Prostate Cancer Throws Vitamin E Another Strike

A tumor prevention trial is stopped early, marking yet another failure for antioxidants.

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Some 35,000 men who participated in a major prostate cancer prevention trial are in the process of getting this disheartening—yet not entirely surprising—letter in the mail from the National Cancer Institute. The message: Vitamin E and selenium, long buzzed about for their supposed prostate cancer-fighting properties, have flopped. Flopped hard.

Officials announced this week that they had accumulated enough data to conclude that taking vitamin E or selenium, or even both together, does not prevent prostate cancer. In fact, vitamin E may even slightly increase the risk. Leaders of the trial, called the Selenium and Vitamin E Cancer Prevention Trial, were also concerned to find that slightly more cases of diabetes arose among men who took selenium. And though officials emphasized to reporters that the increased number of prostate cancer and diabetes cases may have been a coincidence, they aren't taking any chances. That's why participants are being told to stop taking the supplements.

I can't say that I'm shocked. As I've mentioned in this blog before, we have been suffering from a certain degree of "vitamania" in the past few decades. Yes, some promising observational studies, which cannot prove cause and effect, done in the late 1980s and 1990s suggested that certain antioxidants, including vitamins A, C, and E, could protect against heart disease, cancer, and other maladies. But it turns out that those original antioxidant studies were misleading, a steady stream of more recent randomized studies that do prove cause and effect have shown. (If you're interested, New Scientist slogs through some of the disappointing findings on beta carotene, vitamin E, and vitamin C.)

In most instances, the clinical trials have shown that vitamins have no effect and, in some, that they may even cause harm. Still, with the passage of a permissive 1994 law called the Dietary Supplement and Health Education Act that allows manufacturers to sell supplements without first proving that they provide health benefits, consumers have been left with a booming supplement industry quick to offer us a slew of supplements for any and every ailment.

My advice: Be wary when you're wandering through that supplement aisle. It may be appealing to pop a supplement each day in the hope of staving off illness. But if history is any guide, researchers will continue to find that heavily hyped supplements don't work well when put to test, especially when used preventively. It's no wonder, really. Our bodies evolved to eat food—minimally processed plants, meats, and seeds—not megadoses of micronutrients.

And what should men do about prostate cancer? The last time I researched this topic, maintaining a healthy weight and taking finasteride seemed to have the strongest legs to stand on.