TMAO atrial fibrillation risk tied to red meat-related gut byproduct
Researchers linked higher TMAO blood levels to atrial fibrillation risk after studying more than 5,000 heart-procedure patients.
By Priya Raghavan · Science Reporter
3 min read
A Cleveland Clinic-led team has linked higher blood levels of TMAO to atrial fibrillation risk, adding to evidence that gut bacteria may influence heart disease. The finding matters because TMAO is produced when gut microbes digest nutrients found in red meat and other animal products, raising a possible dietary target before an abnormal rhythm develops.
The study, led by Robert Koeth, M.D., Ph.D., examined blood samples from more than 5,000 people who were undergoing heart procedures, according to Cleveland Clinic. Researchers also ran laboratory studies in cells to examine how TMAO could affect heart function.
The team reported that TMAO produced by gut microbes can alter the heart’s electrical environment and make abnormal rhythms more likely. The findings were published in the Journal of Clinical Investigation.
What is TMAO and why is it linked to atrial fibrillation?
TMAO, short for trimethylamine N-oxide, is a compound formed after gut bacteria break down certain nutrients, including nutrients found in red meat and other animal products. Cleveland Clinic researchers said elevated levels of the compound were associated with a higher risk of atrial fibrillation in the people studied.
Atrial fibrillation is a rhythm disorder that starts in the heart’s upper chambers. Cleveland Clinic said it is the most common type of such rhythm disorder, with at least 2.7 million Americans living with it.
Symptoms can include fatigue, palpitations, shortness of breath and dizziness. Known risk factors include high blood pressure, coronary artery disease and obesity.
How researchers studied the gut-heart connection
The Cleveland Clinic-led researchers combined patient blood-sample analysis with cell studies. That design allowed them to look both at the clinical association between TMAO levels and atrial fibrillation risk, and at a possible biological pathway involving the heart’s electrical behavior.
Koeth, senior author of the study and an electrophysiologist in Cleveland Clinic’s Miller Family Heart, Vascular & Thoracic Institute, said the findings point to the possibility of acting earlier through diet rather than only treating atrial fibrillation after it appears. Cleveland Clinic described current treatments as focused largely on managing the condition.
Those treatments can include medications and procedures. One procedure, ablation, creates scar tissue to help the heart’s electrical system work more effectively, and Cleveland Clinic said such approaches can reduce stroke risk.
What the study adds to previous TMAO research
Cleveland Clinic said the new work extends more than a decade of research on the gut microbiome and cardiovascular disease, including studies of TMAO. The same research group has previously reported links between high TMAO levels and higher risk of chronic kidney disease and cardiovascular disease.
Those cardiovascular outcomes include adverse events such as heart attack and stroke, according to Cleveland Clinic. The institution also said TMAO testing is now widely available and has been incorporated into clinical practice.
The study does not turn the association into broad dietary guidance on its own, and Cleveland Clinic did not report that red meat directly causes atrial fibrillation. It does, however, identify a gut-derived compound tied to animal-product digestion as a potential point of interest for earlier risk reduction.
This story draws on original reporting from Medical Xpress.