Spotlight: Vitamin A
Impact of deficiency
Vitamin A deficiency makes children especially vulnerable to infection and worsens the course of many infections. Supplementation with vitamin A is estimated to lower a child's risk of dying by approximately 23 per cent. The deficiency is also the single most important cause of blindness among children in developing countries.
Who is affected
Over 100 million pre-school-age children suffer from vitamin A deficiency. Vitamin A deficiency is also likely to be widespread among women in their reproductive years in many countries.
What vitamin A does
Vitamin A, stored normally in the liver, is crucial for effective immune-system functioning, protecting the integrity of epithelial cells lining the skin, the surface of the eyes, the inside of the mouth and the alimentary and respiratory tracts. When this defence breaks down in a vitamin A-deficient child, the child is more likely to develop infections, and the severity of an infection is likely to be greater.
Depending on the degree of the deficiency, a range of abnormalities also appears in the eyes of vitamin A-deficient children. In the mildest form, night-blindness occurs because the rods in the eye no longer produce rhodopsin, a pigment essential for seeing in the dark. In more severe forms, lesions occur on the conjunctiva and the cornea that if left untreated can cause irreversible damage, including partial or total blindness.
Vitamin A is found as retinol in breast milk, liver, eggs, butter and whole cow's milk. Carotene, a precursor of vitamin A that is converted to retinol in the abdominal walls, is found in green leafy vegetables, orange and yellow fruits, and red palm oil.
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