Are Long-Term Increases in TMAO Associated With Higher CHD Risk?

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Reducing animal product intake and following a primarily plant-based diet may decrease the risk of cardiovascular disease by minimizing the adverse effects of trimethylamine N-oxide (TMAO) – a gut-microbiome associated with increased risk of coronary heart disease (CHD) – according to research published Feb. 17 in the Journal of the American College of Cardiology.

Yoriko Heianza, RD, PhD, et al., examined 760 women in the Nurses' Health Study, a prospective cohort study of 121,701 female registered nurses aged 30 to 55 years old. Women were asked to report data on dietary patterns, smoking habit and physical activity, plus other demographic data and provide two blood samples taken at Cleveland Clinic, 10 years apart.

The researchers measured plasma concentrations of TMAO from the first collection to the second blood collection. After adjusting for participants with available plasma TMAO levels at both collections, there were 380 cases of CHD and 380 demographically matched-control participants without CHD chosen by the researchers included in the analysis.

Results showed that women who developed CHD had higher concentrations of TMAO levels, higher BMI, family history of myocardial infarction and did not follow a healthy diet including higher intake of vegetables and lower intake of animal products. Women with the largest increases in TMAO levels across the study had a 67 percent higher risk of CHD.

The study authors also found no differences in TMAO levels between the CHD and control participants at the first blood sample collection. However, TMAO levels examined in the collection taken 10 years later were significantly higher the participants with CHD. Every increase in TMAO was associated with a 23% increase in CHD risk. This association remained after controlling for demographic, diet and lifestyle factors, confirming the link between higher TMAO levels and CHD risk.

"Our findings show that decreasing TMAO levels may contribute to reducing the risk of CHD, and suggest that gut-microbiomes may be new areas to explore in heart disease prevention," said Lu Qi, MD, the study's senior author. Moving forward, the study authors also support the need for further research to confirm the findings in both men and a more representative population of the U.S.

In an accompanying editorial comment, Paul A. Heidenreich, MD, MS, FACC, and Petra Mamic, MD, explain that, "The findings of the study provide further evidence for the role of TMAO as a predictive biomarker for heart disease and strengthens the case for TMAO as a potential intervention target in heart disease prevention." They add that the results "should encourage us to continue to advocate for a more widespread adoption of healthy eating patterns."

Keywords: Middle Aged, Diet


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