Intestinal microbiota metabolism of l carnitine, a nutrient in red meat, promotes atherosclerosis Nature Medicine Characterization of TMAO productivity from carnitine challenge facilitates personalized nutrition and microbiome signatures discovery Microbiome Springer Nature Link JCI Insight Aorta and liver generated TMAO enhances trained immunity for increased inflammation via ER stress mitochondrial ROS glycolysis pathways Role of L carnitine in Cardiovascular Health: Literature Review Cureus