These changes in the gut microbiota are closely associated with impaired glucose tolerance in prediabetes; for example, FGF15/19 inhibits hepatic gluconeogenesis and promotes glycogen synthesis, while a high abundance of Bacteroides downregulates the expression of the intestinal FXR signaling pathway, thereby reducing FGF15/19 levels, which may lead to hepatic IR and impaired glucose tolerance [36]. This evidence concerns the gene NR1H4 and Impaired glucose tolerance.