Vitamin A Prophylaxis Programs in Developing Countries: Past Experiences and Future Prospects.

Clinical eye signs are estimated to affect 5-10 million children annually in the developing world. Thus most experience with large-scale prophylaxis programs has been with periodic distribution of high-dose vitamin A supplements directed toward preventing ocular problems. However, subclinical vitamin A depletion affects an estimated five- to 10-fold larger population, and evidence is accumulating for a subclinical protective role of vitamin A against risk of mortality, and perhaps morbidity. Current programs aim to integrate prophylaxis with vitamin A supplements into ongoing programs. Decentralization of distribution of supplements and their integration into community-based programs require careful consideration of dosages and frequency to assure safety and broad coverage. Fortification of foods and condiments has not provided adequate prophylaxis in countries with significant vitamin A deficiency. Other strategies recognized as more sustainable, long-term solutions have received less attention, and their potential has not been evaluated. Such strategies aim to increase dietary intake of vitamin A and/or decrease physiologic requirements; these strategies include horticulture, public health, socioeconomic improvement, and nutrition and health education measures.