When most people think of their risk for having a heart attack or stroke, factors like cholesterol and blood pressure come to mind. But a new study by researchers at Cleveland Clinic shows that what’s in your gut can play a role as well.
The research, led by Stanley Hazen, MD, PhD, Section Head of Preventive Cardiology, shows that a compound that occurs in your gut after eating meat or high-fat dairy is a risk factor that can occur even if you have low cholesterol and a healthy blood pressure. The compound, called trimethylamine-N-oxide (TMAO) is formed when microbes in your gut digest foods such as red meat and egg yolks.
The new findings build on several clinical studies — many by Dr. Hazen’s research team — that link elevated blood levels of TMAO with heightened risk of heart and vascular diseases, including atherosclerosis, heart failure and chronic kidney disease. Several substances that are abundant in meat or dairy turn into TMAO after they come in contact with microbes in the gut.
Your digestive tract is full of bacteria. Some of them feed on choline and carnitine, which are nutrients in red meat, egg yolks and high-fat dairy products. As they feed, they give off a chemical called TMA (trimethylamine). Your liver turns TMA into TMAO.
TMAO in your blood affects the inner wall of your blood vessels, causing cholesterol buildup. TMAO also is dangerous because it heightens platelet activity, which can contribute to the formation of vessel-clogging blood clots.
Previous studies have shown that levels of TMAO in your blood can help predict your risk of heart disease. If you have chronically high TMAO, you have double the risk of heart attack, stroke and death.
The most recent study reviewed data from 4,000 patients and found that blood TMAO levels were a strong predictor of heart attack and stroke, independent of other risk factors.
“What we found is that TMAO identifies people at risk independent of their traditional risk factors, and in particular, it seems to help identify people at increased thrombotic event risk,” Dr. Hazen says.
Because TMAO is diet-induced, the study results open the door to new therapeutic targets and possible nutritional interventions as a way to prevent cardiac events, Dr. Hazen says.
Dr. Hazen also believes that this new information can give patients another way to manage their risk factors and improve their heart health.
One of the known ways to lower the production rate of TMAO involves following a diet that is focused on plants.
“A way of lowering your TMAO is to change your diet. It has been shown, and reported by others, that a Mediterranean diet, for example, will lower TMAO production overall,” Dr. Hazan says.
In addition to dietary changes, Dr. Hazen says people with a high TMAO should look at a number of ways to lower cardiovascular risk, including more aggressive monitoring of cholesterol levels and high blood pressure, and routine cardio exercise.
The research appears online in the journal Cell.
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