Diarrhea kills more than two million people every year. Most are young children living in developing countries with poor public health infrastructures that cannot deliver state-of-the-art treatments for diarrhea-causing infections, viruses and food-borne illnesses. Now, a meta-analysis of 22 studies has concluded that a fairly simple and economical measure — taking zinc supplements — can be an effective treatment for diarrhea in children.

While further research will be needed to determine how and why zinc produces its anti-diarrheal effects, this discovery may provide a partial answer to a worldwide health problem.

The 22 studies include 16 that focused on the benefits of zinc in 15,231 children with acute diarrhea and six that looked at 2,968 children with persistent diarrhea.

Zinc use cut the average duration of both acute and persistent diarrhea, says Dr. Marek Lukacik, from the Medical College of Georgia in Augusta. In addition, zinc therapy reduced the average stool frequency by 18.8 percent and 12.5 percent in children with acute and persistent diarrhea.

As Dr. Lukacik and colleagues report in the February issue of Pediatrics, zinc supplements reduced the occurrence of both types of diarrhea by roughly 18 percent compared to a placebo.

The researchers' conclusions? "On the basis of these findings, which now add to the large body of previously published clinical data and update previous meta-analyses and systematic reviews, zinc therapy is useful for treating both acute and persistent diarrhea and for their [prevention]."