NR1I2 and type 2 diabetes mellitus: Interestingly, IPA is also a tryptophan metabolite produced by Clostridium sporogenes that has been considered as a healthy microbiota marker, as it was increased in individuals with high dietary fiber intake, has potent oxygen radical scavenging properties, activates the pregnane X receptor (PXR) (thus decreasing intestinal permeability) and has been associated with neuroprotection and with a lower risk for type 2 diabetes [133].