Zinc: Combats the Common Cold?

By Kyung-Jin Kim

Doctor of Pharmacy Candidate 2006

Shenandoah University, Winchester, VA

 

Consumers are using more and more vitamins and herbal products to treat the common cold. The problem is that they do not know that there is little evidence to support this.

You can see these products on the shelves of most drug stores and supermarkets. One of the most conflicting and popular natural remedies for the common cold is zinc. It is a cold remedy sold over-the-counter (OTC) across the country. However, just recently the Washington Post, January 31, 2006 reported some people have lost their sense of smell after using the zinc nasal products. The symptoms these people reported were similar. . Many of these people have not regained their ability to smell even months later. Because the ability to smell food affects how it tastes, these people can even no longer enjoy what they eat.

Another common cause of losing the sense of smell is viruses in the nose. The researchers are not sure if these people lost their sense of smell because of a virus or because they used the zinc-containing products. However, there is a report that a person developed the same condition hours after using the zinc spray without colds. Losing the sense of smell due to a virus usually happens more slowly. The people described in the Washington Post article lost their sense of smell from using zinc-containing products right away or after a few hours followed by burning pain in the nose.

The two products reported to be linked to a possible loss of smell and taste are Cold-Eeze® and Zicam®. Lawsuits have been filed against their manufacturers claiming that these products caused in either partial or total loss of smell and/or taste. Cold-Eeze® cold remedy nasal spray products were withdrew from the market in 2004. The manufacturer of Zicam® Cold Remedy has agreed to pay $12 million to settle 340 lawsuits brought by consumers on January 31, 2006 . However, the manufacturer still claims that their products are safe and that there were no reports of losing sense of smell in clinical studies.

Some studies have shown the zinc to be effective, while others have not. Some researchers have found that zinc has decreased some degree of ability to smell in laboratory animals. However, no strong evidence has been discovered that zinc has any negative effect on sense of smell in people.

Why Zinc is used by people to fight the common cold?

Many adults and children catch a cold each year. They spend a lot of money on OTC cold and cough medicines to treat the symptoms. There is no cure for common cold. OTC cough and cold medicines relieve the symptoms but do not decrease the severity or length of symptoms.

Zinc may help people get over a common cold faster or at least make the symptoms less severe. It is believed to directly block the action of viruses in the nose or throat if you use zinc as soon as cold symptoms start. Depending on the product you purchased, you dissolve 9-13.3 mg of zinc lozenge in the mouth every 2-4 hours while awake. The zinc spray or gel can be applied into each nostril every 4 hours. The treatment should continue until symptoms disappear, but never for longer than two weeks. Side effects of zinc taken over a longer period are unknown, but too much zinc is toxic to your body. High zinc could weaken your immune responses and decrease the level of copper and good cholesterol in your body.

Zinc is available in many different forms. Lozenges and nasal sprays are most common. You can also get zinc chewing gums, oral mist, nasal swabs and other products. T here is no advantage of using a zinc nasal spray/gel over oral zinc products. The gum may give you bad after-taste and stomach upset. The oral mist also can cause stomach upset if used on empty stomach. However, taking zinc with food can decrease the absorption of zinc. The lozenges may give really bad taste, dry mouth/throat and mouth irritation. The spray or gel can cause irritation in the nose and give burning sensation.

The ones that have so far been linked to cause the loss sense of smell are the nasal gel/swabs and sprays. These products are applied or sprayed directly into the nostrils . The force of spray or sniffing too deeply could send zinc high into the nose and might affect the ability to smell.

Because zinc products are considered natural remedies by the Food and Drug Administration (FDA), they are not required to be tested like prescription medicines. Manufacturers “do not need FDA approval to sell their dietary supplements” and “is responsible for ensuring that its dietary supplement products are safe before they are marketed”. 1

Is Zinc Right for You?

It is unclear exactly how many people are suffering by using zinc-containing products. What really needs to be done is more research. More studies are needed to see reliable evidence in efficacy and safety, and then the public can be informed of any potential risks.

Tips on using zinc in common cold:

1 United States Food and Drug Administration Center for Food Safety and Applied Nutrition. Dietary supplements: overview. www.cfsan.fda.gov/~dms/supplmnt.html (accessed 2006 Feb 14).

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