CAT and inflammatory bowel disease: Earlier studies have repeatedly shown that IBD patients demonstrate a diminished total blood antioxidant status, as reflected by reduced total antioxidant capacity and low levels of antioxidant enzymes such as GSH-Px, superoxide dismutase (SOD), and catalase (CAT).11 However, findings regarding specific enzymatic antioxidants in plasma/erythrocytes remain somewhat contradictory.