Many studies have revealed the anti-colitis mechanism of VitD3, such as deactivation of the local renin-angiotensin system in the colon, inhibition of NLRP3 inflammasome activation, alteration of the composition of the fecal microbiome, and modulation of T helper (Th)1 and Th17 activation (11, 27-29). Here, REN is linked to colitis.