Vitamins are usually classified according to their solubility, in either fat or water.
The four Vitamins A,D,E and K are soluble in fat.
Vitamins C and B complex are water soluble.
They also may be classified according to their function with our body . For example
B- complex vitamins
these function as co enzymes in many varied metabolic reactions involving the release for cellular activity.
Vitamin B-12 and folate are involved in cellular synthesis of the gene- containing material of the cells DNA.