Acute effects on pancreatic hormones and blood lipids of bread and spaghetti consumed within a meal

Abstract To evaluate whether the same amount of carbohydrate (CHO) foods, known to give different glycaemic responses have also different effects on post-prandial lipid concentrations and on pancreatic hormones, 7 diabetic patients were given, in a random order and on different days, two test meals of identical composition. Each meal consisted of a fixed part to which a 50 g CHO portion of either bread (90 g) or spaghetti (65 g) was added. The glycaemic response was significantly higher after ingestion of the bread meal than after the spaghetti (p<0.01). The insulin and C-peptide responses paralleled the blood glucose (BG) response but there were no significant differences. The glucagon response mirrored that of glucose reaching a significant difference at the 3rd and the 4th hour post-prandial (p<0.02). Plasma non-esterified fatty acids (NEFA) decreased after each meal but the rate of decline was similar. The rise in triglycerides was almost identical after the two test meals. This study shows that mixed meals of identical composition, containing different starch foods, differ not only for the post-prandial BG response, but also for post-prandial plasma glucagon and, possibly, insulin and C-peptide concentrations. The effects of the two starch foods on lipid metabolism were much more uniform. These data might support the glycaemic index as a new criterion for selection of CHO foods in the diabetic diet since it is based on physiological rather than on biochemical characteristics of foods.