Gastrointestinal Effects of Oat Bran and Oat Gum: A Review

In addition to the well-known effects of reducing blood cholesterol and affecting glycaemic response, dietary fibre of oat bran has been shown to have numerous other physiological effects. It delays gastric emptying, diminishes absorption of nutrients, affects the motility in the small bowel, and prolongs satiety after the meal. In the large bowel, soluble dietary fibre increases the fermentation activity, especially production of butyric acid, enhances growth and colonisation of some probiotic bacterial strains, increases production of microbial mass and thereby aids the removal of nitrogen via faeces. It also increases wet weight of stools, thereby alleviating constipation. Short-chain fatty acids formed enhance cell proliferation of the colonic mucosa. According to the present view, this reduces the risk of colon cancer. In addition to the effects of the viscosity of the intestinal contents and colon fermentation, the physiological effects are in part mediated via insulin and gastrointestinal hormone secretion. Papers documenting these effects are reviewed.