Fruits and vegetables are often a good source of vitamins.

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Multi-Vitamins

Vitamins are nutrients required in very small amounts for essential metabolic reactions in the body . more...

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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 that are not strictly essential.

Vitamins are biomolecules that act both as catalysts and substrates in chemical reactions. When acting as a catalyst, vitamins are bound to enzymes and are called cofactors. (For example, vitamin K forms part of the proteases involved in blood clotting.) Vitamins also act as coenzymes to carry chemical groups between enzymes. (For example, folic acid carries various forms of carbon groups–methyl, formyl or methylene–in the cell.)

Until the 1900s, vitamins were obtained solely through food intake. Many food sources contain different ratios of vitamins. Therefore, if the only source of vitamins is food, changes in diet will alter the types and amounts of vitamins ingested. However, as many vitamins can be stored by the body, short-term deficiencies (which, for example, could occur during a particular growing season) do not usually cause disease.

Vitamins have been produced as commodity chemicals and made widely available as inexpensive pills for several decades, allowing supplementation of the dietary intake.

History

The value of eating certain foods 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. In 1747, the Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy, a particularly deadly disease in which collagen is not properly formed, and which is characterized by poor wound healing, bleeding of the gums, and severe pain. 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. This led to the nickname Limey for sailors of that organization. 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. 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.