All About Antioxidants and Vitamins -

Beta Carotene

The antioxidant plant pigment beta-carotene is also known as 'provitamin A' because it is converted into vitamin A ( retinal and other forms) in the liver. It is found in whole milk, butter, cheese, egg yolk, liver, yellow and green vegetables and fish, especially in the liver. The same foods also contain a number of different carotene like substances (arytenoids) that cannot be converted to vitamin A and so are wasted.

Retinal and its related substances have many important functions in the body. They are necessary for :  

• Growth and health of the surface and lining tissues and the bones.

• Health of the immune system.

• Protection against cancer.

• Normal vision.

• Health of the corneas.

• Protection against various skin diseases.

• Protection of the skin against sunlight radiation.

• Protection against ageing changes.

People deficient in retinoid suffer night blindness and dryness of the eyes ( exophthalmia). In the case of babies, they may suffer devastating melting of the corneas of the eyes with permanent blindness. Severe deficiency is a common cause of death in small children after severe damage has been sustained by most systems of the body.

A normal, well-balanced diet will provide quite enough retinal to prevent any such effects. If taken as a dietary supplement, 1 mg per day is equivalent to the recommended daily allowance and this dose is probably double the amount needed to prevent deficiency.
Remember that vitamin A or its prvitamin, beta carotene, is not in the same safe category as vitamins C and E. no one who knows anything about the matter would ever think of recommending mega doses of vitamin A.