A recent article in the British Medical Journal about seven medical myths even doctors believe generated a lot of media buzz — and got me wondering about the veracity of several other medical truisms. So I asked some local doctors to set the record straight on what’s hogwash and what’s accurate.
People should drink at least eight glasses of water a day. False with a capital “F.” While water is essential to life, too much can actually lead to death. Documented cases of death from water intoxication include a woman who drank too much, too fast as part of a radio contest, a college student who similarly imbibed an excessive amount too quickly as part of a fraternity hazing, and several marathoners. “We need about four to six quarts of fluid a day,” says Stanley Goldfarb, a kidney specialist and professor of medicine at Penn’s School of Medicine, “but we don’t need to drink water to satisfy that. Typically, all the liquid in our normal diet — coffee, tea, soup, soda, juice, even food itself — is enough.”
Buying glasses weaker than your prescription will keep you from needing stronger glasses later. “There is no good evidence to support this,” says Jefferson Medical College professor Michael Naidoff. The pace and progression of myopia (nearsightedness) and presbyopia (age-related reading problems) are totally independent of the strength of your prescription glasses. Ditto for the myth that carrots are good for the eyes. Naidoff says people might believe it because the beta-carotene in carrots is similar to a compound found in the retina, but adds that we get enough of what we need from our regular diet.
Super Glue can heal wounds. This is actually true — Super Glue has the same active ingredient as prescription medical glues. It became popular during the Vietnam War when medics turned to it to seal battlefield injuries on men headed for the OR. And occasionally, doctors will recommend Super Glue to seal badly cracked skin on heels and fingers, says Joel Gelfand, assistant professor of dermatology at the University of Pennsylvania. “But,” he cautions, “even though it works, it should absolutely not be used on cuts, because it isn’t sterile and can lead to infection or a potentially bad scar.”
White meat is healthier than dark meat. If you’re like me and always feel a tad guilty asking for the thigh at Thanksgiving dinner, you’ll be happy to learn that the Department of Agriculture says the nutritional differences between white and dark meat are minimal, assuming you don’t eat the skin. Dark meat is dark simply because it has myoglobin, the protein that carries oxygen to muscles. Flightless birds have dark, muscular leg meat from walking around their yards. The FDA says an ounce of skinless turkey breast has about 46 calories with one gram of fat; the same amount of dark meat contains 50 calories with two grams of fat — and that includes the healthy Omega-3 variety. Moreover, dark meat has more vitamins and minerals than white meat.
A little alcohol can help cure a cold. Not only can a hot toddy or shot of whiskey make you feel less miserable — they help keep colds at bay. One study at Carnegie Mellon found that moderate drinking increased resistance to colds. Another study, of 4,300 healthy adults in Spain, published in the American Journal of Epidemiology, concluded that eight to 14 glasses of wine a week — especially red wine — gave subjects a 60 percent reduction in the risk of getting the sneezes.
Avoid hospitals on weekends. Several studies have confirmed that this is, in fact, advice worth heeding. One examined records of heart attack victims in New Jersey hospitals and found those who checked in on the weekend tended to have less aggressive treatment and marginally higher death rates; another looked at patients who had non-emergency surgeries on Fridays and found they were 17 percent more likely to die in the next 30 days than people operated on earlier in the week. Sometimes Dr. Mom is right!