Link between meat and heart disease
Consumption of red meat increases the content of metabolites, which are produced by intestinal bacteria from the nutrients it contains. This appears to be at least part of the explanation for why red meat is associated with a higher risk of developing cardiovascular disease.
A new study involving experts from Tufts University has examined associations between the consumption of animal-based foods and the onset of atherosclerotic cardiovascular disease. The results can be found in the journal Arteriosclerosis Thrombosis and Vascular Biology.
How do cardiovascular diseases develop?
Cardiovascular diseases are the leading cause of death worldwide. On the one hand, age increases the risk of these types of diseases, which also include strokes and heart attacks, but on the other hand, there are many risk factors that are influenced by lifestyle. .
According to the team, previous studies have already shown that certain byproducts of food digestion (called metabolites) are associated with a higher risk of cardiovascular disease.
One of these metabolites produced by gut bacteria during the digestion of red meat is trimethylamine N-oxide (TMAO). Trimethylamine N-oxide contains large amounts of L-carnitine.
Health Risks of Trimethylamine N-Oxide
When people have higher levels of trimethylamine N-oxide in their blood, it's associated with a higher risk of developing cardiovascular disease, chronic kidney disease, and type 2 diabetes.
So far, however, it is unclear whether trimethylamine N-oxide and related L-carnitine-derived metabolites could account for the increased cardiovascular risk associated with red meat consumption, the researchers say.
Red meat, intestinal flora and cardiovascular risk
To clarify the question of whether meat influences cardiovascular risk via gut microbiota, the researchers assessed data from 3,931 people who had previously been recruited for the Cardiovascular Health Study (CHS) between 1989 and 1990.
At the start of the study, the participants had no clinical cardiovascular disease. The average age of participants at study enrollment was 73, and nearly two-thirds of participants were female.
All participants underwent medical follow-up for an average of 12.5 years, and in some cases medical follow-up continued for up to 26 years, the team said.
Measurement of blood biomarkers performed
Various blood biomarkers were measured at the start of the study. This happened again in 1996 and 1997. Frozen fasting blood samples were tested for levels of metabolites of various gut microbiota associated with red meat consumption, including trimethylamine N-oxide, gamma- butyrobetaine and crotonobetaine.
In addition, all participants completed two validated questionnaires about their usual eating habits at the start of the study and again between 1995 and 1996.
In their analysis, the researchers then compared the risk of cardiovascular disease among participants who consumed different amounts of animal foods (i.e. red meat, processed meat, fish, chicken and eggs).
Meat increases the risk of cardiovascular disease
The team found that eating more meat, especially red meat and processed meat, was associated with a higher risk of atherosclerotic cardiovascular disease.
According to experts, however, the observed increase in trimethylamine N-oxide and related metabolites in the blood can only explain about a tenth of the increased risk. Additionally, the effects of meat consumption on blood sugar and general inflammatory processes could be a possible explanation for the association between red meat consumption and cardiovascular disease.
According to the study's results, blood sugar and inflammation are more important in the link between red meat consumption and cardiovascular disease than mechanisms related to cholesterol levels or blood pressure, the research team says. .
In the study, the consumption of other foods of animal origin such as fish, poultry and eggs did not lead to a significant increase in the risk of cardiovascular disease.
Defining a new research axis
“Most of the attention that has been paid to red meat consumption and health has focused on saturated fat and blood cholesterol levels,” reports study author Dr. Meng. Wang in a press release from the American Heart Association (AHA).
More research is needed to "better understand the potential health effects of L-carnitine and other compounds in red meat, such as heme iron, that have been linked to type 2 diabetes, rather than focus only on saturated fats". Dr. Wang added.
The current study also suggests that interventions targeting interactions between red meat and the gut microbiome may help reduce cardiovascular risk.
According to researchers, eating fruits, vegetables and other healthy foods, regular physical activity, adequate sleep, healthy body weight, not smoking, and normal blood pressure, cholesterol and blood sugar levels are crucial factors. (as)
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Sources:Meng Wang, Zeneng Wang, Yujin Lee, Heidi TM Lai, Marcia C de Oliveira Otto, et al. : Dietary Meat, Trimethylamine N-Oxide-Related Metabolites, and Incident Cardiovascular Disease in the Elderly: The Cardiovascular Health Study; in: Arteriosclerosis Thrombosis and Vascular Biology (published 8/1/2022), Arteriosclerosis Thrombosis and Vascular BiologyAmerican Heart Association: Red meat-related increased heart disease risk may come from gut microbes' response to digestion (published 2022). 8/1/2022), AHA
This article contains general advice only and should not be used for self-diagnosis or treatment. It cannot substitute a visit to the doctor.