Week of: December 2, 2002
DO ZINC LOZENGES CURE THE COMMON COLD?
No, but zinc lozenges have been shown to reduce the duration of a cold.
Many of us are searching for a cure for the common cold. The common cold is one of the most frequently occurring human illnesses in the world. Each year, adults develop an average of two to four colds and children have an average of six to eight colds. The physical illness and discomfort resulting from the cold and the economic losses in terms of working hours are great.
Cold viruses, which number more than 200, grow mostly in the nose and mouth. Research has shown that the growth of the rhinovirus, which causes about one third of all colds, can be slowed by zinc.
Some studies found that people who took zinc gluconate lozenges every few hours after their first cold symptoms were sick one to three fewer days than people who took a placebo, a similar lozenge without zinc. Other studies did not show any differences between the two groups. Researchers have not been able to determine how zinc reduces the symptoms of a cold.
Zinc is a trace mineral essential for growth. It promotes cell reproduction, tissue growth and repair, and wound healing. It is a part of more than 70 enzymes and helps the body use carbohydrate, protein and fat. Good food sources of zinc are meat, liver, seafood, whole grain products, wheat bran, legumes and soybeans.
The Recommended Daily Intake (RDI) of zinc for adults ranges from 8 to 14 milligrams, depending on the person’s age and gender. The Tolerable Upper Intake Level is 40 milligrams per day, which means that consuming more than that amount is not safe. Zinc lozenges vary from 5 to 23 milligrams of zinc per lozenge. It can be very easy to consume too much with the use of zinc lozenges.
Excess zinc can cause stomach upset, vomiting, reduced HDL ("good") cholesterol levels, interfere with copper absorption and make your immune system less able to fight off disease.
If you decide to take zinc lozenges, consider the following:
- Use lozenges that contain zinc gluconate for best flavour and availability of zinc.
- Start taking the lozenges at the first sign of a cold.
- Use a product that does not contain vitamin C, citric or tartaric acid or sweeteners such as mannitol or sorbitol. These ingredients may bind the zinc and make it unavailable.
- Watch the amount of zinc that you are getting from the zinc lozenges and stay below 40 milligrams per day. If you take zinc lozenges or supplements for an extended period of time, food sources of zinc must be included in the limit of 40 mgs. Talk to your public health nutritionist for amounts of zinc in foods.
- Stop taking the lozenges as soon as your cold has cleared up.
- Talk to your doctor or pharmacist if you are taking any medications. Too much zinc can affect the absorption of some drugs.
In summary, if you suck on zinc lozenges at the first sign of a cold and follow the guidelines listed above, you may reduce the duration of your cold. The use of zinc lozenges will not, however, keep you from getting a cold. If you have any questions about zinc lozenges check with your local pharmacist.
WRITTEN BY THE PUBLIC HEALTH NUTRITIONISTS OF SASKATCHEWAN
Originators: Carolyn Chu
References:
Duyff, Roberta L. The American Dietetic Association’s Complete Food and Nutrition Guide 1998. John Wiley & Sons, Inc. New York, pp. 104.
http://www.acponline.org/journals/annals/15jul96/zincgluc.htm
www.coldcure.com/html.doeszinc.html
www.coldcure.com/html/warning.html
www.infopoems.com/POEMS/JC099808.htm
www.personalmd.com/news/zinc_010300.shtml
"In From the Cold - Do Supplements Work?," Nutrition Action Healthletter, March 2002.
