Understanding the Gut Microbiome’s Surprising Link to Stroke Risk
Recent studies have unveiled a compelling connection between the microbiomes in our gut and mouth and the risk of stroke. This discovery emphasizes the ancient wisdom of Hippocrates, who famously stated, “all disease begins in the gut.” The profound impact of microbiomes on our health is now more apparent than ever, with the gut microbiome playing a pivotal role in managing both acute and chronic conditions. But it’s not just the gut that’s home to these essential microbiomes; our skin and mouth also host unique microbiomes crucial for maintaining health.
The Mouth-Gut Microbiome Connection
The mouth, as the gateway to our digestive system, harbors a microbiome that reflects that of the gut. It starts the digestive process by releasing enzymes to break down food, and the act of chewing is integral to digestion. Notably, the mouth and gut microbiomes have a bidirectional relationship, with imbalances in one potentially affecting the other and overall health.
Microbiomes and Inflammation
Researchers have long explored the gut microbiome’s link to inflammation, a contributor to chronic diseases like heart disease, diabetes, and cancer. However, the connection between microbiomes and stroke is less understood. Studies have shown that stroke survivors often have imbalanced microbiomes, prompting further investigation into factors beyond the brain that may contribute to stroke occurrences and recovery.
Recent Study Findings
Presented at the American Stroke Association’s International Stroke Conference 2025, recent research highlights the presence of trillions of bacteria within our microbiomes. In the gut, this is known as the gut microbiota, while in the mouth, it’s the oral microbiota. The aim is to maintain a balance where beneficial bacteria outnumber the harmful ones.
A previous study linked Streptococcus mutans, a bacteria causing tooth decay, to increased brain bleeding risk, a stroke precursor. The latest research focuses on Streptococcus anginosus, associated with oral and brain abscesses and tooth decay.
Study Methodology and Results
The study involved 250 Japanese participants, averaging 70 years old, divided into test and control groups. The test group included individuals who had a stroke within the past week, while the control group had no stroke history but may have other conditions like high blood pressure or diabetes. Researchers analyzed microbiomes using stool and saliva samples collected from July 2020 to July 2021.
Results showed a significant abundance of Streptococcus anginosus in stroke survivors’ saliva and gut compared to the control group. This bacteria was linked to a 20% higher stroke risk after controlling for vascular risk factors. Conversely, beneficial gut bacteria like Anaerostipes hadrus and Bacteroides plebeius were associated with reduced stroke risk by 18% and 14%, respectively. Over two years, stroke survivors with Streptococcus anginosus faced a higher risk of death and major cardiovascular events, unlike those with beneficial bacteria.
Future Implications and Recommendations
Lead author Shuichi Tonomura, M.D., envisions future tests using mouth swabs to detect harmful bacteria, aiding stroke risk assessment. Until then, maintaining healthy oral and gut microbiomes is vital. This includes good oral hygiene, hydration, avoiding sugary drinks, and regular dental checkups.
Beyond oral health, adopting healthy lifestyle habits is crucial for reducing inflammation and chronic disease risk. This involves a balanced diet, physical activity, adequate sleep, stress management, and nurturing relationships. Incorporating fermented foods like yogurt and kimchi introduces probiotics, beneficial bacteria, to your microbiomes. Prebiotics in fruits, vegetables, and whole grains nourish these probiotics.
Conclusion and Further Reading
This preliminary study suggests a link between harmful bacteria in the gut and mouth and increased stroke risk. While focused on Japanese participants, further research is needed to see if these findings apply to other populations. Meanwhile, maintaining healthy microbiomes through diet and lifestyle choices can help mitigate various disease risks. For more insights, visit www.eatingwell.com.
For related topics, explore our articles on cholesterol fluctuations and dementia risk and dietary supplements’ impact on liver health. Join the discussion and stay informed on the latest health news.
