Vitamin is a kind of organic molecule (or a group of related molecules), which is a small amount of micronutrient needed by the organism for its normal metabolism. It is impossible to synthesize essential nutrients in the organic body, or it is impossible to synthesize enough nutrients at all, so it must be obtained through diet. Vitamin C can be synthesized by some species, not others. It's not a vitamin, it's a second. The term vitamin does not include three other essential nutrients: minerals, essential fatty acids and essential amino acids. Most vitamins are not single molecules, but a group of related molecules called vitamins. For example, vitamin E consists of four tocopherols and four tocotrienols. The 13 kinds of vitamins needed for human metabolism are: vitamin A (retinol and carotenoids), vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyrox alcohol), and vitamin B7 (biotin), vitamin B9 (folic acid or folic acid), vitamin B12 (cobalamin), vitamin C (ascorbic acid), vitamin D (calciferol), vitamin E (tocopherol and tocotrienol) and vitamin K (quinone).

Vitamins have many biochemical functions. Some forms of vitamin A act as regulators of cell and tissue growth and differentiation. B vitamins act as enzyme cofactors (coenzymes) or their precursors. Vitamin D has hormone like functions and can regulate the mineral metabolism of bone and other organs. Vitamins C and e act as antioxidants. Insufficient and excessive intake of vitamins may cause major clinical diseases, although the possibility of intake of water-soluble vitamins is relatively small.

Before 1935, the only source of vitamins was food. If there is a lack of vitamin intake, the result is a lack of vitamins and the accompanying lack of disease. Then, commercially produced tablets of vitamin B complex and semi synthetic vitamin C extracted from yeast can be obtained. Then in the 1950s, large-scale production and marketing of vitamin supplements, including multivitamins, were carried out to prevent vitamin deficiency in the general population. The government requires that vitamins be added to staple foods such as flour or milk, known as fortified foods, to prevent vitamin deficiency. Folic acid supplementation during pregnancy may reduce the risk of neural tube defects in infants. Although there are clear benefits in reducing the incidence of vitamin deficiency, supplements are considered to be of little value to healthy people on a vitamin rich diet.

The word vitamin comes from the word vitamin, which was coined by the Polish biochemist Casimir funk in 1912. He isolated a micronutrient essential to life. He speculated that all these elements were amines. "E" will be removed from the name later when it is determined that this assumption is incorrect. ". All vitamins were found (identified) between 1913 and 1948.