Zinc: The New Proven Coldbuster

by Marissa Camilon, MD 2011 | camilon@myhousecallmd.com

Cold season seems to last longer and longer each year. Rain or shine, you always seem to find yourself around someone with a case of the sniffles. As miserable as it is for the sniffling individual, the common cold is making an even bigger impact on our society’s finances. Each year, the US spends $7.7 billion on 100 million doctors visits, accounting for an average of 2-4 colds for a single adult each year and up to 12 colds for children. American children can miss up to 189 million school days each year due to cold symptoms, causing parents to stay home and lose126 million workdays. Starting to get the picture?  The seemingly benign common cold is making a sizable impact on us as a society.


Contrary to your grandmother’s warnings, you cannot catch the common cold by falling asleep with wet hair or playing in the rain. The common cold is a virus (which you probably knew).  About 80% of colds are caused by a certain type of virus, the rhinovirus. As a viral condition, the medical field currently doesn’t have any great treatments.  Antibiotics don’t work as they kill bacteria, not viruses (though they are given to one third of patients who go to the doctor with cold symptoms).  All this practice does is increase antibiotic resistance…no bueno.  Antiviral medications are reserved for dangerous infections and people at high risk of complications from viral infections given their side effects.  So what are we left with for viruses?

Stat Fact: While wet hair and rain won’t increase your chance of catching a cold, cold weather may increase your odds.  Physicians postulate that the cold, dry winter air dries out the mucous membranes in your nose leading to small cracks in the membrane that allow viruses to enter your body more easily.

Since the 1980’s, zinc has been hypothesized to be a treatment to the common cold. Lab experiments found that at a certain concentration, zinc ions stunt rhinovirus replication. That being said, we still aren’t entirely sure how it works (other scientists believe that zinc binds to attachment sites on your nasal lining that rhinoviruses use to get in your body and start an infection). Dr. Sing and Dr. Das from the Department of Pediatrics in Chandigarh, India, decided to take a comprehensive look at the issue, and analyzed all of the randomized controlled trials that have been done, pooling all the subjects and data from those studies to better understand zinc’s true effect on viruses.

They looked at 15 different trials, each study with anywhere from 50 participants to 250 participants, for an overall 1360 participants included in the analysis. After analysis, they concluded that zinc treatment was, in fact, associated with a reduction in the duration and severity of symptoms from the common cold. For those who started taking zinc at the onset of cold symptoms, usually within the first day, most were symptom-free by their seventh day of treatment. Overall, zinc decreased the number of times participants caught the common cold, the number of school days missed due to symptoms, and the number of antibiotics prescribed.

Of course, every study conclusion has its limitations. While there was an undeniable benefit in individuals receiving zinc, the incidence of side effects from zinc was also higher in that group. The most common side effects were nausea and a bad taste. The bad taste was more common with the use of zinc lozenges and was not seen with zinc syrup or zinc tablets. Rates of constipation, diarrhea, abdominal pain, dry mouth, and oral irritation (commonly associated with zinc use) were actually found to have the same incidence in both groups, regardless of zinc intake or not.  Interesting, eh?  The other factor to take into account is that many studies simply used “common cold symptoms” to enroll patients into their study rather than confirming that their symptoms were actually caused by a rhinovirus. While it appears that zinc has some antiviral effect, there is always the possibility that the data was skewed by improper patient selection.

The Take Home Message:

It looks like we may finally have a weapon against the common cold.  Zinc seems to shorten the duration of the common cold and minimize the length of time people experience symptoms.  The earlier you begin taking zinc, the great impact it has on the virus so start taking it at the first sign of a cold.  The syrup and tablet forms appear to have fewer side effects than lozenges in terms of the bad aftertaste.  Also, beware of nasal zinc swabs (which are now illegal!).  They have been shown to cause anosmia (i.e. an inability to smell).  That’s kind of a big deal in our books and not worth shortening the length of a cold by a few days.  As always, only use zinc as instructed on the package.  More is not better and can lead to a number of dangerous side effects.  We hope you feel better soon.  Oh, and feel free to go outside and play in the rain.  Tell your grandma that your doctor said you could.

References:

1. Singh M and Das RR. “Zinc for the common cold (Review).” The Cochrane Library 2011, 1-58.

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03 2011

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