The Surprising Link Between the Gut and Heart Health
Science has long recognized that what we eat plays a critical role in our heart health. Now the details of this complex connection are coming into focus.
One of the more intriguing recent discoveries has to do with the role of the gut microbiome—the trillions of microbes that reside in the GI tract and influence health by helping digest food, making vitamins, and providing protection against disease-causing microorganisms. Recently Cleveland Clinic researchers reported findings from several studies involving people and animals, that the gut microbiome directly changes the function of blood platelets, influencing the risk for heart attack and stroke.
Here’s how it works: When people ingest certain nutrients, such as choline (abundant in red meat, egg yolks, and dairy products) and L-carnitine (found in red meat as well as some energy drinks and supplements), the gut bacteria that break it down produce a compound called trimethylamine (TMA). The liver then converts TMA into the compound, trimethylene N-oxide (TMAO).
The trouble with TMAO is that data show high levels contribute to a heightened risk for clot-related events such as heart attack and stroke—even after researchers take into account the presence of conventional risk factors and markers of inflammation that might skew the results. In their most recent analysis, scientists showed that high blood levels of TMAO were associated with higher rates of premature death in a group of 2235 patients with stable coronary artery disease. Those found to have higher blood levels of TMAO had a four-fold greater risk of dying from any cause over the subsequent five years.
The implications are intriguing. Taken together, the new studies suggest that positively altering the gut microbiota may help to reduce damage to blood vessels, resulting in a stronger cardiovascular system, and they point to targets for potential new heart disease therapies.
The insights also underscore the potential power of TMAO testing, which can help patients determine if their gut microbiome is contributing to their risk for heart disease and whether they might benefit from limiting foods that contain the building blocks of TMAO. TMAO tests are only available through the Cleveland Heartlab.
To lower your TMAO levels, consider minimizing the consumption of full-fat dairy products, including whole milk, egg yolk, cream cheese, and butter; both processed and unprocessed red meat (beef, pork, lamb, and veal), as well as nutritional supplements and energy drinks containing choline, phosphatidylcholine (lecithin), and/or L-carnitine. Vegetarians and vegans, who avoid meat products, for instance, produce little TMAO.
In general, consuming a diverse diet rich in plant foods and fiber may be helpful. When Cleveland Clinic researchers fed mice a diet rich in TMAO producing nutrients, they identified a compound called DMB capable of minimizing TMAO produced from their gut microbiota. In fact, when DMB was added to their drinking water, they found TMAO levels and the formation of arterial plaques both declined. DMB may be found naturally in many Mediterranean diet foods, including red wine and extra virgin olive oil.
Such an eating pattern may turn out to be key to cultivating a healthy human gut microbiome—one that will fend off myriad illnesses, including heart disease, America’s chief health threat.