Introduction: Blueberries and blueberry leaves, which are rich in flavonoids, have been suggested to have anti-diabetic properties and have been used as a traditional medicine for glycaemic control [1,2]. We have demonstrated that blueberry tea (BBT, containing dried blueberries, cinnamon, raspberry, blueberry and spearmint leaves) improves glucose tolerance and insulin sensitivity in high fat fed rats by improving metabolic and vascular insulin sensitivity in skeletal muscle .
Objective: To determine whether BBT can improve metabolic and vascular health in people with T2D.
Methods: This is an on-going randomised cross-over clinical trial among 18 people with T2D: BBT (3 cups per day) or no-treatment for 4 weeks. Inclusion criteria include: clinical diagnosis of T2D (managed by metformin and/or lifestyle), 18-75 yrs, BMI 2, non-smoker, and no history of cardiovascular disease. Overnight fasted participants will have a blood sample taken for clinical chemistries (glucose, insulin, lipids and HbA1c), and undergo an oral glucose tolerance test (75g glucose x 2hr, OGTT). Central haemodynamics (blood pressure, large artery stiffness and augmentation index) will be measured with a validated Mobil-O-Graph device measured in triplicate prior to the OGTT. Metabolic and vascular testing will be conducted at baseline (at time of enrollment) and after each intervention.
Results and Conclusions: This is an on-going clinical study powered to see a 15% reduction in the OGTT area under the curve following BBT treatment. Results of the trial will be reported at the conference.