SOD1 and inflammatory bowel disease: Recently, multiple studies demonstrate that boosting colonic H2O2 with probiotics can improve mucosal barrier integrity, increase colonization resistance, and suppress inflammatory responses in the colon, whereas exceeding the physiological levels of H2O2 could be detrimental.10, 11, 12 Because SOD converts O2•- to H2O2 and physiological levels of H2O2 are important for gastrointestinal health, it is likely that H2O2 mediates the protective effect of SOD at lower doses in IBD.