Atherosclerosis

A specific compound with a name: TMAO

Atherosclerosis, the buildup of fatty plaques inside artery walls, has one of the best-characterised gut microbiome connections in cardiovascular disease. When gut bacteria break down choline and carnitine, compounds found in red meat, eggs, and other animal products, they produce trimethylamine, which the liver converts into trimethylamine N-oxide, or TMAO. Higher TMAO levels are consistently linked to greater atherosclerotic plaque size and increased cardiovascular risk.

Source: The roles of trimethylamine-N-oxide in atherosclerosis and its potential therapeutic aspect: A literature review

A genuinely direct mechanism, not just a correlation

TMAO doesn't just correlate with atherosclerosis, it appears to actively drive it: research shows TMAO promotes inflammation and injury in the cells lining blood vessels, encourages cholesterol to accumulate inside immune cells within plaques, and interferes with the body's process for clearing excess cholesterol from arteries. Researchers have also found bacterial DNA directly inside atherosclerotic plaques themselves, a striking, direct piece of evidence linking gut bacteria to the physical plaque rather than just blood test markers.

A specific, targetable pathway

Because TMAO's formation depends on specific bacterial enzymes, researchers have identified compounds that block this process at different stages, and dietary choices that reduce choline and carnitine intake, such as eating less red meat, lower TMAO production at the source. As with any gut-focused approach, this isn't about adding a single probiotic strain, but about the overall balance of gut bacteria and the foods that feed TMAO-producing species specifically.

What this means for you

Atherosclerosis needs proper cardiovascular risk assessment and management from a doctor, including standard measures like cholesterol control, blood pressure management, and not smoking, none of which this research changes. Given how well-established the TMAO mechanism is, moderating red meat, egg yolk, and processed meat intake is a reasonable, well-evidenced dietary step that happens to align with general heart-healthy eating advice already given for cardiovascular risk. A varied, plant-rich diet supports a gut bacteria balance that produces less TMAO and more of the short-chain fatty acids this research ties to healthier arteries. That's the same idea behind GutLab, everyday gut health starts with regularly feeding the microbiome a broad range of plant-rich ingredients.