"been destroyed. The modified oil cured the sick dogs, so McCollum concluded the factor in cod liver oil which cured rickets was distinct from vitamin A. He called it vitamin D because it was the fourth vitamin to be named. It was not initially realized that, unlike other vitamins, vitamin D can be synthesised by humans through exposure to UV light. In 1925, it was established that when 7-dehydrocholesterol is irradiated with light, a form of a fat-soluble vitamin is produced (now known as D). Alfred Fabian Hess stated: ""Light equals vitamin D."" Adolf Windaus, at the University of Göttingen"
"be synthetic or naturally derived from lichen, a non-animal source of D3. Vitamin B is the only vitamin not present in plant sources. The largest and most complex of all the vitamins, vitamin B, is synthesized only by bacteria and some archaea species, as eukaryotes lack the enzyme. It is integral to the health and function of the nervous system, key in hematopoiesis, as well as required to synthesize methionine and catabolize propionate for energy. Grazing animals are able to obtain B when they ingest bits of soil with the grass, as the vitamin and B-producing bacteria are found in"
"among non-fortified foods, only those of animal origin contain sufficient amounts. The best source is ruminant food. Vegetarians are also at risk, as are older people and those with certain medical conditions. A 2013 study found that ""vegetarians develop B depletion or deficiency regardless of demographic characteristics, place of residency, age, or type of vegetarian diet. Vegans should take preventive measures to ensure adequate intake of this vitamin, including regular consumption of supplements containing B."" B is produced in nature only by certain bacteria and archaea; it is not made by any animal, fungus, or plant. It is synthesized by"
"constitutes an intellectual achievement of the highest caliber, the Eschenmoser–Woodward synthesis of vitamin B is of no practical consequence due to its length, taking 72 chemical steps and giving an overall chemical yield well under 0.01%. And although there have been sporadic synthetic efforts since 1972, the Eschenmoser–Woodward synthesis remains the only completed (formal) total synthesis. Bacterial (or, perhaps archaeal) fermentation remains the only industrially viable source of the vitamin for food production and medicine. Species from the following genera and species are known to synthesize B: ""Propionibacterium shermanii,"" ""Pseudomonas"" ""denitrificans"", ""Streptomyces"" ""griseus"", ""Acetobacterium"", ""Aerobacter"", ""Agrobacterium"", ""Alcaligenes"", ""Azotobacter"", ""Bacillus"", ""Clostridium"","
"produce no exotoxins or endotoxins and are generally recognized as safe (have been granted GRAS status) by the Food and Drug Administration of the United States, they are presently the FDA-preferred bacterial fermentation organisms for vitamin B production. The total world production of vitamin B, by four companies (the French Sanofi-Aventis and three Chinese companies) in 2008 was 35 tonnes. No eukaryotic organisms (including plants, animals, and fungi) are independently capable of constructing vitamin B. Only bacteria and archaea have the enzymes required for its biosynthesis. Like all tetrapyrroles, it is derived from uroporphyrinogen III. This porphyrinogen is methylated at"
"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. Vitamin 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"
"all of which show physiological activity. It contains the biochemically rare element cobalt (chemical symbol Co) positioned in the center of a corrin ring. The only organisms to produce vitamin B are certain bacteria, and archaea. Some of these bacteria are found in the soil around the grasses that ruminants eat; they are taken into the animal, proliferate, form part of their gut flora, and continue to produce vitamin B. There are no naturally occurring notable vegetable dietary sources of the vitamin, so vegans and vegetarians are advised to take a supplement or fortified foods. Otherwise, most omnivorous people in"
"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. 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"
"absorption of B into the body requires adequate amounts of intrinsic factor, the glycoprotein produced in the parietal cells of the stomach lining. A functioning small intestine is also necessary for the proper metabolism of the vitamin, as absorption occurs within the ileum. B is produced in the digestive tracts of all animals, including humans. Thus, animal-origin food is the only natural food source of vitamin B However, synthesis of B occurs in the large intestine, which is past the point of absorption that occurs within the small intestine. As such, vitamin B must be obtained through diet. Unlike other"
"because the body requires them for good health but cannot synthesize them. Only two fatty acids are known to be essential for humans: alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid). Vitamins are organic molecules essential for an organism that are not classified as amino acids or fatty acids. They commonly function as enzymatic cofactors, metabolic regulators or antioxidants. Humans require thirteen vitamins in their diet, most of which are actually groups of related molecules (e.g. vitamin E includes tocopherols and tocotrienols): vitamins A, C, D, E, K, thiamine (B), riboflavin (B), niacin (B), pantothenic"
"for large companies and January 1, 2021 for small companies. Most omnivorous people in developed countries obtain enough vitamin B from consuming animal products including, meat, fish, eggs, and milk, but there are no vegan sources other than B-fortified foods or B supplements. B is only produced in nature by certain bacteria, and archaea. It is synthesized by some bacteria in the gut flora in humans and other animals, but humans cannot absorb this as it is made in the colon, downstream from the small intestine, where the absorption of most nutrients occurs. Ruminants, such as cows and sheep, absorb"
