FMO5 and inflammatory bowel disease: Noteworthy IBD-related genes in the duodenum and/or jejunum that were affected by the HFDs include Duox2 (dual oxidase 2), a member of the NADPH oxidase family, which was downregulated by the HFDs, and Ephx2 (epoxide hydrolase 2), an enzyme that converts fatty acid epoxides to bioactive dihydrodiols which was upregulated by the HFDs (Fig. 4D).