Oral health isn’t just about your smile—it could help protect your heart, too. A new study finds an unexpected heart health habit can be that regular flossing reduces stroke risk.

Dr. Souvik Sen is the Chair and Professor of Neurology at the University of South Carolina School of Medicine Columbia and Prisma Health Midlands. His study included 6,278 participants who answered questions about home use of dental floss, and around 65 percent of participants reported flossing at least once a week. These participants were followed for 25 years. 

Here, Dr. Sen explains that if you’re skipping out on flossing, you could be putting your heart at risk.

Please tell us the general findings of your study.
This was done as a part of a large cohort study called an ARIC (Atherosclerosis Risk in Communities) study, conducted out of the United States. What it showed was dental flossing leads to reduced risk of irregular heartbeat and ischemic stroke. It further showed that with increased frequency of flossing there was a higher reduction of stroke.

In general, how does oral health affect the heart?
There are two common forms of oral infection that affect the general population. One is gum disease, also called periodontal disease, and there’s dental caries, also called tooth decay. Both are inflammatory conditions, and high levels of inflammation have been tied to the risk of ischemic stroke.

That happens through two proposed mechanisms. One is that higher levels of inflammation lead to hardening of the blood vessels, called atherosclerosis, in the brain, that can lead to stroke or heart attack. Inflammation has also been tied to an irregular heartbeat condition, known as atrial fibrillation, which is a common cause for stroke.

Your study found that flossing once a week was associated with a 22 percent lower risk of ischemic stroke and a 44 percent lower risk of cardio embolic stroke. Can you please explain the difference and how flossing may have an effect?
Stroke is likened to be a brain attack, meaning something in the blood vessel is causing somebody to have stroke symptoms. There are two broad types of stroke. One is lack of blood supply, which is called ischemic stroke, and the other is bleeding into the brain, called hemorrhagic stroke.

In this study, we found a specific association with ischemic stroke.

The ischemic stroke is from blockage in the blood vessel and can arise from a number of reasons. It could be from hardening of the blood vessels, or it could be from an irregular heartbeat condition. In this study, we found that that risk for ischemic stroke was tied to the cardio embolic type of strokes, although there was some association with the hardening kind or thrombotic kind of stroke as well.

How does your research study differ from other studies that examined flossing and heart health?
There have been other studies which have reported flossing linked to reduced cardiovascular disease, which includes stroke, but this is the first study to look at the specific association with stroke and stroke subtype. Flossing was related to a 22 percent risk reduction in ischemic stroke and a 44 percent risk reduction of cardio embolic stroke, and this is probably one of the first looks at that kind of data, in this study.

Is it ever too late for a person to start flossing? How should people in their 40s or 50s or 60s who do not floss regularly react to this study.
It's never too late. This is a great oral hygiene behavior modification, which impacts both gum disease and tooth decay. And if in any way we can lower those chances, we also lower the whole gamut of risk of cardiovascular disease, as well as ischemic stroke, cardio embolic stroke and atrial fibrillation.

I would also like to compare this to other recommended remedies. Aspirin lowers the risk of stroke for somebody at high risk for stroke by 20 to 25 percent. And in our study, we showed that dental flossing reduces the risk of stroke by 22 percent. So it is right in the same ballpark, without the risk of aspirin or other medications that can have hemorrhagic complications.

The last bit I want to point out is cost. Cost-wise, it is a cheap, cheap way. Flossing is affordable and anybody can do it. Whether they're at high or low risk for stroke, anybody can do it and reduce the risk of ischemic stroke.

USC’s Health Watch series helps readers deepen their understanding of the latest health recommendations and news through the expertise of our clinical faculty.