Trimethylamine N oxide (TMAO) is a small molecule produced in humans primarily by the gut liver axis and has become an important biomarker, and possible mediator, of cardiometabolic and renal disease. Dietary choline, phosphatidylcholine ( Full article: Gut microbes with the gbu genes determine TMAO production from L carnitine intake and serve as a biomarker for precision nutrition A note about food and mood. I've spoken in YouTube videos before about the large effect my diet experiments have had my on mental function and wellbeing (depression, or its absence). Over Acetyl L Carnitine NuMedica