Fruits and vegetables are often a good source of vitamins.

A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. A nutrient is food or chemicals that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment ^[1] A compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Biosynthesis is a phenomenon wherein Chemical compounds are produced from simpler Reagents Biosynthesis unlike Chemosynthesis, takes place within living Thus, the term is conditional both on the circumstances and the particular organism. For example, ascorbic acid functions as vitamin C for some animals but not others, and vitamins D and K are required in the human diet only in certain circumstances. This article deals with the molecular aspects of ascorbic acid Vitamin C or L-ascorbate is an Essential nutrient for a large number of higher primate species a small number of other Mammalian Vitamin D is a group of fat-soluble Prohormones, the two major forms of which are vitamin D2 (or Ergocalciferol) and vitamin D3 (or Vitamin K (K from "Koagulations-Vitamin" in German Danish Swedish and Norwegian denotes a group of Lipophilic, Hydrophobic Vitamins that ^[2]

Vitamins are classified by their biological and chemical activity, not their structure. Thus, each "vitamin" actually refers to a number of vitamer compounds, which form a set of distinct chemical compounds that show the biological activity of a particular vitamin. The vitamers of a particular Vitamin are all of the chemical compounds which exhibit vitamin activity Such a set of chemicals are grouped under an alphabetized vitamin "generic descriptor" title, such as "vitamin A," which (for example) includes retinal, retinol, and many carotenoids. Retinal, technically called retinene1 or retinaldehyde, is a light-sensitive Retinene molecule found in the Photoreceptor cells of Retinol (Afaxin, the animal form of Vitamin A, is a fat-soluble vitamin important in vision and Bone growth Carotenoids are organic Pigments that are naturally occurring in Chromoplasts of plants and some other photosynthetic Organisms ^[3] Vitamers are often inter-convertible in the body. The term vitamin does not include other essential nutrients such as dietary minerals, essential fatty acids, or essential amino acids, nor does it encompass the large number of other nutrients that promote health but are otherwise required less often. An essential nutrient is a Nutrient required for normal body functioning that cannot be synthesized by the body and must be obtained from a dietary source Dietary minerals are the Chemical elements required by living Organisms other than the four elements Carbon, Hydrogen, Nitrogen, and Essential fatty acids, or EFAs are Fatty acids that cannot be constructed within an organism from other components (generally all references are to humans by any known chemical An essential amino acid or indispensable amino acid is an Amino acid that cannot be synthesized de novo by the organism (usually referring to ^[4]

Vitamins have diverse biochemical functions, including function as hormones (e. Hormones (from Greek ὁρμή - "impetus" are chemicals released by cells that affect cells in other parts of the body g. vitamin D), antioxidants (e. An antioxidant is a Molecule capable of slowing or preventing the oxidation of other molecules g. vitamin E), and mediators of cell signaling and regulators of cell and tissue growth and differentiation (e. g. vitamin A). ^[5] The largest number of vitamins (e. g. B complex vitamins) function as precursors for enzyme cofactor bio-molecules (coenzymes), that help act as catalysts and substrates in metabolism. A cofactor is a non-protein Chemical compound that is bound (either tightly or loosely to an Enzyme and is required for Catalysis. A biomolecule is any organic Molecule that is produced by living Organisms including large Polymeric molecules such as Proteins Coenzymes are small organic non- Protein Molecules that carry chemical groups between Enzymes Coenzymes are sometimes referred to as cosubstrates Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. When acting as part of a catalyst, vitamins are bound to enzymes and are called prosthetic groups. Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins A prosthetic group is a non-protein (non- Amino acid) component of a Conjugated protein that is important in the protein's biological activity For example, biotin is part of enzymes involved in making fatty acids. Vitamin H redirects here In medical slang "vitamin H" may also refer to Haloperidol. In Chemistry, especially Biochemistry, a fatty acid is a Carboxylic acid often with a long unbranched Aliphatic tail ( chain) which Vitamins also act as coenzymes to carry chemical groups between enzymes. Coenzymes are small organic non- Protein Molecules that carry chemical groups between Enzymes Coenzymes are sometimes referred to as cosubstrates For example, folic acid carries various forms of carbon group – methyl, formyl and methylene - in the cell. Folic acid (also known as Vitamin M and Folacin) and Folate (the Anionic form are forms of the water-soluble Vitamin B9 In Chemistry, a methyl group is a Hydrophobic Alkyl Functional group named after Methane (4 An aldehyde is an organic compound containing a terminal Carbonyl group. Methylene is the chemical species R2C named after Methane, in which two of the carbon atom's valence electrons form no bonds Although these roles in assisting enzyme reactions are vitamins' best-known function, the other vitamin functions are equally important. ^[6]

