Laboratory exercise: study of digestive and regulatory processes through the exploration of fasted and postprandial...

Digestive physiology laboratory exercises often explore the regulation of enzyme action rather than systems physiology. This laboratory exercise provides a systems approach to digestive and regulatory processes through the exploration of postprandial blood glucose levels. In the present exercise, students enrolled in an undergraduate animal physiology course select to participate in either an oral glucose tolerance test (OGTT) or one of the following three meal treatments based on typical student breakfasts: 1) high glycemic load (HGL), 2) moderate glycemic load (MGL), and 3) low glycemic load (LGL). The caloric value of the meals is 540 kcal. An Accucheck glucometer is used to determine fasted and 30-, 60-, and 120-min postprandial blood glucose levels. Students discover that postprandial glucose levels peak similarly for the OGTT and HGL group (137 ± 7.1 and 145 ± 4.7mg/dl) and remain higher than MGL and LGL groups over the 2-h period. Between sampling, vibrant discussion covering such topics as glucose and cognitive function, insulin resistance, epigenetics, and fad diets occurs. The postlaboratory assignment requires students to discuss the importance of glucose homeostasis, graphically summarize their findings, review the literature to describe results in light of published data, and describe relationships between hyperglycemia and hyperinsulinemia and disease processes. Students evaluated this laboratory as highly effective and one of the top three experiences of the course.