Plasma Trimethylamine N-oxide Elevation Induced by L-carnitine Supplementation and Insulin Resistance

The primary aims of the current study: * using L-carnitine supplementation modulate the level of plasma trimethylamine N-oxide to assess its effect on circulating cytokines related to diabetes and metabolic syndrome; * using simulated night-shift work intervention as a stress factor, explore the effect of circulating metabolites on insulin sensitivity The secondary aim is to evaluate the effect of carnitine supplementation on gut microbiome composition.