Until the 1900s, vitamins were obtained solely through food intake, and changes in diet (which, for example, could occur during a particular growing season) can alter the types and amounts of vitamins ingested. Vitamins have been produced as commodity chemicals and made widely available as inexpensive pills for several decades,^[7] allowing supplementation of the dietary intake.

Retinol (one vitamer of Vitamin A)

History

The Ancient Egyptians knew that feeding a patient liver (back, right) would help cure night blindness. The vitamers of a particular Vitamin are all of the chemical compounds which exhibit vitamin activity Vitamin A refers to a family of similarly shaped molecules the Retinoids. Ancient Egypt was an Ancient Civilization in eastern North Africa, concentrated along the lower reaches of the Nile River in what is now The liver is a vital organ in the human body and is present in Vertebrates and some other animals

The value of eating a certain food to maintain health was recognized long before vitamins were identified. The ancient Egyptians knew that feeding a patient liver would help cure night blindness, an illness now known to be caused by a vitamin A deficiency. This article is about the country of Egypt For a topic outline on this subject see List of basic Egypt topics. The liver is a vital organ in the human body and is present in Vertebrates and some other animals Nyctalopia (Greek for " night blindness " is a condition making it difficult or impossible to see in relatively low light Vitamin A refers to a family of similarly shaped molecules the Retinoids. ^[8] The advancement of ocean voyage during the Renaissance resulted in prolonged periods without access to fresh fruits and vegetables, and made illnesses from vitamin deficiency common among ship's crew. The Renaissance (from French Renaissance, meaning "rebirth" Italian: Rinascimento, from re- "again" and nascere

In 1749, 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. Year 1749 ( MDCCXLIX) was a Common year starting on Wednesday (link will display the full calendar of the Gregorian calendar (or a Scotland ( Gaelic: Alba) is a Country in northwest Europethat occupies the northern third of the island of Great Britain. In Medicine, a surgeon is a person who performs Surgery. Surgery is a broad category of invasive Medical treatment that involves the cutting of a James Lind or Jim Lind is the name of James Lind (physician (1716 - 1794 British doctor James F Citrus is a common term and Genus of Flowering plants in the family Rutaceae, originating in tropical and subtropical southeast regions of Scurvy (NLat scorbutus is a disease resulting from a deficiency of Vitamin C, which is required for the synthesis of Collagen in humans Collagen is the main Protein of Connective tissue in Animals and the most abundant protein in Mammals making up about 50% of the whole-body protein The gingiva (sing and plur: gingiva) or gums, consists of the Mucosal tissue that lies over the Alveolar bone. ^[8] 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. Year 1753 ( MDCCLIII) was a Common year starting on Monday (link will display the full calendar of the Gregorian calendar (or a Common year This led to the nickname Limey for sailors of that organization. Limey is an old American and Canadian Slang nickname for the British, originally referring to 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 by maintaining the morale of the crew while on board, rather than by a diet of fresh food. The Royal Navy of the United Kingdom is the oldest of the British armed services (and is therefore known as the Senior Service) The Arctic is the Region around the Earth 's North Pole, opposite the Antarctic region around the South Pole. The 19th century of the Common Era began on January 1, 1801 and ended on December 31, 1900, according to the Gregorian calendar Hygiene refers to practices associated with ensuring good health and cleanliness Morale, also known as esprit de corps when discussing the morale of a group is an intangible term used for the capacity of people to maintain Belief in ^[8] 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 was that scurvy was caused by "tainted" canned food. The twentieth century of the Common Era began on Canning is a method of preserving food in which the food is processed and sealed in an airtight container ^[8]

