GLYCAEMIC RESPONSES TO SOME NIGERIAN STAPLE FOODS

Abstract

This study was designed to investigate the influence of the mode of preparation of Nigerian staple foods on postprandial glycaemia and to determine the metabolic effects of different types of dietary fibre in these foods. The usefulness of the concept Glycaemic index was also discussed. To determine the effect of different foods on plasma glucose levels. Cassava and Beans were processed using two different methods of processing and administered to a group of sixteen healthy, young adults and a group of ten non-insulin dependent diabetic patients. The meals (Eba, Lafun, Boiled Beans and Moinmoin-dehulled, blended and steamed) were served in iso-glucide and isocaloric portions and as part of a mixed meal. Plasma glucose levels were measured over four hours and expressed as a percentage of the area under the glucose response curve when the same amount of carbohydrate was taken as glucose. Peak values, incremental peak values and peak time were also calculated. The mean glucose response was lowest following the ingestion of Boiled beans in the two groups and Lafun in the normal, healthy group. Mixed meal glycaemic responses were blunted with the co-ingestion of protein and fat in the normal group but not significantly different in the diabetic subjects. The dietary fibre content (soluble, insoluble and total) of the meals were determined. Total dietary fibre content was higher in the beans meals compared with the Cassava group. However, the ratio of soluble fibre to insoluble dietary was higher in the cassava group. A positive significant relationship was observed between postprandial glucose rise (incremental peak value and area under the curve) and soluble fibre content of the test meals but not with the insoluble dietary fibre content. The study confirms that starchy meals induces different glycaemic responses depending on the source of the starch used also on the extent of processing the food is subjected to as in the case of the bean meals. The addition of protein and fat to the starchy foods attenuated the postprandial glycaemia.