Zinc really might work to prevent the common cold and lessen the severity of symptoms, according to a new review, but the prevalence of side effects might make you think twice about taking it. Scientists searched for randomized, double-blind, placebo-controlled trials conducted since 1984, identifying 13 treatment studies totaling 966 participants and 2 prevention trials with 394 participants. Taken together, the treatment trials showed that zinc reduced the average duration of cold symptoms by nearly a day when taken within 24 hours of first feeling the sniffles. After seven days, 37% of the zinc groups were still symptomatic compared with 56% of the control groups. In the prevention studies, 38% of those taking zinc developed colds versus 62% of those getting placebos. But 56% of people given zinc reported side effects-especially nausea and bad taste-compared to 48% in the placebo groups. That led researchers to conclude, Given that some formulations (especially lozenges) produced side effects and not all formulations may be effective, the use of zinc to treat common cold symptoms is presently advised with caution.
TO LEARN MORE: The Cochrane Library, dx.doi.org/10.1002/14651858.CD001364.pub3.