In 1881, Russian surgeon Nikolai Lunin studied the effects of scurvy while at the University of Tartu in present-day Estonia. Year 1909 ( MCMIX) was a Common year starting on Friday (link will display full calendar of the Gregorian calendar (or a Common year starting Retinol (Afaxin, the animal form of Vitamin A, is a fat-soluble vitamin important in vision and Bone growth This article is about the fish extract for the traditional Newfoundland song see " Cod Liver Oil (song " Year 1912 ( MCMXII) was a Leap year starting on Monday (link will display the full calendar of the Gregorian calendar (or a Leap year starting For the similarly spelled pyrimidine see Thymine Thiamin or thiamine, also known as Vitamin B1 Bran is the hard outer layer of Grain and consists of combined Aleurone and Pericarp. This article deals with the molecular aspects of ascorbic acid The lemon ( Citrus × limon) is a hybrid in cultivated wild plants Year 1918 ( MCMXVIII) was a Common year starting on Tuesday (link will display the full calendar of the Gregorian calendar (or a Common Vitamin D is a group of fat-soluble Prohormones, the two major forms of which are vitamin D2 (or Ergocalciferol) and vitamin D3 (or This article is about the fish extract for the traditional Newfoundland song see " Cod Liver Oil (song " Year 1920 ( MCMXX) was a Leap year starting on Thursday (link will display 1920 of the Gregorian calendar Riboflavin ( E101) also known as vitamin B2, is an easily absorbed Micronutrient with a key role in maintaining Health An egg is a round or oval body laid by the female of many animals consisting of an Ovum surrounded by layers of Membranes and an outer casing which acts to nourish Year 1922 ( MCMXXII) was a Common year starting on Sunday of the Gregorian calendar. Tocopherol, a class of chemical compounds of which many have Vitamin E activity describes a series of Organic compounds consisting of various methylated phenols Wheat germ oil is extracted from the germ of the Wheat kernel, which makes up only 2½% by weight of the Kernel. Year 1926 ( MCMXXVI) was a Common year starting on Friday (link will display the full calendar of the Gregorian calendar. The liver is a vital organ in the human body and is present in Vertebrates and some other animals Year 1929 ( MCMXXIX) was a Common year starting on Tuesday (link will display the full calendar of the Gregorian calendar. Vitamin K (K from "Koagulations-Vitamin" in German Danish Swedish and Norwegian denotes a group of Lipophilic, Hydrophobic Vitamins that Year 1931 ( MCMXXXI) was a Common year starting on Thursday (link will display full 1931 calendar of the Gregorian calendar. Pantothenic acid, also called Vitamin B5 (a B vitamin) is a water- Soluble vitamin required to sustain life ( The liver is a vital organ in the human body and is present in Vertebrates and some other animals Vitamin H redirects here In medical slang "vitamin H" may also refer to Haloperidol. The liver is a vital organ in the human body and is present in Vertebrates and some other animals Year 1934 ( MCMXXXIV) was a Common year starting on Monday (link will display full 1934 calendar of the Gregorian calendar. Pyridoxine is one of the compounds that can be called Vitamin B6, along with Pyridoxal and Pyridoxamine. Bran is the hard outer layer of Grain and consists of combined Aleurone and Pericarp. Year 1936 ( MCMXXXVI) was a Leap year starting on Wednesday (link will display the full calendar of the Gregorian calendar. Niacin, also known as vitamin B3, is a water-soluble vitamin which prevents the deficiency disease Pellagra. The liver is a vital organ in the human body and is present in Vertebrates and some other animals Year 1941 ( MCMXLI) was a Common year starting on Wednesday (the link will display 1941 calendar of the Gregorian calendar. Folic acid (also known as Vitamin M and Folacin) and Folate (the Anionic form are forms of the water-soluble Vitamin B9 The liver is a vital organ in the human body and is present in Vertebrates and some other animals Year 1881 ( MDCCCLXXXI) was a Common year starting on Saturday (link will display the full calendar of the Gregorian calendar (or a Common Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending ^[9] He fed mice an artificial mixture of all the separate constituents of milk known at that time, namely the proteins, fats, carbohydrates, and salts. A mouse (plural mice) is a small Animal that belongs to one Milk is an opaque white liquid produced by the Mammary glands of female Mammals (including Monotremes. Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water Carbohydrates (from ' Hydrates of Carbon ' or saccharides ( Greek σάκχαρον meaning " Sugar " are the most Salt is a Dietary mineral composed primarily of Sodium chloride that is essential for Animal life but toxic to most land plants 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. "^[9] However, his conclusions were rejected by other researchers when they were unable to reproduce his results. One difference was that he had used table sugar (sucrose), while other researchers had used milk sugar (lactose) that still contained small amounts of vitamin B. Solubility of Pure SucroseTemperature(Cg Lactose (also referred to as milk sugar) is a Sugar which is found most notably in Milk. The B vitamins are eight water-soluble Vitamins that play important roles in cell Metabolism.

