VDR and colitis: Dysbiotic gut microbiota profiles with an increased abundance of the phyla Bacteroidetes and Proteobacteria and decreased abundance of the phyla Firmicutes and Deferribacteres in the feces were reported in VDR knockout mice vs. wild-type mice, and the disorder was more likely to induce colitis in VDR knockout mice, whereas after vitamin D supplementation, inflammation was controlled and the proportion of Firmicutes and Deferribacteres was restored (Ooi et al., 2013).