Zinc: Nothing to sneeze at?

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Throughout the ages, people have resorted to countless methods to cure the common cold, yet such bugs continue to plague people around the world, with no cure in sight. However, the results of a recent meta-analysis suggests that there may be an evidence-based treatment that could shorten a cold s duration even if it s still not the cure we ve been searching for.

According to a review published in the Canadian Medical Association Journal, zinc may cut the time adults have to suffer from a cold. The researchers, led by Dr. Michelle Science from the Hospital for Sick Children in Toronto, analyzed 17 randomized controlled clinical trials that compared the effects of taking zinc to either a placebo or no treatment at all in people who had colds. Overall, these studies included more than 2,000 individuals, ranging in age from one to 65 years old.

Although the review found that taking zinc did not alter the duration of a cold in children, colds did last an average of two and a half days fewer among the adult group receiving zinc. The researchers acknowledged that it is still unknown why zinc seems to work to some extent in adults, and why it does not work in children. Various theories are being investigated.

The researchers also found what appears to be a dose-response relationship: Adults who took higher dosages of zinc had shorter cold durations than those adults taking lower dosages. But although zinc did seem to reduce the duration of adults colds, it didn t alter the severity of symptoms that patients experienced while in recovery: On day three, the participants symptom severity did not correspond to whether or not they were taking zinc.

Taking zinc for a cold is not without side effects, however. The most significant side effects noted were an unpleasant metallic taste and an increased risk of nausea. The authors also caution that as in most meta-analyses the studies under review varied in quality. Furthermore, none of the studies investigated the effects of taking other vitamins along with zinc, nor did they include zinc nasal sprays, which have been linked to loss of smell a condition that can be permanent. Dr. Science did, however, conclude that for healthy adults ¦it s probably an individual decision and it s something they can talk to their physician about.

Indeed, these results are in agreement with a 2011 review by the Cochrane Collaboration. Shortening the average duration of a cold by a couple of days could be a significant advance, since, according to the U.S. National Institutes of Health, there are about 62 million cases of the common cold in the U.S. each year, which lead to 22 million days of missed work. Reducing a cold s duration by two and a half days is pretty substantial, comments ACSH s Dr. Gilbert Ross. Overall, the results seem to suggest that taking zinc may have a real effect on cold duration.

However, ACSH s Dr. Josh Bloom cautions, Zinc studies are a dime a dozen. Some studies say it doesn t work, and some say the opposite. Given its unpleasant side effects and the potential for toxicity with overdose, I d rather be sneezing a few days longer.