused on the need to ensure adequate nutrition, especially in processed foods. Robert W. Yoder is credited with first using the term vitamania, in 1942, to describe the appeal of relying on nutritional supplements rather than on obtaining vitamins from a varied diet of foods. The continuing preoccupation with a healthy lifestyle has led to an obsessive consumption of additives the beneficial effects of which are questionable.
Anti-vitamins are chemical compounds that inhibit the absorption or actions of vitamins. For example, avidin is a protein in raw egg whites that inhibits the absorption of biotin; it is deactivated by cooking. Pyrithiamine, a synthetic compound, has a molecular structure similar to thiamine, vitamin B1, and inhibits the enzymes that use thiamine.
|Year of discovery||Vitamin||Food source|
|1913||Vitamin A (Retinol)||Cod liver oil|
|1910||Vitamin B1 (Thiamine)||Rice bran|
|1920||Vitamin C (Ascorbic acid)||Citrus, most fresh foods|
|1920||Vitamin D (Calciferol)||Cod liver oil|
|1920||Vitamin B2 (Riboflavin)||Meat, dairy products, eggs|
|1922||Vitamin E (Tocopherol)||Wheat germ oil, |
unrefined vegetable oils
|1929||Vitamin K1 (Phylloquinone)||Leaf vegetables|
|1931||Vitamin B5 (Pantothenic acid)||Meat, whole grains, |
in many foods
|1931||Vitamin B7 (Biotin)||Meat, dairy products, Eggs|
|1934||Vitamin B6 (Pyridoxine)||Meat, dairy products|
|1936||Vitamin B3 (Niacin)||Meat, grains|
|1941||Vitamin B9 (Folic acid)||Leaf vegetables|
|1948||Vitamin B12 (Cobalamins)||Meat, organs (Liver), Eggs|
The value of eating certain foods to maintain health was recognized long before vitamins were identified. The ancient Egyptians knew that feeding liver to a person may help with night blindness, an illness now known to be caused by a vitamin A deficiency. The advancement of ocean voyages during the Renaissance resulted in prolonged periods without access to fresh fruits and vegetables, and made illnesses from vitamin deficiency common among ships' crews.
In 1747, the Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy, a particularly deadly disease in which collagen is not properly formed, causing poor wound healing, bleeding of the gums, severe pain, and death. In 1753, Lind published his Treatise on the Scurvy, which recommended using lemons and limes to avoid scurvy, which was adopted by the British Royal Navy. This led to the nickname limey for British sailors. Lind's discovery, however, was not widely accepted by individuals in the Royal Navy's Arctic expeditions in the 19th century, where it was widely believed that scurvy could be prevented by practicing good hygiene, regular exercise, and maintaining the morale of the crew while on board, rather than by a diet of fresh food. As a result, Arctic expeditions continued to be plagued by scurvy and other deficiency diseases. In the early 20th century, when Robert Falcon Scott made his two expeditions to the Antarctic, the prevailing medical theory at the time was that scurvy was caused by "tainted" canned food.
During the late 18th and early 19th centuries, the use of deprivation studies allowed scientists to isolate and identify a number of vitamins. Lipid from fish oil was used to cure rickets in rats, and the fat-soluble nutrient was called "antirachitic A". Thus, the first "vitamin" bioactivity ever isolated, which cured rickets, was initially called "vitamin A"; however, the bioactivity of this compound is now called vitamin D. In 1881, Russian medical doctor Nikolai I. Lunin studied the effects of scurvy at the University of Tartu . He fed mice an artificial mixture of all the separate constituents of milk known at that time, namely the proteins, fats, carbohydrates, and salts. The mice that received only the individual constituents died, while the mice fed by milk itself developed normally. He made a conclusion that "a natural food such as milk must therefore contain, besides these known principal ingredients, small quantities of unknown substances essential to life." However, his conclusions were rejected by his advisor, Gustav von Bunge, even after other students reproduced his results. A similar result by Cornelius Pekelharing appeared in a Dutch medical journal in 1905, but it was not widely reported.
