Medical myths even doctors believe

In a study entitled “Medical Myths Even Doctors Believe” published in the Christmas issue of the British Medical Journal, Indiana University School of Medicine researchers explored seven commonly held medical beliefs.

The researchers explored various myths including:

* People only use 10 percent of their brains
* Hair and fingernails continue to grow after we die
* Eating turkey makes you sleepy

These beliefs are commonly accepted, not only by the general population, but also by many physicians. The authors’ surprising findings, when they reviewed medical literature – all the beliefs were unproven or untrue.

"We got fired up about this because we knew that physicians accepted these beliefs and were passing this information along to their patients. And these beliefs are frequently cited in the popular media. We didn’t set out to become myth busters,” said co-author Aaron Carroll, M.D., M.S., assistant professor of pediatrics and a Regenstrief Institute, Inc. affiliated scientist.

“Whenever we talk about this work, doctors at first express disbelief that these things are not true. But after we carefully lay out medical evidence, they are very willing to accept that these beliefs are actually false,” said co-author Rachel Vreeman, M.D., a pediatrics research fellow.

The first belief they explored - people should drink at least eight glasses of water a day. This advice has been promoted as healthful as well as a useful dieting or weight control strategy.

“When we examined this belief, we found that there is no medical evidence to suggest that you need that much water,” said Dr. Vreeman. She thinks this myth can be traced back to a 1945 recommendation from the Nutrition Council that a person consume the equivalent of 8 glasses (64 ounces) of fluid a day. But an important part of the Council’s recommendation has been lost over the years - the large amount of fluid contained in food, especially fruits and vegetables, as well as in the coffee and soda people drink each day should be included in the recommended 64- ounce total. Drinking excess water can be dangerous, resulting in water intoxication and even death, the study authors note.

Dr. Vreeman and Dr. Carroll also explored the popular belief that we use only 10 percent of our brains. Frequently cited by everyone from physicians to comedians (Jerry Seinfeld) and erroneously credited to Albert Einstein, the authors found that there are a lot of ways to disprove this belief. MRI scans, PET scans and other imaging studies show no dormant areas of the brain, and even viewing individual neurons or cells reveals no inactive areas of the brain. Metabolic studies of how brain cells process chemicals show no nonfunctioning areas.

Dr. Carroll and Dr. Vreeman think this myth probably originated with self improvement experts in the early 1900s who wanted to convince people that they had yet not reached their full potential. With the help of these self proclaimed experts (perhaps the descendents of snake oil salesmen), one could tap into the 90 percent of the brain supposedly not being used.