"Vitamin 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"
"Whether cholecalciferol and all forms of vitamin D are by definition ""vitamins"" can be disputed, since the definition of vitamins includes that the substance cannot be synthesized by the body and must be ingested. Cholecalciferol ""is"" synthesized by the body during UVB radiation exposure. The three steps in the synthesis and activation of vitamin D are regulated as follows: Cholecalciferol is produced industrially for use in vitamin supplements and to fortify foods. As a pharmaceutical drug it is called cholecalciferol (USAN) or colecalciferol (INN, BAN). It is produced by the ultraviolet irradiation of 7-dehydrocholesterol extracted from lanolin found in sheep's"
"a person's vitamin D is taken by mouth, as sun exposure in the population is variable and recommendations about the amount of sun exposure that is safe are uncertain in view of the skin cancer risk. Vitamin D from the diet or skin synthesis is biologically inactive; enzymatic conversion (hydroxylation) in the liver and kidney is required for activation. As vitamin D can be synthesized in adequate amounts by most mammals exposed to sufficient sunlight, it is not an essential dietary factor, and so not technically a vitamin. Instead it could be considered a hormone, with activation of the vitamin"
"The only archaea that make glutathione are halobacteria. Glutathione is not an essential nutrient for humans, since it can be synthesized in the body from the amino acids -cysteine, -glutamic acid, and glycine; it does not have to be present as a supplement in the diet. The sulfhydryl group (SH) of cysteine serves as a proton donor and is responsible for its biological activity. Cysteine is the rate-limiting factor in cellular glutathione biosynthesis, since this amino acid is relatively rare in foods. Cells make glutathione in two adenosine triphosphate-dependent steps: Animal glutamate cysteine ligase (GCL) is a heterodimeric enzyme composed"
"be obtained from the diet. The term is conditional both on the circumstances and on the particular organism. For example, ascorbic acid (vitamin C) is a vitamin for anthropoid primates, humans, guinea pigs and bats, but not for other mammals. Vitamin D is not an essential nutrient for people who get sufficient exposure to ultraviolet light, either from the sun or an artificial source, as then they synthesize vitamin D in skin. Humans require thirteen vitamins in their diet, most of which are actually groups of related molecules, ""vitamers"", (e.g. vitamin E includes tocopherols and tocotrienols, vitamin K includes vitamin"
"produced by human tissue. MK-7 may be converted from phylloquinone (K) in the colon by ""Escherichia coli"" bacteria. However, these menaquinones synthesized by bacteria in the gut appear to contribute minimally to overall vitamin K status. MK-4 and MK-7 are both found in the United States in dietary supplements for bone health. The U.S. Food and Drug Administration (FDA) has not approved any form of vitamin K for the prevention or treatment of osteoporosis. MK-4 (45 mg daily) has been approved by the Ministry of Health in Japan since 1995 for the prevention and treatment of osteoporosis. All K vitamins"
"every part of the human body, including the skeleton, the immune system, and brain requires vitamin D. Sunlight is necessary for the production of vitamin D. Vitamin D production in the skin begins when UV radiation penetrates the skin and interacts with a cholesterol-like molecule produce pre-vitamin D3. This reaction only occurs in the presence of medium length UVR, UVB. Most of the UVB and UVC rays are destroyed or reflected by ozone, oxygen, and dust in the atmosphere. UVB reaches the Earth’s surface in the highest amounts when its path is straight and goes through a little layer of"
"needs can be met via the human body's own generation upon sufficient and sensible exposure to ultraviolet (UV) light in sunlight. Products including milk, soy milk and cereal grains may be fortified to provide a source of Vitamin D. For those who do not get adequate sun exposure or food sources, Vitamin D supplementation may be necessary. Vitamin D, or ergocalciferol is found in fungus (except alfalfa which is a plantae) and created from viosterol, which in turn is created when ultraviolet light activates ergosterol (which is found in fungi and named as a sterol from ergot). Any UV-irradiated fungus"
"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 B (thiamine), vitamin B (riboflavin), vitamin B (niacin), vitamin B (pantothenic acid), vitamin B (pyridoxine), vitamin B (biotin), vitamin B (folic acid or folate), vitamin B (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols), and vitamin K (quinones). Vitamins have diverse biochemical functions. Some forms of vitamin A function as regulators of cell and tissue"
"synthesized in the skin in the presence of UVB radiation, and many animal species can synthesize vitamin C.) Vitamin deficiencies may result in disease conditions, including goitre, scurvy, osteoporosis, impaired immune system, disorders of cell metabolism, certain forms of cancer, symptoms of premature aging, and poor psychological health, among many others. 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. Phytochemicals such as polyphenols are compounds produced naturally in plants (phyto means ""plant"" in Greek). In general, the term"
"Vitamin B12 Vitamin B, also called cobalamin, is a water-soluble vitamin that is involved in the metabolism of every cell of the human body: it is a cofactor in DNA synthesis, and in both fatty acid and amino acid metabolism. It is particularly important in the normal functioning of the nervous system via its role in the synthesis of myelin, and in the maturation of developing red blood cells in the bone marrow. Vitamin B is one of eight B vitamins; it is the largest and most structurally complicated vitamin. It consists of a class of chemically related compounds (vitamers),"
