What is TMAO, and why should you avoid it?

The bacterial flora of the intestines convert choline into trimethylamine, which again is
converted into TMAO (trimethylamine-N-oxide) by the involvement of an enzyme from
the liver.

Choline is found in animal-derived products like eggs, dairy products, and meat.
The following study investigated the involvement of TMAO and major adverse cardiovascular
events (death, myocardial infarction, or stroke) during 3 years of follow-up in 4007 patients
(Tang WH, et.al., 2013).

The researchers found that increased plasma levels of TMAO were associated with an
increased risk of a major adverse cardiovascular event. An elevated TMAO level predicted an
increased risk of major adverse cardiovascular events after adjustment for traditional risk
factors, as well as in lower-risk subgroups.

In other words, TMAO is an additional cardiovascular risk factor many are not aware of.
This research documents that TMAO triggers inflammation and is involved in the process of
forming atherosclerosis (Seldin MM, et.al., 2016).
The bacterial flora of people eating animal-derived products is producing TMAO, vegans and
vegetarians don’t produce much, because they have a different bacterial flora of the intestinal
tract (Koeth RA, et.al., 2019).

References:

Koeth RA, Lam-Galvez BR, Kirsop J, Wang Z, Levison BS, Gu X, Copeland MF, Bartlett D,
Cody DB, Dai HJ, Culley MK, Li XS, Fu X, Wu Y, Li L, DiDonato JA, Tang WHW, Garcia-Garcia
JC, Hazen SL. l-Carnitine in omnivorous diets induces an atherogenic gut microbial pathway in
humans. J Clin Invest. 2019 Jan 2;129(1):373-387.

Seldin MM, Meng Y, Qi H, Zhu W, Wang Z, Hazen SL, Lusis AJ, Shih DM. Trimethylamine
N-Oxide Promotes Vascular Inflammation Through Signaling of Mitogen-Activated Protein
Kinase and Nuclear Factor-κB. J Am Heart Assoc. 2016 Feb 22;5(2). pii: e002767.

Senthong V, Li XS, Hudec T, Coughlin J, Wu Y, Levison B, Wang Z, Hazen SL, Tang
WH. Plasma Trimethylamine N-Oxide, a Gut Microbe-Generated Phosphatidylcholine Metabolite,
Is Associated With Atherosclerotic Burden. J Am Coll Cardiol. 2016 Jun 7;67(22):2620-8.