Classification  of Vitamins

Vitamins  widely  vary from each  other  from  tlie  structural point  of  view. Conventionally, they  are  classified on  the  basis  of  their solubility  in  water or  fat. Accordingly, they are classified as:

Water soluble  vitamins, which include thiamin (vitamin B1),  riboflavi'n (vitamin B?),  niacin and  nicotinamide  (vitamin  B3),  pantothenic acid (vitamin  B5),  pyridoxine and related  compounds  (vitamin  B6), cyanocobalamin  and related
compounds  (vitamin Biz), ascorbic acid (vitamin C), biotin (vitamin H) and folic  acid  (vitamin M).

Fat-soluble vitamins,  which include  retinol  (vitamin  A),  cholecalciferol (vitamin D),  tocopherols (vitamin E)