TMAO (TriMethyl Amine Oxide) is a recognized risk factor for heart attack and stroke. Most functional medicine and plant-based diet fans are aware of this. But we usually don't screen for, at least at first.

Choline, which is found in animal products, is broken down by the gut microbiome to TMA ( TriMethyl Amine). As the TMA passes through the liver, it is oxidized to TMAO.

Elevated TMAO has been shown multiple times to be associated with increased all-cause mortality, and has been associated with CV inflammation and plaque.

The above link is to an article published in Nature Magazines Scientific Reports 7, Article number: 13781 (2017). It is a follow-up on serum and data collected in Groningen, Netherlands using the PREVENT study.

The study supported a significant increase in all-cause mortality with increased TMAO. But this association was seen only in patients with kidney disease, not with those without kidney disease.

So it raises again the question of causality. Is it the TMAO, or kidney disease, or (more likely) an intertwined mechanism? And the fact that kidney disease is most often associated with diabetes raises again the comorbidities question.