Grant: Randomized Controlled Trials

Current oral anti-diabetic medications have been very successful in controlling glycemia and reducing the microvascular complications of diabetes but have largely failed to deliver the anticipated benefit of reduced macrovascular disease. One notable exception has been the alpha-glucosidase inhibitor, acarbose, which effectively converts the diet into a low-glycemic index diet through slowing the rate of carbohydrate absorption. This manipulation has resulted in reduced progression of high risk people to diabetes, hypertension and coronary heart disease. To determine whether dietary advice to lower the glycemic index of the diet can also reduce the burden of macrovascular disease, 160 subjects with type 2 diabetes taking oral hypoglycemic medications will be randomized to receive advice to consume either a low glycemic index (GI) diet or a conventional high fibre diet in a 3y parallel design. The main outcome of vascular disease will be measured by magnetic resonance imaging (MRI) as arterial damage assessed by the extent of plaque and its vulnerability at 1y and 3y. Other outcomes will include HbA1c, blood glucose, body weight, cholesterol profile, and markers of inflammation. These data will indicate whether a dietary strategy to lower the glycemic-index of the diet is more effective in reducing or slowing the progression of macrocvascular disease than conventional high fibre advice in people with type 2 diabetes.