Researchers in Korea have unlocked new wisdom that may speak even more to the importance of a healthy, diverse diet.
As researchers explore deeper into the world of gut health, they’re learning that trillions of bacteria found primarily in the large intestines affect many parts of our wellbeing—including our hearts. A breaking November 2025 study by the American Society for Microbiology (ASM) has looked closely at the gut microbiomes of people with coronary artery disease and observed important distinctions that may help explain why some people develop this version of heart disease.
The Cleveland Clinic describes coronary artery disease as a condition that “limits blood flow in your coronary arteries, which deliver blood to your heart muscle. Cholesterol and other substances make up plaque that narrows your coronary arteries.” The Clinic calls chest pain the most common symptom, adding: “[Coronary artery disease] can lead to a heart attack, abnormal heart rhythms or heart failure.”
With that background, the study, published in the ASM journal mSystems, compared gut bacteria from 14 people with coronary artery disease, and 28 people without the disease matched for similar age, sex, and body mass index profiles.
The researchers discovered that 15 types of gut bacteria appeared to be linked to the arterial condition—especially a group called Lachnospiraceae, which “were significantly enriched in patients with CAD,” the researchers report. National Institutes of Health literature has referred to Lachnospiraceae as “controversial”: they help digest plant fibers and produce beneficial compounds that help keep the gut healthy. They’re also among the most abundant types of bacteria in the gut. However, previous research had suggested that a “reduction in Lachnospiraceae within the gut microbiota has been associated with a range of conditions, including allergies, inflammatory bowel disease, and metabolic disorders.” The 2025 study may help highlight the importance of a balanced amount.
At the same time, in the 2025 study, people with coronary artery disease had lower levels of helpful bacteria, such as Faecalibacterium prausnitzii and Slackia isoflavoniconvertens. These bacteria produce short-chain fatty acids (SCFAs), which reduce inflammation and support a healthy gut. When they’re depleted, inflammation may rise and contribute to heart disease over time. A few foods that help produce them have been identified as whole grains, legumes, and fruits—particularly those with pectins, like apples and peaches.
The study authors also noted that those with certain gut bacteria had “overactive metabolic pathways,” which influence how the body processes certain nutrients and which chemicals the bacteria produce. The research team found people with coronary artery disease had more activity in the urea cycle (which converts ammonia to urea for the kidneys to excrete through urine but can lead to conditions like kidney stones when uric acid levels are high) and L-citrulline metabolic pathways (involved in relaxing the blood vessels). Higher levels of a molecule called inosine, related to energy and cell function, were also flagged.
Once the team pinpointed these differences, they wanted to see how well they could be used to diagnose coronary artery disease using a computer model. That model correctly identified coronary artery disease patients from healthy people almost 90% of the time, using genomic sequencing data on their gut health. They found that having low levels of Faecalibacterium prausnitzii and high levels of inosine were two of the most reliable predictors of coronary artery disease.
However, the team also noted that different strains of the same bacterial species could have opposite effects on cardiovascular health, depending on which genes they carried—highlighting the complexity of their findings. For instance, in a news release, Han-Na Kim, PhD, a genomicist at Sungkyunkwan University in Seoul and a co-author of the study, described Lachnospiraceae as “the Dr. Jekyll and Mr. Hyde of the gut,” noting that it can be depleted or run rampant in people with coronary artery disease.
“The big unanswered question now is which strains are the healers, and which are the troublemakers,” Dr. Kim said. “We’ve gone beyond identifying ‘which bacteria live there’ to uncovering what they actually do in the heart-gut connection,” she added.
So, while scientists are working hard to unravel the intricate genomic links between gut health and heart health, the good news is that your job is simple: Maintaining a healthy gut to the best of your ability. Be sure to follow a well-rounded, minimally processed diet rich in prebiotic and probiotic foods, including plenty of fruits, veggies, whole grains, legumes, and fermented foods. Someday, doctors may use studies like these to supplement those good gut habits with targeted treatments—but for now, a healthy diet is a strong line of defense.
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