Review finds zinc supplementation breaks grip of common cold

ZINC supplementation can reduce the length and severity of the common cold in adults and children, a Cochrane review shows. 

The review of 15 randomised trials showed zinc – taken as syrup, lozenges or tablets – needs to be administered within 24 hours of symptom onset to be effective. 

Zinc supplementation also led to a reduction in cold incidence and school absences, and to decreased antibiotic use in children when used prophylactically over five months.

However, adverse events were common. Eleven trials reported bad taste, nausea, constipation, diarrhoea, abdominal pain, dry mouth or irritation.

Dosage regimens varied, with side-effects more likely to be reported by those taking lozenges, the reviewers said. 

In 10 trials reporting the duration of cold, six results could be pooled to show a significant reduction in cold duration, on average 42%. 

Of these, two used a daily dose of 30