Effects of Zinc Supplementation in Occurrence and Duration of Common Cold in School Aged Children during Cold Season: a Double-Blind Placebo-Controlled Trial

Zinc deficiency is common in children in developing countries due to low intake of animal foods, and high dietary phytate content. Zinc deficiency impairs overall immune function and resistance to infection. The effect of zinc on the common cold is still questionable. To determine whether supplementation of zinc could reduce frequency rate and duration of common cold during cold season in school aged children living in a low socioeconomic suburb of Mashhad (Altimor), north-east Iran.Methods: We designed a randomized double-blind, placebo-controlled efficacy trial. Subjects were 200 grade 2 primary school children who all completed the trial. Intervention supplementation was zinc sulfate tablets (10 mg elemental) and placebo tablets for case and control groups, respectively. Tablets were taken on a daily basis, 6 days a week, for 5 months (November to March).Findings: Among the zinc-supplemented group common cold incidence of 1.37±0.86 episodes per child during the study period was recorded in comparison to 3.15±0.55 cold episodes per child among the placebo group (P 0.001). Mean overall missing days from school was 0.55±1.09 days and 1.35±1.79 days for zinc-supplemented and placebo groups, respectively. The need for administration of antibiotics for bacterial infections (pharyngitis, acute otitis media, sinusitis, pneumonia) were 20 and 47 courses for zinc-supplemented and placebo groups, respectively (P 0.01). Conclusion: This study showed that zinc supplementation has a beneficial impact on the occurrence of common cold.