The News: Supplements, Cancer Risk, and Health

When studies are continuously finding evidence of how a vitamin, mineral or phytonutrient can help our health, it’s tempting to assume more is better. But no, suggests a growing body of evidence. The past few days have seen a flurry of studies on the possible harms linked to supplements, with one of the largest focused on cancer.

The new cancer-supplement study looked at vitamin E and selenium’s link to prostate cancer.

Years ago, researchers hypothesized that these two supplements would protect against prostate cancer — and other diseases. A large study of almost 35,000 men turned up no reduction in risk but a hint of an increase in risk with vitamin E. That study began a decade ago and the results were published in 2008.

This new study continued to follow the 35,000 men though July of this year. The men had taken daily supplements for three years beginning in 2001. They were randomly assigned to take either vitamin E, selenium, both, or a placebo. Compared to those who had taken a placebo, the men who had taken vitamin E had a 17 percent increased risk of developing prostate cancer. No link was found with selenium.

The findings suggest the health effects can continue even after men stop taking the supplement.

The study was published in JAMA; here’s the abstract.

Another large new study focused on older women. Here, researchers found that several commonly-used supplements linked to an earlier death.

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