Nightly News   |  October 11, 2011

Vitamin E may be risky for prostate

A daily dose of vitamin E could actually increase a man's risk of prostate cancer, a new study shows. NBC’s Robert Bazell reports.

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This content comes from a Full-Text Transcript of the program.

BRIAN WILLIAMS, anchor: Tonight's health news story, as we said, is another example, in a string of them, of something we've been told was good for us but turns out not to be, at least according to the latest study. It was last night we began this broadcast with the news that some of those ubiquitous vitamin supplements may be more harmful for older women. Less than a week ago we were told the PSA , the benchmark prostate cancer test we've been told about for years, may not save lives after all. Where tonight there is more about prostate cancer , and the headline here is vitamin E may have exactly the opposite effect than most people taking it may think. The report tonight from our chief science correspondent, Robert Bazell .

ROBERT BAZELL reporting: Bill Roth started taking vitamin E regularly more than 20 years ago on his doctor's advice because he has a strong family history.

Mr. BILL ROTH: My father is a prostate cancer survivor. He's been battling prostate cancer now for about 20 years.

BAZELL: But vitamin E may actually increase risk for prostate cancer by 17 percent, according to results from the so-called SELECT trial of vitamin E and selenium that began in 2001 .

Conclusion: significantly increased the risk of prostate cancer among healthy men 35,533 Men

BAZELL: SELECT researchers followed 35,000 men who were taking one or both of the supplements or a placebo. This type of study is considered the gold standard of medical research.

Dr. ERIC KLEIN (Cleveland Clinic): I was surprised by the result of this trial. There was a substantial amount of evidence going into SELECT when it was designed in the early 2000s to suggest that vitamin E or selenium might actually prevent prostate cancer .

BAZELL: Much of the evidence comes from an idea popular at the time that because fresh fruits and vegetables have lots of vitamins called antioxidants that prevent against cancer and other diseases, that taking them in a pill form would provide even more protection. The SELECT trial was stopped in 2008 because the vitamins clearly weren't helping, but researchers continued to monitor the study subjects and found an increase in prostate cancer among those taking vitamin E. The final verdict on selenium is not in yet. Because vitamins and supplements are not regulated as strictly as medicines, some vitamin E bottles still advertise they promote prostate health.

Dr. KLEIN: Consumers should be skeptical about claims that are made on bottles or elsewhere.

Mr. ROTH: Nice.

BAZELL: Bill Roth stopped taking vitamin E as soon as he heard the latest results, and many doctors say others should do the same. Robert Bazell , NBC News, Chicago.