News tagged with vitamin

Related topics: vitamin d

Vitamin E intake critical during 'the first 1,000 days'

Amid conflicting reports about the need for vitamin E and how much is enough, a new analysis published today suggests that adequate levels of this essential micronutrient are especially critical for the very ...

Sep 15, 2014
popularity 3.3 / 5 (45) | comments 1

B vitamins could delay dementia

(Medical Xpress)—Despite spending billions of dollars on research and development, drug companies have been unable to come up with effective treatments for dementia and Alzheimer's Disease (AD). Now, A. ...

May 21, 2013
popularity 4.9 / 5 (22) | comments 1 | with audio podcast report

Vitamins can damage the body's own defences

Each year, we spend billion of dollars on dietary supplements. New research indicates that vitamin pills may upset the fragile balance in our cells and thus cause more harm than good.

Nov 26, 2013
popularity 3.8 / 5 (21) | comments 4

Study links vitamin D to quality of life

Canadians wait for it every year: the annual flight of the snowbirds in winter. Could there be an underlying health reason these birds take flight to sunnier climates? A researcher at the University of Alberta ...

Sep 12, 2014
popularity 4.7 / 5 (12) | comments 3

Metformin may increase risk of cognitive impairment

(HealthDay)—Metformin may increase the risk of cognitive impairment in patients with diabetes; however, calcium supplementation may attenuate this risk, according to research published online Sept. 5 in ...

Sep 21, 2013
popularity 4.3 / 5 (9) | comments 0

Repairing mitochondria in neurodegenerative disease

(Medical Xpress)—The relationship between fine-scale structure and function in the brain is perhaps best explored today by the study of neurodegenerative disease. Disorders like Rett syndrome may be considered developmental in origin—and defined by exotic mechanisms in ...

Dec 11, 2013
popularity 4.3 / 5 (8) | comments 0 | with audio podcast report

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