Type 2 Diabetes and Glycemic Response to Grapes or Grape Products

Type 2 diabetes affects approximate to 7% of the population in the United States and is characterized by decreased disposal of glucose in peripheral tissues due to insulin resistance and overproduction of glucose by the liver, defects in pancreatic b-cell function, and decreased b-cell mass. Obesity, decreased physical exercise, and consumption of foods with a high glycemic index (GI) and load are major predisposing factors in the development of type 2 diabetes. The GI is used to evaluate the rise in blood glucose levels in response to food. The GI provides an indication of the quality of carbohydrate in a food. The glycemic load (GL) is used to provide information about the quantity of carbohydrates in a food and the insulin demand. Individuals with diabetes are advised to maintain a diet of low-GL foods, because low-GL diets improve diabetes symptoms. Grapes have a mean GI and GL in the low range. Little research has been performed with grapes and/or grape products to determine the glycemic response either alone or with a meal. Grapes and other fruits contain numerous polyphenols, including the stilbene resveratrol, the flavanol quercetin, catechins, and anthocyanins that have shown potential for reducing hyperglycemia, improving b-cell function, and protecting against b-cell loss. Therefore,with a lowmean GI and GL, grapes or grape products may provide health benefits to type 2 diabetics. J. Nutr. 139: 1794S-1800S, 2009.