environmental factors: Many hypotheses have been raised for environmental contributants to the pathogenesis of ulcerative colitis. they include the following: Diet: as the colon is exposed to many dietary substances which may encourage inflammation, dietary factors have been hypothesized to play a role in the pathogenesis of both ulcerative colitis and Crohn's disease. there have been few studies to investigate such an association, but one study showed no association of refined sugar on the prevalence of ulcerative colitis.