Flossing your teeth at least once a week might do more than just protect your gums — it could help lower your risk of stroke and irregular heartbeats, according to a new preliminary study.
The research, led by Dr. Souvik Sen and his team at the University of South Carolina School of Medicine, will be presented at the American Stroke Association’s International Stroke Conference 2025, a major gathering of experts in brain and heart health.
Poor oral health is one of the most widespread health problems worldwide. In fact, a recent global report showed that about 3.5 billion people suffered from untreated tooth decay or gum disease in 2022.
Since oral inflammation has been linked to overall inflammation in the body, the study aimed to find out which dental habits—like brushing, flossing, or visiting the dentist—had the strongest connection to stroke prevention.
To explore this, researchers used data from the long-running Atherosclerosis Risk in Communities (ARIC) study. This U.S.-based study collected information from more than 6,000 people who answered detailed questions about their dental hygiene habits. The focus was on flossing, and researchers compared it with brushing frequency and dentist visits.
Out of the participants who flossed, 4,092 had not had a stroke, and 4,050 had not been diagnosed with atrial fibrillation (AFib), a common heart rhythm problem that can lead to strokes.
Over 25 years of follow-up, 434 participants had strokes — including 147 caused by large clots in major brain arteries, 97 caused by clots from the heart (cardioembolic), and 95 from the narrowing of smaller brain arteries. During the same period, 1,291 people developed AFib.
The results showed that people who flossed regularly had:
- 22% lower risk of ischemic stroke (caused by blocked blood flow to the brain),
- 44% lower risk of cardioembolic stroke (when a clot travels from the heart to the brain),
- 12% lower risk of developing AFib.
Even more surprising, these benefits were independent of other dental habits like brushing and routine dentist visits. The more frequently people flossed, the greater the potential benefit appeared to be. Flossing was also linked to fewer cavities and less gum disease.
Researchers believe the link may lie in inflammation. Poor oral health can lead to gum infections, which may cause long-term inflammation in the body. This inflammation could contribute to the hardening of arteries, irregular heart rhythms, and eventually strokes. Flossing may help prevent these problems by reducing inflammation-causing bacteria in the mouth.
“Flossing is an affordable, easy, and widely available habit,” said Dr. Sen. “Our study suggests that even something as simple as flossing once a week might offer significant protection against serious health problems like stroke and AFib.”
Still, there are some limitations to the study. The data on flossing was based on participant self-reports at the beginning of the study, and the researchers didn’t track changes in dental habits over the 25-year follow-up. They also focused only on stroke and heart-related outcomes, not ongoing oral hygiene behaviors.
Despite these limitations, experts say the findings are worth further exploration. Dr. Daniel T. Lackland, a stroke expert at the Medical University of South Carolina who was not involved in the study, said, “This research gives us new insight into how specific dental habits may affect stroke risk. With more evidence, flossing and other oral health practices could one day become part of the standard advice for reducing cardiovascular risk.”
In short, while brushing and dentist visits are still important, flossing — a quick, inexpensive, and often overlooked part of daily hygiene — may offer real benefits for your heart and brain.
If you care about tooth health, please read studies about an important causes of tooth decay and gum disease, and common tooth disease that may increase risks of dementia.
For more health information, please see recent studies about mouthwash that may increase your tooth damage, and results showing this diet could help treat gum disease.
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