Chronic red meat consumption alters gut microbiota, raises heart disease risk.
It is known that saturated fat in red meat has long been linked to a raised risk of heart disease, and that TMAO (trimethylamine N-oxide), a gut microbiota-generated metabolite, is also linked to the pathogenesis of heart disease. However, the link between chronic dietary patterns on TMAO production, metabolism, and renal excretion is still unclear. Now, a study from researchers at the Cleveland Clinic identifies new mechanisms which demonstrate that regularly eating red meat can increase the risk of heart disease, and the role gut microbiota plays in this process. The team state their study shows that a diet rich in red meat as the primary protein source significantly increases circulating TMAO levels via gut bacteria, compared to diets with white meat or non-meat as protein sources. The opensource study is published in the European Heart Journal.
Recent studies from the lab show that TMAO, a gut bacteria byproduct formed during digestion, can lead to the development of cardiovascular disease, including heart attacks and strokes; TMAO tests are now used in the clinical. TMAO is produced when gut bacteria digest choline, lecithin and carnitine, nutrients which are abundant in animal products such as red meat and liver and other animal products. The current study shows chronic red meat consumption elevates the production of TMAO by gut microbes and reduces the kidneys’ efficiency of expelling it, raising the risk of heart disease.
The current study follows 113 participants on meal plans prepared using either red meat, white meat or non-meat (vegetarian) protein sources as 25% of their daily calories. Results after one month show that study participants following the red meat diet experience a rise in TMAO levels in the blood and urine, which subsides once the red-meat diet is stopped. TMAO levels in the blood and urine increase 3-fold during the red meat diet, with some patients showing over a 10-fold rise, compared to the white meat or non-meat diets.
The group state that the participant’s chronic dietary choice also impacts kidney function by changing the effectiveness of the kidneys to expel compounds, with the red meat diet decreasing TMAO excretion, and increasing the excretion efficiency of carnitine and other carnitine-derived metabolites. They go on to hypothesize the design of a potential new class of drugs for the prevention of heart disease which interrupts the microbial pathway by which choline is converted into TMAO.
The team surmise that their data shows the pathway between chronic red meat consumption and heart disease, and the gut microbiota’s role in this pathogenesis. For the future, the researchers state by uncovering this new pathway, the global medical community can potentially develop new treatments to interupt the development and progression of cardiovascular disease.
Source: The Cleveland Clinic