In mice fed on PD, RS exposure for 14 days markedly worsened colitis symptoms afterward, as shown by colonic shortening (Fig. 1f), histology (Supplementary Fig. 2a), loss of goblet cells (Supplementary Fig. 2b), and inflammatory cytokines (IL-6, MCP-1, TNF-α; Fig. 1g). Here, TNF is linked to colitis.