Health

Do you need vitamin-enhanced foods?

(HealthDay)—Many packaged foods have the potential to give you vitamin overload, especially if you're already taking a daily multivitamin. Here's what you need to know.

Health

Broccoli you are sure to love

(HealthDay)—Looking to boost your fiber and vitamin C in one bite? Forget dietary supplements—emerald green broccoli is the answer.

Oncology & Cancer

Too many antioxidants may cause lung cancer spread

A new study explains why lung cancer spreads faster in patients with certain genetic changes, and suggests that taking vitamin E, long thought of as preventive, may cause the same spread.

Medical research

Muscling in on the role of vitamin D

A recent study conducted at The Westmead Institute for Medical Research has shed light on the role of vitamin D in muscle cells. The study looked at the role of vitamin D in muscles in mice, and showed that vitamin D signaling ...

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Vitamin

A 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.

This text uses material from Wikipedia, licensed under CC BY-SA