Dietary Choline Supplements, but Not Eggs, Raise Fasting TMAO Levels in Participants with Normal Renal Function: A Randomized Clinical Trial.
Level 2 - randomized trial
Randomized clinical trial with five parallel intervention arms
PubMed 33872583 · doi:10.1016/j.amjmed.2021.03.016
What was done
Healthy adults with normal renal function (median age 28 years, 41% male, 81% Caucasian, n=82 total) were randomized to 1 of 5 daily interventions for 4 weeks: 1) 4 hardboiled eggs (n=18), 2) choline bitartrate supplements (n=20), 3) hardboiled eggs + choline bitartrate (n=16), 4) egg whites + choline bitartrate (n=18), or 5) phosphatidylcholine supplements (n=10). Fasting blood and urine samples were measured for trimethylamine-N-oxide (TMAO), precursors, and platelet aggregometry.
What was found
Plasma TMAO levels increased significantly in all 3 intervention arms containing choline bitartrate (all P < .0001), but did not significantly increase with 4 large eggs daily (P = .28) or phosphatidylcholine supplements (P = .27). Platelet reactivity also increased significantly in all 3 choline bitartrate arms (all P < .01), but not with eggs (P = .10) or phosphatidylcholine supplements (P = .79).
Why it matters
Systemic TMAO elevation and platelet responsiveness depend on the specific dietary source and form of choline, showing that whole-egg consumption does not elevate TMAO or platelet reactivity in the manner seen with synthetic choline bitartrate supplements.
Limits
Sample sizes were small across all five groups (10 to 20 per arm). The study lasted only 4 weeks in young, predominantly Caucasian adults with normal kidney function, and measured laboratory surrogate markers rather than cardiovascular clinical events.