In the Orient where polished white rice was the common staple food of the middle class, beriberi resulting from lack of vitamin B was endemic. Beriberi (pronounced Berry-berry) is a Nervous system ailment caused by Thiamine (vitamin B1 deficiency In 1884, Takaki Kanehiro, a British trained medical doctor of the Japanese Navy observed that beriberi was endemic among low ranking crew who often ate nothing but rice but not among crews of Western navies and officers who were entitled to a Western-style diet. was a Japanese naval Physician. Early life Born in Hyuga Province (present-day Miyazaki Prefecture) as the son of a Kanehiro initially believed that lack of protein was the chief cause of beriberi. With the support of 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. A battleship is a large heavily armored Warship with a main battery consisting of the largest Calibre of Guns Battleships were The group that ate only white rice documented 161 crew with beriberi and 25 deaths, while the latter group had only 14 cases of beriberi and no deaths. This convinced Kanehiro and the Japanese Navy that diet was the cause of beriberi. This was confirmed in 1897, when Christiaan Eijkman discovered that feeding unpolished rice instead of the polished variety to chickens helped to prevent beriberi in the chickens. Year 1897 ( MDCCCXCVII) was a Common year starting on Friday (link will display the full calendar of the Gregorian Calendar (or a Common Christiaan Eijkman ( August 11, 1858, Nijkerk &ndash November 5, 1930, Utrecht) was a Dutch Physician Rice is a Cereal foodstuff which forms an important part of the diet of many people worldwide and as such it is a staple food for many The following year, Frederick Hopkins postulated that some foods contained "accessory factors"—in addition to proteins, carbohydrates, fats, et cetera—that were necessary for the functions of the human body. Sir Frederick Gowland Hopkins OM FRS ( June 20, 1861 Eastbourne, Sussex - May 16, 1947 Cambridge ^[8] Hopkins was awarded the 1929 Nobel Prize for Physiology or Medicine with Christiaan Eijkman for their discovery of several vitamins. Year 1929 ( MCMXXIX) was a Common year starting on Tuesday (link will display the full calendar of the Gregorian calendar. The Nobel Prize in Physiology or Medicine (Nobelpriset i fysiologi eller medicin is awarded once a year by the Swedish Karolinska Institute.

