Although physician-scientists and supplement manufacturers are often at odds, they don’t spend much time sparring over multivitamins. In fact, half the physicians on the Harvard Men’s Health Watch advisory board report taking a multivitamin themselves. In recent years, Harvard Men’s Health Watch has also endorsed these popular supplements, reasoning that even if they don’t help, they won’t hurt. However, the March 2008 issue of the newsletter states that a reappraisal of that advice is in order.
Harvard Men’s Health Watch notes that some recent studies have linked multivitamin use to prostate cancer. More convincingly, studies have linked high intakes of folic acid to colon polyps, the precursors of colorectal cancer. Researchers speculate that high intakes of folic acid, which was first added to grain products in the 1990s, may have contributed to an increase in colorectal cancers in the mid-1990s.
What does all of this have to do with multivitamins? Now that folic acid is added to so many grain products, it’s easy to see how a healthy diet, combined with a multivitamin, could boost a person’s daily intake to 1,000 mcg or more, potentially increasing the risk of colorectal and possibly prostate and breast cancers.
In light of this research, Harvard Men’s Health Watch suggests that the average man give up the multivitamin, at least until scientists solve the puzzle of folic acid and cancer. However, if you stop taking a multivitamin, consider taking a vitamin D supplement, the newsletter says. The typical diet for most men and women doesn’t supply enough of this crucial vitamin, and while sun exposure boosts vitamin D production, it has health risks of its own.