TMI on TMAO? How Your Diet Impacts Your Heart Health

heart health

Taking Control Over Heart Health

Americans have been facing an uphill battle against cardiovascular disease for the last forty years. Every 33 seconds, a person dies from cardiovascular disease in the United States, with nearly 650,000 deaths from heart disease each year. A staggering number – translating to nearly 1 in every 4 deaths that can be attributed to cardiovascular events. Yet, there are many ways people can begin to take control over their heart health today. Scientists have found strong associations that dietary and lifestyle changes can significantly strengthen the heart, lessening the impact of many cardiovascular disease risk factors.

Even so, the field of nutrition has been predominantly responsible for making profound improvements in disease research, showing the impact various foods can have on different people over time. Historically, research has shown many foods rich in saturated fats and high and cholesterol may impact heart health by increasing the prevalence of plaques. These arterial blockages can lead to coronary heart disease and increase the likelihood of cardiovascular events. For example, scientists have reported for some time that there seemed to be a higher correlation of heart disease from individuals that frequently consumed red meat. Innumerable studies have supported this complex relationship of red meat and cardiovascular disease, however what might actually be causing this interaction has been a hot topic for debate. Originally, scientists believed the high concentration of saturated fat and cholesterol may be the culprit – yet various studies were unable to determine it for sure. Instead, scientists have begun to explore a new hypothesis, and this one might have more to do with mischievous activities of certain microbes in our gut.

The 411 on TMAO

In the search to better define cardiovascular disease risk, scientists found that high circulating levels of a certain compound called trimethylamine N-oxide, or TMAO, was common in cardiovascular disease patients. In one study, researchers found that people with a higher level of TMAO in their blood more than doubled their risk of heart attack, stroke, or other cardiovascular events. In addition to heart health, TMAO levels were also shown to be connected to chronic kidney disease – making it even more concerning for scientists. Where did this elevation in TMAO come from? And how was it affecting people?

Although scientists expected these answers may have their origins from the food we eat and our digestion – their attention took an unexpected turn toward the gut.

The compound TMAO is actually formed from foods that are rich in the substances carnitine and choline, found in many foods such as eggs, fish, poultry, and red meat. Once consumed, as these foods get digested, certain microbes in your gut actually eat at the compounds and create a metabolite called trimethylamine – a precursor to TMAO. The more foods rich in carnitine or choline you consume (like red meat) the more these feasting microbes reproduce, creating more and more TMA. A vicious cycle.

When our body absorbs the TMA into our blood, it travels to our liver where it gets converted into TMAO. Once fully formed, TMAO can wreak havoc on your body by promoting inflammation and changing how we metabolize cholesterol, even increasing the risk of plaque development – all risk factors of cardiovascular disease. Eventually, it passes to the kidney to be excreted in our urine. As levels of TMAO climb, they eventually can induce kidney fibrosis, leading to scar tissue formations within the organ. Researchers have linked this development to TMAO’s impact on kidney health. As the level of fibrosis increases, kidney function deteriorates leading to chronic kidney disease.

Targeting the Gut for Heart Health

Considering the strong role TMA-producing microbes play in the generation of TMAO, scientists are finding the gut might have an advantageous potential for combating heart disease. Already, several different therapies have been tested, such as employing specific antibiotics to change the prevalence of TMA-producing microbes – but these treatments are rarely as effective (and without adverse reactions) as specialists hope. However, there are many ways diet can be used to change the impact these gut microbes have on TMA production.

The Vegan Experiment

One might consider, that if the more meat you consume, the more TMA-producing microbes might reproduce within the gut microbiome – what happens when you don’t consume meat? This question seemed to really interest scientists, so they began testing the gut microbiome of vegetarians and vegans to explore what their TMAO footprint was.

In one study, scientists were able to see that following a diet with no animal product slowly reduced the level of these microbes, and in time – even eliminated them from the gut microbiome. Without these microbes, their body didn’t produce TMAO at all. However, if these same groups continued their diet but took carnitine supplements, their TMAO production levels would slowly rise. The lead scientist on this study, Dr. Hazen, considered how this interaction provided key insights that could be used to impact risk of heart disease. More so, Dr. Hazen hypothesized that developing a therapy that disrupted the biological pathway of TMAO might then be a great target for cardiovascular disease treatment.

But focusing on preventative methods now, what can a person do to take control over their heart health today? Does it mean following an extremely restrictive diet? Should you expect the same results as others in a clinical study?

These are all good questions, and some that scientists are still trying to determine.

But when we look at how unique and individual each person is, it may not seem fair to give recommendations that are made to fit a generalized group. And even if TMAO may be responsible for all signs of cardiovascular disease (which, when is one thing ever really an answer in science?) – who is to say that completely eliminating meat or animal products from your diet is the best choice for you?

We’re only at the foot of the mountain, looking up. There is still so much about microbial pathways we have yet to understand and how they impact our health. Fortunately, we are getting better at finding out how your diet impacts you. And how quickly things can change!

Get your diet on track – discover food recommendations to help boost your heart health, one bite at a time.


  • Heart Disease Facts. (n.d.).

  • M. A. Briggs, K. S. Petersen, P. M. Kris-Etherton. (2017, Jun 21). National Library of Medicine, PubMed Central.

  • E. Battaglia Richi, B. Baumer, B. Conrad, R. Darioli, A. Schmid, U. Keller. (2015). National Library of Medicine,

  • J. Abbasi. (2019, May 22). JAMA

  • M. T. Velasquez, A. Ramezani, A. Manal, D. S. Raj. (2016, Nov 8). National Library of Medicine, PubMed Central.

  • J. R. Stubbs, J. A. House, A. J. Ocque, S. Zhang, et al. (2016, Jul 30). National Library of Medicine, PubMed Central.

  • R. A. Koeth, B. R. Lam-Galvez, J. Kirsop, Z. Wang, et al. (2018, Dec 10). The Journal of Clinical Investigation.