Oral zinc may lessen common cold symptoms but adverse effects are common

Oral zinc treatments may shorten the duration of symptoms of the common cold in adults, although adverse effects are common, according to a study published in CMAJ (Canadian Medical Association Journal).

Canadian researchers looked at 17 with 2121 participants between 1 and 65 years of age to determine the efficacy and safety of zinc in treating the common cold. All trials were double-blinded and used placebos as well as oral zinc preparations. The authors found that, compared with placebos, zinc significantly reduced the duration of cold symptoms, although the quality of evidence was moderate. High doses of ionic zinc were more effective than lower doses at shortening the duration of cold symptoms.

"We found that orally administered zinc shortened the duration of ," writes Dr. Michelle Science, The Hospital for (SickKids), Toronto, with coauthors at McMaster University. "These findings, however, are tempered by significant and quality of evidence."

There was weak evidence that people taking zinc were less likely to have symptoms after one week, although there was no difference in symptoms between the two groups at three days. While zinc appeared to reduce the duration of symptoms in adults, there was no apparent effect in children. Participants taking zinc treatment were more likely to experience adverse effects including bad taste and nausea.

Previous studies have shown conflicting effects of zinc in reducing cold symptom severity and the duration of symptoms.

"Until further evidence becomes available, there is only a weak rationale for physicians to recommend zinc for the treatment of the common cold," conclude the authors. "The questionable benefits must be balanced against the potential adverse effects."

More information: www.cmaj.ca/lookup/doi/10.1503/cmaj.111990

add to favorites email to friend print save as pdf

Related Stories

Zinc lozenges may shorten common-cold duration

Jul 26, 2011

Depending on the total dosage of zinc and the composition of lozenges, zinc lozenges may shorten the duration of common cold episodes by up to 40%, according to a study published in the Open Respiratory Medicine Journal.

Zinc lozenges may shorten common cold duration

Aug 16, 2011

Depending on the total dosage of zinc and the composition of lozenges, zinc lozenges may shorten the duration of common cold episodes by up to 40%, says Dr. Harri Hemila from the University of Helsinki.

Zinc reduces the burden of the common cold

Feb 16, 2011

Zinc supplements reduce the severity and duration of illness caused by the common cold, according to a systematic review published in The Cochrane Library. The findings could help reduce the amount of time lost from work a ...

Zinc lozenges an ineffective treatment for colds

Aug 02, 2007

Despite 20 years of research, the benefits of zinc lozenges as a therapy for the common cold have not been proven. A new study, published in the Sept. 1 issue of Clinical Infectious Diseases, currently available online, review ...

Recommended for you

Have a cold? Don't ask your doctor for antibiotics

23 hours ago

Antibiotic resistance is a major threat to public health. Resistance makes it harder for physicians to treat infections and can increase the chance patients will die from an infection. What is more, the treatment ...

Powdered measles vaccine found safe in early clinical trials

Nov 25, 2014

A measles vaccine made of fine dry powder and delivered with a puff of air triggered no adverse side effects in early human testing and it is likely effective, according to a paper to be published November 28 in the journal ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.