When Myth Trumps Science

Those illusory correlations seem particularly strong with one of the more controversial myths that Vreeman and Carroll debunked that sugar causes hyperactivity in children (it doesn't). There's a slew of double-blinded, randomized trials that have shown no connection between sugar consumption and a child's increase in energy. "For that one, anecdote seems to trump science," says Carroll. "They don't care how many good studies are out there, they've seen it happen with their child so they know it must be true." Carroll suspects that parents will often associate situations with sugar a birthday party, for example with hyperactivity and immediately identify sugar as the culprit, rather than considering the other factors that could cause a burst in energy.

Medical myths usually stick around because no one's on a public-health crusade to set the record straight. Of all the battles to pick in health care, chances are convincing Americans that they don't need to have eight glasses of water is nowhere near a top priority. And if parents restrict their child's sugar intake because they're worried about hyperactivity, is it really all that bad? "For a lot of these things, the danger is negligible," says Carroll. "Let's say my mom knew reading in the dark was okay, so I would have gotten to read in bed more. But in the end, who really cares?"

There are, however, a few in their book though that the authors believe are worthy of a public-health crusade, particularly the supposed link between vaccines and autism that has not been validated by the research. Yet, believers may be inclined to overlook the science in favor of anecdotal evidence. (Think Jenny McCarthy's appearance on Oprah during which she describes watching her son, who has autism, get a vaccine and seeing the "soul gone from his eyes.") "People want to understand the world so they latch onto a reason," says Carroll. "We all know autism incidence is increasing and it's devastating. People looked for a pattern and when one emerged, they grabbed it." But it frustrates Carroll, a pediatrician by practice, that this medical myth not only misleads parents but also distracts the autism community. "Nothing would please me more than to find a cure for autism," he says. "Every dollar we sink into trying to combat these myths could be put towards research."

Will their book rid the world of medical myths and set the record straight? Carroll and Vreeman are realistic about their prospects and aren't on a crusade to end the eight-glass myth. It's instinctual to make sense of the patterns we see, to assign some kind of order to the mystifying connections that continually occur around us. Medical myths, however inaccurate they may be, will continue to persist because they make complicated material a little bit easier to wrap our heads around. So the authors don't expect their readers to come away form the book with a complete medical education, but rather a willingness to question their doctor's expertise. "I consider it a success if we got a few people to ask why," says Carroll. "If we empower patients to ask why, do we have to do this." It's a prescription that's probably good for any patient, regardless of how much water they're drinking.

© 2009