This protein's effect on your heart actually may actually start in the gut.
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illustration of a gut and red meat
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If you're trying to eat a heart-healthy diet, there's a pretty good chance you've scaled back the amount of red meat you eat. Red meats, like beef, pork, lamb and venison, often contain more saturated fat than chicken or fish, according to the American Heart Association. Since too much saturated fat can lead to higher cholesterol levels and a higher risk of heart disease, experts have suggested laying off of steak and bacon to protect your ticker—but red meat's effects on your health might be a little more complicated than that.

A new study published in Arteriosclerosis, Thrombosis, and Vascular Biology suggests that the connection between red meat and higher risk of heart disease may stem from the gut microbiome. Generally, the digestive tract will produce chemicals called metabolites once it has digested the food you just ate. While those resulting chemicals aren't always unhelpful, certain metabolites are associated with a higher risk of cardiovascular disease, and red meat tends to result in an influx of those harmful metabolites.

"Most of the focus on red meat intake and health has been around dietary saturated fat and blood cholesterol levels," co-lead author of the study Meng Wang, Ph.D., said in a media release. "Based on our findings, novel interventions may be helpful to target the interactions between red meat and the gut microbiome to help us find ways to reduce cardiovascular risk."

The researchers consulted food frequency questionnaires, blood tests and demographic information from nearly 4,000 people who participated in the Cardiovascular Health Study. On average, the participants were around 73 years old. The research team compared risk for cardiovascular disease among participants based on what sources of protein they ate the most and found that eating more meat—especially red meat and processed meat—was associated with a 22% higher risk for about every 1.1 serving per day.

The study found that 10% of the elevated risk could be explained by the gut microbiome's response to red meat. Researchers also found that blood sugar could be a possible connection between eating red meat and increased heart disease risk.

"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," Wang said.

Meanwhile, the study found no link between heart disease risk and eating poultry, fish or eggs, so if you prefer having grilled chicken or roasted salmon for dinner, you might be doing your heart a favor. (Heart-healthy dinners like our Green Veggie Bowl with Chicken & Lemon-Tahini Dressing and Lemon-Garlic Pasta with Salmon are pretty tasty options.)

These findings still need to be confirmed by further research, but it does expand on research previously published in the European Heart Journal. That study found that trimethylamine-N-oxide (TMAO), a metabolite linked to heart disease risk, shows up after the digestion tract processes red meat. The good news is that eating more plant-based foods—and especially more plant-based proteins—can be good for your heart and your gut. In 2021, a study in the Journal of the American Heart Association found that eating a plant-focused diet could lower your heart disease risk by 61%, while a 2022 study found that a flexitarian diet fostered the widest variety of gut bacteria in participants.

The Bottom Line

New research published in Arteriosclerosis, Thrombosis, and Vascular Biology found that red meat's effect on your heart health may start with your gut. Past research has indicated that the gut microbiome, a collection of diverse bacteria that helps manage your overall health, also has an impact on your blood pressure, mental health and sleep. Cutting back on certain foods—like red meat and other processed meats—can help keep your gut in tip-top shape, especially if you add more gut-friendly foods to your routine, like fermented kimchi, creamy kefir and plenty of fruits and veggies.