For years, diets low in red meat have been believed to be the healthiest for our hearts.
Now, new research is uncovering the ways in which a red meat-rich diet can impact heart disease risk.
The study, led by Stanley Hazen, M.D., Ph.D., chair of the Cleveland Clinic Department of Cellular and Molecular Medicine, shows the link between red meat and heart health happens in the gut, where a compound called TMAO (trimethylamine N-oxide) is formed.
TMAO is a compound that is made by gut microbes during digestion. The compound is known to contribute to the development of heart disease, including heart attacks and strokes.
Study participants ate, in random order, specific protein diets for one month each -- a red meat-rich diet, a white meat diet and non-meat, predominantly plant-based protein diet.
And while researchers suspected the red meat diet could raise TMAO levels, Hazen said they were surprised to see just how much levels were raised, and why they increased as much as they did.
“Eating a diet that’s rich in red meat, significantly raises one’s TMAO level, by at least two- to threefold compared to eating a diet with either a white meat or plant-based protein source diet,” said Hazen.
Hazen said not only did the gut microbes of individuals on the red meat diet make more TMAO, but the red meat diet made the kidneys less efficient at eliminating TMAO.
In contrast to the red meat-rich diet, researchers also found that those who ate a white meat or plant-based protein diet actually had suppressed gut microbe formation of TMAO, and improved kidney function and elimination of TMAO, which supports previous research that says these types of diets are healthier for our hearts and bodies.
Hazen said when the people who ate the red meat diet stopped eating red meat, their TMAO levels came back down to normal within three to four weeks.
He said this research tells us that TMAO levels are modifiable, meaning we can change our heart disease risk by making changes to our diets.Â
“We can use a TMAO level to help personalize dietary choices in an individual to help identify, for a given person, how much red meat is too much, and how to try to chase after lowering the level -- much in the same way we do with cholesterol levels or triglyceride levels or glucose levels now by selections or choices in our diet,” Hazen said.
Complete results of the study can be found in European Heart Journal.