Lately, red meat can’t seem to catch a break. It’s been touted as inflammatory, is a contributor to greenhouse gas emissions, and is thought to be linked to common health woes like cardiovascular disease. But what, exactly, is it about red meat that’s causing such a stir?
Well, researchers have set out to find exactly what happens to the human body when red meat is consumed. And the answer just might be in this food group’s interactions within the gut.
Red Meat Alters the Risk for Cardiovascular Disease
Research published in 2022 in Arteriosclerosis, Thrombosis, and Vascular Biology, the peer-reviewed journal by the American Heart Association, suggests that red meat may be processed differently than other foods once it reaches the gut.
In this study, a team of researchers worked with approximately 4,000 adult participants, all of whom participated in the Cardiovascular Health Study (CHS) that began in 1989/1990 and conducted follow-ups after approximately 12.5 years. All of those participants were not diagnosed with cardiovascular disease when they began the CHS, and they had an average age of 73. Throughout the CHS, participants’ medical histories, blood biomarkers, and dietary habits were all tracked. So, when the researchers for the 2022 study began their work, they utilized the data and samples collected.
In particular, the researchers looked at fasting blood samples from the participants. They looked for several blood biomarkers that were linked to red meat consumption, including biomarkers called TMAO, gamma-butyrobetaine, and crotonobetaine. Then, they compared that information to the participants’ self-reported dietary questionnaires, looking at what animal food sources individuals consumed (for example, red meat, fish, chicken, or processed meat).
At the study’s end, the findings showed that participants who are more meat – and more red meat in particular – saw a higher risk for developing atherosclerotic cardiovascular disease. That’s cardiovascular disease accompanied by thickening of the arteries.
And the increased risk wasn’t minimal, either. Participants saw a 22% higher risk of atherosclerotic cardiovascular disease for every 1.1 serving they ate per day.
Interestingly, those who are fish, poultry, and eggs did not see a significant link between consumption of these foods and a higher risk of cardiovascular disease.
What Happens in the Gut When Red Meat is Consumed
So, what does this increased risk of cardiovascular disease have to do with the gut? Well, the researchers also pinpointed a few particular biomarkers that may suggest it’s how red meat and the gut interact with each other that holds the answer.
In the participants’ blood samples, researchers measured the levels of metabolites present. They found increased levels of those aforementioned red meat biomarkers, like TMAO. These metabolites – and TMAO in particular – were produced by the gut’s bacteria while digesting red meat that contains high amounts of a chemical called L-carnitine.
This increase in TMAO and other related metabolites found in participants’ blood samples are thought to play a role in increasing the risk of cardiovascular disease. The researchers suggested that these gut metabolites may affect blood sugar levels and inflammation within the body, which may play a role in the known link between red meat consumption and cardiovascular issues. Blood sugar and inflammation may be increasingly important for heart health – even though high cholesterol levels and high blood pressure are currently more commonly looked to as key factors that can hamper cardiovascular health.
But, as the study’s co-lead author Meng Wang, Ph.D. and postdoctoral fellow at the Friedman School of Nutrition Science and Policy at Tufts University, told Science Daily, more research is needed to fully understand this connection: “Research efforts are needed to better understand the potential health effects of L-carnitine and other substances in red meat such as heme iron, which has been associated with Type 2 diabetes, rather than just focusing on saturated fat.”
So, Should Red Meat Be Cause for Concern?
The findings of this study point to the gut as holding potential clues for how our bodies react to red meat – and why eating red meat may be so closely linked with cardiovascular health concerns. But the results don’t necessarily mean you should swear off red meat altogether.
As the co-lead author Wang mentioned, more research is needed to fully understand how, exactly, eating red meat may affect what’s happening in the gut. This initial study did have some limitations, which may have shaped the findings. For example, the study was observational; it couldn’t prove cause and effect between eating red meat and cardiovascular disease, nor how it may directly affect chemicals generated by gut microbes. And participants self-reported their food intake, meaning errors could’ve happened along the way.
So, while red meat may have links to heart health concerns and cardiovascular disease, there’s no reason to cut it from your diet entirely. Anything, when eaten too often or in too large quantities, can have negative effects on your wellness. But when incorporated into a balanced diet, there’s no need to fear red meat.
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