J Food Bioact What Is Carnitine? TMAO? What's Their Link To Red Meat? Pritikin Characterization of TMAO productivity from carnitine challenge facilitates personalized nutrition and microbiome signatures discovery Microbiome Springer Nature Link Characterization of TMAO productivity from carnitine challenge facilitates personalized nutrition and microbiome signatures discovery Microbiome Springer Nature Link TMAO Is Both a Biomarker and a Renal Toxin Circulation Research