Stephanie Stahl reports…

PHILADELPHIA (CBS) — A vitamin thought to prevent cancer might actually cause it. Scientists were suspicious for years, now there’s finally proof. Vitamin E does more harm than good, and men who take high doses face an increased risk of developing prostate cancer.

Ralph Sanderson was part of the government research to see if vitamin E could prevent prostate cancer.

“I had a couple of friends who had prostate cancer and I thought this would be worth doing,” said Ralph.

There had been preliminary evidence that vitamin E and selenium might reduce the risk of prostate cancer. The SELECT study of 35,000 healthy men, aimed to prove that, at a cost of 130 million dollars.

But results show men who took 400 international units of just vitamin E had a 17 percent increased risk of developing prostate cancer.

“I think it’s important that you had a trial like this that now gives us solid evidence to start looking and making reasonable recommendations to people,” said Dr. Bruce Malkowicz, a Urologist at the Hospital of the University of Pennsylvania. He ran the SELECT trial locally.

“Right now I don’t think anyone would recommend using vitamin E, or a supplement like that, for prostate cancer health,” said Dr. Malkowicz.

“We really don’t know why men who took vitamin E are at higher risk of getting prostate cancer. Interestingly, men who took Vitamin E and Selenium together were not at higher risk, so there must be some interesting biology there yet, but we haven’t figured it out,” said Dr. Eric Klein, Study Researcher with the Cleveland Clinic.

The daily dose of vitamin E in the study was much more than what’s found in over-the-counter multi-vitamins.

The clinical trial also shows no benefits from taking vitamin E or selenium when it comes to lung, colorectal cancer or cardiovascular disease.

Ralph was not one who developed prostate cancer, but he, like others in the study, will continue to be followed.

Reported by Stephanie Stahl, CBS 3

Stephanie Stahl