The increased risk of heart disease from red meat may be due to the digestive response of the gut microbe

Embargo 4:00 CT/5:00 ET Monday, August 1, 2022

Highlights of the study:

  • Chemicals produced in the digestive tract by gut microbes after eating red meat (eg, beef, pork, bison, venison) explain a significant portion of the higher risk of cardiovascular disease associated with high red meat consumption, a new study suggests.

  • High blood sugar and inflammation also increase cardiovascular risk associated with red meat consumption, but blood pressure and cholesterol are not associated with higher CVD risk associated with red meat consumption.

  • Total consumption of fish, poultry, and eggs was not associated with increased cardiovascular risk.

(NewMediaWire) – August 01, 2022 – DALLAS Chemicals produced in the digestive tract by gut microbes after eating red meat may help explain the higher risk of cardiovascular disease associated with red meat consumption, according to a new study published today in American Heart. Peer-reviewed journal of the association Arteriosclerosis, Thrombosis and Vascular Biology (ATVB).

In the United States and worldwide, cardiovascular disease is the leading cause of death. While the risk of cardiovascular disease, including heart attack and stroke, increases with age, other risk factors are influenced by lifestyle. Lifestyle and behaviors known to improve cardiovascular health include eating healthy foods, especially fruits and vegetables; regular physical exercise; get enough sleep; maintain a healthy body weight; stop smoking; and controlling high blood pressure, high cholesterol, and blood sugar.

“Much of the focus on red meat and health benefits has focused on dietary saturated fat and blood cholesterol levels,” said study co-author Meng Wang, Ph.D., a postdoctoral fellow in the Friedman School of Nutrition. in Politics from Tufts University in Boston. “Based on our findings, new interventions may be useful for the interaction between red meat and the gut microbiome to help us find ways to reduce cardiovascular risk.”

Previous studies have found that chemical byproducts of certain digestive metabolites are associated with a higher risk of cardiovascular disease. One of these metabolites is TMAO, or trimethylamine N-oxide, which is produced by gut bacteria to digest red meat, which contains large amounts of the chemical L-carnitine.

High blood levels of TMAO in humans may be associated with increased risk of CVD, chronic kidney disease, and type 2 diabetes. However, it remains unclear whether L-carnitine-derived TMAO and related metabolites can help explain the effects of red meat intake on cardiovascular risk and how they may contribute to the cardiovascular risk associated with meat consumption.

To understand these questions, the researchers who conducted this study measured the levels of metabolites in blood samples. They also investigated whether blood sugar, inflammation, blood pressure, and blood cholesterol may account for the increased cardiovascular risk associated with red meat consumption.

Study participants included nearly 4,000 of the 5,888 adults originally recruited for the Cardiovascular Health Study (CHS) from 1989 to 1990. Participants selected for the current study were free of clinical cardiovascular disease at the time of enrollment at CHS, an observational study of risk factors for cardiovascular disease in adults aged 65 and older. The CHS included 5,888 participants drawn from four communities: Sacramento, California; Hagerstown, Maryland; Winston-Salem, North Carolina; and Pittsburgh, Pennsylvania. The average age of participants at enrollment was 73, nearly two-thirds of participants were female, and 88% of participants identified as white. The average follow-up time for participants was 12.5 years, and in some cases up to 26 years. At the follow-up meeting, participants’ medical history, lifestyle, health status, and sociodemographic characteristics such as household income, education, and age were assessed.

Several blood biomarkers were measured at the beginning of the study and in 1996-1997. Fasting blood samples frozen at -80 degrees were tested for levels of several gut microbiome compounds associated with red meat consumption, including TMAO, gamma-butyrobetaine, and crotonobetaine.

In addition, all study participants answered two validated food frequency questionnaires at baseline and from 1995 to 1996 about their usual dietary habits, including consumption of red meat, processed meat, fish, poultry, and eggs. For the first questionnaire. Participants indicated how often they had eaten a variety of foods over the past 12 months, ranging from “never” to “almost every day or five times a week,” based on average portion size. based on the food source. The second questionnaire used a ten-category frequency of standard portion sizes, ranging from “never or less than once a month” to “six+ servings per day” in the past 12 months.

For the current analyses, the researchers compared the risk of cardiovascular disease among participants who ate different amounts of animal-source foods (ie, red meat, processed meat, fish, chicken, and eggs). They found that eating more meat, especially red meat and processed meat, was associated with an increased risk of atherosclerotic cardiovascular disease – about 22% higher for every 1.1 servings per day.

According to the authors, increased blood levels of TMAO and related metabolites explained about one-tenth of this increased risk. They also noted that blood sugar and common inflammatory pathways may help explain the link between red meat and cardiovascular disease. Blood sugar and inflammation are also more important for linking red meat intake and cardiovascular disease than pathways related to blood cholesterol or blood pressure. Consumption of fish, poultry, and eggs was not significantly associated with a higher risk of cardiovascular disease.

“Research efforts are needed to better understand the health effects of L-carnitine and other substances in red meat, such as those associated with type 2 diabetes, without focusing on saturated fat,” Wang said.

The study had several limitations that may have affected its results. The study was observational, meaning it could not control for all risk factors for cardiovascular disease and could not prove a cause-and-effect relationship between meat consumption and cardiovascular disease or its mediation by gut microbe chemicals. In addition, dietary intake was self-reported, so reporting errors are possible. Because most of the study participants were older, white men and women in the United States, the findings may not generalize to younger or more racially diverse populations.

Lead author Zeneng Wang, Ph.D. Co-authors Eugene Lee, Ph.D.; Heidi TM Lai, MD; Marcia C. de Oliveira Otto, MD; Roseanne N. Lemaître, MD, MPH; Amanda Fretts, Ph.D., MPH; Nona Sotoodehnia, MD, MPH; Matthew Badoff, MD; Joseph A. DiDonato, MD; Barbara McKnight, Ph.D.; Wilson Tang, MD; Bruce M. Psati, candidate of medical sciences; David S. Siscovick, MD, MPH; Stanley L. Hazen, MD, Ph.D.; and Dariush Mozaffaran, MD. Authors’ statements appear in the manuscript.

The study was funded by the National Heart, Lung, and Blood Institute, with additional support from the National Institutes of Health, the National Institute of Neurological Disorders and Stroke, and the National Institute on Aging.

Research published in the American Heart Association’s scientific journals is peer-reviewed. Statements and conclusions in each manuscript are solely those of the study authors and do not necessarily reflect the policy or position of the Association. The Association makes no representations or warranties as to their accuracy or reliability. The Association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers, and other companies) also make charitable contributions and fund specific programs and activities of the Association. The association has a strict policy to prevent these relationships from influencing the content of science. Revenues from pharmaceutical and biotech companies, device manufacturers and health insurance companies and general financial information for the Association are available here.

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