Zinc may shorten common colds in adults, a review of 17 studies finds
By Linda Searing,
THE QUESTION When seeking relief from a cold, people often turn to supplements. Might zinc — a nutrient known to help the immune system fight off viruses and bacteria — be worth trying?
THIS STUDY analyzed data from 17 studies, involving 2,121 people, 1 to 65 years old, who had been randomly assigned to take zinc or a placebo within three days of coming down with a cold. Medication was taken either as a lozenge, as a tablet or in syrup form. Cold symptoms disappeared about three days sooner among adults who took zinc than they did for those taking the placebo, especially when higher doses of zinc were taken. Among children, the length of a cold did not differ between those who did and did not take zinc. Reports of a bad taste or nausea were more frequent in the zinc group.
WHO MAY BE AFFECTED? Anyone with a cold, a common ailment that can be caused by a variety of viruses and generally lasts one to two weeks. On average, adults get one to three colds a year, and children get three to six. No cure has been found.
CAVEATS Children generally took smaller doses of zinc and took the medication less often than adults, which could have affected the results. The authors said the bad taste and nausea effects from taking zinc might outweigh any benefit. All of the original studies were funded by pharmaceutical companies.
FIND THIS STUDY May 8 issue of the Canadian Medical Association Journal (www.cmaj.ca).
— Linda Searing
The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.