Deficiency diseases

In the rats deficiency of tocopherols results in damage of the reproductive system in males and females. Germinal epithelium is permanently damaged. Even if pregnancy occurs it results in death of the fetus and the fetus resorption occurs. In human subjects, however, no such relationship of vitamin E with reproductive system has been decidedly proved. Attempts to establish relation of vitamin E with reproductive physiology has given doubtful results in human subjects. In the nutrition charts, however, daily intake of vitamin E is recommended.

Vitamin E maintains the structural integrity of the muscles and peripheral vascular system in the animals. Consequently deficiency of this vitamin leads to dystrophy of such tissues.

In rabbits nucleic acid biosynthesis has been reported to be reduced in vitamin E deficiency. Most probably incorporation of the purine nucleotides in the biogenesis of nucleic acids is inhibited. Thus, alienation excretion is increased and the tissue nucleic acid content is lowered.

Involvement of vitamin E in biological oxidation has also been reported. Most probably, it is involved between cytochrome b and c. Vitamin E is an antioxidant. On account of this property it is believed to protect the cell membranes and prevent oxidation of unsaturated fatty acids forming integral part of the membrane lipids. Besides these, deficiency of this vitamin in the animals may cause hemolysis. The rate of lipogenesis is also decreased, the membranes of cells loose integrity and the rate of biological oxidation is also decreased.

Requirement The daily requirement of vitamin E of the adults has been recommended between 10-30 mg.

Vitamin K

The different vitamins K are fat-soluble, heat-stable and resistant to reducing agents, however these are light sensitive. These vitamins are destroyed by light, alkalies, strong acids and various oxidizing agents. There are some of vitamins K: K1, K2 and menadione. VK1 has been obtained from alfalfa leaves, vK2 has been obtained from Bacillus brevis (it is also named farnoquinone).

Sources and absorption Important sources of vitamins K group are alfalfa, cabbage, cauliflower, tomatoes, spinach and other green vegetables. Among the animal sources are fish, liver, cheese and egg-yolk. The intestinal flora of microorganism can also synthesize these vitamins.

Absorption of these vitamins occurs in the intestine and it requires bile-salts. Presence of bile-salts is essential. In obstruction of biliary tract, the absorption of vK is markedly reduced. In such cases, bile-salt preparation must be orally administrated to promote vitamin K absorption. Although, vitamin K are stored but the site of storage is not known deficiency.

Functions: vK promote the biosynthesis of prothrombin in the liver tissue. Prothrombin in an important protein which after converting into thrombin acquires enzymic activity and converts fibrinogen into fibrin (blood ) – thus, vK facilitates the process of blood coagulation. Therefor deficiency of this vitamin delayes in coagulation of blood. This vitamin can pass from mother to fetus with considerable difficulty.

Since, vK possess quinoid structure which can be readily reduced and deoxidized. The possibility of its involvement in biological oxidation can not ruled out. Current view is that vK in the form of coenzyme Q forms the normal electron carrier and is also believed to help in the oxidative phosphorylation process.

It has been indicated that vK acts as an induser for RNA formation. These RNA molecules help in the biosynthesis of prothrombin and possibly other proteins in the clotting process.

Requirement: the daily norm do not established, appr. 2mg/day