Researchers have dispelled fears that adding zinc to the diets of HIV-positive children could worsen their infections.
The scientists say zinc supplements are a safe, simple, and cost-effective way to reduce illnesses such as watery diarrhoea, a major cause of death in zinc-deficient children in the developing world.
"There were concerns over the safety of zinc supplements because the HIV virus needs zinc for its structure and function," says William Moss of the US-based Johns Hopkins School of Public Health, whose team's findings are published today (25 November) in The Lancet.
"We were worried that giving zinc to children with HIV could enhance the virus's replication."
The study was carried out in children with HIV because they are most at risk from opportunistic diseases such as pneumonia and diarrhoea, especially in parts of Asia and sub-Saharan Africa. These illnesses each account for about 20 per cent of child deaths worldwide.
"There is accumulating evidence that zinc supplements can reduce episodes of diarrhoea and pneumonia in non-HIV children," Moss told SciDev.Net. "Now we know it is also safe for children with HIV."
The trial involved 96 South African children aged between six months and five years. They were randomly given either ten milligrams of zinc sulphate, or a placebo, each day for six months.
The levels of HIV virus in children receiving zinc did not rise, indicating the supplements are safe, say the researchers. These children also had half as many diarrhoea episodes as those given the placebo.
Zinc is found in protein-rich foods, with the highest concentrations in beef, pork, poultry, fish and shellfish. Smaller amounts are found in eggs and dairy products, as well as nuts, seeds and pulses.
"No one knows exactly why zinc reduces diarrhoea and pneumonia, but it appears to have a number of different effects on the immune system," says Moss.
"Zinc is not stored in the body, so supplements have to be given daily. The ideal way to provide it is through supplementary food."
Link to full paper in The Lancet*
Reference: The Lancet 366, 1862 (2005)