Zinc Supplements Important in Combating Diarrhea

Researchers at the Johns Hopkins School of Public Health have found that zinc supplements help children suffering from acute and persistent diarrhea significantly reduce the duration of their symptoms. The study can be found in the December 2000 issue of the American Journal of Clinical Nutrition.

"Diarrhea is a very serious public health problem in developing countries, resulting in millions of deaths each year. Those who survive are often left with malnutrition. This study was important because it measures the effect of supplemental zinc given in conjunction with oral rehydration therapy during the recovery from acute or persistent diarrhea," said study co-coordinator Robert Black, MD, MPH, professor and chair, International Health, Johns Hopkins School of Public Health.

The researchers analyzed ten randomized, controlled studies that had assessed the therapeutic benefit of zinc supplements in children under age five. In the case of the acute-diarrhea trials, diarrhea was defined as three or four loose stools in a 24-hour period. For persistent diarrhea, the original trials' definitions for diarrhea and recovery were retained. All trials used the standard World Health Organization recommendations for fluid and dietary case management of diarrhea. The researchers divided the participants of all the reviewed studies into subgroups according to sex, age, weight-for-height, and initial plasma zinc concentration, and then evaluated the overall effect of zinc on each group.

Results of the study showed that the children who were given a zinc supplement during the acute-diarrhea trials were 15 percent less likely than controls to still have diarrhea by a given day; children in the persistent-diarrhea trials had a 24 percent lower risk of the diarrhea continuing. The authors said their meta-analysis showed that zinc apparently offers comparable benefits to all subgroups, a finding that indicates the nutrient needn't be aimed only at certain narrow populations but is feasible for wide use in the developing world.

Although future studies are still needed to examine the effect of zinc supplementation on other measures of severity, such as diarrheal output, occurrence of dehydration, treatment failure, or death, the researchers believe attention should now focus on the best means of providing zinc during diarrhea, as well as on other ways to increase the zinc intake of children in developing countries.

This study was supported by the Johns Hopkins Family Health and Child Survival Cooperative Agreement with the U.S. Agency for International Development, by the World Health Organization's Division of Child Health and Development, and by the Rockefeller Foundation's Bellagio Study and Conference Center.