Why Medical Advice Seems to Change So Frequently
Take your medical news and recommendations with a dose of healthy skepticism, especially regarding nutrition.
By Aaron E. Carroll
Jan 16 2017
Medical scientists and academics must publish their research to advance. Medical organizations must release health recommendations to remain relevant. News organizations feel they must report on research and recommendations as they are released. But sometimes it’s hard to separate what’s truly a medical certainty from what is merely solid scientific conjecture.
I thought about this recently when the National Institute of Allergy and Infectious Diseases expert panel changed course and recommended that we start giving babies peanut powder or extract in food before they are six months old rather than make sure they go nowhere near it. The panel said this is good advice, especially if the babies are at higher risk for developing an allergy.
I’ve written about the research supporting these new recommendations before. A recent well-designed study showed that infants exposed to peanut protein developed significantly fewer peanut allergies than those who were not. The measurement, called number needed to treat (N.N.T.), was powerful: For every seven infants exposed to peanut protein, one fewer developed allergies. In the high-risk population, for every four infants exposed, one fewer became allergic. Those numbers are stunning.
But it’s important to remember that the earlier recommendation wasn’t made in the Dark Ages. As recently as 2000, the American Academy of Pediatrics declared that children at risk for allergies be given no peanuts until they were 3 years old. It’s not unrealistic to think that this might have increased the number of children with peanut allergies, not decreased them.
This isn’t an isolated incident. As a pediatrician, I’m more aware of the academy’s recommendations than those of some other medical organizations, and I’ve taken to The Upshot to discuss their statements on car seats on planes, the use of retail clinicsand where babies should sleep. In each case, I’ve expressed concerns that the recommendations, which were not supported by strong evidence, may be doing more harm than good.
The American Academy of Pediatrics isn’t acting in bad faith, though, nor is it alone. Recommendations from other medical organizations for mammograms, which weren’t supported by well-designed randomized controlled trials but for years went unchecked, are now being scaled back because of concerns that they may be leading to bad outcomes without compensating benefits.