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The effect of total milk protein, casein, and whey protein ingestion on blood glucose and insulin in rats.

B. Luhovyy

Events

06-23-2020

Abstract:

203
The effect of total milk protein, casein, and whey protein ingestion on blood glucose and insulin in rats.
T. Olowookere1, E. Vandenboer1, Y. Anini2, M. Akbarifakhrabadi1, C. Kale1, N. Tari3, B. Luhovyy*1,2. 1Mount Saint Vincent University Halifax, NS, Canada, 2Dalhousie University Halifax, NS, Canada, 3University of Guelph Guelph, ON, Canada.

High-protein dairy products may reduce postprandial blood glucose and lead to the transient increase of insulin. The ingredients used in high-protein dairy products may include total milk protein (TMP), casein (CN) and whey protein (WP). However, their direct effect on insulin and BG remains unclear. Our objective was to investigate the acute effect of commercial TMP, micellar CN and WP isolates on BG and insulin response in rats. We hypothesized that the magnitude of insulin and BG response would depend on the type of protein. Six male Wistar Han rats with jugular vein catheters and vascular access buttons were used in a randomized crossover. After 6h daylight fasting, each rat was gavaged with 350 mg/3 mL of either TMP, CN, WP or glucose (G) reflecting a human dosage of 10g calculated based on allometric scaling. Each rat received all treatments in random order with a 48h in between. Blood was collected at 0, 15, and 30min for insulin measured with Ultra-Sensitive Rat Insulin ELISA, and at 0, 15, 30, 60, 90, and 120min for glucose measured with HemoCue 201 Glucose Analyzer. The data were analyzed with 2-way RM ANOVA followed by Tukey-Kramer post hoc test. There was an effect of treatment (P = 0.0002), time (P < 0.0001) and a treatment by time interaction (P < 0.0001) on BG over 120min. At 15min TMP, CN and WP, and at 30min CN and WP led to reduced BG compared with G (P < 0.05). At 30min, BG was lower after WP compared with CN (P < 0.05). There was an effect of treatment on BG area under the curve (AUC) over 120min (P = 0.001). All protein treatments resulted in a lower BG AUC compared with G (P < 0.05). There was an effect of treatment (P = 0.02), time (P < 0.0001) and treatment by time interaction (P < 0.0001) on insulin over 30min. At 15min, only TMP and CN but not WP led to reduced insulin compared with G (P < 0.05). There was an effect of treatment on insulin AUC over 30min (P = 0.006). All protein treatments resulted in a lower insulin AUC compared with G (P < 0.05). In conclusion, although TMP, CN and WP follow a similar pattern in their effect on BG and insulin, they demonstrate distinct properties at 15 and at 30 min after ingestion.

Keywords: milk proteins, blood glucose, insulin.

Biography: Dr. Bohdan Luhovyy is Associate Professor in the Department of Applied Human Nutrition of Mount Saint Vincent University in Halifax, Nova Scotia. He had completed his PhD from Lviv National University in Ukraine in 2001. Bohdan was a postdoctoral fellow at the University of Pennsylvania (2002-2005), and research associate at the University of Toronto (2006-2011). In 2011, Bohdan joined Mount Saint Vincent University. In 2017, he was awarded The President and Vice President's Advanced Career Teaching Award. His research is focused on milk proteins and dairy products, and their effect on blood glucose control and satiety.