Vitamins

The use of vitamins to prevent or cure disease. Many physicians are now recognizing the beneficial uses of anti-oxidant and other vitamins for a wide variety of conditions, often as a complementary therapy to accompany medication or other treatments. One variant on this theme, megavitamin therapy, is still rather controversial. Always consult your doctor before adding vitamin supplements to your health regimen.

High doses of certain vitamins can have adverse effects. For example, high doses of vitamin A can cause headaches, vomiting, liver damage, brain swelling, and bone abnormalities. High doses of vitamin D can lead to high levels of calcium in blood and kidney and heart damage. Therefore, high doses of vitamins should NOT be given to infants and young children without supervision by their pediatricians.

A vitamin is an organic molecule required by a living organism in minute amounts for proper health. An organism deprived of all sources of a particular vitamin will eventually suffer from disease symptoms specific to that vitamin.

Vitamins can be classified as either water soluble, which means they dissolve easily in water, or fat soluble, which means they are absorbed through the intestinal tract with the help of lipids.

In general, an organism must obtain vitamins or their metabolic precursors from outside the body, most often from the organism's diet. Examples of vitamins that the human body can derive from precursors include vitamin A, which can be produced from beta carotene; niacin from the amino acid tryptophan; and vitamin D through exposure of skin to ultraviolet light.

The term vitamin does not encompass other essential nutrients such as dietary minerals, essential fatty acids, or essential amino acids, nor is it used for the large number of other nutrients that merely promote health, but are not strictly essential.