Vitamin
hideA vitamin is an organic compound required as a nutrient in tiny amounts by an organism. A compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. 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. 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.
Vitamins are classified by their biological and chemical activity, not their structure. Thus, each "vitamin" may refer to several vitamer compounds that all show the biological activity associated with a particular vitamin. Such a set of chemicals are grouped under an alphabetized vitamin "generic descriptor" title, such as "vitamin A," which includes the compounds retinal, retinol, and many carotenoids. Vitamers are often inter-converted in the body.
Vitamins have diverse biochemical functions, including function as hormones (e.g. vitamin D), antioxidants (e.g. vitamin E), and mediators of cell signaling and regulators of cell and tissue growth and differentiation (e.g. vitamin A). 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. When acting as part of a catalyst, vitamins are bound to enzymes and are called prosthetic groups. For example, biotin is part of enzymes involved in making fatty acids. Vitamins also act as coenzymes to carry chemical groups between enzymes. For example, folic acid carries various forms of carbon group – methyl, formyl and methylene - in the cell. Although these roles in assisting enzyme reactions are vitamins' best-known function, the other vitamin functions are equally important.
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, allowing supplementation of the dietary intake.
For more information about Vitamin, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with vitamin
Citrus surprise: Vitamin C boosts the reprogramming of adult cells into stem cells
Dec 24, 2009 |
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Famous for its antioxidant properties and role in tissue repair, vitamin C is touted as beneficial for illnesses ranging from the common cold to cancer and perhaps even for slowing the aging process. Now, ...
More effort needed to crack down on 'secret remedies'
Dec 17, 2009 |
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The medical establishment and politicians must do more to crack down on alternative medicine, argues a senior scientist on BMJ.com today.
Multiple health concerns surface as winter, vitamin D deficiences arrive
Nov 23, 2009 |
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A string of recent discoveries about the multiple health benefits of vitamin D has renewed interest in this multi-purpose nutrient, increased awareness of the huge numbers of people who are deficient in it, spurred research ...
Millions of US children low in vitamin D (w/ Video)
Aug 03, 2009 |
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Seven out of ten U.S. children have low levels of vitamin D, raising their risk of bone and heart disease, according to a study of over 6,000 children by researchers at Albert Einstein College of Medicine of Yeshiva University. ...
Housewife Remedy for Scurvy Preceded Medical Discovery
Mar 11, 2009 |
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(PhysOrg.com) -- A 100-page handwritten book by Mrs. Ebot Mitchell written in 1707 on household remedies contains among other things a recipe to treat scurvy. The recipe containing extracts from plants, orange ...
New study links vitamin D deficiency to cardiovascular disease and death
Nov 16, 2009 |
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While mothers have known that feeding their kids milk builds strong bones, a new study by researchers at the Heart Institute at Intermountain Medical Center in Salt Lake City suggests that Vitamin D contributes to a strong ...
Vitamin E extract could help tackle cancer tumours
Dec 03, 2009 |
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(PhysOrg.com) -- An extract of vitamin E could have a key role to play in the treatment of cancerous tumours, according to newly-published research today.
Plugging in Molecular Wires
Feb 11, 2009 |
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(PhysOrg.com) -- Plants, algae, and cyanobacteria (blue-green algae) are masters of everything to do with solar energy because they are able to almost completely transform captured sunlight into chemical energy. This is in ...
Heart failure linked to gene variant affecting vitamin D activation
Dec 01, 2009 |
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Previous studies have shown a link between low vitamin D status and heart disease. Now a new study shows that patients with high blood pressure who possess a gene variant that affects an enzyme critical to normal vitamin ...
Could antioxidants make us more, not less, prone to diabetes? Study says yes
Oct 06, 2009 |
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We've all heard about the damage that reactive oxygen species (ROS) - aka free radicals - can do to our bodies and the sales pitches for antioxidant vitamins, skin creams or "superfoods" that can stop them. In fact, there ...
Research shows why low vitamin D raises heart disease risks in diabetics
Aug 22, 2009 |
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Low levels of vitamin D are known to nearly double the risk of cardiovascular disease in patients with diabetes, and researchers at Washington University School of Medicine in St. Louis now think they know ...
Autism treatment: Risky alternative therapies have little basis in science
Nov 24, 2009 |
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James Coman's son has an unusual skill. The 7-year-old, his father says, can swallow six pills at once. Diagnosed with autism as a toddler, the Chicago boy had been placed on an intense regimen of supplements and medications ...
Study supports possible role of urate in slowing Parkinson's disease progression
Oct 12, 2009 |
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By examining data from a 20-year-old clinical trial, a research team based at the MassGeneral Institute for Neurodegenerative Diseases (MGH-MIND) and Harvard School of Public Health (HSPH), has found evidence supporting the ...
Vitamin C deficiency impairs early brain development
Sep 02, 2009 |
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(PhysOrg.com) -- Faculty of Life Sciences at University of Copenhagen shows that vitamin C deficiency may impair the mental development of new-born babies.
Key feature of immune system survived in humans, other primates for 60 million years
Aug 18, 2009 |
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A new study has concluded that one key part of the immune system, the ability of vitamin D to regulate anti-bactericidal proteins, is so important that is has been conserved through almost 60 million years of evolution and ...
