Correcting zinc deficiency in world populations should be a top priority for health organisations, according to one expert writing in this week's British Medical Journal.
Dr Ananda Prasad says that although the problem has been known for 40 years, a solution is still outstanding. He writes: "Despite all the evidence practically no attention has been given to the problem of zinc deficiency by the world's organisations." Prasad added that slower growth and increased susceptibility to infectious and cognitive impairment are common in developing countries where many people are deficient of the mineral.
Prasad argues that a correction of zinc deficiency is likely to have a great impact on the health of a large population in the developing world. The editorial points to several studies showing the benefits of the mineral.
Dietary zinc deficiency currently affects nearly 2 billion people in the developing world, according to the author. He cites a meta-analysis of 33 trials of zinc supplementation and its effects on children's growth in many countries which shows that zinc supplementation alone had a significant effect on both growth and body weight gain, indicating that other deficiencies that may have been present were not responsible for slowing growth. Zinc supplements have also been shown to improve mental functions in children with zinc deficiency and reduce the incidence of diarrhoea and acute lower respiratory tract infections in children in developing countries, resulting in decreased mortality.
Prasad also refers to a recent study by the National Institutes of Health's Eye Institute involving 3640 elderly participants, which showed that antioxidants and zinc supplements delayed progression of age related macular degeneration and reduced the risk of loss of vision.
The author concludes that zinc deficiency has now been recognised to be associated with many diseases, including malabsorption syndrome, chronic liver disease, chronic renal disease, sickle cell disease and diabetes. The World Health Organization should therefore act to reduce the problem, says Prasad. He does however point out that deficiencies of other micronutrients such as vitamins and other trace elements may also be associated. "It should be emphasised that nutritional zinc deficiency in the developing countries does not occur in isolation."