In 1910, Japanese scientist Umetaro Suzuki succeeded in extracting a water-soluble complex of micronutrients from rice bran and named it aberic acid. ( April 7, 1874 &ndash September 20, 1943) was a Japanese scientist born in Shizuoka Prefecture. For the similarly spelled pyrimidine see Thymine Thiamin or thiamine, also known as Vitamin B1 He published this discovery in a Japanese scientific journal. ^[10] 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. Polish biochemist Kazimierz Funk isolated the same complex of micronutrients and proposed the complex be named "Vitamine" (a portmanteau of "vital amine") in 1912. Kazimierz Funk ( February 23, 1884 – January 19, 1967) commonly anglicized as Casimir Funk, was a Polish biochemist ^[11] The name soon became synonymous with Hopkins' "accessory factors", and by the time it was shown that not all vitamins were amines, the word was already ubiquitous. Amines are Organic compounds and Functional groups that contain a basic Nitrogen Atom with a Lone pair. In 1920, Jack Cecil Drummond proposed that the final "e" be dropped to deemphasize the "amine" reference after the discovery that vitamin C had no amine component. Year 1920 ( MCMXX) was a Leap year starting on Thursday (link will display 1920 of the Gregorian calendar Sir Jack Cecil Drummond DSc, FRIC, FRS ( 12 Jan 1891 &mdash 4 Aug or 5 Aug 1952) was a distinguished Vitamin C or L-ascorbate is an Essential nutrient for a large number of higher primate species a small number of other Mammalian

Riboflavin (Vitamin B₂)

Throughout the early 1900s, the use of deprivation studies allowed scientists to isolate and identify a number of vitamins. Riboflavin ( E101) also known as vitamin B2, is an easily absorbed Micronutrient with a key role in maintaining Health The B vitamins are eight water-soluble Vitamins that play important roles in cell Metabolism. Year 1900 ( MCM) was an exceptional Common year starting on Monday (link will display the full calendar of the Gregorian calendar Initially, lipid from fish oil was used to cure rickets in rats, and the fat-soluble nutrient was called "antirachitic A". Fish oil is Oil derived from the tissues of Oily fish. Fish oil is recommended for a healthy diet because it contains the Omega-3 Rickets is a softening of the bones in children potentially leading to fractures and deformity Rats are various medium sized long-tailed Rodents of the superfamily Muroidea The irony here is that the first "vitamin" bioactivity ever isolated, which cured rickets, was initially called "vitamin A", the bioactivity of which is now called vitamin D. Vitamin D is a group of fat-soluble Prohormones, the two major forms of which are vitamin D2 (or Ergocalciferol) and vitamin D3 (or ^[12] What we now call "vitamin A" was identified in fish oil because it was inactivated by ultraviolet light. Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays In 1931, Albert Szent-Györgyi and a fellow researcher Joseph Svirbely determined that "hexuronic acid" was actually vitamin C and noted its anti-scorbutic activity. Year 1931 ( MCMXXXI) was a Common year starting on Thursday (link will display full 1931 calendar of the Gregorian calendar. Albert Szent-Györgyi de Nagyrápolt ( September 16, 1893 &ndash October 22, 1986) was a Hungarian Physiologist who Vitamin C or L-ascorbate is an Essential nutrient for a large number of higher primate species a small number of other Mammalian Scurvy (NLat scorbutus is a disease resulting from a deficiency of Vitamin C, which is required for the synthesis of Collagen in humans In 1937, Szent-Györgyi was awarded the Nobel Prize for his discovery. The Nobel Prize in Physiology or Medicine (Nobelpriset i fysiologi eller medicin is awarded once a year by the Swedish Karolinska Institute. In 1943 Edward Adelbert Doisy and Henrik Dam were awarded the Nobel Prize for their discovery of vitamin K and its chemical structure. Year 1943 ( MCMXLIII) was a Common year starting on Friday (the link will display full 1943 calendar of the Gregorian calendar. Edward Adelbert Doisy ( November 3, 1893 &ndash October 23, 1986) was an American Biochemist. Henrik Dam (Full name Carl Peter Henrik Dam) ( February 21, 1895 – April 17, 1976) was a Danish biochemist The Nobel Prize in Physiology or Medicine (Nobelpriset i fysiologi eller medicin is awarded once a year by the Swedish Karolinska Institute. Vitamin K (K from "Koagulations-Vitamin" in German Danish Swedish and Norwegian denotes a group of Lipophilic, Hydrophobic Vitamins that

