Butyrate is a histone deacetylase (HDAC) inhibitor.57–59 In macrophages, butyrate decreases inflammatory cytokine production57,68 while also increasing microbial killing through increased phagocytosis and anti-microbial activity.69 SCFAs also increase differentiation and function of Treg cells, including IL-10 production70–72 which limits pathology in colitis models.70,73 HDAC inhibition can be counterbalanced by intestinal microbe metabolism of phytate to inositol-1,4,5-trisphosphate (InsP3) which also promotes epithelial growth and intestinal repair.74 This evidence concerns the gene HDAC9 and colitis.