Can Your Gut Impact Heart Health?

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Healthy diet patterns have long been associated with reduced risk of cardiovascular disease and with increasing longevity. Research has proven:

• Fruit and vegetable consumption is associated with a lower risk of heart disease and stroke.
• Lean protein sources have a more positive impact on health compared to protein sources high in trans and saturated fats.
• Increased whole grain intake is associated with lower risks of developing or dying from cardiovascular disease.    

Now, new research suggests that the cardiovascular benefits of healthy diets may be determined by not only the foods we eat, but also by how our gut metabolizes those foods. 

Our intestines are full of bacteria (gut microbiota) which metabolize our food, breaking it down into smaller components or chemicals that then enter the blood stream. There is emerging evidence that some of these chemicals derived from the digestion of food may play a role in the development of chronic diseases. Trimethylamine, or TMA, is one such chemical which may be linked to the development of cardiovascular disease as well as other chronic diseases. 

Dietary choline (found in foods such as egg yolks and high-fat dairy products) and L-carnitine (found in red meat and some energy drinks) is metabolized into TMA in the intestine, and then travels to the liver where it is converted to trimethylamine oxide, or TMAO. TMAO then enters the blood steam, where it may contribute to the development of plaque or atherosclerosis in the arteries. 

In one study of 4,000 patients who were either at very high risk for heart disease or already had a heart attack, those who had the highest levels of TMAO were 2.5 times more likely to have an adverse cardiovascular event over a three year period compared to those who had the lowest levels of TMAO.  

Interestingly, our dietary habits may also influence the makeup of the bacteria in our gut. Small, preliminary studies suggest a diet high in L-carnitine may alter the bacteria in our gut so more carnitine is metabolized and more TMAO is made. On the other hand, if vegans and vegetarians are introduced to a high L-carnitine food that they normally do not eat, their gut microbe composition has a reduced capacity to make TMAO.

The TMAO story is far from complete and its role in cardiac risk prediction is not perfectly defined. For example, eggs are a big source of choline and are associated with TMAO production, but many large epidemiologic studies have demonstrated egg consumption is not associated with an increased risk of heart disease. TMAO is naturally found in fish, and yet there are many epidemiologic studies demonstrating fish consumption reduces the risk of heart disease. Whether TMAO predicts cardiac risk in generally healthy people is not known, but our researchers at The Cooper Institute plan to shed light on this topic in the near future. 

The identification of chemicals such as TMAO heralds the arrival of fascinating new areas of medical research focusing on how our gut bacteria influence the development of disease and in turn, how our health behaviors influence the makeup of those bacteria in our gut. 

For more information about cardiovascular screenings at Cooper Clinic, visit cooper-clinic.com or call 972.560.2667. 

Article provided by Nina Radford, MD, Cooper Clinic Cardiologist.