A new study, published in the Journal of the American College of Cardiology, highlights how certain diets can decrease the risk of cardiovascular disease. Researchers have found that following a diverse and healthy diet, rich in plants can decrease the risk of heart disease by reducing levels of a molecule called trimethylamine N-oxide (TMAO). TMAO is produced when the gut microbiota digests nutrients commonly found in red meat and is one of the molecules that forms atheromatous plaques in the blood, leading to an increased risk of cardiac or circulatory system conditions, such as heart attack or stroke.
This new study expands on these findings by examining 380 women between the ages of 30 and 55. Researchers collected information on diet and nutrient intake using a questionnaire and used a “healthy eating index,” in which healthy plant foods are given positive scores, and other foods are given negative scores. Participants were then asked to e two blood samples 10 years apart, allowing researchers to look at how TMAO blood plasma levels changed over the 10-year period. TMAO levels are known to change based on diet and nutrient intake, and authors looked at how diet quality modified the association between TMAO and coronary heart disease (CHD). Overall, they found that women who developed CHD had higher concentrations of TMAO at second blood collection and had a higher intake of animal products and a lower intake of plants.
Compared to participants with the lowest TMAO levels, participants with the largest increases in TMAO (average increase of 3.7 mmol/l) had a 1.67 times higher risk of contracting CHD. Although this study only collected data from women, the results nevertheless strengthen the existing overall link between heart health and diet.
“Our findings suggest that gut-microbiomes may be new areas to explore in heart disease prevention,” says Li Qi, MD, director of the Tulane University Obesity Research Center (USA) and the study’s senior author. Paul A. Heidenreich, MD, MS of Stanford University School of Medicine in USA suggests that TMAO may be used as a predictive biomarker for heart disease and may even be targeted for heart disease prevention.
Overall, this study emphasizes that adhering to a diverse diet that is rich in plant-based foods may decrease cardiovascular disease risk by influencing the type of metabolites produced by the gut microbiota and, therefore, reducing atherogenic molecules. While many factors can influence cardiovascular risk, including age, lifestyle and other health indicators, these results should “encourage us to advocate for a more widespread adoption of healthy eating patterns.”
 Mmol/L or millimole per liter is the standard unit of measuring the quantity of a substance within a liquid.
Heianza, Yoriko, Wenjie Ma, Joseph A. DiDonato, Qi Sun, Eric B. Rimm, Frank B. Hu, Kathryn M. Rexrode, Jo Ann E. Manson, and Lu Qi. 2020. “Long-Term Changes in Gut Microbial Metabolite Trimethylamine N-Oxide and Coronary Heart Disease Risk.” Journal of the American College of Cardiology 75 (7): 763–72. https://doi.org/10.1016/j.jacc.2019.11.060.