Dietary choline supplements, but not eggs, up fasting TMAO levels

A recent study has shown no significant rise in trimethylamine-N-oxide (TMAO) or platelet reactivity in healthy individuals who consumed four eggs daily, despite high choline content in egg yolks. However, choline bitartrate supplements providing similar total choline has increased both TMAO and platelet reactivity, indicating that the form and source of dietary choline differentially contribute to systemic TMAO levels and platelet responsiveness.

In this study, the investigators recruited healthy volunteers (median age 28 years, 41 percent male, 81 percent Caucasian) with normal renal function (estimated glomerular filtration rate >60) and assigned them to one of five daily interventions for 4 weeks: 1) hardboiled eggs (n=18); 2) choline bitartrate supplements (n=20); 3) hardboiled eggs + choline bitartrate supplements (n=16); 4) egg whites + choline bitartrate supplements (n=18); 5) phosphatidylcholine supplements (n=10).

The investigators also collected fasting blood and urine samples for quantification of TMAO, its precursors, and platelet aggregometry.

Plasma TMAO levels in participants significantly increased in all three intervention arms containing choline bitartrate (p<0.0001 for all). However, daily consumption of four large eggs (p=0.28) or phosphatidylcholine supplements (p=0.27) did not increase plasma TMAO levels. In addition, platelet reactivity significantly increased in the three intervention arms containing choline bitartrate (p<0.01 for all), but not with eggs (p=0.10) or phosphatidylcholine supplements (p=0.79).

“Choline is a dietary precursor to the gut microbial generation of the prothrombotic and proatherogenic metabolite TMAO,” the investigators said.