Zinc Reduces Pneumonia, Diarrhea In Children In Developing Countries

Dec. 7, 1999 (Los Angeles) -- A new report shows that zinc supplementation substantially lowers the occurrence of diarrhea and pneumonia, the leading causes of child death in the developing world. And although the study deals primarily with developing nations, it has relevance for Americans, according to one of its co-authors.

"Just because we get adequate calories does not necessarily mean that our [intake of vitamins and minerals] is sufficient," explains Robert E. Black, MD, MPH, a co-author and one of the coordinators of the report. "In fact, several studies in the U.S. and Europe have documented mild to moderate zinc deficiency in some populations. These same studies also showed positive effects of zinc supplementation." The paper, published in the latest issue of the Journal of Pediatrics, presents the results of analyses from 10 studies in nine developing nations.

Black tells WebMD, "The effect of zinc supplementation on the prevention of diarrhea that we found compares favorably with other preventive measures, including clean water, sanitation, or breast feeding, and zinc has a greater preventive effect for pneumonia than any other current effort."

Black and his colleagues researched past studies in the area of vitamin and mineral nutrition. To be eligible for inclusion in the study, a trial had to include at least half the U.S. recommended daily allowance for zinc in children.

In all there were seven continuous trials in which the supplements were given over the entire study period, and three "short-course" trials, in which supplements were given for two weeks. In general, the children in the short-course trials were not as well-nourished as the children in the continuous trials.

Zinc supplementation reduced the occurrence of diarrhea by up to 25%, an effect the researchers described as "substantial and consistent," and which compares favorably with other steps taken to reduce diarrhea, such as improved sanitation and vitamin supplementation. The incidence of pneumonia was reduced by 41%, an effect greater than that estimated for any other form of pneumonia prevention.

This analysis, says Black, who teaches at the Johns Hopkins School of Medicine in Baltimore, "was one important step necessary to move zinc into child health programs around the world. We currently have a large-scale trial in place to determine zinc's effect on child mortality. An earlier trial in low birth-weight babies showed that zinc reduced their mortality by 34%."

Despite the fact that many products in U.S. markets, such as cereal, are fortified with zinc, Black says there is still a need for doctors to emphasize the importance dietary zinc. "The take-home message for doctors in the U.S. is for them always to consider patients' nutritional status when treating them for conditions that may seem unrelated, such as infectious diseases."

• Zinc supplementation lowers the incidence of diarrhea by 25% and pneumonia by 41%, according to an analysis of studies on children in developing countries.
• In the U.S., even though children get enough calories, some populations have mild to moderate zinc deficiency.
• Physicians should always consider a patient's nutritional status, even when a condition may seem unrelated.