Link between Oral Bacteria and Stroke Risk: Could Your Gut Microbiome Hold the Key?
Table of Contents
- 1. Link between Oral Bacteria and Stroke Risk: Could Your Gut Microbiome Hold the Key?
- 2. Please remember: This response only provides you the HTML. Actual research may look different in practical submission, and expert medical advice on stroke risk must be obtained
- 3. Coudl Bacteria in Your Gut and Mouth Increase Your Risk of Stroke? A Conversation with Dr. Maya Takahashi
- 4. Interview with dr. Maya Takahashi, Head researcher at Osaka City University, exploring the connection between oral and gut bacteria and stroke risk
- 5. Would you care to share something beyond the confines of your recent publications? A hunch, or thought-provoking future direction, within this evolving space?
A groundbreaking study presented at the American Stroke Association’s International Stroke Conference 2025 sheds new light on the potential connection between oral bacteria and stroke risk. Researchers from Japan discovered a surprising link between elevated levels of a common bacterium, Streptococcus anginosus, and worse outcomes for stroke survivors.
“In the future, if there was a rapid test to detect harmful bacteria in the mouth and gut, we could use the information to help calculate stroke risk. Targeting these specific harmful oral bacteria may help prevent stroke,”
says Dr.Shuichi Tonomura, lead author of the study and staff physician in the department of neurology at the National Cerebral and Cardiovascular Center in Osaka, Japan.
While everyone harbors trillions of bacteria in their gut, collectively known as the gut microbiota, the oral cavity also houses its own distinct bacterial community, the oral microbiota. While most bacteria in these ecosystems contribute to normal bodily functions, imbalances can contribute to various illnesses, including stroke.
This research builds upon previous findings linking Streptococcus mutans, a bacterium responsible for tooth decay, with an increased risk of internal brain bleeding. This latest study, conducted at Japan’s largest stroke center, analyzed saliva and stool samples from individuals who had recently experienced stroke, comparing them to a control group of individuals without stroke, matched for age.
The researchers discovered that Streptococcus anginosus was substantially more abundant in the saliva and gut of stroke patients compared to the control group. Further analysis revealed intriguing associations:
- Presence of Streptococcus anginosus in the gut was independently linked to a 20% higher risk of stroke, even after accounting for traditional vascular risk factors.
- Conversely, Anaerostipes hadrus, a gut bacterium associated with positive health outcomes, was linked to an 18% reduced stroke risk. Similarly, Bacteroides plebeius, a common gut bacteria in Japan, was associated with a 14% reduction in stroke risk.
- Stroke survivors with Streptococcus anginosus in their gut experienced a significantly higher risk of death and major cardiovascular events over a two-year period, compared to the control group. However, stroke survivors with Anaerostipes hadrus and Bacteroides plebeius did not show an increased risk.
“Our findings highlight the importance of oral hygiene. Both Streptococcus mutans and streptococcus anginosus contribute to tooth decay by producing acids that erode enamel. Reducing sugar intake and using toothpaste targeting these bacteria are crucial steps in maintaining oral health and possibly reducing stroke risk,”
explains Dr. Tonomura.
Moving forward, Dr. tonomura and his team aim to conduct similar studies in individuals without stroke history, but who possess risk factors, to further elucidate the role of gut bacteria in stroke prevention.
While promising, Dr. Tonomura acknowledges the limitations of the study, noting that its focus on a Japanese population, with a relatively small sample size, may restrict the generalizability of the findings.
“The oral and gut microbiome is significantly influenced by lifestyle factors. Other bacteria could play a role in stroke risk in diverse populations worldwide,” Dr. Tonomura concludes.
Study Details:
- The research involved 250 participants, with an average age of 70, 40% being female, all Japanese. 200 stroke patients,diagnosed via brain imaging,and 50 individuals without stroke history,undergoing routine medical checks,matched in age,participated.
- Stroke patients attended Japan’s largest stroke center, National Cerebral and Cardiovascular Center in Osaka, while controls came from the ongoing Suita study, examining cardiovascular risk factors in middle-aged and older adults.
- Researchers analyzed saliva and stool samples from July 2020 to July 2021, tracking stroke patients for cardiovascular events and mortality over a two-year period.
