Similarly, administration of the commensal strain Lactobacillus reuteri, which exhibits high AhR-ligand production, improves glucose clearance, insulin sensitivity, and liver steatosis in HFD-fed mice, whereas administration of a non-indole-producing Lactobacillus strain does not rescue the HFD-induced dysregulation of glucose metabolism. The gene discussed is AHR; the disease is fatty liver disease.