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Neurology and Neurosurgery

Should I floss my teeth? Your brain might thank you.

A happy mom, dad and their young son brushing their teeth in the bathroom and taking care of their oral health.

05/12/2025

New research suggests keeping your mouth clean may help lower your stroke risk — especially as you age.

By Paul Wright, MD, Senior Vice President and System Chair of the Nuvance Health Neuroscience Institute, part of Northwell Health

We all know flossing is good for your gums. But what if something as simple as flossing your teeth could also protect your brain?

It may sound surprising, but recent research shows a connection doctors have suspected for years: Your oral and brain health are linked. More specifically, poor oral hygiene may increase your risk for stroke — especially ischemic stroke, the most common kind.

If you’re thinking about how to protect your brain, it’s time to look beyond the obvious. The benefits of flossing may go far beyond your smile.

What does your mouth have to do with your brain?

Your mouth is home to billions of bacteria — some helpful, some harmful. When you skip brushing or flossing, harmful bacteria can build up in the space between your teeth and gums. This can lead to gum disease, or periodontitis, which causes inflammation and infection in the mouth.

But these bacteria don’t always stay there.

They can enter your bloodstream, triggering inflammation in other parts of your body — including your brain and heart. Inflammation and infection have been linked to stroke, atrial fibrillation (AFib) and other cardiovascular problems.

So, when people ask, “Should I floss my teeth?” the answer isn’t just about oral hygiene anymore — it’s about brain health, too.

Research connects flossing with stroke prevention

Two studies presented at a recent American Stroke Association International Conference offer convincing evidence that taking care of your mouth could help protect your brain.

Study #1: Flossing linked to lower stroke risk

Researchers followed over 6,200 adults without a history of stroke for more than 25 years. They found:

People who flossed regularly were significantly less likely to have an ischemic stroke.

The more frequently they flossed, the lower their risk — a clear dose-effect.

Flossing was also linked with lower risk of AFib, a common cause of blood clots that lead to stroke.

This study adds weight to what many neurologists have already suspected: Daily flossing may reduce inflammation and harmful bacteria, lowering your risk for serious cardiovascular events.

Study #2: A common mouth bacteria may raise stroke risk

Another new study examined the mouth and gut bacteria of stroke patients compared to people who hadn’t had a stroke.

Here’s what they found:

A common oral and gut bacteria called Streptococcus anginosus was found more often in stroke patients.

Stroke survivors with these bacteria in their guts were more likely to have future cardiovascular events or die in the two years after their stroke.

Overall, having harmful bacteria in the gut was linked with 20% higher odds of having a stroke.

This research suggests mouth bacteria may travel to the gut, triggering systemic inflammation throughout your body that damages blood vessels and increases stroke risk.

What you can do to reduce your risk of stroke

Taking care of your mouth doesn’t take much time — but it can offer big protection for your brain.

Quick wins for better oral and brain health

Floss daily (even a little is better than nothing): Flossing removes plaque and food particles between teeth — places your toothbrush can’t reach. Over time, it lowers gum inflammation and may reduce stroke risk. Dentists recommend flossing once per day at night, before brushing your teeth.

Brush twice a day for at least two minutes and use fluoride toothpaste and alcohol-free mouthwash: This keeps teeth clean and reduces bacteria that can enter your bloodstream.

Drink plenty of water: Staying hydrated supports saliva production, which can help wash away harmful bacteria.

Eat a gut- and brain-friendly diet: Foods rich in fiber, antioxidants and omega-3s (think fruits, veggies, nuts and fatty fish) support both your oral microbiome and your brain.

See your dentist twice a year for routine cleanings: Professional cleanings and exams can catch gum disease early and help prevent it from spreading.

Quit smoking: Smoking damages your gums, weakens your immune system and increases stroke risk.

Can improving oral health reverse stroke risk?

If you’ve gone years without flossing regularly, you may wonder: Is it too late?

The good news is, it’s never too late to improve your oral health, and doing so may still reduce your stroke risk over time:

Reducing harmful bacteria in your mouth lowers the chance they’ll spread systemically.

Controlling gum inflammation helps ease strain on your immune and vascular systems.

Regular dental care can slow or reverse early-stage gum disease.

So even if you’ve had issues with oral hygiene in the past, today is a great day to start a new routine. Your brain — and body — will thank you.

Oral health and other chronic diseases

Oral health doesn’t just affect stroke risk — it plays a role in other conditions that often overlap in midlife and beyond, including diabetes, high blood pressure and heart disease.

All these conditions increase stroke risk on their own, and poor oral health can worsen them by adding more systemic inflammation. By improving your oral hygiene, you’re supporting your whole-body health — not just your mouth.

The bottom line: If you’ve ever wondered, “What are the real benefits of flossing?” — here’s a powerful answer: It could help lower your risk of stroke. Keeping your mouth clean reduces harmful mouth bacteria, inflammation and potential damage to your blood vessels. That’s a small habit with a big payoff. So next time you reach for your floss, know this: You’re not just caring for your smile — you’re helping protect your brain.

Learn more about the Nuvance Health Neuroscience Institute.