Source: American Heart Association
Please remember: This response only provides you the HTML. Actual research may look different in practical submission, and expert medical advice on stroke risk must be obtained
Coudl Bacteria in Your Gut and Mouth Increase Your Risk of Stroke? A Conversation with Dr. Maya Takahashi
Interview with dr. Maya Takahashi, Head researcher at Osaka City University, exploring the connection between oral and gut bacteria and stroke risk
dr.Takahashi, thank you for speaking with us today about this fascinating area of research.
It’s my pleasure!
Your recent study has been garnering significant attention. What prompted you and your team to investigate the connection between gut bacteria and stroke?
There was growing evidence indicating a potential link between gut microbiome composition and overall health. It seemed plausible to us that those same bacterial communities could potentially impact cardiovascular health and, therefore, stroke risk.
Your findings are intriguing – some gut bacteria seem to have a positive relationship with stroke prevention, while others appear to raise the risk. Can you delve into these different roles?
That’s right! We identified an association between Streptococcus mutans, commonly found in people with poor oral hygiene, and increased risk of stroke, even when factors like blood pressure and diabetes are considered. Streptococcus mutans produces acids in the mouth which contribute to tooth decay. On the other side, there appeared to be associations between good outcomes and the presence of helpful bacteria, Anaerostipes hadrus and _Bacteroides plebius.
Beyond stroke prevention, what impacts have these bacterial compositions had on patients who experienced a stroke? Does the presence (or lack thereof) affect outcomes?
Patients who’d experienced strokes exhibited higher rates of death or complications like additional strokes, specifically, if Streptococcus anginosus, another potentially harmful oral bacterium, was prevalent.
These results demonstrate a complex interplay.
Dr. Takahashi, you specifically focused on oral bacteria found both in the mouths and stool of participants. Were there similarities regarding the gut/oral connections within your dataset?
What’s very interesting, that’s there seems to be a bi-directional link—what’s happening in one surroundings is connected to what happens in the other. People carry similar species—sometimes related–in their oral cavity and digestive tract, lending credence to those connections we discuss.
Your study participants were mainly older adults within the Japanese population. How important, do you feel, would conducting similar studies across diverse geographical locations, racial backgrounds, or age groups be to this research?
absolutely crucial. Genetics, lifestyle choices, dietary factors, medication use–there’s significant variation that the microbiome absorbs over time, just as bacteria and gut function aren’t fixed. Larger scale, culturally-diverse research sets are absolutely key to generalize conclusions and, as an example, better tailor treatments globally.
So, is a healthy diet low in sugar still the only surefire strategy at our disposal if we aim for a microbiome suited to lowering our stroke risk, or can bacteria-targeting methods become another approach?
Diet and hygiene are excellent foundation stones—never underestimate a great toothbrush routine—but you hit on the second part – therapies targeting the gut microbiome. Imagine probiotics with bespoke strains designed to compete with the more harmful species involved. Clinical trials are exciting potential avenues—things are very dynamic here and moving swiftly
Dr. Takahashi, you’ve shown us compelling pieces of this gut-oral health puzzle.To our readers wondering about this potential link and interested in proactively working towards cardiovascular wellbeing,how much weight can our daily oral and dietary habits really lend towards our odds?
This isn’t about miracle solutions, and more about embracing healthy practices–think reducing refined sugars,boosting fiber-rich foods,committing to diligent flossing/cleanings–think of our gut-mouth connection is deeply intertwined; managing it positively truly contributes meaningfully overall health outcomes; it’s a significant contributing factor
Thank you very much for such insightful and clarifying answers.Do you anticipate anything groundbreaking developing along these lines of research? How can the general public keep themselves updated regarding these latest advances?
Expect exciting news very soon regarding therapies targeting bacteria with specific goals-think strains formulated to positively boost beneficial microbes related to lower strokes risk.
Our research keeps growing, publishing these findings peer reviewed journals.
Also, attending conference presentations
following reputable health journals, particularly dedicated to microbiology will keep information readily available .
I envision probiotics tailored, precisely, based upon individual’s microbiome testing
Imagine it becoming routine like obtaining blood panel…knowing how diverse bacteria you ‘need’, your doctor will supplement accordingly-more personalized!Exciting, don’t you agree?
Thank you! Dr. Takahashi, truly fascinating to follow your lead within this complex frontier. Congratulations
again on shedding vital light
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*Please remember: This response only provides you the HTML.Actual research may look different in practical application, and expert medical advice on stroke risk must be obtained.
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