Vitamin E

Question 1

Vitamin E is the collective name for a group of closely related lipids called ________, all of which contain a substituted aromatic ring and a long isoprenoid side chain.

Answer 1

tocopherols

Note: Because they are hydrophobic, tocopherols associate with cell membranes, lipid deposits, and lipoproteins in the blood.

Question 2

State the dietary sources for vitamin E.

Answer 2

Tocopherols are found in eggs and vegetable oils and are especially abundant in wheat germ.

Question 3

State the roles of vitamin E.

Answer 3

(1) Protection of phospholipids of cell membranes against oxidative attack by free radicals and organic peroxides.
(2) Prevents membrane lipid peroxidation.
(3) Critical to defence against oxidative injury and to help the body combat the development of tumors and to slow aging.

Question 4

Discuss Vitamin E deficiency.

Answer 4

☑ Vitamin E deficiency in the rabbit or rat is accompanied by muscular degeneration (muscular dystrophy).
☑ Sterility in rats
☑ Fragile erythrocytes

Further notes:
☛ Vitamin E deficiency can lead to increased fragility of red blood cells due to its role as an antioxidant. Vitamin E, particularly alpha-tocopherol, prevents lipid perodixation of polyunsaturated fatty acids in cellular membranes. This is particularly important in the context of red blood cells, which have a high concentration of polyunsaturated fatty acids in their membranes.
☛ Polyunsaturated fatty acids are fatty acids that contain more than one double-bond in their backbone. There are two main types of PUFAs: omega-3 and omega-6 fatty acids. These are essential to brain function and cell growth. PUFAs have to be obtained from diet.