Reducing animal product intake and following a primarily plant-based diet can decrease your risk of heart disease by minimizing the adverse effects of a gut-microbiome associated with increased risk of coronary heart disease, according to research published today in the Journal of the American College of Cardiology.
Gut microbiota and diet
The body’s gut microbiota is comprised of a series of microbes that play an important role in our metabolism, nutrient absorption, energy levels and immune response. A gut-microbiota related metabolite known as trimethylamine N-oxide (TMAO) is produced when gut bacteria digests nutrients commonly found in animal products such as red meat. It has been connected to increased heart attack and coronary heart disease risk. Maintaining a vegan or vegetarian diet has been found to reduce the amount of trimethylamine N-oxide produced in the body.
Vegetarian diet: The Nurses’ Health Study
The study authors 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 trimethylamine N-oxide from the first collection to the second blood collection. After adjusting for participants with available plasma trimethylamine N-oxide levels at both collections, there were 380 cases of coronary artery disease and 380 demographically matched-control participants without coronary artery disease chosen by the researchers included in the analysis.
The risk of coronary artery disease
The risk of coronary artery disease was calculated by changes in trimethylamine N-oxide levels in the body throughout the follow-up period. Assessing this substance levels relies on diet and nutrient intake; the researchers investigated how diet quality modifies the association between trimethylamine N-oxide and coronary artery disease.
Higher concentrations of trimethylamine N-oxide
Women who developed coronary artery disease had higher concentrations of trimethylamine N-oxide levels, higher Body Mass Index, family history of heart attack and did not follow a healthy diet including higher intake of vegetables and lower intake of animal products. Women with the largest increases in trimethylamine N-oxide levels across the study had a 67% higher risk of coronary artery disease.
“Diet is one of the most important modifiable risk factors to control trimethylamine N-oxide levels in the body,” said Lu Qi, MD, director of the Tulane University Obesity Research Center and the study’s senior author. “No previous prospective cohort study has addressed whether long-term changes in trimethylamine N-oxide are associated with coronary artery disease, and whether dietary intakes can modify these associations. Our findings show that decreasing trimethylamine N-oxide levels may contribute to reducing the risk of coronary artery disease, and suggest that gut-microbiomes may be new areas to explore in heart disease prevention.”
Gut microbiota and coronary artery disease risk
The study authors found no differences in trimethylamine N-oxide levels between the coronary artery disease and control participants at the first blood sample collection. trimethylamine N-oxide levels examined in the second blood sample collection taken 10 years later were significantly higher the participants with coronary artery disease. Every increase in trimethylamine N-oxide was associated with a 23% increase in coronary artery disease risk. This association remained after controlling for demographic, diet and lifestyle factors, confirming the link between higher trimethylamine N-oxide levels and coronary artery disease risk.
“The findings of the study provide further evidence for the role of trimethylamine N-oxide as a predictive biomarker for heart disease and strengthens the case for trimethylamine N-oxide as a potential intervention target in heart disease prevention,” said Paul A. Heidenreich, professor of medicine at the Stanford University School of Medicine, in an accompanying editorial comment. “The results should encourage us to continue to advocate for a more widespread adoption of healthy eating patterns.”
The study authors support the need for further research to confirm the findings in both men and a more representative population of the United States.
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