S. N

Fat soluble vitamins

Water-soluble vitamins

1.

Chemical composition: contains only hydrogen, carbon and oxygen.

Along with C, H, O also contains either nitrogen, sulphur or cobalt.

2.

Occurrence: can occur in plant tissues in form of provitamin which can be converted to vitamin in animal body.

Vitamins are not universally distributed rather completely absent from some tissues.

No provitamins are known for any water-soluble B vitamins.

Water soluble B-vitamins are universally distributed in every living tissues.

3.

Physiological action: members of this group are required for regulation of metabolism of structural units and each member appears to have one or more specific and independent roles.

Water-soluble B-vitamins are universally concerned with the transfer of energy in every cell.

4.

Absorption: absorbed from intestinal tract in presence of fat and thus related with factors which governs fat absorption.

Absorption is simple process as there is constant absorption of water from intestines.

5.

Storage: any of the fat-soluble vitamins can be stored wherever fat is deposited. Amount to be stored depends on intake.

Not stored in same way or to same extent

6.

Excretion: excreted usually through feces.

Also present in feces but chief pathway of excretion following metabolic use is through urine.