Zinc has long been used as a home remedy for the common cold, but doctors have been hesitant to get behind the mineral so as to recommend it.
A new study -- published in the Canadian Medical Association Journal and conducted by researchers from Toronto's Sick Kids Hospital and McMaster University -- suggests that zinc might be minimally effective, as long as the user can stomach it.
After conducting 17 trials including 2121 participants, researchers found that adult patients receiving zinc had a shorter duration of cold symptoms than those who took placebos. Zinc lozenges reduced symptoms for 1.6 days off the usual seven-day cold.
Zinc showed no significant effect in children with colds, reports CBC.
The study also found that not all zinc formulations were equally effective. Zinc acetate seemed to better treat colds than either zinc gluconate or zinc sulphate.
"The chemistry is important," zinc researcher Dr. Ananda Prasad, who was not involved in the study, tells WebMD. "The chemical composition has to be right so zinc is released, and it must be started within 24 hours of cold onset to be effective."
While there's now evidence that zinc might be worth considering more seriously, the study's findings are still rather weak.
The study, authored by Dr. Michelle Science of Toronto's Sick Kids Hospital, added that adverse effects — 17 per cent of participants reported nausea — were common. The report also reads that these preliminary findings indicate "large high-quality trials are needed before definitive recommendations for clinical practice can be made."
This Canadian study isn't the first to look at zinc as a cold treatment. Last year, the Cochrane Database of Systemic Reviews looked at 15 studies on the effects of zinc on the common cold and found its benefits were "significant," shortening colds by a day or more on average.
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