Vitamin A assists in carrying out many of the functions of the human body. An inadequate supply of vitamin A affects the functioning of different organs of our body. The deficiency could be a result of a prolonged dietary deprivation. It could also be due to inadequate conversion of carotene to vitamin A. In certain cases the deficiency could be due to the interference with the absorption and storage of the vitamin.
Food sources rich in Vitamin A are fish liver oils, liver, butter, egg yolks and cream. Fresh green leafy and yellow vegetables contain beta-carotene, which are later converted into retinal and subsequently to retinol.
The first signs of a vitamin A deficiency could be a weakened immune system, broken nails, dry skin and hair and night blindness.
Vitamin A deficiency is common in the under developed and developing countries, especially in children and working women. When mothers are vitamin A deficient, the breast feeding infants also become deficient in vitamin A.
The compound retinol, a component of vitamin A, is essential for maintaining healthy vision. Vitamin A deficiency causes problems related to vision. Deficiency of retinol, results in a condition where people cannot see in the dark. The rod cells in the retina, which helps to see at night, are affected due to this deficiency. The deficiency causes the eye to become dry as the moisture content is lost. Night blindness in pregnant women was found to be common in pregnant women of some Asian countries like India and Bangladesh.
Research has proved that a deficiency of vitamin A can increase the mortality rate. This deficiency disturbs the proper functioning of the immune system. As a result, the self-defense system is weakened and becomes difficult to fight the bodily invaders.
It also causes problems like allergies, acne and a loss of appetite. Vitamin A is also essential for cell growth and repair, reproduction and bone growth. It is also important for the integrity of intestinal, urinary and respiratory tracts.
Any deficiency of vitamin A that has been detected should be corrected. Sub clinical VAD (Vitamin A Deficiency) can be treated by consuming foods rich in Vitamin A like, carrots, leafy green vegetables, sweet potatoes, mango, eggs, fortified milk, poultry, beef and liver. Oral supplements are required for VAD syndromes. 600 mcg for children below 3 years, 900 mcg for children between 4-8 years, 1700 mcg for children between 9-13 years, 2800 mcg for people aged 14-18 years and 3000 mcg for adults is a recommended dose. The dose will have to be increased according to the severity of the disease. Therapeutic doses include 60,000 mcg.
Vitamin A deficiency can be corrected by taking vitamin supplements. Beta-carotene, retinyl palmitate and retinyl acetate are the forms in which vitamin A occur in these supplements.