Zinc Speeds Respiratory Infection Recovery in Boys

Healthnotes Newswire (July 29, 2004)—Young boys with severe acute lower respiratory infections (ALRI) may recover more quickly when given extra zinc, according to a study in the American Journal of Clinical Nutrition (2004;79:430–6). Vitamin A was also studied but was not shown to be effective for ALRI.

Zinc, an essential mineral needed for proper growth, immune function, wound healing, and metabolism, is found in large amounts in meat, eggs, and shellfish. Zinc decreases the severity and duration of diarrhea and prevents pneumonia in children in developing countries, where zinc deficiency is common.

Vitamin A is a fat-soluble vitamin that enhances immune function. It plays an important role in the normal functioning of the lungs, skin, intestines, and eyes. Food sources of vitamin A include liver and dairy products. Vitamin A supplementation decreases childhood mortality in developing countries; however, results of studies using vitamin A to treat pneumonia and ALRI are conflicting.

The new study evaluated the effect of zinc and high-dose vitamin A supplementation on recovery rates in children suffering from ALRI in India. One hundred fifty-three hospitalized children aged 2 to 24 months with severe ALRI were enrolled in the study and observed for five days. The children were randomly assigned to receive either (1) 10 mg zinc acetate two times per day for five days plus a placebo for vitamin A, (2) 33,300 IU vitamin A (as retinyl palmitate) two times per day for four days plus a placebo for zinc, (3) zinc and vitamin A, or (4) placebo for zinc and vitamin A. All children also received standard medical treatment for their condition, including antibiotics, medications to ease breathing (bronchodilators), and oxygen. Doctors measured the time for very ill status and fever to resolve, and noted the presence of abnormally rapid breathing and difficulty feeding.

Boys who received the zinc supplement recovered from very ill status 2.6 times faster and from fever 3.1 times faster than children not taking zinc. Similar trends were seen for rapid breathing resolution and feeding difficulty among boys taking zinc. Zinc supplementation had no significant effect in girls. Vitamin A supplementation provided no significant benefit for children with ARLI. In fact, more diarrhea was noted among those children taking vitamin A. Children taking vitamin A also needed more changes in antibiotic prescriptions due to lack of responsiveness or worsening of their condition.

It is not clear from this study why boys but not girls seem to benefit from supplementing with zinc.