The burning question in the news last week was this: should you bother flossing?
The answer for decades has been “of course.” And it’s likely you’ve heard something similar from your dentist. I know I have.
But, while the importance of flossing may have been widely accepted, the evidence supporting it turns out to be surprisingly thin. At least that’s the conclusion of health experts who developed the recently released Dietary Guidelines for Americans, 2015-2020. These guidelines are issued every five years by the U.S. Department of Health and Humans Services and the U.S. Department of Agriculture “…to reflect the current body of scientific evidence on nutrition, food, and health.” The 2010 edition included this sentence:
“A combined approach of reducing the amount of time sugars and starches are in the mouth, drinking fluoridated water, and brushing and flossing teeth, is the most effective way to reduce dental caries.”
But, the latest edition leaves this sentence out. That’s because the authors of these guidelines could not find convincing evidence to support flossing, and the guidelines are supposed to be evidence-based. According to reviews of the evidence published in 2011 and 2015, there is minimal, short-term, and generally unreliable evidence that flossing might reduce gum inflammation, but no convincing evidence that it promotes plaque removal or prevents tooth decay or dental caries (cavities).
Is the lack of evidence for flossing big news?
I’ve seen several eye-grabbing headlines regarding this development, including:
- “Feeling Guilty About Not Flossing? Maybe There’s No Need” (New York Times)
- “Guilty No More: Flossing Doesn’t Work” (Mother Jones)
- “A big problem with flossing” (CBS News)
It is surprising to learn that there is so little evidence to support such a well-accepted bit of health dogma. Yet, there may be less here than meets the eye.
In fact, I think these headlines (and some of the comments I’ve heard from friends and family) miss the mark on this flossing kerfuffle. There’s a saying in the science world that “absence of proof isn’t proof of absence.” That is, just because the evidence isn’t there doesn’t mean an idea is wrong. Unproven is unproven, not disproven!
A cousin emailed me to say “Good, now I can feel less guilty about not flossing.” I’m all for people feeling empowered with their health decisions (especially if they are well-informed). But the experts who removed the flossing recommendations from the dietary guidelines did not find