The supplementation of the diet in mice with an AHR ligand (e.g. FICZ) or a Lactobacillus strain that produces AHR ligand(s) is capable of improving metabolic syndrome factors, such as hepatic triglyceride levels, fasting glucose levels, and insulin in ob/ob mice.120 Importantly, in humans, a high body mass index correlated with a reduced level of AHR active tryptophan metabolites and overall AHR activation potential in fecal extracts. The gene discussed is AHR; the disease is metabolic syndrome.