"Essential amino acid An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized ""de novo"" (from scratch) by the organism, and thus must be supplied in its diet. The nine amino acids humans cannot synthesize are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine. Recently, it's been found that histadine can be made in the body if the other eight essential amino acids are supplied. Six other amino acids are considered conditionally essential in the human diet, meaning their synthesis can be limited under special pathophysiological conditions, such as prematurity in the"
"same enzymatic cofactor(s), which is active in the body as a form of the vitamin. As part of the definition of vitamin, the body cannot completely synthesize an optimal amount of vitamins from simple foodstuffs, without some minimal amount of a vitamer molecule as a foundation. Typically not all vitamers possess exactly the same vitamin potency, per mass. This is due to differences in absorption and interconversion of the various vitamers of a vitamin. Often for the same reason, the toxicity of vitamers varies by molecule, as is the case with vitamin E. A set of chemicals may be (but"
"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"
"and any further vitamin D that is produced is degraded. This process is less efficient with increased melanin pigmentation in the skin. Endogenous production with full body exposure to sunlight is comparable to taking an oral dose between 250 µg and 625 µg (10,000 IU and 25,000 IU) per day. Vitamin D oral supplementation and skin synthesis have a different effect on the transport form of vitamin D, plasma calcifediol concentrations. Endogenously synthesized vitamin D travels mainly with vitamin D-binding protein (DBP), which slows hepatic delivery of vitamin D and the availability in the plasma. In contrast, orally administered vitamin"
"from riboflavin. Bacteria, fungi and plants can produce riboflavin, but other eukaryotes, such as humans, have lost the ability to make it. Therefore, humans must obtain riboflavin, also known as vitamin B2, from dietary sources. Riboflavin is generally ingested in the small intestine and then transported to cells via carrier proteins. Riboflavin kinase (EC 2.7.1.26) adds a phosphate group to riboflavin to produce flavin mononucleotide, and then FAD synthetase attaches an adenine nucleotide; both steps require ATP. Bacteria generally have one bi-functional enzyme, but archaea and eukaryotes usually employ two distinct enzymes. Current research indicates that distinct isoforms exist in"
"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. 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 one or more of the essential amino acids is described as protein-energy malnutrition. Essential amino acid An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized ""de novo"" (from scratch) by the organism, and thus must be supplied in its diet. The nine amino acids humans cannot synthesize are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine. Recently, it's been found that histadine can be made in the body if the other eight essential amino acids are supplied. Six other amino acids are considered conditionally essential in the human diet, meaning"
"levels (30–180 mg daily). Adsorption is only about 50% for daily doses of 1 g. Oral administration, even of mega doses, cannot raise blood concentration above 0.22 mM. Humans and other species that do not synthesize vitamin C carry a mutated and ineffective form of the enzyme L-gulonolactone oxidase, the fourth and last step in the ascorbate-producing machinery. In the anthropoids lineage, this mutation likely occurred 40 to 25 million years ago. The three surviving enzymes continue to produce the precursors to vitamin C, but the process is incomplete and the body then disassembles them. In the 1960s, the Nobel-Prize-winning"
"material of proteins) called lysine, forming a complex called biocytin. Biotinidase removes biotin from biocytin and makes it available to be reused by other enzymes. Biotin, sometimes called vitamin H, is an important water-soluble vitamin that aids in the metabolism of fats, carbohydrates and proteins. The human body cannot produce biotin, but it can obtain it from the diet, internal recycling and at some extent from intestinal bacteria. Biotin deficiency can result in behavioral disorders, lack of coordination, learning disabilities and seizure. Unlike most vitamins, which are noncovalently bound to enzymes, biotin is chemically linked (covalently bound), and therefore cannot"
"given by intravenous or intramuscular injection. Thiamine supplements are generally well tolerated. Allergic reactions, including anaphylaxis, may occur when repeated doses are given by injection. Thiamine is in the B complex family. It is an essential micronutrient, which cannot be made in the body. Thiamine is required for metabolism including that of glucose, amino acids, and lipids. Thiamine was discovered in 1897, was the first vitamin to be isolated in 1926, and was first made in 1936. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Thiamine"
"and anabolism. Catabolism breaks down molecules, and anabolism puts them together. Catabolic reactions generate ATP, and anabolic reactions consume it. It also serves as a carrier of phosphate groups in phosphorylation reactions. A vitamin is an organic compound needed in small quantities that cannot be made in cells. In human nutrition, most vitamins function as coenzymes after modification; for example, all water-soluble vitamins are phosphorylated or are coupled to nucleotides when they are used in cells. Nicotinamide adenine dinucleotide (NAD), a derivative of vitamin B (niacin), is an important coenzyme that acts as a hydrogen acceptor. Hundreds of separate types"