Increased heart disease risk from red meat

Chemicals produced in the digestive tract by gut microbes after eating red meat may help explain part of the higher risk of cardiovascular disease associated with red meat consumption, according to new research published today in the American Heart Association's peer-reviewed journal Arteriosclerosis, Thrombosis, and Vascular Biology (ATVB).

Previous research has found that certain metabolites are associated with a greater risk of cardiovascular disease. One of these metabolites is TMAO, or trimethylamine N-oxide, which is produced by gut bacteria to digest red meat that contains high amounts of the chemical L-carnitine.

High blood levels of TMAO in humans may be associated with higher risks of CVD, chronic kidney disease, and Type 2 diabetes. However, whether TMAO and related metabolites derived from L-carnitine may help explain the effects of red meat intake on cardiovascular risk.

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

Study participants included nearly 4,000 of the 5,888 adults initially recruited from 1989 to 1990 for the Cardiovascular Health Study (CHS).

Several blood biomarkers were measured at the start of the study and again in 1996-1997.

For the current analyses, the researchers compared the risk of cardiovascular disease among participants who ate different amounts of animal source foods (i.e., red meat, processed meat, fish, chicken, and eggs). They found that eating more meat, especially red meat and processed meat, was linked to a higher risk of atherosclerotic cardiovascular disease - a 22% higher risk for about every 1.1 serving per day.

According to the authors, the increase in TMAO and related metabolites found in the blood explained roughly one-tenth of this elevated risk. They also noted that blood sugar and general inflammation pathways may help explain the links between red meat intake and cardiovascular disease. Blood sugar and inflammation also appear to be more important in linking red meat intake and cardiovascular disease than pathways related to blood cholesterol or blood pressure. Intake of fish, poultry, and eggs was not significantly linked to a higher risk of cardiovascular disease.

Ref:

Meng Wang et. al, Arteriosclerosis Thrombosis, and Vascular Biology, 1-Aug-2022, 10.1161/ATVBAHA.121.316533