The WHO programme of prevention and control of vitamin A deficiency, xerophthalmia and nutritional blindness

Abstract

The vast extent and the world wide distribution of vitamin A deficiency is discussed. Its epidemiology is reviewed and sources of vitamin A in diets recorded, along with the high requirements of children. Strategy for prevention is described under three headings--short, medium and long term steps. Strategies in many countries received notice.

PIP: Conservative estimates project over 500,000 cases/year of new active corneal lesions and 6-7 million cases of noncorneal xerophthalmia attributable to vitamin A deficiency on a worldwide basis. Vitamin A deficiency affects growth, the differentiation of epithelial tissues, and immune competence. The most dramatic impact, however, is on the eye and includes night blindness, xerosis of the conjunctiva and cornea, and ultimately corneal ulceration and necrosis of the cornea. Vitamin A deficiency occurs when body stores are exhausted and supply fails to meet the body's requirements, either because there is a dietary insufficiency, requirements are increased, or intestinal absorption, transport and metabolism are impaired as a result of conditions such as diarrhea. Vitamin A deficiency is the single most frequent cause of blindness among preschool children in developing countries. The younger the child, the more severe is the disease and the higher the risk that corneal destruction will be followed by death. The most important step in preventing vitamin A deficiency is ensuring that children's diets include adequate amounts of carotene containing cereals, tubers, vegetables, and fruits. An overall strategy designed to prevent and control vitamin A deficiency, xerophthalmia, and nutritional blindness may be defined in terms of action taken in the short, medium, and long term. A short-term, emergency measure includes the administration to vulnerable groups of single, large doses of vitamin A on a periodic basis. In the medium-term, the fortification of a dietary vehicle (e.g., sugar or monosodium glutamate) with vitamin A can be initiated. Increased dietary intake of vitamin A through home gardening and nutrition education programs comprises the longterm solution to this problem. The World Health Organization plans to launch a 10-year program of support to countries where vitamin A deficiency is a significant public health problem.