The role of probiotic cultures in the prevention of colon cancer

Risk factors for colon cancer include both hereditary and environmental fac tors. Dietary patterns represent controllable risk factors for the developm ent of colon cancer. Much attention has focused on decreasing colon cancer risk through increasing intake of dietary fiber; recently, this has include d interest in the consumption of prebiotics and probiotics. Because factors involved in the initiation and promotion of colon cancer might be separate d in time from actual tumor development, it is difficult to choose "outcome s" or "end points" that are definitive indicators of efficacy of probiotics or prebiotics. Studies that have explored the cause-effect relationship di rectly have used animal models. In this review, we have confined our discus sion to animal studies from the last 10 years that have examined most direc tly the relationship between prebiotic and probiotic consumption and colon cancer development. To present the consensus of these studies first, it app ears that probiotics with or without prebiotics have an inhibitory effect o n the development of aberrant crypts (precancerous lesions) and tumors in a nimal models. The effect is not completely consistent and is small in some studies, but this may represent a dose or time effect.