Quercetin for Acute Glucose Tolerance in Type 2 Diabetes

Principal Investigator: Marisa Pellegrini, ND

Co-Investigator: Ryan Bradley ND, MPH

Purpose: To test the effects of the dietary polyphenolic compound quercetin on acute glucose tolerance, insulin release and endothelial function following a disaccharide challenge test in people with type 2 diabetes.

Methods: Nineteen participants with sub-optimally controlled type 2 diabetes were randomly assigned to take either: bquercetin (2 grams), the alpha-glucosidase inhibitor drug Acarbose (100 mg) or placebo in a cross-over fashion on three occasions 5 minutes before consuming a 100 g oral maltose tolerance test (OMTT). Serum glucose and insulin were measured while fasting, and again 30-, 60- and 120-minutes after the OMTT. Endothelial function was also measured while fasting and 90-minutes after the OMTT as the reactive hyperemia index (RHI) using peripheral tonometry. Changes in serum glucose and insulin between fasting and 120-minutes after the OMTT were compared between groups by ANOVA. Changes in RHI post OMTT were also compared between groups by ANOVA. Exploratory analyses evaluated for within group changes.

Results: There were no significant differences in age, gender distribution, fasting glucose, fasting insulin or RHI between treatment groups at baseline. Changes in glucose between fasting and 120 minutes post-OMTT did not vary between groups (ANOVA p=0.81). Neither acute insulin response at 30-minutes post-OMTT or changes in insulin between fasting and 120-minutes changed significantly (ANOVA p= 0.48 and p=0.62 respectively). Similarly RHI did not change significantly between groups (ANOVAp=0.65). Changes within treatment groups also demonstrated no effects.

Conclusion: The polyphenolic compound quercetin at a dose of 2 grams does not acutely affect glucose tolerance, insulin release or endothelial function following a 100-gram maltose challenge in people with sub-optimally controlled type 2 diabetes.

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