Zinc supplementation benefits children suffering from diarrhoea in developing countries, but only in infants over six months old, Cochrane Researchers have found. Their study supports World Health Organization (WHO) guidelines for the treatment of diarrhoea with zinc, although not in the very young.
"Zinc is clearly of benefit to children with diarrhoea," says lead researcher Marzia Lazzerini, who works at the Unit of Research on Health Services and International Health in Trieste, Italy.
Diarrhoea is a common cause of death for children in the developing world, occurring most often in children aged between six months and five years. It is estimated that two million children die every year as a result of the disease. Zinc is a micronutrient that plays a critical role in physical growth as well as in gastrointestinal and immune function. Its main dietary sources are red meat, fish and dairy products, but these are costly and in short supply in many developing countries. Currently the WHO advises treating a child with zinc for between 10 and 14 days, as well as giving oral rehydration salts to reduce the risk of death due to dehydration.
The Cochrane Researchers identified 18 trials of zinc treatment that together involved 6,165 people from Asia, South America and Africa. Collectively the trials show that zinc is effective in reducing the duration of diarrhoea in children aged between six months and five years. Below six months, two large trials involving 1,334 children, in three continents found no effect.
"These studies back up previous research that shows zinc can play an important role in restoring children with diarrhoea to full health. No conclusions regarding zinc's impact on hospitalisation or death could be drawn form the trials, but given these results it's expected that a policy of zinc supplementation during diarrhoea in the community could also reduce hospitalisation rate and mortality," says Lazzerini.