Are the beneficial metabolic effects of fibre enriched foods preserved when consumed within a composite meal?

Abstract The aim of this study was to compare, in patients with non-insulin dependent diabetes mellitus (NIDDM) the postprandial plasma glucose response of a carbohydrate-rich food additioned with a viscous fibre, either consumed alone or as part of a composite meal. We performed two experiments in two groups of diabetic patients. In the first experiment 8 NIDDM patients consumed, in random order and on alternate days, either 55 g biscuits (carbohydrate 57%, fat 35%, protein 8%, kcal 174) containing 5 g of viscous fibre (glucomannan) or 50 g biscuits without fibre. In the second experiment 12 NIDDM patients consumed, in random order and on alternate days, either 55 g biscuits enriched with glucomannan or 50 g plain biscuits added to a mixed meal (carbohydrate 50%, fat 29%, protein 21%, fibre 3 g, kcal 627). In the first experiment incremental areas under the 180-min curve were significantly lower for both plasma glucose and insulin after glucomannan biscuits than after plain biscuits (p < 0.02) while in the second experiment the meal rich in glucomannan biscuits stimulated a similar postprandial glycaemic response but a lower plasma insulin response (p < 0.008) than the meal with plain biscuits. The capability of fibre added to foods to reduce the postprandial blood glucose response in diabetic patients is lost when fibre-enriched foods are consumed within a mixed meal. --------------------------------------------------------------------------------