UNDERSTANDING THE TMAO LINK
TMAO’s, whilst seldom discussed, are actually a serious cause for concern to human health at high levels. High levels of TMAO in the blood have been linked to the development of an increased risk of cardiovascular disease, kidney disease and atherosclerosis by promoting the accumulation of cholesterol in the arteries and promoting inflammation.
Elevated TMAO levels are also associated with Alzheimer’s disease, obesity and mortality from type 2 diabetes. So what exactly are TMAOs, and what can we do to reduce them?
TMAOs (trimethylamine N-oxides) are small organic compounds that are produced in the gut by certain bacteria during the digestion of foods that contain either choline or carnitine.
A simplified process for the formation of TMAOs is to ingest choline or carnitine-inclusive foods. This is then metabolised by certain bacteria in our digestive system to make TMA (trimethylamine). Our system then absorbs the compound TMA, which in turn is oxidised by the liver and turned into TMAO.
Carnitine and choline are two components known to facilitate the production of TMAO, so where do we get these in our diet?
Carnitine
Carnitine is an amino acid derivative that is found in many animal products, including red meat, certain energy drinks, and carnitine supplements. Within 24 hours of consumption of carnitine, it can be metabolised by certain bacteria in the gut to produce TMA. TMA is then absorbed into the bloodstream and transported to the liver where it is converted into TMAO
Choline
Choline is an essential nutrient found in a variety of foods such as eggs, dairy products, poultry, fish, and certain vegetables like broccoli and cauliflower. Research has shown that a diet high in choline can increase TMAO levels in the blood, and this may contribute to an increased risk of cardiovascular disease. But hang on. isn’t Choline an essential nutrient? Isn’t Choline deficiency dangerous for vegans and vegetarians?
Yes, it is, but we don’t need to get it from meat, eggs and dairy. Thankfully, we can get all we need from fruits, vegetables, beans, and nuts.
So can we get too much choline from plants? Do we need to worry about high-choline plant foods, like broccoli and cauliflower?
No. In fact, consumption of cruciferous vegetables is associated with a significantly longer life and less cardiovascular disease mortality, To see what was going on, researchers took the vegetables highest in choline, brussels sprouts, and had people eat two cups a day for three weeks.
What happened? Their TMAO levels actually went down. It turns out that brussels sprouts appear to naturally downregulate the TMAO liver enzyme
There are several ways to naturally reduce TMAO levels:
- Reduce consumption of foods that are high in choline, carnitine, and betaine, such as red meat, eggs, dairy products, and seafood.
- Increase consumption of plant-based foods that are high in fibre and antioxidants, such as fruits, vegetables, whole grains, and legumes.
- Probiotics and prebiotics can help to promote the growth of beneficial gut bacteria that do not produce TMAO.
- Regular exercise has been shown to reduce TMAO levels, possibly by increasing the production of beneficial gut bacteria.
Here’s an interesting study. People who eat completely plant-based may not make any TMAO at all—even if they try. You can give a vegan a steak, which contains both choline and carnitine, and there will not even be a bump in TMAO. Why not?
Vegetarians and vegans have different gut microbial communities. If we don’t eat steak, then we don’t foster the growth of steak-eating bacteria in our gut.
Food for thought wouldn’t you say?