Blood Pressure and the Bacteria in your Belly
High blood pressure (hypertension) is common and serious—it raises the risk of heart failure, stroke, kidney disease, and more. In 2022, high blood pressure was a primary or contributing cause of 685,875 deaths in the United States. For every decrease of 10mmHg in your systolic blood pressure reading, you lower your risk of stroke by 27%, heart failure by 29%, coronary artery disease by 17% and dying from any cause by 13%.
What’s new is how much our gut microbiome—the trillions of bacteria living in our intestines—may influence blood pressure. The American Heart Association (AHA) recently published a “Science Advisory” on this topic, which is a formal position statement from the AHA that is intended to offer guidance on a prominent and evolving scientific issue related to cardiovascular health. The goal of these “advisory” statements is to provide evidence-based positions for both health professionals and the public on significant topics, with the intent of promoting optimal patient care and scientific advancement.
Why did the AHA publish this now? Recent advances in gut microbiome and hypertension research have suggested a novel therapeutic opportunity: targeting the bacteria in our intestines to achieve blood pressure control!
The Gut–Blood Pressure Connection
People with high blood pressure often show an imbalance in gut bacteria (also called dysbiosis). All sorts of different research studies have shown evidence of the relationship between blood pressure and intestinal health.
- Fasting & time-restricted eating: In small studies, intermittent fasting changed gut bacteria and lowered blood pressure for some people. Not everyone responds, and more research is needed to know who benefits most.
- Fiber & Short Chain Fatty Acids (SCFAs): Higher fiber diets are consistently linked with lower blood pressure. One research trial delivered SCFAs to the colon via special fiber and lowered 24-hour systolic blood pressure. But taking butyrate (one of the SCFAs) pills alone raised blood pressure in one small study—suggesting that there is no easy fix, and how and where these metabolites are delivered really matters.
- Probiotics: Meta-analyses of many small trials show modest average reductions (about 1–3 mm Hg). Species, dose, and duration vary widely, so there isn’t one proven “hypertension probiotic.”
- Antibiotics: Early research in resistant hypertension (when people on ≥3 meds) found that using a specific antibiotic to kill certain bacteria led to modest blood pressure drops and signals of reduced brain inflammation.
- Fecal microbiome transplant (FMT): In animal studies, if you actually transplant gut bacteria from hypertensive donors into healthy animals, you can actually cause the recipient to have blood pressure! In humans, however, taking bacteria from a healthy person and transplanting them into someone with high blood pressure has shown mixed results; but some studies report small, short-term blood pressure reductions, especially when paired with fiber.
How does this all work? How is blood pressure affected by the bacteria in our bellies? There are lots of theories, and several different mechanisms could be involved:
- Leaky gut & immune activation: An unhealthy gut lining can spark inflammation that pushes blood pressure up.
- Microbial metabolites: Healthy gut bacteria LOVE fiber, and when fiber is fermented by these bacteria, they produce short-chain fatty acids (SCFAs). These compounds can relax blood vessels and may support healthy blood pressure.
- Kidney effects: Some microbial products appear to influence kidney hormones and even scarring/fibrosis of the kidneys, which are tied to blood pressure control.
- Brain–gut signaling: Bacteria in our intestines help shape signals through the vagus nerve (the main nerve that connects the brain and the intestines) and also influence levels of neurotransmitters like serotonin, which can affect blood pressure regulation in the brain.
And don’t forget the role of salt! A high-sodium diet can disturb gut bacteria, for example decreasing levels of helpful Lactobacillus and activating inflammatory immune cells. Salt intake may also lower beneficial, blood-pressure–friendly metabolites and alter stress hormone pathways. We have known for a long time that low sodium diets lead to better blood pressure. Maybe part of the reason is from having a healthier microbiome.
While the research is still developing, there are certainly things that we know are effective and you can do now:
- Build a fiber-first plate.
Aim for 25–35 grams of fiber daily from whole foods: vegetables, fruits, beans/lentils, nuts/seeds, and whole grains (oats, barley, quinoa). Fiber feeds beneficial gut bacteria, which create short-chain fatty acids that can support healthier blood pressure. - Mind the sodium.
Most adults benefit from lowering sodium, often toward 1,500–2,000 mg/day. Cook more at home; limit processed meats, canned soups, fast foods, and salty snacks. Read labels—sodium hides everywhere. - Choose a microbiome-friendly eating pattern.
Plant-based or Mediterranean-style diets naturally combine lower sodium with high fiber, healthy fats, and plenty of plants—great for blood pressure and your gut. - Consider fermented foods.
Yogurt with live cultures, kefir, sauerkraut, kimchi, and tempeh may support a diverse microbiome. They aren’t magic bullets, but they can complement a high-fiber diet. - Be cautious with probiotics.
Probiotics can modestly lower blood pressure on average, but results vary. If you try one, look for reputable products and give it time. It took 8-12 weeks in one study to see an effect. - Avoid unnecessary antibiotics.
Antibiotics can disrupt your microbiome for weeks to months. Use them when medically indicated—but not for viral illnesses or “just in case.” If you have a cold, RESIST the urge to call your doctor for a “Z-pack”! - Keep the fundamentals strong.
Regular physical activity, good sleep, stress reduction, moderating alcohol, and not smoking remain core blood pressure strategies—and are microbiome-friendly as well.
The purpose of the recent AHA Science Advisory was to highlight the emerging research that shows that your gut microbiome and your blood pressure are connected. If you had said that at a medical conference just a few decades ago, you probably would have been laughed off the stage. Now it is being published by one of our most respected organizations.
The evidence is clear, and we are learning more every day. While there are no interventions that are truly “ready for prime time” yet, until then we know this for a fact: High-fiber, lower-sodium eating patterns help both the microbiome and blood pressure. And that is something you can safely start today.
At Wisconsin Cardiology Associates, we counsel our patients to aim for a healthy, plant-based diet, emphasizing fruits, vegetables, beans, lentils, whole grains and nuts. Have questions about the best way you can prevent heart disease? Call us and make an appointment for a consultation.
References:
Yang, T et al. Hypertension Volume 82, Issue 9, September 2025; Pages e160-e170
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