Slowing starch digestibility in foods: Formulation, substantiation and metabolic effects related to health

Decreasing postprandial (= post-meal) glucose responses (PPG) is beneficial for health. We have shown that it is possible to lower the PPG to carbohydrate-rich staple products (flat breads) by incorporating a mix of viscous fibre and legume flour. In addition, the PPG responses to rice is substantially reduced by choosing the right cultivar (e.g. high amylose rice) and processing steps (e.g parboiling rice, short-cooking time, cooling/reheating cycles). It is often assumed that PPG is directly reduced by slowing the rate of digestion of carbohydrates, resulting in a slower influx of glucose from the intestine. However, the PPG is not determined just by this influx, but also by the hepatic glucose production rate and tissue glucose uptake. Studies using stable isotopes show that reductions in the influx of glucose from the intestine are associated with reductions in PPG, postprandial hormonal response (glucose-dependent insulinotropic polypeptide (GIP) and insulin), and the uptake of glucose by the tissues. Even if slower digestion does not directly lead to a lower PPG response, the indirect effects (including lower GIP and insulin responses) can be beneficial for health. Furthermore, metabolomics analyses show that a delay in the uptake of glucose from the intestine leads to a delay in the formation of metabolites of glucose in the body. Overall, decreasing the digestion rate gives a more desired cascade of metabolic effects and can be used for development of healthier carbohydrate-rich products. Consumers can prepare healthier carbohydrate-rich products at home by introducing shorter cooking times and cooling/reheating cycles.