Zinc and the Common Cold

Flu season is not just around the corner.

It is here and Influenza A and B have both been isolated several times in our metro area.

The "common cold" is not Influenza and is treated differently. Adults get an average of three colds per year, and children can get as many as eight to 10.

Over-the-counter medications can help alleviate the sneezing, congestion, runny nose and sore throat, but medical science has yet to find a cure.

There are dozens of advertisements for remedies, but do any actually work?

Recently, the most popular lozenges, nasal sprays and nasal gels contain the essential element zinc.

Regardless of their mode of delivery, all of these zinc treatments claim to shorten the duration and lessen the severity of a cold if taken at the first sign of symptoms.

But the real effectiveness of zinc treatments on the cold is unclear.

There are numerous studies cited on the usefulness of zinc, but there are just as many showing no benefit.

A medical student in his last year of training at the Stanford University School of Medicine decided to bring together and analyze all of the available research on zinc as a treatment for the common cold.

He along with his professors gathered every study on zinc and the common cold published between 1966 and 2006. There were 105 studies in all.

Only 14 of the 105 were so-called randomized, placebo-controlled clinical trials, considered the gold standard of medical research.

Their study, published in the September issue of the journal Clinical Infectious Diseases, found that exactly half of those 14 studies reported a positive effect of zinc on the common cold, with the other half reporting no effect.

Then the author applied a further set of quality-control criteria and after this was done, only four of the 14 studies made the cut: two that examined zinc lozenges, one that studied a nasal spray and one that studied a nasal gel.

Three of the four found that zinc had no effect on the common cold. Only the study looking at the effectiveness of nasal gel found an effect: The patients who received the zinc nasal gel had colds that lasted an average of two-and-a-half days, whereas the patients who received a placebo were sick for an average of nine days.

All Zinc cold treatments claim to work by delivering zinc to the nasal tissue that has been infected by cold viruses and scientists propose that zinc fights colds by keeping rhinoviruses, the main type of cold virus, from attaching to cells in the nose.

The theory is that if they can't attach, they can't infect. Thus if someone began zinc treatment during the early stages of a cold, he or she might reduce the number of viruses that infected the nasal cells and therefore shorten the cold's duration.

This explanation is entirely theoretical and has never been demonstrated in an experiment.

The most common side effects of zinc cold treatments are an unpleasant taste in the mouth and an upset stomach and some people who have used the nasal sprays and gels report a stinging sensation and a lawsuit was filed because of the allegation patients lost their sense of smell.

As for now, the zinc market is a multimillion dollar business with no real clinical proof it does anything.