Can Gum Disease Harm Your Heart? New Study Links Oral Bacteria To Dangerous Heart Rhythm

A landmark study from Hiroshima University is shedding new light on a question that has long intrigued doctors and researchers: can your gums affect your heart? Published in Circulation, the recent study identifies Porphyromonas gingivalis, a key bacterium behind gum disease, as a potential contributor to atrial fibrillation (AFib) — a serious heart rhythm disorder associated with strokes and heart failure.

The researchers demonstrated that P. gingivalis can travel through the bloodstream and infiltrate the heart's left atrium. Once there, it contributes to fibrosis, or scar tissue formation, which disrupts the heart's normal electrical signals and architecture, leading to AFib. This connection between poor oral health and heart disease has been observed before, but the Hiroshima study offers a direct mechanism for how it could happen.

Using mice infected with P. gingivalis, scientists showed the bacterium moving from dental tissue to the heart via the bloodstream. These mice developed more atrial fibrosis (21.9% versus 16.3% in controls) and were six times more likely to develop AFib. Human tissue samples from 68 AFib patients confirmed the presence of P. gingivalis, with a clear link between bacterial load, gum disease severity, and the degree of heart fibrosis.

What Is AFib And How Dangerous Is It?

Atrial fibrillation (AFib) is an irregular and often very rapid heart rhythm. According to Mayo Clinic, an irregular heart rhythm is called an arrhythmia and it can lead to blood clots in the heart. The condition also increases the risk of stroke, heart failure and other heart-related complications.

Dr Nischal N Hegde, an interventional cardiologist at Bangalore Hospitals (Jayanagar, Kengeri – Bengaluru), elaborates on the "unlikely but important link" between Dental hygiene and Heart Disease.  "While brushing and flossing may seem far removed from matters of the heart, growing evidence suggests that poor dental hygiene can contribute to atherosclerotic cardiovascular disease (ASCVD)," Dr Hegde said.

"Chronic gum infections like periodontitis trigger systemic inflammation, a key player in the development and progression of atherosclerosis. Harmful oral bacteria can enter the bloodstream, damaging blood vessel walls and accelerating plaque buildup," Dr Hegde said.

He further said that controlling traditional risk factors like diabetes, hypertension, and cholesterol improves outcomes. "But we must not overlook oral health. Regular dental check-ups and good oral hygiene can reduce inflammation and potentially lower cardiovascular risk," he said.

The findings by the researchers at Hiroshima University support earlier observations from Harvard Health Publishing. According to Dr Robert H Shmerling, senior faculty editor, "Study after study has shown that people who have poor oral health (such as gum disease or tooth loss) have higher rates of cardiovascular problems, such as heart attack or stroke, than people with good oral health."

But why this connection exists is still debated. Dr Shmerling outlines several theories, including the possibility that: "The bacteria that infect the gums and cause gingivitis and periodontitis also travel to blood vessels elsewhere in the body where they cause blood vessel inflammation and damage; tiny blood clots, heart attack and stroke may follow."

Dr Shmerling also said that the role of inflammation or even common risk factors like smoking and poverty that affect both oral and heart health. As he put it: "Rather than bacteria causing the problem, it's the body's immune response — inflammation — that sets off a cascade of vascular damage throughout the body, including the heart and brain."

While some large-scale studies have challenged a direct causal link, especially after adjusting for smoking, the Hiroshima study renews attention to P. gingivalis specifically. This bacterium has also been associated with other systemic diseases like rheumatoid arthritis and pancreatic cancer.

Dr Shmerling, in his study, noted: "Whether the link is direct, indirect or coincidence, a healthy mouth and a regimen to keep it that way (including not smoking, and getting regular dental care) can help you keep your teeth. That's reason enough to do what you can to make oral health a priority. Perhaps it will turn out to have other benefits, though much of that remains speculative."

Your dental pearls may be worth protecting for larger benefits. While we chew on available findings and await further research, this latest study by Hiroshima University is a powerful reminder: oral hygiene is not just about your teeth; it may protect your heart, too. Don't stop your practice of regular brushing, flossing and seeing the dentist.

Kirti Pandey is a senior independent writer. 

[Disclaimer: The information provided in the article, including treatment suggestions shared by doctors, is intended for general informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition.]

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