Regular flossing may do more than improve oral health ? it could help stave off stroke, suggests new research.

Flossing at least once weekly was significantly associated with a 22-percent lower risk of ischaemic stroke (adjusted hazard ratio [aHR], 0.79) and a 44-percent lower risk of cardioembolic stroke (aHR, 0.56). Additionally, flossing reduced the risk of atrial fibrillation (AF) by 12 percent (aHR, 0.88).

“We knew that flossing regularly lowers body inflammation and oral infection. Now, our study showed that flossing can reduce the rate of stroke, atrial fibrillation, and cardioembolic stroke,” said study investigator Dr Souvik Sen, professor and chair, Department of Neurology, University of South Carolina School of Medicine in Columbia, South Carolina, US.

Do you floss, and how often?

Sen and his team sought to determine which oral hygiene behaviour ? dental flossing, brushing, or regular dentist visits ? impacts stroke prevention the most by analysing data from 6,278 participants in the Atherosclerosis Risk in Communities (ARIC) study, a large-scale investigation in the US to study heart health. They were asked if they flossed, how often they did, and how frequently they visited a dentist. They also reported vascular risk factors and socio-demographic features. [ISC 2025, abstract 19]

There were 4,092 flossers and 2,186 non-flossers, with more women in the flosser group than the nonflosser group. More than 31 percent of flossers had hypertension and 11.7 percent had diabetes, compared with 36.3 percent and 16.1 percent, respectively, of the non-flossers.

Stroke risk down regardless of brushing habits

During the follow-up period, 434 strokes were identified. Of these, 147 were thrombotic, 102 cardioembolic, and 95 lacunar subtypes. Additionally, 1,291 participants experienced AF.

After 25 years, individuals who flossed regularly experienced a significant reduction in stroke risk, independent of their brushing habits or frequency of dental visits. Flossers also had significantly higher high-density lipoprotein (HDL) levels and significantly lower levels of periodontal disease and dental caries. Increasing the frequency of flossing also enhanced its protective effects.

Sen said flossing removes food particles and plaque stuck between the teeth and cleans the gums better than brushing. He added that plaque can cause gum disease and tooth decay, leading to inflammation. “Inflammation has been tied to hardening of the blood vessels, or atherosclerosis, and that leads to heart attack, and based on our study, stroke and irregular heartbeat.”

“The results are above and beyond taking care of your oral health and suggest that flossing has an additional impact,” Sen pointed out.

Easy to adopt and affordable

“Flossing is a healthy habit that is easy to adopt, affordable, and accessible everywhere. It could play a key role in preventing life-altering health events as part of a broader stroke prevention strategy, particularly in areas with poor access to dental care,” he added.

Commenting on the study, Professor Daniel Lackland from the University of South Carolina in Columbia, South Carolina, US, who was not involved in the study, said the finding offers more insights into the specific dental health behaviours that may be linked to stroke risks and potential risk reduction. “With further research, dental health practices could possibly be incorporated into the ‘Life’s Essential 8’ risk factors, which include diet, physical activity, nicotine exposure, sleep, BMI, blood pressure, blood glucose, and blood lipids.”

While the study is promising, he said more studies are warranted to fully understand the health benefits of flossing.