| Popis: |
Vitamins are a group of organic compounds which are essential in very small amounts for the normal functioning of the human body. They have widely varying chemical and physiological functions and are broadly distributed in natural food sources. Thirteen vitamins are recognized in human nutrition and these may be conveniently classified, according to their solubility, into two groups. The fat-soluble vitamins are represented by vitamins A, D, E and K; also included are the 50 or so carotenoids that possess varying degrees of vitamin A activity. The water-soluble vitamins comprise vitamin C and the members of the vitamin B group, namely thiamin (vitamin B1), riboflavin (vitamin B2), niacin, vitamin B6, pantothenic acid, biotin, folate and vitamin B12. This simple classification reflects to some extent the bioavailability of the vitamins, as the solubility affects their mode of intestinal absorption and their uptake by tissues. The solubility properties also have a direct bearing on the analytical methods employed in vitamin assays. |
