Disclosed are nutritional compositions comprising a synergistic combination of cereal beta-glucans, including oat and or barley beta-glucans and Salacia extract, including Salacia oblonga, that are particularly useful in controlling the blood glucose response in a diabetic or other appropriate individual. The nutritional compositions are especially useful when formulated in powder form and then reconstituted with an appropriate liquid or sprinkled onto food during a meal, to thus control the postprandial blood glucose response to that meal.