Core Viewpoint - The research published by Professor Ren Wenkai's team from South China Agricultural University indicates that Lactobacillus reuteri and its metabolite L-theanine enhance the catabolism of branched-chain amino acids (BCAA), providing a potential therapeutic pathway for metabolic disorders associated with elevated BCAA levels [2][6]. Group 1 - The study reveals that gut microbiota can regulate circulating BCAA levels through direct conversion, and it uncovers an indirect mechanism by which gut microbiota influences host BCAA metabolism [4]. - The research team compared germ-free mice and pigs with wild-type counterparts, finding that Lactobacillus reuteri and L-theanine are associated with enhanced BCAA catabolism [5]. - Experiments on pig cell lines demonstrated that L-theanine increases the expression of branched-chain amino transferase (BCAT), which is involved in BCAA catabolism, by promoting BCAT2 mRNA expression and stabilizing the BCAT2 protein [5]. Group 2 - Overall, the study provides a potential pathway for developing therapies targeting metabolic disorders related to elevated BCAA levels [6].