Vitamin E supplements and prostate cancer risk in healthy men
What it found
Men taking 400 IU of vitamin E daily had a 17% higher chance of being diagnosed with prostate cancer compared to those taking a dummy pill.
The extra risk started to appear about two years into the trial.
What they found
Studies in people
Higher prostate cancer risk
Out of every 1,000 person-years, there were 1.6 more prostate cancer cases in the vitamin E group than in the dummy pill group. In total, 620 men on vitamin E developed prostate cancer compared to 529 on the dummy pill.
No benefit from combining supplements
Taking selenium together with vitamin E did not raise prostate cancer risk in the same way. The authors suggest selenium may have blocked the extra risk seen with vitamin E alone.
Cancer grade and survival
The types and stages of prostate cancer found were similar across all groups. There was no difference in overall survival between men taking vitamin E, selenium, both, or dummy pills.
Other cancers and heart events
Longer follow-up showed no benefit from either supplement for preventing lung cancer, bowel cancer, or serious heart problems. There was also no difference in deaths from any cause.
When the risk appeared
The higher rate of prostate cancer in the vitamin E group became clear during the third year of the trial. The gap between the groups grew slightly larger each year after that.
What the authors conclude
- They conclude that taking 400 IU of vitamin E daily significantly raised the risk of prostate cancer in healthy men.
- They advise consumers to be skeptical of health claims made for over-the-counter supplements without strong proof from clinical trials.
- They also warn that vitamins are biologically active and can cause harm at high doses.
How it was done
Prostate cancer is very common, and treating it can cause serious side effects and high costs. Earlier research suggested selenium and vitamin E might lower the risk, so scientists set up this large trial to test that idea.
Researchers assigned 34,887 healthy men across the United States, Canada, and Puerto Rico to take selenium, vitamin E, both, or dummy pills. Men took 400 IU of vitamin E or 200 μg of selenium each day. They were followed for up to 12 years to see who developed prostate cancer.
What it can’t tell you
- This trial only included men, so it cannot show what happens in women or children.
- It tested one specific dose and form of vitamin E, so results might differ for other amounts or types.
- The researchers do not yet know the biological reason why vitamin E raised the cancer risk.
Who paid
- Funding
- Funded by NCI NIH HHS (from the PubMed record).
- Authors work at
- Glickman Urological and Kidney Institute, USA
The paper
- Title
- Vitamin E and the risk of prostate cancer: the Selenium and Vitamin E Cancer Prevention Trial (SELECT)
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Klein EA, Thompson IM, Tangen CM, et al (2011). Vitamin E and the risk of prostate cancer: the Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA. doi:10.1001/jama.2011.1437Free full textPubMed 21990298DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error