Results of earlier studies were inconsistent as to whether zinc reduced cold symptoms and duration, the researchers noted.
Dr. Robert Schwartz, chairman of family medicine at the University of Miami School of Medicine, said that "this has been a homeopathic remedy that's been around for a while, but there really aren't a lot of studies that demonstrate it helps a cold. There isn't a lot of clinical-based data to show it's effective."
Schwartz said he tries to explain to patients how viruses work, and what will work and what won't. There are medicines to treat fever and aches and congestion that come with a cold, but there is no cure. Usually a cold passes within a week or so.
"But we live in a world were people want an instant cure, and people want to get better immediately," he said.
When it comes to zinc, Schwartz tells patients if they want to try it, it's not poisonous, but there is no evidence that it will improve a cold any faster than doing nothing.
As for the side effects, Schwartz said a bad taste in the mouth and nausea are what usually accompanies digesting any heavy metal. "These are typical side effects," he said.
For more on colds, visit the U.S. National Library of Medicine.
SOURCES: Michelle Science, M.D., The Hospital for Sick Children, Toronto; Robert Schwartz, M.D., chairman, family medicine, University of Miami School of Medicine; May 7, 2012, CMAJ
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