The Heart-Gut Axis; the Link Between the Microbiome and Blood Pressure

Maintaining healthy blood pressure is critical for increasing lifespan and improving healthspan. While lifestyle changes can greatly influence cardiovascular health, researchers are eager to explore connections between blood pressure and systems of the body so they can target them in devising a solution for heart health.

Despite the many unknowns, scientists are aware that the microbiome plays a key role. Of course, the exact mechanisms linking gut and oral bacteria and blood pressure remain a mystery. To discover what researchers do know and how you can boost your microbiome and cardiovascular health, read on. 

Both the gut and oral microbiome are involved

Researchers have found links between blood pressure and both the gut and oral microbiome. In fact, some believe communication takes place between the bacteria in these different parts of the body. Supporting this hypothesis is the interplay among oral, lung, and gut microflora in the development of certain health conditions. 

Biological stress is a major factor

The gut microbiota impact immunity and biological responses to stress, which could in turn affect blood pressure. When the gut microbiome is out of balance, the body can experience a state of stress. In this state, it can produce harmful byproducts that can lead to elevated blood pressure. One of these byproducts is trimethylamine N-oxide (TMAO), which has been linked to plaque build-up inside the arteries. Similarly, researchers are investigating the connection between gum health and elevated blood pressure. 

Blood pressure linked with gut microbiome features

Scientists have discovered that people with elevated blood pressure have less microbial diversity and different compositions of microorganisms than people with normal blood pressure. Those with elevated blood pressure have a higher ratio of Firmicutes to Bacteroidetes—unfortunate since Bacteroidetes help boost immunity by strengthening the mucosal barrier of the gastrointestinal tract. Accordingly, research has found a link between elevated blood pressure and reduced gut barrier function. Unfortunately, this can also result in lower levels of bacteria that produce short-chain fatty acids (SCFA), which help protect the body against immune responses. This population also has higher levels of metabolites (like TMAO) that can stimulate stress and harm cardiovascular health, resulting in elevated blood pressure.

The nitrate-nitrite mechanism and the oral microbiome

In the mouth, certain microorganisms produce an enzyme that reduces dietary nitrate to nitrite. Once this nitrite reaches the gut, the gut converts it into nitrous oxide—which helps enlarge blood vessels, improving blood pressure. When there aren’t enough of these nitrate-reducing bacteria in the mouth, blood pressure can rise. Meanwhile, several flora associated with gum disease are also linked with vascular health, suggesting other types of microorganisms in the mouth could play a role. 

How to improve microbiome health and blood pressure

Scientists believe that genes don’t significantly contribute to blood pressure issues, suggesting that lifestyle changes (like switching up the diet or cultivating the oral and gut microbiome) could prove most impactful in maintaining blood pressure.

Consider probiotics*: Researchers found that taking probiotics helped balance the gut microbiome and optimize the blood pressure of rats with elevated blood pressure. Similarly, people with elevated blood pressure who drank milk fermented with beneficial bacteria improved their health. Results were more significant when people took supplements with a greater variety of species and for a period of at least eight weeks. To experience these benefits, investigate with your doctor whether probiotics could benefit you.

Eat a prebiotic-rich diet: Consuming foods high in indigestible carbohydrates helps feed the healthful bacteria in your gut. For rich sources, try onions, leeks, bananas, sunchokes, and garlic.

Don’t use antiseptic mouthwash: Rinsing with this type of product depletes the oral bacteria that convert nitrate into nitrite, reducing nitrite production. Studies have shown that people who use antiseptic mouthwash experience an elevation in their blood pressure.¹

Avoid unnecessary use of antibiotics: Similarly, heavy antibiotic use can destroy the population of healthful gut bacteria and elevate blood pressure. Only use antibiotics when they are prescribed by your healthcare provider.

Eat beets: Studies have shown that consuming nitrate-rich foods (like beets) is associated with a reduction in blood pressure. Ask your doctor if these sweet root vegetables would support your health. If so, pick up vacuum-packed pre-cooked beets in the refrigerated produce section of the grocery store for a quick way to get your fill. Then, slice and add to salads, as with sliced oranges, olives, and arugula. Or, for an instant pick-me-up, drink beet juice (squeeze in some fresh lemon or orange juice for a kick). Otherwise, try throwing some pre-cooked beets into a smoothie with berries or cocoa powder (both of which will help disguise the taste).

Resources:

¹ Bryan, N.S. et al. (2017). [Oral Microbiome and Nitric Oxide study]. Current Hypertension Reports. Link.springer.com.

Naik, S.S. et al. (2022). [Study on microbiome imbalance and hypertension]. Cureus.com.

Jose, P.A. et al. (2015). [Gut microbiot in hypertension]. HHS Public Access, PubMed Central.

Gordon, J.H. et al. (2019). [Study on oral microbiome and blood pressure in women]. HHS Public Access, PubMed Central.

Kapil, V. et al. (2012). [Nitrate reducing oral bacteria and blood pressure control]. sciencedirect.com.

Barbadoro, P. et al. (2020). [Study on hypertension, oral microbiome and salivary nitric oxide]. sciencedirect.com.