Several children in developing countries are at an increased risk for zinc deficiency. Zinc supplements have been earlier shown to deliver therapeutic benefits in diarrhea. The main objective of this study was to evaluate the efficacy and safety of oral zinc supplements during recovery from acute or persistent diarrhea.

A meta-analysis of randomized and controlled trials to compare the effectiveness and safety of oral zinc supplements with placebo in children with acute and persistent diarrhea was conducted. Results of the meta-analysis were stated using a pooled relative risk or by a weighted mean difference. A total number of 22 studies were selected for inclusion; 16 observed acute diarrhea (n = 15,231), and 6 observed persistent diarrhea (n = 2968).

The results of the analysis showed that mean duration of acute diarrhea and persistent diarrhea was significantly low for zinc supplements as compared with placebo. Occurrence of diarrhea between zinc supplements and placebo at day 1 was not suggestively different in acute diarrhea or persistent diarrhea trials. On the 3^rd day, incidence was significantly lower for the zinc group in persistent diarrhea trials (n = 221) but not in acute diarrhea trials. In general, children who received zinc documented an 18.8% and 12.5% decrease in average stool frequency, 15.0% and 15.5% shortening of diarrhea duration, and a 17.9% and 18.0% possibility of reducing diarrhea as compared to placebo in acute and persistent trials, respectively.

The meta-analysis concluded that zinc supplementation can reduce the duration and severity of acute and persistent diarrhea. But the mechanisms through which zinc exerts its antidiarrheal effect has not been entirely explained.

Source: Lukacik M, Thomas RL, Aranda JV. A meta-analysis of the effects of oral zinc in the treatment of acute and persistent diarrhea. Pediatrics. 2008;121(2):326-336. doi:10.1542/peds.2007-0921