Metabolic responses to starch in oat and wheat products. On the importance of food structure, incomplete gelatinization or presence of viscous dietary fibre

Objective: Evaluate the impotrtance of incomplete gelatinization, food structure and presence of viscous dietary fibre for the postprandial glycaemic and insulinaemic responses to oat and wheat products. Design: Three common breakfast meals were tested, "raw" rolled oats (muesli), boiled rolled oats (oat porridge) and white wheat bread. Boiled intact oat and wheat kernels (kernel porridges) were also included. For comparison, glycemic indices (GIs) were calculated both from analysis of capillary and venous blood samples. Subjects: Nine healthy male volunteers between 65 and 70 years of age participated in the study. Results: The rolled oats and oat porridge elicited high metabolic responses. No differences in glycaemic and insulinaemic indices (IIs) were seen between these products and white bread. In contrast, the kernel porridges produced low glucose and insulin responses. No differences were obtained in GI values whether based on capillary or venous blood. However, with some products capillary blood allowed smaller differences to be detected. Conclusions: Neither incompleate gelatinization in rolled oats nor naturally occuring viscous dietary fibre in oats affect postprandial glycaemia, whereas enclosure if intact kernels significantly blunt metabolic responses