- Green mucus = go to the doctor. NOT TRUE. Somewhere, somehow, someone started the myth that while it's ok to have clear or white snot or phlegm, green snot is an ominous sign, and means that you must seek medical attention, quick! In fact, any run-of-the-mill respiratory virus can produce a whole palette of lovely snot shades, from palest ivory to pea-soup green. This has been studied; color of sputum has never been shown to indicate whether an infection is viral or bacterial. (And the vast, vast majority of illnesses that cause you to cough up nasty greenies are viral.) There is a type of pneumonia that can cause rust-colored sputum, but we don't see this much, and in those cases the sputum alone is not the only clue as to what's going on. Yet doctors keep on asking patients about the hue of their snot, and every magazine article about respiratory infections says, "you don't need to see the doctor unless you have green phlegm."
- "It's just a virus." And its corollary, "you don't need antibiotics." NOT TRUE. Patients get frustrated when they go to the doctor feeling lousy and are told the above, and they should; they're really sick, and they shouldn't be told they're not. Viruses are bad; viruses can kill you, or at least make you wish you were dead. We don't give antibiotics for them because the antibiotics we have, with the exception of a couple of flu medicines, don't work on viruses, not because you don't "need" them. Believe me, if and when an anti-cold virus antibiotic is developed, we will be using it. (Of course, you won't have to take these hypothetical antibiotics, but then, you don't have to take antibiotics for bacterial infections, either. Yes, you can survive many bacterial infections without antibiotics.)
- High blood pressure gives you headaches. NOT TRUE. Studies such as this, this and this have repeatedly shown that this is not true, yet patients and doctors continue to believe it. The problem with this is twofold: patients may assume that if they don't have a headache, their blood pressure must be ok, and patients don't get their headaches adequately treated.
- Drinking lots of water is good for you. NOT TRUE. This one really gives me a headache. I think it started because of a misunderstood study long ago that the average amount of water a person uses for the business of existing for 24 hours is equal to about 8 eight-ounce glasses of water. The misunderstanding is that this is not EXTRA water; it's the water that already exists in all the foods and beverages a person takes in during the day. Thirst is actually a wonderful mechanism for telling you how much water you need. Extra water does not benefit you. It doesn't help constipation, it doesn't help your skin, it doesn't benefit your kidneys (unless you have kidney stones), it doesn't help you exercise. Perhaps it helps some people avoid eating and drinking a lot of fattening junk, but this is questionable. What it DOES do is make you pee constantly, and in severe instances can actually kill you. If you're truly dehydrated, you don't need water, you need water plus electrolytes. The water myth is reprinted in every issue of every health and beauty magazine published, so I have little hope of it dying.
- Coffee is bad for you. NOT TRUE. People have been trying to prove this for decades, and they haven't been able to do it convincingly. (Which means that there have probably been a lot of unpublished studies that showed no harm.) In fact, there's evidence that coffee may be good for you. Now, plenty of people don't tolerate caffeine well, but for those who do, drink up!
Friday, January 20, 2006
Five medical myths I wish would die a horrible death: