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Doctor: Dietary Supplements May Actually Increase Risk Of Cancer

AURORA, Colorado (WWJ) -- Dietary supplements are advertised as a way to improve your health, but years of research shows they may do more harm than good, even increase the risk of certain types of cancer.

University of Colorado researcher Dr. Tim Byers said that studies over the past 20 years show dangers of taking extra dietary supplements.

"Taking higher than nutritional levels of that B vitamin called folic acid can also increase cancer, especially colon cancer," Byers said. "Selenium -- given to try to reduce skin cancer risk -- actually increased skin cancer risk."

Dietary supplement manufacturers and distributors are not required to obtain FDA approval.

"What we found, in a nut shell, is that taking vitamin supplements does not reduce cancer risk," Byers said. "The surprising finding is that in several of these studies we found actually higher cancer risk in the groups that took supplements compared to those who took placebos."

Byers said that vitamin E supplements, which would normally be taken to help prevent prostate cancer actually increased the risk by 17 percent.

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