The quality of evidence is downgraded by inconsistency (unexplained variability in results).
A Cochrane review [Abstract] 1 included 33 studies with a total of 10 841 subjects. The majority of the data is from Asia, from countries at high risk of zinc deficiency. The most frequent zinc dose was 20 mg/day.
Acute diarrhoea: In children aged greater than 6 months with acute diarrhoea, zinc supplementation shortened the duration of diarrhoea by around half a day (MD -11.46 hours, 95% CI -19.72 to -3.19; statistical heterogeneity I2 =71%; 9 studies, n=2 581), and reduced the number of children whose diarrhoea persisted until day seven (RR 0.73, 95% CI 0.61 to 0.88; 6 studies, n=3 865). In children with signs of malnutrition the effect appeared to be greater, reducing the duration of diarrhoea by around a day (MD -26.39 hours, 95% CI -36.54 to -16.23; statistical heterogeneity I2 =62%; 5 studies, n=419). In children aged less than 6 months, zinc supplementation did not have effect on mean diarrhoea duration (MD 5.23 hours, 95% CI -4.00 to 14.45; 2 studies, n=1 334) or the number of children who still have diarrhoea on day seven (RR 1.24, 95% CI 0.99 to 1.54; 1 study, n=1 074). There was not enough evidence to be able to say whether zinc supplementation during acute diarrhoea reduces death or hospitalization. None of the included studies reported serious adverse events, but zinc supplementation during acute diarrhoea increased the risk of vomiting in both age groups (children greater than 6 months of age: RR 1.57, 95% CI 1.32 to 1.86; 6 studies, n=2 605; children less than 6 months of age: RR 1.54, 95% CI 1.05 to 2.24; 2 studies, n=1 334).
Persistent diarrhea: In children with persistent diarrhoea, zinc supplementation shortened the duration of diarrhoea by around 16 hours (MD -15.84 hours, 95% CI -25.43 to -6.24; 5 studies, n=529).
Primary/Secondary Keywords