Saturated fat? Cholesterol? Sure, red meat has plenty of those, but it also contains a compound that toys with gut bacteria and can lead to clogged arteries.
When it comes to explaining exactly why steaks and hamburgers and other red meats can be so harmful to the heart, the saturated fat that the body breaks down and sequesters in blood vessel walls where they can form dangerous plaques is an easy and obvious culprit. But the high rates of heart disease in the developed world suggest that these fats may not be working alone, say a group of researchers from the Cleveland Clinic who study how microbes and bacteria in our gut influence heart disease.
Our gut is full of bacteria — good strains that don’t cause disease — and recent studies show that these microbes can have a significant impact on our health, affecting our propensity for obesity, asthma, inflammatory diseases and even cancer. Not surprisingly, what we eat can influence which populations of bacteria are more common at any given time, so the researchers of the new study, published in the journal Nature Medicine, focused on how these gut microbes responded to a diet that included meat.
Specifically, they looked at a compound called carnitine, which is abundant in meats like beef, lamb, duck and pork, but is also a popular dietary supplement in energy drinks. In previous work on mice, the scientists found that gut bacteria can transform choline, a vitamin B group nutrient, from the diet into a compound called trimethylamine N-oxide (TMAO) that transports cholesterol to arteries where it forms potentially heart-stopping plaques. Carnitine, it turns out, is structurally similar to choline, so the researchers set out to document whether carnitine is metabolized by human gut bacteria in a similar way to gum up heart vessels and cause atherosclerosis.