VITAMINS....!!

  A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamer's) that is an essential micronutrient...

 A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamer's) that is an essential micronutrient which an organism needs in small quantities for the proper functioning of its metabolism.

      Essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet. Vitamin C can be synthesized by some species but not by others; it is not a vitamin in the first instance but is in the second. The term vitamin does not include the three other groups of essential nutrients: minerals, essential fatty acids, and essential amino acids.Most vitamins are not single molecules, but groups of related molecules called vitamer's. For example, there are eight vitamer's of vitamin E: four tocopherol's and four tocotrienols.

      Some sources list fourteen vitamins, by including choline, but major health organizations list thirteen: vitamin A  (as all-trans-retinol, all-trans-retinyl-esters, as well as all-trans-beta-carotene and other provitamin A carotenoids), vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B7 (biotin), vitamin B9 (folic acid or folate), vitamin B12 (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols), and vitamin K (phylloquinone and menaquinones).

Vitamin

Drug class

A bottle of B-complex vitamin pills

Pronunciation

UK: /ˈvɪtəmɪn, ˈvaɪ-/

US: /ˈvaɪtəmɪn/[1]

Vitamins have diverse biochemical functions. Vitamin A acts as a regulator of cell and tissue growth and differentiation. Vitamin D provides a hormone-like function, regulating mineral metabolism for bones and other organs. The B complex vitamins function as enzyme cofactors  (coenzymes) or the precursors for them. Vitamins C and E function as antioxidants. Both deficient and excess intake of a vitamin can potentially cause clinically significant illness, although excess intake of water-soluble vitamins is less likely to do so.

Before 1935, the only source of vitamins was from food.[citation needed] If intake of vitamins was lacking, the result was vitamin deficiency and consequent deficiency diseases. Then, commercially produced tablets of yeast-extract vitamin B complex and semi-synthetic vitamin C became available.[citation needed] This was followed in the 1950s by the mass production and marketing of vitamin supplements, including multivitamins, to prevent vitamin deficiencies in the general population. Governments mandated addition of vitamins to staple foods such as flour or milk, referred to as food fortification, to prevent deficiencies. Recommendations for folic acid  supplementation during pregnancy reduced risk of infant neural tube defects.

The term vitamin is derived from the word vitamine, which was coined in 1912 by Polish biochemist Casimir Funk, who isolated a complex of micronutrients essential to life, all of which he presumed to be amines.When this presumption was later determined not to be true, the "e" was dropped from the name.All vitamins were discovered (identified) between 1913 and 1948[citation needed].

Biochemical functions :-

Each vitamin is typically used in multiple reactions, and therefore most have multiple functions.

On fetal growth and childhood development

Vitamins are essential for the normal growth and development of a multicellular organism. Using the genetic blueprint inherited from its parents, a fetus develops from the nutrients it absorbs. It requires certain vitamins and minerals to be present at certain times.These nutrients facilitate the chemical reactions that produce among other things, skin, bone, and muscle. If there is serious deficiency in one or more of these nutrients, a child may develop a deficiency disease. Even minor deficiencies may cause permanent damage.

On adult health maintenance

Once growth and development are completed, vitamins remain essential nutrients for the healthy maintenance of the cells, tissues, and organs that make up a multicellular organism; they also enable a multicellular life form to efficiently use chemical energy provided by food it eats, and to help process the proteins, carbohydrates, and fats required for cellular respiration.