Evidence-Based Standards Should Apply to Dietary Supplements, Too

Dan Hurley


July 30, 2007

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Evidence-based medicine is the rallying cry of a generation of physicians. So why do so many physicians ignore the evidence when it comes to dietary supplements?

Today, 73% of US adults use some kind of supplement at least once a year, according to a recent FDA-sponsored survey.[1]

Much of that use can be traced to physicians' practices. Many children -- my own daughter included -- are prescribed a chewable multivitamin by their pediatrician. Yet no major medical group or government agency recommends them for otherwise healthy children or adults, because evidence-based reviews have found no benefit. Indeed, a review in the Journal of the American Medical Association concluded that antioxidant vitamins slightly raise the risk of premature death.[2] Another study, just published on May 15, found that heavy multivitamin use in men increases the risk of advanced or fatal prostate cancer.[3]

Beyond vitamins, some physicians even recommend herbal remedies and specialty supplements.[4] Yet randomized trials supported by the National Center for Complementary and Alternative Medicine have concluded that glucosamine-chondroitin does not relieve arthritic pain,[5] that echinacea does not prevent colds,[6] that black cohosh and other herbs do not relieve the symptoms of menopause,[7] and that saw palmetto does not relieve benign prostate hyperplasia.[8]

The evidence for potential harmfulness, meanwhile, grows ever stronger. Since 1983, the American Association of Poison Control Centers has tallied more than 1.6 million reports related to the use of supplements, including 251,799 serious enough to require hospitalization.[9]

While only a minority of physicians recommend herbs, surveys show that most fail to even raise the subject when taking a history.[10] As a result, case reports of interactions with prescription medications have become commonplace in the medical literature.[11]

It's time for physicians to face [the fact] that the majority of their patients use supplements. They need to ask all their patients about them -- Do you take vitamins? Do you take any herbs or other supplements? -- and apply evidence-based standards in discussing their merits.

That's my opinion. I'm Dan Hurley, medical journalist and author of Natural Causes: Death, Lies and Politics in America's Vitamin and Herbal Supplement Industry.

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