A recent study demonstrated that metabolic syndrome is linked to a reduced microbial capacity to produce AHR-activating tryptophan metabolites, and restoring this function through AHR agonists or a Lactobacillus strain with high ligand-producing capacity improves glucose metabolism and liver steatosis by enhancing intestinal barrier function and stimulating GLP−1 secretion.182. Here, AHR is linked to fatty liver disease.