In humans

Vitamins are classified as either water-soluble, meaning that they dissolve easily in water, or fat-soluble vitamins, which are absorbed through the intestinal tract with the help of lipids (fats). Water is a common Chemical substance that is essential for the survival of all known forms of Life. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water Lipids are broadly defined as any fat- Soluble ( lipophilic) naturally-occurring Molecule, such as fats oils waxes cholesterol sterols fat-soluble In general, water-soluble vitamins are readily excreted from the body. Each vitamin is typically used in multiple reactions and, therefore, most have multiple functions. ^[13]

In humans there are 13 vitamins: 4 fat-soluble (A, D, E and K) and 9 water-soluble (8 B vitamins and vitamin C).

In nutrition and diseases

Vitamins are essential for the normal growth and development of a multicellular organism. Vitamin K (K from "Koagulations-Vitamin" in German Danish Swedish and Norwegian denotes a group of Lipophilic, Hydrophobic Vitamins that Phylloquinone is a Polycyclic Aromatic Ketone, based on 2- Methyl - 14-naphthoquinone, with a 3- phytyl Substituent Vitamin K (K from "Koagulations-Vitamin" in German Danish Swedish and Norwegian denotes a group of Lipophilic, Hydrophobic Vitamins that In Medicine ( Hematology) bleeding diathesis is an unusual susceptibility to bleeding ( Hemorrhage) due to a defect in the system of Coagulation Using the genetic blueprint inherited from its parents, a fetus begins to develop, at the moment of conception, from the nutrients it absorbs. A fetus (or foetus or fœtus) is a developing Mammal or other Viviparous Vertebrate, after the Embryonic stage and 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. The skin is the outer covering of living tissue of an animal (or plant Bones are rigid organs that form part of the Endoskeleton of Vertebrates They function to move support and protect the various organs of the body produce Muscle (from Latin musculus, diminutive of mus "mouse" is contractile tissue of the body and is derived from the 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. ^[22]

For the most part, vitamins are obtained with food, but a few are obtained by other means. For example, microorganisms in the intestine—commonly known as "gut flora"—produce vitamin K and biotin, while one form of vitamin D is synthesized in the skin with the help of natural ultraviolet in sunlight. The gut flora are the Microorganisms that normally live in the Digestive tract and can perform a number of useful functions for their hosts The skin is the outer covering of living tissue of an animal (or plant Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays Sunlight, in the broad sense is the total spectrum of the Electromagnetic radiation given off by the Sun. Humans can produce some vitamins from precursors they consume. Examples include vitamin A, produced from beta carotene, and niacin, from the amino acid tryptophan. Vitamin A refers to a family of similarly shaped molecules the Retinoids. Beta-carotene is an Organic compound - a Terpenoid, a red-orange pigment abundant in plants and fruits In Chemistry, an amino acid is a Molecule containing both Amine and Carboxyl Functional groups In Biochemistry, this Tryptophan (abbreviated as Trp or W) is one of the 20 standard amino acids, as well as an Essential amino acid in the Human diet ^[14]

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 respiration.

Deficiencies

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. ^[21] 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. A disease is an abnormal condition of an organism that impairs bodily functions and can be deadly

Because human bodies do not store most vitamins, humans must consume them regularly to avoid deficiency. Human bodily stores for different vitamins vary widely; vitamins A, D, and B₁₂ are stored in significant amounts in the human body, mainly in the liver,^[21] and an adult human's diet may be deficient in vitamins A and B₁₂ for many months before developing a deficiency condition. The liver is a vital organ in the human body and is present in Vertebrates and some other animals Vitamin B₃ is not stored in the human body in significant amounts, so stores may only last a couple of weeks. ^[15][21]

