The Missing Link In Heart Health Your Doctor May Not Tell You

… Why Gut TMA Is Not TMI

As the “Happy Gut® Doctor,” I’ve spent a good portion of my time educating people around the world about gut health and how most health issues can be traced back to the gut. And if you’ve been following my previous blog posts, you’d know things like: how depression can actually start in the gut, because more serotonin is made in the gut than in the brain; how a leaky gut can lead to chronic inflammation, put your immune system on high alert, and even result in autoimmune disease; and how weight gain is tied to certain gut bacteria that can make it harder to lose those excess pounds.

And now this month, in honor of American Heart Health Month, I’m talking about the undeniable connection between gut health and heart disease .

Explaining the Link Between Diet & Heart Disease

While diseases like Alzheimer’s and type 2 diabetes have made a lot of headlines recently — mostly due to the sharp uptick in cases — cardiovascular disease remains the leading cause of death worldwide for both men AND women, killing more than 17.9 million people each year worldwide. We’ve known for decades that our diet influences our cardiovascular health (dietary changes have always been one of the first recommendations for issues like high cholesterol, high blood pressure, or atherosclerosis); that said, most resources tend to gloss over exactly why this connection exists and how it actually works.

This is because until not long ago, we didn’t exactly understand how this connection works. But in recent years, researchers have uncovered more details as to why the strong connection between diet and heart disease exists — and surprise! It has everything to do with the gut bacteria.

Here’s what I mean: In the last few years, researchers have published several studies done on people and animals that have linked specific gut bacteria to an increased risk for heart attack and stroke. More specifically, the researchers found that when you eat certain foods that contain L-carnitine, which is found in red meat, and phosphatidylcholine, which is found in foods like eggs, cheese and shellfish, it promotes the growth of more certain gut bacteria, which then start producing higher levels of a compound called trimethylamine, or TMA. If it stopped there, it probably wouldn’t be so damaging. But the issue arises when TMA is metabolized in our livers.

Once in the body, TMA is quickly transformed by the liver into something called trimethylamine N-oxide (TMAO). And here’s where the bad news comes in: While it’s totally normal for gut bacteria to produce metabolites like TMA, the specific metabolite TMAO has been linked to cardiovascular disease risk. And it can only be produced in the liver by a process called biotransformation — in this case, by an enzyme known as flavin monooxygenase (FMO for short). Why is this important? Because people can have genetic differences in the activity of the FMO enzyme, leading to more or less conversion of TMA to TMAO.

Understanding TMAO & Heart Health

This newly discovered link isn’t a weak one, either. Studies have shown that people with higher TMAO in their blood are twice as likely to have a heart attack, stroke, or other cardiovascular emergency than those with normal TMAO levels. The results of a recent study also showed that people with high blood levels of TMAO were more likely to die prematurely. High TMAO has also been connected to heart failure and chronic kidney disease .

TMAO makes your blood clot-forming cells (aka platelets) sticky, which means it increases the likelihood they’ll stick to the inside of an artery and cause a blockage, like what happens during a heart attack or stroke.

And here’s where things get really interesting: It seems that the more red meat you eat, the more you promote the growth of “meat eating” gut bacteria in your gut and the more TMAO you end up producing when you eat meat. In contrast, vegans and vegetarians tend to have lower levels of TMAO and TMAO-producing bacteria. Talk about a vicious cycle!

Eating large and frequent amounts of red meat and animal products changes the makeup of your microbiome, causing it to produce more TMAO. #mindblown

Research has shown that about 25% of metabolites are different between omnivores and vegans and that people who adhere strictly to a plant-based diet are 25% less likely to develop heart disease. Interesting how these numbers line up, isn’t it? So while this is not a causational relationship (meaning, it’s not proven that one causes the other), it does force us to consider the idea that the changes in the gut microbiota and their metabolites are really what’s responsible for the negative effects of red meat and animal products on heart health.

Linking TMAO, Red Meat, and Saturated Fat

After reading the above, you might be scared that the next piece of advice I’ll give you is to cut out all meat, dairy, and animal-based products. Well, you can exhale because that’s not the advice I’m about to give! From my perspective, the recent learnings about red meat consumption and TMAO should encourage us to focus on eating a diet that is guided by balance and moderation.

Why? Well, research shows that those who eat a plant-rich diet have fewer TMA-producing bacteria and therefore produce less TMAO after eating animal products. In fact, vegans and vegetarians who eat meat will not initially be able to synthetize TMA in the gut or convert it to TMAO in the liver at all. It isn’t until a person continues to eat red meat regularly over a long period of time that they are able to produce these metabolites. This means that as long as you’re eating plenty of plants and only eating red meat (along with shellfish, eggs, and dairy) in moderation, your TMAO levels should stay in a healthy range. If you want to continue to enjoy red meat but want to avoid unhealthy TMAO levels, follow the five steps below.