The Glycemic Index of standard and diabetes-specific enteral formulas.

A recent meta-analysis showed that foods with a low Glycemic Index (GI) have a clinically useful effect on glycemic control in patients with diabetes. Although diabetes-specific enteral formulas are commonly used for diabetic patients with insufficient oral intake, not much is known about the GI of these formulas. Therefore the purpose of this study was to assess the GI of several diabetes-specific formulas and to compare them with standard formulas. The randomised, double blinded, crossover study included twelve products which were tested in 7 - 10 individuals from a pool of 14 healthy volunteers. After an overnight fast, volunteers were given a portion of a product containing 25 grams of carbohydrate or the reference feed (200 ml containing 25 gram glucose) on different occasions in random order. Postprandial blood glucose levels were measured in venous whole blood for two hours after intake of the products and positive incremental area under the curve (AUC) was calculated for both the products and the reference feed. The GI of the test products was determined by dividing AUC (test products) by the AUC (reference feed). Enteral formulas varied widely in their GI values with the diabetes-specific enteral formulas being characterized by a significant (P=0.004) lower GI (average +/- SEM: 19.4 +/- 1.8) than standard formulas (42.1 +/- 5.9). However, there was an overlap between the two types of formulas. Three of the diabetes-specific formulas had significantly lower GI than 3 of the standard products. Although there is some overlap with the GI of diabetes-specific and standard formulas, certain diabetes-specific formulas had very low GI values, which may be clinically beneficial due to better glycemic control. Therefore the use of diabetes-specific formulas with a low GI should be the preferred option for the nutritional management of diabetic patients in need of nutritional support.