Zinc for Colds: Lozenges & Nasal Sprays
Introduction
You've probably heard a lot about
zinc for colds. But is zinc really effective for reducing the duration of cold
symptoms? Here's what you should know about zinc and colds.
What is zinc?
Zinc is an essential mineral that is found in almost every
cell. Zinc has antioxidant effects and is vital to the body's resistance to
infection. It's also important for tissue repair.
Zinc is found naturally in shellfish, beef and other red meats, nuts and
seeds, beans, and milk and cheese. Tea, coffee, and certain medications may
interfere with zinc absorption in the intestines.
Is zinc an effective cold remedy?
Researchers have studied the use of zinc as
a cold remedy and as a way to treat the cold virus. Still, the data from years
of scientific studies is mixed.
In some studies, researchers found that zinc lozenges or nasal sprays
decreased the duration of colds. In other studies, they found no differences in
cold symptoms between those who took zinc and those who took a placebo or sugar
pill.
What do these findings on zinc and colds mean to you and your family? For
now, the study results on using zinc as a cold remedy are inconclusive. For
every study showing a positive benefit with zinc, there's another study showing
no benefit at all. In fact, it's believed that if there is any benefit in taking
zinc or zinc lozenges, it is very minor.
Is zinc a safe cold remedy?
The effectiveness of zinc as a cold remedy relies
on frequent dosing during the illness, which means zinc lozenges must be taken
every two to four hours. Short-term use of zinc — less than 5 days — has not
lead to serious side effects but can cause mouth irritation and stomach upset.
However, experts recommend that zinc should not be taken for more than 5 days.
Long-term use of zinc — for more than 6 weeks — can lead to copper deficiency.
Zinc nasal sprays are known to cause a loss of the sense of smell in animals,
and there have been several reports of people losing their sense of smell from
zinc nasal sprays. Due to this risk of a loss of smell, many experts recommend
that you avoid zinc nasal sprays completely.
Zinc supplements are not recommended for children as they are even more
sensitive to zinc and develop side effects at much lower zinc levels.
Yes, zinc is necessary for optimal health and is safe to take when ingested
through food sources such as seafood and eggs. But supplementing with higher
doses of zinc, particularly long term, can be toxic.
What's the bottom line on zinc and colds?
While some research has shown some
benefit from zinc lozenges and nasal sprays, studies have been inconsistent and
additional research is needed to see if, in fact, zinc is an effective cold
remedy. Zinc's side effects may outweigh any potential benefit and the benefit
may be minimal at best.
WebMD Medical Reference
Sources: NIH Office of Dietary Supplements: "Zinc." American Family
Physicians: "Treatment of the Common Cold." Scientific American: "No proof zinc
lozenges help cold symptoms." US Pharmacist: "Zinc and the Common Cold: What
Pharmacists Need to Know." Medscape: "Efficacy of Zinc Lozenges Against Common
Cold Viruses." Oregon State University, Micronutrient Information Center:
"Zinc."
Reviewed by Michael W. Smith, MD on December 18, 2007
© 2007 WebMD, Inc. All rights reserved.
Last Editorial Review: 2/28/2008
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