Anti-Colitis Effects of Brown Rice Reported by Experimental Studies

Toru Shizuma

Abstract

Brown (unpolished) rice is a good source of vitamins, minerals, and dietary fiber and is consumed as a health food, particularly in Asian countries. Although a limited number of studies have investigated the anti-colitis effects of brown rice, including rice bran and treated brown rice, some have reported the protective effects of brown rice in animal models of dextran sulfate sodium-induced colitis in the following settings: 1) Rice bran oil, 2) Brown rice fermented by Aspergillus oryzae, 3) Enzyme-treated rice fiber, and 4) Kurozu (fermented vinegar made from brown rice). The possible mechanisms underlying the anti-colitis effects of brown rice include anti-oxidant effects, inhibition of proinflammatory cytokine production, myeloperoxidase activity, neutrophil infiltration in the colonic mucosa, activation of nuclear factor kappa B (NF-κB), and improvement of dysbiosis. However, the active components in dietary products derived from brown rice or treated brown rice have not yet been identified. This report summarizes the studies demonstrating the anti-colitis effects of brown rice or treated brown rice in animal models of colitis.