Vitamin E and Prostate Cancer: Is There a Connection?

One large federal study investigated the role of vitamin E on prostate cancer. Published in the journal of American Medical Association, it found that men who take vitamin E may be increasing their risk for prostate cancer by up to 17 percent.

Lead researcher, Eric A. Klein, MD, chair of the Glickman Urological Kidney Institute at the Cleveland Clinic explained what this means for the general population: "For every 1,000 men who take vitamin E, 76 will get cancer compared with 65 if they were taking the placebo," Klein explained in a press release.

Why this is the case isn't fully understood, according to Klein who cautions the public against using vitamin supplements as some sort of insurance policy. "Consumers tend to believe vitamins are innocuous substances and you can take them with impunity," Klein added. "Clearly that is not the case."

The Selenium and Vitamin E Cancer Prevention Trial—also know as SELECT—was a randomized trial that started in 2001. 35,000 men age 55 and older in the U.S., Canada, and Puerto Rico were divided into four groups each with a different daily diet supplement—vitamin E (400 IU/day), selenium (200 micrograms/day), both vitamin E and selenium, or a placebo pill.

Researchers said they expected the numbers of prostate cancer to be smaller in the group of men taking vitamin E since it has long been touted to offer protection against cancer, heart disease, dementia, and other health-related problems. But SELECT found the opposite result.

Given that other data suggest more than 50 percent of men 60 and older take supplements containing vitamin E and 23 percent take as much as 400 international units (IU) a day despite the recommended daily dietary allowance of only 22.4 IU, the study authors called the implications of the SELECT finding "substantial."

Healthy men who eat a normal diet may be better off than those who take supplemental vitamins. According to the researchers, there is no compelling evidence for taking vitamin E at this dose. "It doesn't provide any health benefits and the SELECT findings strongly suggest vitamin E increases your risk for getting prostate cancer," Klein reported in the press.

Researchers noted that among all the men in the trial, 529 men taking a placebo developed prostate cancer compared with 620 men taking vitamin E. An additional 575 men taking selenium and 555 men taking both supplements also developed the cancer.

Prostate Cancer 101

Prostate cancer accounts for about 10 percent of cancer-related deaths in men between the ages of 60 and 79 and nearly 25 percent in those over the age of 80, according to the American Cancer Society. The prostate, which is part of the male reproductive system, is a small gland located below the bladder and in front of the rectum. The fluid it secretes makes up part of the semen.

Interestingly, more men are diagnosed with prostate cancer than actually die from it. The fact is 1 in approximately 6 American men over the age of 50 will be diagnosed with prostate cancer in his lifetime and it kills roughly 1 in every 33 men over the age of 50.

Although the causes of prostate cancer are not entirely understood, there are known risk factors including:

  • Age—prostate cancer is rarely found in men younger than 40.
  • Smoking
  • Ethnicity—being African American doubles your risk.
  • Family history
  • Diet—some studies suggest antioxidants from soy, lycopene in cooked tomatoes, fish oil, and drinking green tea may help reduce the risk of developing prostate cancer.
  • Vasectomy
  • Vitamins and supplement regimen.

Critics of the SELECT study caution men currently taking vitamin E that the study looked at too many subgroups to effectively conclude that the risk for prostate cancer is more than chance.

Regardless of the findings, all experts agree that there's no substitute for living a healthy lifestyle. Eat a balanced diet, get plenty of exercise, and maintain a normal body weight. These habits are all solid preventive measures, and there's no disputing that.



Journal of the American Medical Association

National Institutes of Health

National Cancer Institute

The American Urological Association