- Drinking lots of water is good for you. NOT TRUE. (Yes, this is a repeat from my last medical myths post, but it seems to be the one people are most skeptical about, so I think it bears repeating. I'm not lying, y'all.) This myth probably 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 (including caffeinated ones!) 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 some instances can actually kill you. The water myth is reprinted in every issue of every health and beauty magazine published, so I have little hope of it dying.
- Bedrest prevents preterm births. NOT TRUE. I know that it seems to make sense—it must help to "rest," right? And if you stand up, the baby might just fall out!—but studies have shown that it's useless. So why does nearly every OB in the country keep recommending it? Well, think about it. What if they didn't recommend it, and a baby is born prematurely? Yeah, they could be sued, but also, they'd feel awful. If they prescribe bedrest and the baby is born prematurely anyway, everybody says, "well, at least they did everything they could." And what you'll often hear is, "it may not help, but it can't hurt"—a saying that really lights my fuse. In fact, it can be harmful—scratch that: it almost always IS harmful. Maybe only slightly harmful, in that the mother becomes physically deconditioned and has a harder time with delivery and postpartum recovery, and in that the mother gets put out of work earlier than she may have wanted, but sometimes very harmful. I'll give you an illustrative anecdote: a woman who works in my institution as a secretary has preterm labor at twenty-some weeks, and was put on strict bedrest. Weeks and weeks. She nearly went crazy, but even worse, she developed a blood clot from inactivity. So she had to go on blood thinners to prevent her from dying from a blood clot to her lungs. And then had a terrible GI bleed from being on blood thinners and had to have a transfusion. So bedrest almost killed her TWICE. But did she even think about suing the doctors who prescribed bedrest? Of course not, because she believed that she had to do all of this for the baby's sake, and the baby was born healthy.
I think the bedrest myth is also harmful in that it adds to the fear that women of childbearing age might be a liability in the workforce. There's a doctor in my institution who is on her third month of bedrest, and the burden on her department is substantial. I wouldn't be surprised if they hesitate to hire the next 30-year-old woman who applies for a position. But god forbid a pregnant woman has any problems and DOESN'T go on bedrest. Oh, the guilt! I had preterm contractions (rather than true preterm labor, in which there are cervical changes), which has not really been shown to predict early delivery, but there are plenty of women who are guilted into bedrest for even this condition, and people tried it on me—"Don't you realize that your baby is more important than your job?" (Part of the whole infuriating pregnant-woman-as-vessel thing.) I was fortunate to have a super-smart OB who is also my good friend, so I had someone backing me up in refusing to be put to pasture, but few women are this lucky.
I think that the biggest obstacle to making people stop putting women on bedrest is that almost nothing has been shown to be effective in the long term to prevent threatened preterm delivery, and until there's something that CAN be done, it's very hard to get people to stop doing things that don't work. (There was a recent meta-analysis that old-fashioned progesterone might be helpful—keep your fingers crossed.)
- Taking lots of vitamins is good for you. NOT TRUE. Taking a regular multivitamin probably isn't a bad idea, but in most studies, high doses of vitamins have been shown to be either useless or harmful. (The studies that show possible benefits get lots of press; the later ones debunking them, very little.) Fat-soluble vitamins (A, D, and E) can build up in your tissues, causing hypervitaminosis. Water-soluble vitamins (the B vitamins and C) are generally excreted by your body if they're not needed, though they'll turn your pee nearly fluorescent. Folate (vitamin B9) helps prevent neural tube defects in embryos, but it's added to all grain products these days, so deficiency is much more rare than it used to be.
- Refined sugar is worse for you than honey. NOT TRUE. Sweet things in excess are bad for you, whether their sweetness comes from refined sugar, raw sugar, honey, fruit, high-fructose corn syrup, or whatever else is invented next. (I'm reserving judgment on artificial sweeteners for now, but kicking the sweet habit altogether is probably better than relying on these.) What do I mean by "in excess"? I can't describe it, but I know it when I see it. Or eat it.
- If something is herbal/all natural, it's safe. NOT TRUE. For all its faults, the FDA does do a fairly good job of ensuring that drugs that enter the marketplace are reasonably safe and effective. But the FDA is powerless over "nutritional supplements" and herbal medications. It's not that herbal remedies are necessarily useless; several prescription medications have been developed from herbs, in fact. It's that they are almost entirely unregulated. There is no guarantee that what is printed on the side of a bottle of, say, milk thistle is a true representation of what lies within, and plenty of evidence that it is often a gross misrepresentation. There are some real rip-offs out there. And some herbs are powerful poisons.
Somehow people started believing that doctors can't be trusted when we warn against natural remedies because we're biased against them. I'm not sure why we would be; we recommend plenty of things that don't require a prescription: a good diet, exercise, good sleep habits, quitting smoking. All of these things are all-natural and patient-initiated. And we'd love it if someone found a miracle cure for, well, anything, regardless of whether it required a prescription. I don't mind if a patient wants to try something herbal (in fact, I'll admit it, I'm happy if they get a placebo effect), as long as it's reasonably safe and not expensive. I just don't want my patients shelling out lots of money for anything that is useless and/or harmful.
Any more myths you'd like to have debunked?