by Carol Milano

Every year, pneumonia and diarrhea kill children in developing countries and poor communities. Could a simple dietary supplement save millions of lives? Knowing zinc's importance in the immune system, Robert Black, M.D., M.P.H. and Sunil Sazawal, M.P.H., Ph.D., of Johns Hopkins School of Public Health, set out to examine relationships among zinc, immune deficiency and infectious disease.

Working closely with the World Health Organization, the researchers meta-analyzed original data from seven continuous trials that provided 1 to 2 RDA of zinc, and three two-week trials which administered 2 to 4 RDA. The Zinc Investigators' Collaborative Group found that oral zinc supplementation reduces the incidence of pneumonia by 41% and of diarrhea by up to 25% in young children.

They learned that for pneumonia, zinc has unsurpassed preventive effect; for diarrhea, it compares favorably with clean water, sanitation measures and breastfeeding. Trial length was not significant. "Zinc intake must be relatively consistent," notes Dr. Black, a researcher in the Peruvian, Guatemalan, and Indian studies. Through diet or supplements, children need 5 mgs per day during their first year; preschoolers require 10 mgs per day, he stresses.

Dietary surveys show that American and European children in all income levels commonly consume too little zinc. Adults need 15 mg daily. Zinc supplements are recommended for pregnant women, diabetics, heart patients on low-fat or meat- restricted diets, and senior citizens who may have shifted to softer foods less likely to contain this important mineral.

The best natural sources of zinc are animal products, especially meat. For vegetarians or lower-income families buying little meat, zinc supplements will be very helpful. A three-month trial with zinc-fortified bread reduced diarrhea, respiratory illness and skin infections by 56% among Turkish schoolchildren. Many American cereals and baby foods are zinc-fortified.

"To me, it makes sense that zinc supplmentation would have added value for not only the two conditions cited, but also a variety of other ailments. An essential nutrient, needed for well over 200 enzymatic reactions in the body, zinc can be considered a key for immune activity, insulin regulation, endocrine function, wound healing, and other functions," observes James B. LaValle, R.Ph, at University of Cincinnati College of Pharmacy.

The study was published in the Journal of Pediatrics (December, 1999)

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