Endpoint: surrogate — fasting plasma TMAO, chronic (4-week) feeding, head-to-head food-vs-supplement design.
30 healthy young adults, 13-week crossover: 3 eggs/day vs. a choline-bitartrate supplement (~400 mg choline total from either source) for 4 weeks each. Fasting plasma choline rose 20% with egg intake but did not change with the supplement; plasma TMAO was not different between treatments or vs. baseline for EITHER arm.
relevance_note: a second chronic null-TMAO-from-eggs primary, but notable because here even the choline-supplement arm was null — this is in tension with Wilcox 2021 (this pool, Cleveland Clinic lab), where a choline-bitartrate supplement DID raise TMAO. Worth flagging as a genuine cross-lab discrepancy on the supplement comparator, not just on eggs.