Zinc May Shorten Cold Symptoms, But With Side Effects

Consuming zinc supplements can shorten the duration of common cold symptoms in adults with small side effects such as nausea and an unpleasant mouth taste.

“Based on an evaluation of 17 trials, people who received zinc had a shorter duration of cold symptoms compared with patients given placebo,” wrote Dr. Michelle Science and colleagues of the Hospital for Sick Children in Toronto. 

Zinc is an important mineral that body uses in a variety of processes such as the function of the immune system. Since the nutrient is commonly deficient in the diet of many people, there has been a debate over the benefits of taking zinc supplements for conditions involving the immune system such as infections and cancer.  To evaluate the effectiveness of taking zinc for common cold, the Canadian team analyzed data from previous studies involving 2,121 people of 1 to 65 years old, who took zinc or a placebo within three days of coming down with a cold. 

Findings showed that the overall duration of the disease reduced by a little more than two and a half days in patients taking zinc than those who took dummy pills or syrups, says the report published in the Canadian Medical Association Journal (CMAJ). 

Taking zinc had no effect on the severity of cold symptoms and little difference was seen in cold duration in children, perhaps because adults tended to use a different form of zinc than kids, Dr. Science and colleagues suggest. 

Taking zinc supplements were, however, not easy for all cold patients. About 64 percent of those who consumed daily zinc supplements experienced nausea and 65 percent found an unpleasant taste in their mouths, which may not be tolerable for all people. 

“The results of our meta-analysis showed that oral zinc formulations may shorten the duration of symptoms of the common cold,” the authors concluded. “However, large high-quality trials are needed before definitive recommendations for clinical practice can be made.”