Vitamin A

Vitamin A

It is also known as antixoroplzthalmic vitamin or retinol It was discovered by Mc Collum 1913. It is richly found in fish liver oil* butter, egg, carrot, peas, fruits like mango, papaya etc. Animal’s synthesis this vitamin from a yellow pigment called carotene. So carotene called provitamin A. In the, body each carotene molecule gives two molecules of vitamin A.

Vitamin A is essential for vision. Visual pigments such as rhodopsin of rod cells and iodopsin cone cells in the retina are synthesized from vitamin A. Rhodopsin is essential for night vision or vision in dim light. So vitamin A deficiency causes a disease known as nyctalopia or night blindness in adult and xerophthalmia in children. Another defect due to vitamin A deficiency is keratomalacia. Vitamin A is also essential for the normal health and growth of the epithelial tissue. Higher doses of vitamin A (hypervitaminosis) may cause drowsiness, sluggishness, severe head-ache, vomiting etc.

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