The study you refer to, called SELECT, was launched in 2001 to follow up on evidence from earlier research suggesting that selenium and vitamin E might reduce the risk of prostate cancer. More than 35,000 men at 400 locations in the U.S., Canada and Puerto Rico enrolled between 2001 and 2004 and participated in the study. Some took 400 IU of vitamin E daily, some took a combination of vitamin E and selenium, some took selenium alone and some were given placebos. This was a double-blind, placebo-controlled trial, meaning that neither the participants nor the researchers knew which men were getting which supplement and that results of each arm of the trial could be compared to those from the control group, where participants received placebos.
Long term follow up results were recently published in the October 12 issue of the Journal of the American Medical Association, and reported that there were 17 percent more cases of prostate cancer among men who took vitamin E alone than among the men who took the placebo.
The SELECT trial results on selenium aren't in yet, so we'll have to wait and see whether or not they're any better than the vitamin E findings.
The initial SELECT findings on vitamin E, published in 2009 in the Journal of the American Medical Association, suggested that taking vitamin E or selenium did not protect against prostate cancer (the new data just published showed the 17 percent increase in prostate cancer among men who took 400 IUs vitamin E daily).
On the basis of the 2009 data, we removed the extra vitamin E from my Prostate Support Formula almost two years ago. Unfortunately, the SELECT trail failed to actually give vitamin E to participants, and only provided one component, dl-alpha-tocopherol. The best conclusion we have at present is that taking this isolated form of the vitamin may not be beneficial to prostate health. Because vitamin E remains important to overall health, I recommend that you make an effort to get it through your diet and a daily antioxidant formula which contains a mixture of both tocopherols and tocotrienols, all eight of the compounds that make up natural vitamin E. Dietary sources of vitamin E include almonds, sunflower seeds, peanut butter, spinach, broccoli, kiwi fruit and mangoes.
Andrew Weil, M.D.