The studies, both led by Dr Stanley Hazen from the Cleveland Clinic, suggest that bacteria in our guts digest certain nutrients found in foods – and particularly in red meat – in to potentially damaging metabolites that are linked to an increased risk of heart disease.
The team behind the work suggest that the findings could lead to new strategies to avoid such risks, and may also provide scientists with a new biomarker for cardiovascular risk.
"The findings identify the pathways and participants involved more clearly, and help identify targets for therapies for interventions to block or prevent heart disease development," commented Hazen. "While this is into the future, the present studies may help us to develop an intervention that allows one to 'have their steak and eat it too' with less concern for developing heart disease."
Red meat, gut bacteria, and TMAO
In the first study, published in the Journal of the American College of Cardiology, the team showed that a metabolic by-product of gut bacteria-dependent digestion, TMAO (trimethylamine N-oxide) is associated with heart failure and worse long-term prognosis.
TMAO, the researchers previously found, is produced when intestinal bacteria digest L-carnitine, a nutrient that is found in red meat, egg yolks, liver and some energy supplements.
As part of this research, Hazen and his team followed 720 heart failure patients over a five-year period – finding that higher TMAO levels predicted higher future risk of death from heart failure, independent of other clinically used blood tests or risk factors.
"I am excited that these studies suggest TMAO testing may not only help identify those patients at greatest risk and for whom more aggressive monitoring is needed, but also that TMAO testing may help to tailor dietary efforts to the individual in the hopes of reducing future risks among those high-risk subjects," said Hazen.