The mineral has already been shown to prevent such infections, a leading cause of childhood death.
The study in India, carried out on 153 children aged between two months and two-years-old, who were hospitalised with severe acute lower respiratory infections, found that recovery from very ill status and from fever in zinc-treated boys were 2.6 times and three times those in non-zinc-treated children.
In contrast, the treatment did not benefit girls, and may actually slow their recovery from such infections, suggest the results.
Supplements of vitamin A, also known to reduce childhood mortality, had no effect on recovery from pneumonia either, found the study, published in the March issue of the American Journal of Clinical Nutrition (vol 79, no 3, 430-436).
In the controlled trial the children were randomly assigned to receive 10 mg zinc as acetate (twice daily for five days), 10 000 µg retinol equivalents vitamin A (twice daily for four days), both nutrients combined, or a placebo.
The team from the Society for Applied Sciences in Kolkata, India, and colleagues could not explain why boys, but not girls, benefited from zinc. They add that analysis of previous zinc trials for gender-based differences could help understand the findings.