Vitamins in Milk and Dairy Products

Abstract

Vitamins are organic chemicals required by the body in trace amounts but which cannot be synthesized by the body. The vitamins required for growth and maintenance of health differ between species; compounds regarded as vitamins for one species may be synthesized at adequate rates by other species. For example, only primates and guinea pigs require ascorbic acid (vitamin C; see Sect. 6.4) from their diet; other species possess the enzyme gluconolactone oxidase which is necessary for the synthesis of vitamin C. The chemical structures of the vitamins have no relationship with each other. Vitamins may be classified based on their solubility in water. Water-soluble vitamins are the B group [thiamine, riboflavin, niacin, biotin, pantothenate, folate, pyridoxine (and related substances, vitamin B₆)] and cobalamin (and its derivatives, vitamin B₁₂) and ascorbic acid (vitamin C) while the fat-soluble vitamins are retinol (vitamin A), calciferols (vitamin D), tocopherols (and related compounds, vitamin E) and phylloquinone (and related compounds, vitamin K). The water-soluble vitamins and vitamin K function as co-enzymes while vitamin A is important in the vision process, vitamin D functions like a hormone and vitamin E is primarily an antioxidant.