Effects of Indigestible Carbohydrates and GI of Cereal Products on Glucose Metabolism, Satiety and Cognitive Function in Healthy Subjects; Emphasising mechanisms for glycaemic regulation at the acute, second and third meal

The metabolic syndrome includes a cluster of dysfunctions that identifies subjects at high risk of developing type 2 diabetes and cardiovascular disease. The prevalence of the metabolic syndrome has increased markedly over the last two decades. Central to this syndrome is insulin resistance and hyperglycaemia, but also other manifestations, e.g. central obesity, dyslipidaemia, elevated blood pressure, imbalance in lipoproteins and pro-thrombotic factors, or sub-clinical inflammation, are involved. Diets with a low glycaemic index (GI) have proven beneficial in prevention and treatment of diabetes, cardiovascular disease, and the metabolic syndrome. Furthermore, a whole grain diet has shown similar benefits adjunct to these diseases. Less is known regarding the effect of GI or other food characteristics on cognitive function. However, due to the significant differences in postprandial blood glucose profiles after a high- compared with a low-GI meal, cognitive functions during the postprandial phase could be expected to differ depending on the choice of carbohydrate food and time point in the postprandial phase. The purpose of the present thesis was to evaluate the importance of GI features and/or contents of indigestible carbohydrates of cereal products on glycaemic regulation, metabolic risk markers, and cognitive function in healthy subjects. The test products were either evaluated in the acute postprandial phase, or following one or two subsequent standardised meals. The results of the present thesis show that certain cereal products, with low GI and/or with a specific mixture of resistant starch (RS) and dietary fibre (DF) have the capacity to reduce glucose response not only in the acute phase, but also the incremental blood glucose responses following two consecutive meals during the course of a whole day, and in the perspective from a late evening meal to a subsequent breakfast. Boiled barley- and rye kernels, or a white wheat bread (WWB) added with RS and barley DF in an amount similar to that in barley ...