A new study from Hiroshima University reveals that neglecting your dental hygiene might not just affect your smile—it could also harm your heart.
The research, published in Circulation, found that the bacterium Porphyromonas gingivalis(P. gingivalis), commonly linked to gum disease, can travel from the gums to the heart.
Once there, it triggers scar tissue buildup in the left atrium, leading to atrial fibrillation (AFib)—a serious heart rhythm disorder that increases the risk of stroke, heart failure, and other life-threatening conditions.
AFib cases have nearly doubled in the last decade, growing from 33.5 million in 2010 to about 60 million in 2019.
While doctors have long known that people with gum disease are more prone to cardiovascular problems, this study is the first to provide clear evidence of P. gingivalis migrating from the gums to the heart and causing damage.
“The causal relationship between periodontitis and atrial fibrillation is still unknown,” said Shunsuke Miyauchi, the study’s first author. “But the spread of periodontal bacteria through the bloodstream may connect these conditions.”
The research team explored two main questions: Can P. gingivalis move from infected gums to the heart? And if so, does it contribute to atrial fibrosis and AFib? To find out, they conducted experiments using a mouse model.
They introduced P. gingivalis into the tooth pulp of 13-week-old male mice, while another group of mice remained uninfected as a control. The researchers then monitored the mice for 12 to 18 weeks to observe any cardiovascular changes.
The results were striking. At 12 weeks, there was no significant difference in heart rhythm problems between the two groups. But by 18 weeks, the mice infected with P. gingivalis were six times more likely to develop abnormal heart rhythms. About 30% of the infected mice showed AFib symptoms compared to just 5% of the uninfected group.
Tests on their hearts revealed stiff and scarred tissue in the left atrium, a classic sign of fibrosis. When the researchers examined the heart tissue, they found traces of P. gingivalis, confirming that the bacteria had indeed traveled from the gums to the heart.
The study also included a human element. Researchers analyzed tissue samples from the left atrium of 68 AFib patients who had undergone heart surgery. They found P. gingivalis in these tissues, particularly in patients with severe gum disease. This discovery supports the theory that oral health directly affects heart health.
What makes P. gingivalis so dangerous is its ability to hide from the body’s immune system. Past research has shown that it can invade host cells and evade the cellular cleanup process called autophagy.
This allows the bacteria to persist in tissues like the heart, slowly causing inflammation and scar tissue. In the study, the infected mice displayed high levels of galectin-3, a biomarker for fibrosis, and increased expression of Tgfb1, a gene associated with inflammation and tissue scarring.
These findings suggest that maintaining good oral hygiene could be more important than ever—not just for your teeth, but for your heart as well. Brushing, flossing, and regular dental checkups might prevent P. gingivalis from entering the bloodstream and wreaking havoc on the heart’s electrical system.
According to Miyauchi, “Periodontal treatment, which can block the gateway of P. gingivalis translocation, may play an important role in AFib prevention and treatment.”
The research team is now working to create stronger collaborations between medical and dental professionals in Hiroshima to improve cardiovascular care. They hope to expand this model nationwide, emphasizing the importance of oral health in preventing heart disease.
“For the next step, we’re investigating the specific mechanisms by which P. gingivalis affects heart cells,” Miyauchi said. “We also plan to establish a collaborative medical and dental system to better treat cardiovascular diseases, including atrial fibrillation.”
This study serves as a wake-up call to take gum health seriously. What happens in your mouth doesn’t just stay in your mouth—it can travel through your body and harm your heart. Keeping your gums healthy could be a simple but powerful way to protect your heart and prevent serious health complications.
If you care about heart health, please read studies about how eating eggs can help reduce heart disease risk, and Vitamin K2 could help reduce heart disease risk.
For more information about heart health, please see recent studies about how to remove plaques that cause heart attacks, and results showing a new way to prevent heart attacks, strokes.
The research findings can be found in Circulation.
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