Supplements Debunked for Prostate Cancer
Studies refute belief that certain supplements can reduce risk
(HealthDay News) -- Preventing prostate cancer apparently takes more than a vitamin supplement.
That's the conclusion of two large studies, involving more than 50,000 men, that found that supplements of selenium or vitamins E and C did not reduce the risk for prostate cancer.
"Our results showed no evidence of benefit from selenium and vitamin E on prostate cancer and other cancers," Dr. Scott Lippman, lead author of one of the studies, and a professor of medicine in the division of cancer medicine at M.D. Anderson Cancer Center in Houston, told HealthDay. The second study looked at vitamins E and C and found no benefit from either when it came to preventing prostate cancer.
Previous research had suggested that these nutrients, particularly selenium, might be helpful in preventing prostate cancer.
Lippman's study, known as the SELECT trial, included more than 35,000 men. Most of the men were older than 55, but it also included black men older than 50. The study included younger black men because, according to the American Cancer Society, blacks are more likely to develop prostate cancer than are men of other races.
During the five-year study, the men were randomly assigned to take selenium, vitamin E, selenium plus vitamin E or a placebo pill daily.
In the second study, which was conducted by Harvard researchers, nearly 15,000 men older than 50 were randomly assigned to take daily vitamin E, vitamin C or a placebo for about eight years.
Neither study found any convincing evidence that a single nutritional supplement was effective in preventing prostate cancer. Results of both trials were published in the Journal of the American Medical Association.
"Single-agent interventions, even in combinations, may be an ineffective approach to primary prevention in average-risk populations," wrote Dr. Peter Gann in an editorial on the findings, also published in the journal.
According to Andrew Shao, vice president of scientific and regulatory affairs for the Council for Responsible Nutrition in Washington, D.C., nutritional supplements are "not magic bullets, though they do have tangible effects."
But, he added, "it would be a mistake to look at one trial that answers a very specific question and say these nutrients don't work at all."
Lippman said he doesn't advise anyone to use supplements for cancer prevention. "There's no evidence to support taking these," he noted.
This isn't the first time that nutrients have disappointed in the prostate cancer field. Some years ago, the natural substance known as lycopene (found in tomatoes, pink grapefruit and watermelon) was touted as being prostate cancer-preventive. However, more recent research has failed to confirm that benefit, according to the American Cancer Society.
Some researchers have now turned their attention to the soy proteins known as isoflavones, with the hope that soy can help prevent prostate cancer. Studies are currently ongoing, according to the society.
On the Web
Learn more about prostate cancer from the U.S. National Cancer Institute. http://www.cancer.gov/cancertopics/wyntk/prostate
SOURCES: HealthDay News; Scott Lippman, M.D., professor, medicine, Department of Cancer Prevention, M.D. Anderson Cancer Center, Houston; Andrew Shao, Ph.D., vice president, scientific and regulatory affairs, Council for Responsible Nutrition, Washington, D.C.; Jan. 7, 2009, Journal of the American Medical Association; American Cancer Society (www.cancer.org)
Author: Serena Gordon
Publication Date: Jan. 31, 2010
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