Glycemic Variations after Ingestion of Different Carbohydrate-Containing Foods Assessed by Continuous Glucose Monitoring in Healthy and Diabetic Individuals in Daily Life

Abstract

Background: To better guide diabetic patients by diet therapy with carbohydrate counting, which is becoming popular as a meal planning approach, we evaluated glycemic variation after the ingestion of three different carbohydrate-containing foods, chosen from the Food Exchange Lists 1 (starchy foods), 2 (fruits) and 4 (dairy foods), edited by the Japan Diabetes Society, by continuous glucose monitoring in healthy and diabetic individuals. Method: After an overnight fast, seven healthy persons and four each of type 1 and type 2 diabetic patientswere instructed to eat 40 g of carbohydrate-containing breakfast within 10 minutes, as with 100 g cooked rice with green tea seasoning (183 kcal), 300 g apples (162 kcal), and cereal with 180 ml milk (253 kcal), respectively, for three consecutive days in daily life. The glycemic profiles measured every 5 minutes over three hours were assessed by continuous glucose monitoring with iPro2®. Type 2 diabetic patients took prescribed oral hypoglycemic agents after breakfast, excluding sulfonylurea that was taken after lunch during the study. Type 1 diabetic patients reduced their bolus insulin doses for breakfast to 40-50% of usual doses, which were fixed during the study. The present study was approved by the Ethical Review Board of National Hospital Organization Matsumoto Medical Center. Result: The respective profiles of glycemic responses to the ingestion of three different carbohydrate-containing foods varied among individuals. The sums of glycemic increments at the time interval of 0 to 180 min after the ingestion of apples and cereal with milk were 322±123 and 181±275 mg/dl in healthy persons and 528±471 and 766±1374 mg/dl in diabetic patients. These were significantly (p < 0.05) lower than those of 543±209 and 1442±1025 mg/dl after the rice ingestion, respectively. In healthy persons, the increments after the apple and cereal+milk ingestion (163±92 and 92±155 mg/dl) were significantly (p < 0.05) lower than those after the rice ingestion (286±108 mg/dl) only at the time interval of 60 to 120 minutes. In diabetic patients, the increments after the apple ingestion (363±306 and -193±275 mg/dl) were significantly (p < 0.05) lower than those after the rice ingestion (680±390 and 342±612 mg/dl) at the time intervals of 60 to 120 and 120 to 180 minutes; and those after the cereal+milk ingestion (184±196 mg/dl) significantly (p < 0.01) lower than those after the rice ingestion (420±197 mg/dl) only at the time interval of 0 to 60 minutes. The diabetic patients, whose intrinsic insulin secretion was presumed to be greatly diminished or depleted, showed a delayed hyperglycemia after the cereal+milk ingestion. When glycemic indexes were calculated with rice as a reference in this study using the mean values at the time interval of 0 to 180 minutes, those of apple and cereal+milk were 59 and 33 in healthy persons, and 37 and 53 in diabetic patients. Conclusion: The inter-individual variations of postprandial glycemia with three different carbohydrate-containing foods were large in healthy persons and especially in diabetic patients. The average profiles of postprandial glycemia approximately accorded with standardized glycemic indexes previously reported. Interestingly, type 1 diabetic patients seemed to show a delayed hyperglycemia after the ingestion of cereal with milk. We should be aware of such individual variations in glycemic effects of controlling carbohydrate intake in daily life.