Well-known human vitamin deficiencies involve thiamine (beriberi), niacin (pellagra), vitamin C (scurvy) and vitamin D (rickets). Beriberi (pronounced Berry-berry) is a Nervous system ailment caused by Thiamine (vitamin B1 deficiency Pellagra is a Vitamin Deficiency disease caused by dietary lack of Niacin (B3 and Protein, especially proteins containing the Scurvy (NLat scorbutus is a disease resulting from a deficiency of Vitamin C, which is required for the synthesis of Collagen in humans Rickets is a softening of the bones in children potentially leading to fractures and deformity 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, often called fortification. ^[14][21]

Recent lines of evidence also suggest a link between nutrition and mental disorders, as evidenced by Lakhan & Vieira (2008). ^[23]

Side effects and overdose

In large doses, some vitamins have documented side effects that tend to be more severe with a larger dosage. The likelihood of consuming too much of any vitamin from food is remote, but overdosing from vitamin supplementation does occur. At high enough dosages some vitamins cause side effects such as nausea, diarrhea, and vomiting,^[15][24]

When side effects emerge, recovery is often accomplished by reducing the dosage. The concentrations of vitamins an individual can tolerate vary widely, and appear to be related to age and state of health. ^[27] In the United States, overdose exposure to all formulations of vitamins was reported by 62,562 individuals in 2004 (nearly 80% of these exposures were in children under the age of 6), leading to 53 "major" life-threatening outcomes and 3 deaths^[28]—a small number in comparison to the 19,250 people who died of unintentional poisoning of all kinds in the U. S. in the same year (2004). ^[29]

Supplements

Dietary supplements, often containing vitamins, are used to ensure that adequate amounts of nutrients are obtained on a daily basis, if optimal amounts of the nutrients cannot be obtained through a varied diet. Scientific evidence supporting the benefits of some dietary supplements is well established for certain health conditions, but others need further study. ^[30] Some research has suggested that supplements do not only provide no tangible health benefits for generally healthy individuals, but may actually increase mortality. ^[31]

In the United States, advertising for dietary supplements is required to include a disclaimer that the product is not intended to treat, diagnose, mitigate, prevent, or cure disease, and that any health claims have not been evaluated by the Food and Drug Administration. Health claims on food labels are claims by manufacturers of Food products that their food will reduce the risk of developing a Disease or condition ^[30] In some cases, dietary 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. ^[30] Vitamin supplements may also contain levels of vitamins many times higher, and in different forms, than one may ingest through food. ^[32]

Intake of excessive quantities can cause vitamin poisoning, often due to overdose of Vitamin A and Vitamin D (The most common poisoning with multinutrient supplement pills does not involve a vitamin, but is rather due to the mineral iron). Vitamin poisoning, or hypervitaminosis, refers to a condition of high storage levels of Vitamins which can lead to Toxic Symptoms The medical Vitamin A refers to a family of similarly shaped molecules the Retinoids. Vitamin D is a group of fat-soluble Prohormones, the two major forms of which are vitamin D2 (or Ergocalciferol) and vitamin D3 (or Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Due to toxicity, most common vitamins have recommended upper daily intake amounts.

Governmental regulation of vitamin supplements

Most countries place dietary supplements in a special category under the general umbrella of foods, not drugs. This necessitates that the manufacturer, and not the government, be responsible for ensuring that its dietary supplement products are safe before they are marketed. Unlike drug products, that must explicitly be proven safe and effective for their intended use before marketing, there are often no provisions to "approve" dietary supplements for safety or effectiveness before they reach the consumer. Also unlike drug products, manufacturers and distributors of dietary supplements are not generally required to report any claims of injuries or illnesses that may be related to the use of their products. ^[33][34]

Names in current and previous nomenclatures

The reason the set of vitamins seems to skip 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 Koagulation of blood following wounding. At the time, most (but not all) of the letters from F through J were already designated, so the use of the letter K was considered quite reasonable.

The following table 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:

See also

References

External links

• USDA RDA chart in PDF format
• Health Canada Dietary Reference Intakes Reference Chart for Vitamins
• NIH Office of Dietary Supplements: Fact Sheets
• NIH Office of Dietary Supplements. Dietary Supplements: Background Information