In East Asia, where polished white rice was the common staple food of the middle class, beriberi resulting from lack of vitamin B1 was endemic. In 1884, Takaki Kanehiro, a British-trained medical doctor of the Imperial Japanese Navy, observed that beriberi was endemic among low-ranking crew who often ate nothing but rice, but not among officers who consumed a Western-style diet. With the support of the Japanese navy, he experimented using crews of two battleships; one crew was fed only white rice, while the other was fed a diet of meat, fish, barley, rice, and beans. The group that ate only white rice documented 161 crew members with beriberi and 25 deaths, while the latter group had only 14 cases of beriberi and no deaths. This convinced Takaki and the Japanese Navy that diet was the cause of beriberi, but they mistakenly believed that sufficient amounts of protein prevented it. That diseases could result from some dietary deficiencies was further investigated by Christiaan Eijkman, who in 1897 discovered that feeding unpolished rice instead of the polished variety to chickens helped to prevent beriberi in the chickens. The following year, Frederick Hopkins postulated that some foods contained "accessory factors" — in addition to proteins, carbohydrates, fats etc. — that are necessary for the functions of the human body. Hopkins and Eijkman were awarded the Nobel Prize for Physiology or Medicine in 1929 for their discoveries.
In 1910, the first vitamin complex was isolated by Japanese scientist Umetaro Suzuki, who succeeded in extracting a water-soluble complex of micronutrients from rice bran and named it aberic acid (later Orizanin). He published this discovery in a Japanese scientific journal. When the article was translated into German, the translation failed to state that it was a newly discovered nutrient, a claim made in the original Japanese article, and hence his discovery failed to gain publicity. In 1912 Polish-born biochemist Casimir Funk, working in London, isolated the same complex of micronutrients and proposed the complex be named "vitamine". It was later to be known as vitamin B3 (niacin), though he described it as "anti-beri-beri-factor" (which would today be called thiamine or vitamin B1). Funk proposed the hypothesis that other diseases, such as rickets, pellagra, coeliac disease, and scurvy could also be cured by vitamins. Max Nierenstein a friend and reader of Biochemistry at Bristol University reportedly suggested the "vitamine" name (from "vital amine"). The name soon became synonymous with Hopkins' "accessory factors", and, by the time it was shown that not all vitamins are amines, the word was already ubiquitous. In 1920, Jack Cecil Drummond proposed that the final "e" be dropped to deemphasize the "amine" reference, after researchers began to suspect that not all "vitamines" (in particular, vitamin A) have an amine component.
In 1930, Paul Karrer elucidated the correct structure for beta-carotene, the main precursor of vitamin A, and identified other carotenoids. Karrer and Norman Haworth confirmed Albert Szent-Györgyi's discovery of ascorbic acid and made significant contributions to the chemistry of flavins, which led to the identification of lactoflavin. For their investigations on carotenoids, flavins and vitamins A and B2, they both received the Nobel Prize in Chemistry in 1937.
In 1931, Albert Szent-Györgyi and a fellow researcher Joseph Svirbely suspected that "hexuronic acid" was actually vitamin C, and gave a sample to Charles Glen King, who proved its anti-scorbutic activity in his long-established guinea pig scorbutic assay. In 1937, Szent-Györgyi was awarded the Nobel Prize in Physiology or Medicine for his discovery. In 1943, Edward Adelbert Doisy and Henrik Dam were awarded the Nobel Prize in Physiology or Medicine for their discovery of vitamin K and its chemical structure. In 1967, George Wald was awarded the Nobel Prize (along with Ragnar Granit and Haldan Keffer Hartline) for his discovery that vitamin A could participate directly in a physiological process.
The term vitamin was derived from "vitamine", a compound word coined in 1912 by the Polish biochemist Casimir Funk when working at the Lister Institute of Preventive Medicine. The name is from vital and amine, meaning amine of life, because it was suggested in 1912 that the organic micronutrient food factors that prevent beriberi and perhaps other similar dietary-deficiency diseases might be chemical amines. This was true of thiamine, but after it was found that other such micronutrients were not amines the word was shortened to vitamin in English.
