Nutrition Facts

Vitamin E is the name of a group of closely related compounds that occurs in nature as fat soluble compounds called “tocopherols” and “tocotrienols”. Out of all the tocopherols, the alpha tocopherol is the most active and potent.

Sources of Vitamin E:

Vitamin E is widely distributed in nature, both in plant sources as well as animal sources. The rich plant sources of vitamin E are vegetable oils (tocopherols are present in sunflower oil, cotton seed oil, safflower oil, wheat germ oil etc. and gamma tocotrienols are present in corn oil and Soya bean oil etc.), nuts, cereals and foods that are rich in polyunsaturated fatty acids. Fruits and vegetables contain small amount of vitamin E. Rich animal source of vitamin D includes meat, egg (mainly egg yolk), butter, milk etc.

Daily Requirement of Vitamin E:

Daily recommended dose of vitamin E or RDA (recommended daily allowance) is dependent on the amount of essential fatty acids we consume. The more essential fatty acid consumption the more is the requirement of vitamin E. But the requirement is about 0.8mg/gram of essential fatty acid consumption. RDA is 15 mg/ day and the requirement is higher if more polyunsaturated fat is consumed.

Functions of vitamin E:

Vitamin E acts as a chain breaking antioxidant and is efficient in removing the chemicals that protects low density lipoproteins (LDLs) and polyunsaturated fats in membranes from oxidation. Other antioxidants like vitamin C helps to keep vitamin E in remaining reduced state. Vitamin E also inhibits synthesis of prostaglandins.

Other Advantages of Vitamin E:

There are many other advantages of vitamin E, but these advantages can not be proved strongly. Vitamin E at high dose may prevent retrolental fibroplasia (opacity of cornea in premature infants due to administration of pure 100% oxygen after delivery or birth), bronchopulmonary dysplasia and intraventricular hemorrhage of premature infants. Vitamin E is supposed to have aphrodisiac effect and also increase sexual performance. Vitamin E is also used in treatment of slowing aging process and intermittent claudication. High doses (60–800 mg/d) of vitamin E have been shown to improve immune function and to reduce colds in nursing home residents. When vitamin E is combined with other antioxidants, it can prevent macular degeneration of eye.

Excess intake of vitamin A (more than recommended daily allowance or RDA for long time, the RDA of vitamin A for normal healthy adult is 600 mcg of retinol) for long duration can lead to vitamin A toxicity, unlike water soluble vitamins, which do not have toxicity due to removal of excess water soluble vitamins through urine as they are water soluble.

Vitamin A toxicity was first reported among Arctic explorers who ate liver of polar bear and vitamin A toxicity is also seen if it is given at very high dose of more than 150 mgs in adults and 100 mgs in children. The vitamin A toxicity is seen more commonly is Eskimos, because they eat polar bear liver and seal livers, both are very rich in vitamin A. the staple diet of Eskimo is made up of rich source of vitamin A.

Excess intake of vitamin A in the form of retinol or any other form can lead to nausea, vomiting, anorexia and sleep disturbances. These are followed by desquamation of skin, enlargement of the liver and papillar edema. Increased intracranial pressure, vertigo, diplopia, bulging fontanels in children, seizures, and exfoliative dermatitis are the common symptoms of vitamin A toxicity and in severe cases it may cause death. Other common symptoms include dry skin, cheilosis, glossitis, vomiting, alopecia, bone demineralization and pain, hypercalcemia, lymph node enlargement, hyperlipidemia, amenorrhea etc. The toxicity of vitamin A mainly occurs if excess amount of vitamin A is consumed for long time from animal sources. Excess plant vitamin A usually does not lead to severe toxicity. Excess beta carotene as found in carrots and other yellow vegetables can lead to yellow coloration of plasma and skin (called carotenemia), but this do not appear to be harmful or dangerous. But excess plant carotinoids should be avoided as it can increase chance of lung cancer in smokers. Hypothyroid patients are more susceptible to the development of carotenemia due to impaired breakdown of carotene to vitamin A. Reduction of carotenes from the diet results in the disappearance of skin yellowing and carotenemia over a period of 30–60 days in these patients.

Most recently the teratogenic (abnormality of fetus due to some compounds) effect of vitamin A is the focus of research. If excess vitamin A is given to pregnant women spontaneous abortions, craniofacial abnormalities, and valvular heart disease has been reported. So in pregnancy daily dose should not be more than 3 mgs. 13-cis-retinoic acid which is commercially available can cause birth defects and should not be given during pregnancy and pregnancy should be avoided by contraception at least for 1 year after giving 13-cis-retinoic acid.