Every now and then the topic of trimethylamine N-oxide, or TMAO, is extracted from its watery grave by some “cardiovascular expert” in efforts to convince us that this is something to worry about. So here’s the rundown on TMAO…get ready for a Deep Dive into a Mariana Trench-worthy morass of conflicting data!
TMAO is found in sea creatures and essentially helps prevent them from exploding; the metabolite helps them retain buoyancy without being overwhelmed by hydrostatic pressures. But since you aren’t a puffer fish (probably), it’s probably more relevant to discuss how TMAO is synthesized in the human body.
Your body makes TMAO from trimethylamine, or TMA. The TMA is generated from dietary choline, phosphatidylcholine, or L-carnitine by gut bacteria, and all you have to do is add an O, and there you go! Simple! Eggs, red meat, dairy products, and fish are all potential food sources that can result in the eventual production of TMAO.
But what if someone lacks the liver enzyme FMO3 that converts TMA to TMAO? Well, that person will have some terrible FOMO, since his or her social life will probably be non-existent. People who lack this enzyme constantly smell like fish, since their breath, sweat, and urine will all be perpetually tinged with TMA. Maybe that’s TMI, but I think it’s good to know!
Ok, back to TMAO, which is aromatically less pungent than TMA but will still leave your mind swimming in befuddlement. Elevated TMAO is associated with cardiovascular disease in multiple studies…but not in other studies. TMAO is often higher in folks with diabetes, but pretty much everything bad is high in that disease state. And since the kidney clears TMAO from the body, TMAO is elevated in people with kidney disease. So it’s unclear whether TMAO is a bystander or contributor to these conditions.
Additionally, the Mediterranean Diet, which is fairly universally regarded as “Heart Healthy” and has two cardiovascular outcome trials (PREDIMED and CORDIOPREV) supporting this notion, failed to reduce TMAO levels in this study. But you know what DOES decrease TMAO levels? Antibiotics. So maybe we all just need daily Augmentin to save the world from Heart Disease!
Other ways to reduce TMAO would be taking meldonium (the performance-enhancing drug for which tennis star Maria Sharapova was busted). I’m sure she was taking it for TMAO reduction. And maybe you could decrease your L-carnitine usage…although L-carnitine itself is a confounding compound that has actually been used for athletic performance enhancement and has even decreased mortality in patients post-heart attack.
There’s other stuff we could discuss, but it would even further muddy the waters. When “experts” confidently assert that they know exactly what to do about TMAO, it makes me LMAO. And whatever other recommendations they’re making about your health might be a little fishy, too.