- Jones, Daniel (2011). Roach, Peter; Setter, Jane; Esling, John, eds. Cambridge English Pronouncing Dictionary (18th ed.). Cambridge University Press. ISBN 978-052-115255-6.
- Maton, Anthea; Jean Hopkins; Charles William McLaughlin; Susan Johnson; Maryanna Quon Warner; David LaHart; Jill D. Wright (1993). Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall. ISBN 0-13-981176-1. OCLC 32308337.
- Bender DA (2003). Nutritional biochemistry of the vitamins. Cambridge, U.K.: Cambridge University Press. ISBN 978-0-521-80388-5.
- "Food Fortification Initiative". Food Fortification Initiative, Enhancing Grains for Better Lives. Retrieved 18 August 2018.
- Wilson RD, Wilson RD, Audibert F, Brock JA, Carroll J, Cartier L, et al. (June 2015). "Pre-conception Folic Acid and Multivitamin Supplementation for the Primary and Secondary Prevention of Neural Tube Defects and Other Folic Acid-Sensitive Congenital Anomalies". Journal of Obstetrics and Gynaecology Canada. 37 (6): 534–52. doi:10.1016/s1701-2163(15)30230-9. PMID 26334606.
- Fortmann SP, Burda BU, Senger CA, Lin JS, Whitlock EP (2013). "Vitamin and mineral supplements in the primary prevention of cardiovascular disease and cancer: An updated systematic evidence review for the U.S. Preventive Services Task Force". Annals of Internal Medicine. 159 (12): 824–834. doi:10.7326/0003-4819-159-12-201312170-00729. PMID 24217421.
- Combs GF (2007-10-30). The Vitamins. Elsevier. ISBN 9780080561301.
- Dietary Reference Intakes (DRIs) Food and Nutrition Board, Institute of Medicine, National Academies
- "Vitamin A: Fact Sheet for Health Professionals". National Institute of Health: Office of Dietary Supplements. 5 June 2013. Retrieved 2013-08-03.
- "Thiamin, vitamin B1: MedlinePlus Supplements". U.S. Department of Health and Human Services, National Institutes of Health.
- Hardman, J.G.; et al., eds. (2001). Goodman and Gilman's Pharmacological Basis of Therapeutics (10th ed.). p. 992. ISBN 0071354697.
- "Pantothenic acid, dexpanthenol: MedlinePlus Supplements". MedlinePlus. Retrieved 5 October 2009.
- Vitamin and Mineral Supplement Fact Sheets Vitamin B6. Dietary-supplements.info.nih.gov (15 September 2011). Retrieved on 2013-08-03.
- Vitamin and Mineral Supplement Fact Sheets Vitamin B12. Dietary-supplements.info.nih.gov (24 June 2011). Retrieved on 2013-08-03.
- The Merck Manual: Nutritional Disorders: Vitamin Introduction Please select specific vitamins from the list at the top of the page.
- Gaby AR (2005). "Does vitamin E cause congestive heart failure? (Literature Review & Commentary)". Townsend Letter for Doctors and Patients.
- Higdon, Jane (2011)Vitamin E recommendations at Linus Pauling Institute's Micronutrient Information Center
- Rohde LE, de Assis MC, Rabelo ER (January 2007). "Dietary vitamin K intake and anticoagulation in elderly patients". Current Opinion in Clinical Nutrition and Metabolic Care. 10 (1): 1–5. doi:10.1097/MCO.0b013e328011c46c. PMID 17143047.
- Institute of Medicine (1998). "Niacin". Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: The National Academies Press. pp. 123–149. ISBN 0-309-06554-2. Retrieved 2018-08-29.
- Fukuwatari T, Shibata K (June 2008). "Urinary water-soluble vitamins and their metabolite contents as nutritional markers for evaluating vitamin intakes in young Japanese women". Journal of Nutritional Science and Vitaminology. 54 (3): 223–9. doi:10.3177/jnsv.54.223. PMID 18635909.
- Bellows L, Moore R. "Water-Soluble Vitamins". Colorado State University. Retrieved 7 December 2008.
