Colonic fermentation of indigestible carbohydrates of a previous evening meal increases tissue glucose uptake

Abstract

Evening meals rich in indigestible carbohydrates have been shown to lower postprandial glucose concentrations after ingestion of a high glycemic index breakfast. This phenomenon is linked to colonic fermentation of indigestible carbohydrates but the underlying mechanism is not fully elucidated. We examined in which way glucose kinetics after the breakfast are changed due to colonic fermentation. In a cross‐over manner 10 healthy male subjects (21 ± 2 years, BMI: 21,4 ± 1 kg/m2) ingested as an evening meal either white wheat bread or cooked barley kernels, rich in indigestible carbohydrates. In the morning the dual isotope technique was applied to determine glucose kinetics after intake of 50 g 13C‐enriched glucose. Plasma insulin and non‐esterified fatty acid concentrations were measured as well as hydrogen excretion in breath. Postprandial glucose response was 29 % lower after the barley evening meal, whereas the concentrations of insulin and non‐esterified fatty acids were the same. Exogenous glucose appearance in the systemic circulation and endogenous glucose production did not differ, but tissue glucose uptake was increased after the barley evening meal. Hydrogen excretion was higher after the barley meal indicating increased colonic fermentation. Factors related to colonic fermentation of indigestible carbohydrate seem to have the ability to increase tissue insulin sensitivity in healthy subjects.