The Benefits and Concerns Related to Vitamin A Supplementation

Extract

There has been considerable interest in the role that vitamin A plays in child health. Discovered in 1913 by E. V. McCollum, vitamin A is essential for the production of rhodopsin, the light-sensitive chemical in the retina, and its deficiency results in night blindness and more-severe forms of xerophthalmia, including corneal ulcers and blindness. A role for vitamin A deficiency in the etiology of infections was proposed in the period immediately after its discovery [1], but research to identify whether a causal relationship existed was not pursued. While conducting an observational study to understand the epidemiological aspects of xerophthalmia in Indonesia in the early 1980s, Sommer et al. found that children who had xerophthalmia were more likely to die than were other children [2]. In their first large community trial in Aceh, Indonesia, Sommer et al. found that children >6 months old who received vitamin A every 6 months were significantly less likely to die than were those who did not receive vitamin A [3]. This landmark study led to substantial investments in research and, eventually, field programs related to vitamin A supplementation in developing countries. These findings were confirmed in several other randomized, placebo-controlled trials in diverse populations that were presumably largely free of HIV infection [4], and they have also been extended to children who are HIV infected [5, 6]. Periodic vitamin A supplementation, costing 0.02 US $/dose, to children >6 months old is being implemented in >70 countries and is considered by many international agencies to be one of the most-effective public health interventions ever undertaken