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Can something as simple as flossing your teeth actually reduce your risk of having a stroke? The headlines certainly make it sound like a breakthrough. Some recent news stories claim flossing can reduce stroke risk by as much as 50%, especially for certain types of strokes. But is this true—or is it another case of sensational science reporting? As with many health headlines, the reality is more nuanced.

Let’s break down what we know, what’s still speculative, and how to think critically about studies like this one.

A Catchy Headline—But Is There Substance Behind the Claim?

The media buzz started with a presentation at the American Stroke Association’s International Stroke Conference in 2025. According to reports from sources like the New York Post, The Times UK, and San Francisco Chronicle, researchers presented findings from the Atherosclerosis Risk in Communities (ARIC) study suggesting that individuals who floss regularly had a 20% to 50% lower risk of stroke—particularly ischemic and cardioembolic types.

You’d be forgiven for thinking this was definitive proof that flossing saves lives. But let’s pause.

Understanding the Study—and Its Limits

The ARIC study is a long-term observational cohort following over 6,000 people for more than 25 years. In this dataset, about 65% of participants reported flossing regularly. Those who did had significantly fewer strokes. Sounds promising, right?

Except the study is not yet peer-reviewed. It was only presented in abstract form at a conference. That means no other scientists have had a chance to fully examine the methods, check for errors, or verify the findings. And it’s important to remember that correlation doesn’t equal causation. As the American Heart Association has clearly noted, while observational studies link oral health and cardiovascular disease, they do not prove that improving oral health prevents heart attacks or strokes (AHA Statement). If interested, here are other examples and discussion around health headlines.

Is There a Biologically Plausible Link Between Flossing and Stroke?

Yes—and that’s where things get interesting.

We carry about a billion bacteria in our mouths. When we brush, chew, or floss, those bacteria can enter the bloodstream. Once there, they might trigger inflammation, which has been linked to cardiovascular issues, including heart attacks and strokes. In fact, higher levels of inflammation, as measured by markers like CRP (C-reactive protein), are associated with a greater risk of heart disease (study). Encouragingly, research shows that improving oral health can lower these inflammatory markers (study).

So the theory holds water: better oral hygiene could reduce inflammation, which in turn could reduce cardiovascular risk. Other ways to reduce risk are discussed here.

But Here’s the Catch: No Clinical Trials

As of today, there are no randomized controlled trials (RCTs)—the gold standard of medical research—that test whether flossing prevents strokes. Observational data can raise good questions, but without controlled trials, we can’t draw firm conclusions.

To evaluate these kinds of claims, scientists often use a framework called the Bradford Hill criteria. These include questions like: Is the association strong? Is it consistent across studies? Is there a dose-response relationship? Is it biologically plausible?

In this case:

• The association is fairly strong.
• It is biologically plausible.
• But it hasn’t been replicated, nor have we seen dose-response data (i.e., does flossing more frequently reduce risk further?).
• And again, the data isn’t peer-reviewed or published.

Where the Evidence Stands—and What You Can Do

The link between oral health and cardiovascular disease remains biologically plausible and supported by observational evidence—but not yet proven. The connection between flossing and stroke specifically? Intriguing, but unconfirmed.

That said, maintaining good oral hygiene is still one of the simplest ways to support your health. According to one study, people who brush twice a day had a significantly lower risk of heart disease than those who brushed less frequently (study). And flossing, while not universally practiced—only about one-third of Americans floss daily (CDC data—remains a key strategy in reducing gum disease and improving overall mouth health.

My Take?

I brush twice a day and floss nightly. I also use a water jet and mouthwash. Not because I’m convinced it’ll prevent a stroke—but because I know it improves my oral health, which is valuable in its own right.

Whether or not flossing reduces your stroke risk, your gums and your future self will thank you for keeping your mouth healthy.

Health headlines are often more hype than help. The best approach? Stay curious, look at the evidence, and ask good questions. Flossing is a low-risk, low-cost habit that could have broader health benefits—but let’s wait for the science to catch up before calling it a miracle.

Until then, floss because it’s good for your gums. And if it helps your heart or brain too? That’s a bonus.