Red-Meat Diet and Heart Disease Seems to Start in the Gut

Avoiding or limiting the intake of red meat is recommended to avoid heart disease. Now researchers have uncovered how consuming too much red meat can increase our chances of developing cardiovascular disease from changes in gut bacteria. 

It's a two-step process

Eating too much red meat leads to harmful substances that are produced in the gut which, in turn, promote blood clots. 

Researchers have tried to understand why some people develop blood clots in the arteries that can lead to stroke and heart attack; in response to eating certain foods. 

In the past, it was suggested that cholesterol in foods was the main culprit that contributes to heart disease, but many scientists have suggested it isn't just about how much cholesterol we consume. 

Controversy still exists about how inflammation and heart attack might stem from dietary intake. 
Cleveland Clinic researchers now have more insight into the two-step process that occurs. 

According to their findings, the gut converts carnitine in red meat into a substance called TMAO or trimethylamine N-oxide - a highly inflammatory substance that could also lead to other ailments associated with systemic inflammation, including mysterious auto-immune disorders. (Front. Immunol., 16 September 2020)

It's not TMAO itself that leads to heart disease. Nor is it its precursor, TMA.

The researchers say an intermediary molecule - y-butyrobetaine (yBB) contributes to atherosclerosis and heart disease. It hasn't been clear what bacteria in the gut is responsible for the cascade of events that causes TMAO levels to rise and lead to blood clots. 

Scientists, based on this newest study, suggest yBB is metabolized into harmful TMA by the gut bacteria Emergencia timonensis.

The study authors found an abundance of the Emergencia timonensis in study participants given a red-meat diet; compared to people given white meat or non-meat diet. 

To test the effect of red meat and TMAO levels participants were given each diet, with a two-week wait period between switching. Plasma TMAO levels were measured. 

Stanley Hazen, MD, Ph.D. who spearheaded the study said:

“In omnivores, Emergencia timonensis is the primary human gut microbe involved in the transformation of γBB to TMA/TMAO. Conversely, long-term vegetarians and vegans have very low levels of this microbe in their gut and therefore have minimal to no capacity to convert carnitine into TMAO.”

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What the study means for anyone at risk for heart disease is that switching from a diet rich in red meat would change gut bacteria and lower the chances of heart disease and heart attack. 


Front. Immunol., 16 September 2020 |

Image: Wikimedia Commons