Effect of Fermentable Carbohydrate on Glucose Homeostasis

The rise in the prevalence of type 2 diabetes is related to recent lifestyle changes leading to a rise in obesity. Obesity is a risk factor for Impaired Glucose Tolerance (IGT) and diabetes. A type of fibre - fermentable carbohydrate - may help prevent diabetes in individuals with IGT by reducing appetite and food intake, and improving insulin sensitivity. Although fermentable carbohydrate is not absorbed in the small intestine it is full fermented by the colonic bacteria. The fermentation of this carbohydrate produces short chain fatty acids which act on specific G protein coupled receptors (GPR41/43) in the intestine to release GLP-1 and PYY. GLP-1 and PYY are hormones which act on appetite centres in the brain to decrease appetite. GLP-1 incretin effects and possible effect of the beta cell will increase insulin sensitivity. Short chain fatty acids also suppress the release of free fatty acids from adipocytes. Lower levels of free fatty acids in insulin resistant subject's leads to improved insulin sensitivity. This body of work will examine the effect of fermentable carbohydrate on appetite, weight loss, blood glucose control which will give an indication of the possibility of fermentable carbohydrate to prevent type 2 diabetes in this at-risk group.