May 6, 2015
Taking Too Much of OTC Dietary Supplements Could
Increase Cancer Risk

Philadelphia—When it comes to OTC dietary supplements, too much of a good thing could potentially lead to cancer, according to a recent conference presentation.

At a forum at the American Association for Cancer Research (AACR) Annual Meeting 2015 in Philadelphia, Tim Byers, MD, MPH of the University of Colorado Cancer Center in Aurora, discussed his research, which indicated that exceeding the recommended daily dosages of OTC supplements might increase cancer risk.

“We are not sure why this is happening at the molecular level but evidence shows that people who take more dietary supplements than needed tend to have a higher risk of developing cancer,” explained Byers.

Intrigued by the observation that people who ate more fruits and vegetables tended to have less cancer, Byers and other researchers began research to see if taking extra vitamins and minerals would reduce cancer risk even further.

“When we first tested dietary supplements in animal models we found that the results were promising,” he recounted. “Eventually we were able to move on to the human populations. We studied thousands of patients for ten years who were taking dietary supplements and placebos.”

The results were surprising, however. “We found that the supplements were actually not beneficial for their health. In fact, some people actually got more cancer while on the vitamins,” Byers said.

One trial, which explored the effects of beta-carotene supplements, suggested that taking more than the recommended dosage increased the risk for developing both lung cancer and heart disease by 20%, while another showed that folic acid increased the number of colon polyps although it was thought to do the opposite.

“This is not to say that people need to be afraid of taking vitamins and minerals,” Byers pointed out. “If taken at the correct dosage, multivitamins can be good for you. But there is no substitute for good, nutritional food.”

He also noted that a healthy diet should provide the daily recommended doses of vitamins and minerals, negating the need for vitamins. “At the end of the day we have discovered that taking extra vitamins and minerals do more harm than good,” Byers said.

U.S. Pharmacist Social Connect