- Maqbool A, Stallings VA (November 2008). "Update on fat-soluble vitamins in cystic fibrosis". Current Opinion in Pulmonary Medicine. 14 (6): 574–81. doi:10.1097/MCP.0b013e3283136787. PMID 18812835.
- Kutsky, R.J. (1973). Handbook of Vitamins and Hormones. New York: Van Nostrand Reinhold, ISBN 0-442-24549-1
- Gavrilov, Leonid A. (10 February 2003) Pieces of the Puzzle: Aging Research Today and Tomorrow. fightaging.org
- "USDA Table of Nutrient Retention Factors, Release 6" (PDF). USDA. USDA. Dec 2007.
- Comparison of Vitamin Levels in Raw Foods vs. Cooked Foods. Beyondveg.com. Retrieved on 3 August 2013.
- Effects of Cooking on Vitamins (Table). Beyondveg.com. Retrieved on 3 August 2013.
- Pemberton J (June 2006). "Medical experiments carried out in Sheffield on conscientious objectors to military service during the 1939-45 war". International Journal of Epidemiology. 35 (3): 556–8. doi:10.1093/ije/dyl020. PMID 16510534.
- Wendt D (2015). "Packed full of questions: Who benefits from dietary supplements?". Distillations Magazine. 1 (3): 41–45. Retrieved 22 March 2018.
- Price C (2015). Vitamania: Our obsessive quest for nutritional perfection. Penguin Press. ISBN 978-1594205040.
- Lakhan SE, Vieira KF (January 2008). "Nutritional therapies for mental disorders". Nutrition Journal. 7: 2. doi:10.1186/1475-2891-7-2. PMC 2248201. PMID 18208598.
- Boy E, Mannar V, Pandav C, de Benoist B, Viteri F, Fontaine O, Hotz C (May 2009). "Achievements, challenges, and promising new approaches in vitamin and mineral deficiency control". Nutrition Reviews. 67 Suppl 1 (Suppl 1): S24–30. doi:10.1111/j.1753-4887.2009.00155.x. PMID 19453674.
- Tolerable Upper Intake Levels For Vitamins And Minerals (PDF), European Food Safety Authority, 2006
- Dietary Reference Intakes for Japanese (2010) National Institute of Health and Nutrition, Japan
- Gummin DD, Mowry JB, Spyker DA, Brooks DE, Fraser MO, Banner W (2017). "2016 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 34th Annual Report" (PDF). Clinical Toxicology. 55 (10): 1072–1254. doi:10.1080/15563650.2017.1388087.
- "Nutrient Requirements and Recommended Dietary Allowances for Indians: A Report of the Expert Group of the Indian Council of Medical Research. pp.283-295 (2009)" (PDF). Archived (PDF) from the original on June 15, 2016.
- "Overview on Dietary Reference Values for the EU population as derived by the EFSA Panel on Dietetic Products, Nutrition and Allergies" (PDF). 2017. Archived (PDF) from the original on August 28, 2017.
- Dietary Reference Intakes: The Essential Guide to Nutrient Requirements, published by the Institute of Medicine's Food and Nutrition Board, currently available online at "Archived copy". Archived from the original on 2014-07-05. Retrieved 2014-07-14.
- Moyer VA (2014). "Vitamin, mineral, and multivitamin supplements for the primary prevention of cardiovascular disease and cancer: U.S. Preventive services Task Force recommendation statement". Annals of Internal Medicine. 160 (8): 558–564. doi:10.7326/M14-0198. PMID 24566474.
- Jenkins DJ, Spence JD, Giovannucci EL, Kim YI, Josse R, Vieth R, et al. (2018). "Supplemental Vitamins and Minerals for CVD Prevention and Treatment". Journal of the American College of Cardiology. 71 (22): 2570–2584. doi:10.1016/j.jacc.2018.04.020. PMID 29852980.
- 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): 842–857. doi:10.1001/jama.297.8.842. PMID 17327526.
