Another way in which the gut microbiome can potentially have harmful effects on the heart is through the production of trimethylamine-N-oxide (TMAO)Trusted Source.

“When gut microbes feed on choline — found in red meatTrusted Source, poultry, eggs, [and] certain fish — they make trimethylamineTrusted Source (TMA), which is absorbed into the body and goes to the liver where it is changed into TMAO,” Dr. John P. Higgins, a sports cardiologist at McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth) explained.

“TMAO is bad because it is associated with cholesterol and artery narrowing plaque in important arteries in the body, especially the coronary arteries which supply blood to the heart. So people with high levels of TMAO are at increased risk of heart attacks or stroke,” he noted.

“Studies have associated TMAO with aspects of inflammation and blood vessel dysfunction,” Dr. Chen added. “It also promotes foam cellsTrusted Source in the blood vessels. All of these different things end up promoting different types of heart disease, such as atherosclerosis, and they can also lead to different aspects of cardiovascular risk factors such as high blood pressure.”

A study published in October 2019 linked TMAO to disease severity and mortality rate in people with peripheral artery diseaseTrusted Source.

Research published in March 2023 reported an increase of TMAO in blood plasma was an independent predictor for major adverse cardiac and cerebrovascular eventsTrusted Source in people who experienced acute myocardial infarction (heart attack).

And a study published in March 2022 correlated elevated TMAO levels with large artery atherosclerotic ischemic strokeTrusted Source.

As the gut microbiome influences not only heart health, but the well-being of the entire body, experts agree that it must be well-balanced for optimal function.

“An easy way to think about the gut microbiome is like a beautiful farm garden,” Monique Richard, a registered dietitian nutritionist and owner of Nutrition-In-Sight explained to MNT.

“The various gut bugs, or microbiota, are like the components of the garden, each having their own job function to contribute to a bountiful harvest. The garden needs components like healthy soil, clean water, proper nutrients, structure, and tender love and care,” she continued the analogy.

According to Dr. Lebowitz:

“If we eat foods that feed the good bacteria — an alkaline diet high in fruits and veggies — we will be fostering the health of a healthy microbiome. Eating foods that contain too much refined carbohydrates, sugar, and processed foods can have the opposite effect and feed bad bacteria which can trigger inflammation that causes disease — and the arteries and the heart are no exception to this. If there is inflammation in the arteries, as an example, cholesterol will stick to it.”

Richard said it is also important to note that each person’s gut microbiota has its function in helping process what we eat and supporting various functions of digestion and systemic function.

“One example includes our gut microbes breaking down compounds into what are called short-chain fatty acidsTrusted Source (SCFAs) like butyrateTrusted Source,” she continued.

“Butyrate has many known benefits which include being anti-inflammatory and cardio-protective. The better equipped our gut is with benefits to nurture the components of our internal ‘garden,’ the more robust the rest of our systems will be since it is all connected and work together,” explained Richard.

In addition to following a heart-healthy diet, medical experts agree that getting enough dietary fiber is also required to keep the gut-heart connection thriving.

“Foods that contain fiber are pretty heart healthy — low in saturated fats, low in sodium,” Dr. Chen explained. “And fiber itself is actually food for the gut bacteria. So the more fiber you have, the healthier they will be. They process the fiber and break it down.”

“Fiber-rich foods definitely lower the risk of heart disease and stroke by quite a bit,” Dr. Rudolph Bedford, a board-certified gastroenterologist at Providence Saint John’s Health Center in Santa Monica, CA, told MNT. “Fiber in itself will help to not only take away many of the bad toxins but will also lower the cholesterol level.”

“High fiber diets are great because the microbiome breaks fiber down into beneficial things like short-chain fatty acids which are associated with improved blood pressure, blood sugar, less inflammation, and weight loss — all of which can boost [cardiovascular] health,” Dr. Higgens added.

Past studies have linked higher dietary fiber intake with lowerTrusted Source long-term cardiovascular disease risk, as well as reduced incidence and mortalityTrusted Source from heart disease.

While eating the right foods can help keep the gut microbiome healthy, there has been a lot of talk over the past few years about taking prebiotic and probiotic supplements to aid with gut health.

In the most basic terms, probiotics are bacteria beneficial to the gut microbiome, while prebiotics are food for those bacteria.

Some foods are natural prebiotics — these include oats, bananas, onions, artichokes, spinach, and chia seeds.

“The problem with probiotics is that they’re a ‘food supplement,’ and much of this is strain-dependent —in other words, what type of strains are within those probiotics,” Dr. Bedford explained. “There’s no doubt that certain strains of probiotics may certainly aid in gut health and may even help in decreasing your risk of cardiovascular disease.”

“But the fact of the matter is that there are just so many different probiotics out there and none of this is regulated by any government agency,”he continued. “It’s somewhat of a challenge to recommend probiotics to patients, depending upon what it is that they’re actually getting. You should definitely speak to your physician before you start a probiotic or prebiotic.”