- Zhao JG, Zeng XT, Wang J, Liu L (2017). "Association Between Calcium or Vitamin D Supplementation and Fracture Incidence in Community-Dwelling Older Adults: A Systematic Review and Meta-analysis". Jama. 318 (24): 2466–2482. doi:10.1001/jama.2017.19344. PMC 5820727. PMID 29279934.
- Use and Safety of Dietary Supplements NIH office of Dietary Supplements.
- Legislation. Fda.gov (15 September 2009). Retrieved on 2010-11-12.
- "Adverse Event Reporting System (AERS)". FDA. 20 August 2009. Retrieved 2010-11-12.
- U.S. Food and Drug Administration. CFR – Code of Federal Regulations Title 21. Retrieved 16 February 2014.
- not EUR-Lex – 32002L0046 – EN. Eur-lex.europa.eu. Retrieved on 12 November 2010.
- Bennett D. "Every Vitamin Page" (PDF). All Vitamins and Pseudo-Vitamins.
- Davidson, Michael W. (2004) Anthranilic Acid (Vitamin L) Florida State University. Retrieved 20-02-07.
- García González JA (December 1979). "[Mother-child relations]". Nueva Enfermeria. 327 (7): 15–20. doi:10.1136/bmj.327.7424.0-h. PMC 261797.
- "Vitamins and minerals – names and facts". pubquizhelp.34sp.com. Archived from the original on 2007-07-04.
- "B Vitamins". NeuroSoup. 2013-04-15. Archived from the original on 3 March 2016.
- Vitamins: What Vitamins Do I Need?. Medical News Today. Retrieved on 2015-11-30.
- Price C (Fall 2015). "The healing power of compressed yeast". Distillations Magazine. 1 (3): 17–23. Retrieved 20 March 2018.
- Roth KS (September 1981). "Biotin in clinical medicine--a review". The American Journal of Clinical Nutrition. 34 (9): 1967–74. doi:10.1093/ajcn/34.9.1967. PMID 6116428.
- Rindi G, Perri V (July 1961). "Uptake of pyrithiamine by tissue of rats". The Biochemical Journal. 80 (1): 214–6. PMC 1243973. PMID 13741739.
- McDowell LR (2012). Vitamins in Animal Nutrition: Comparative Aspects to Human Nutrition. Elsevier. p. 398. ISBN 9780323139045.
- Jack Challem (1997)."The Past, Present and Future of Vitamins"
- Jacob RA (1996). "Three eras of vitamin C discovery". Sub-Cellular Biochemistry. Subcellular Biochemistry. 25: 1–16. doi:10.1007/978-1-4613-0325-1_1. ISBN 978-1-4613-7998-0. PMID 8821966.
- Bellis M. "Production Methods The History of the Vitamins". Retrieved 1 February 2005.
- 1929 Nobel lecture. Nobelprize.org. Retrieved on 3 August 2013.
- Gratzer W (2006). "9. The quarry run to earth". Terrors of the table: the curious history of nutrition. Oxford: Oxford University Press. ISBN 978-0199205639. Retrieved 5 November 2015.
- Rosenfeld L (April 1997). "Vitamine--vitamin. The early years of discovery". Clinical Chemistry. 43 (4): 680–5. PMID 9105273.
- Carpenter K (22 June 2004). "The Nobel Prize and the Discovery of Vitamins". Nobelprize.org. Retrieved 5 October 2009.
- Suzuki, U.; Shimamura, T. (1911). "Active constituent of rice grits preventing bird polyneuritis". Tokyo Kagaku Kaishi. 32: 4–7, 144–146, 335–358.
- Combs, Gerald (2008). The vitamins: fundamental aspects in nutrition and health. ISBN 9780121834937.
- Funk, C. and Dubin, H. E. (1922). The Vitamines. Baltimore: Williams and Wilkins Company.
- "Paul Karrer-Biographical". Nobelprize.org. Retrieved 8 January 2013.
- "The Nobel Prize in Chemistry 1938". Nobelprize.org. Retrieved 5 July 2018.
- Iłowiecki M (1981). Dzieje nauki polskiej. Warszawa: Wydawnictwo Interpress. p. 177. ISBN 83-223-1876-6.