The Health Effects of Blueberry Anthocyanins in Metabolic Syndrome (the CIRCLES-study)

The Effects of Blueberry Anthocyanins on Insulin Resistance and Vascular, Lung and Cognitive Function in a Population With Metabolic Syndrome.

The purpose of this study is to determine the dose-dependent impact of 6 month freeze-dried blueberry powder intake on insulin sensitivity and resistance, cardiovascular disease risk factors, and lung and cognitive function in overweight and obese participants with metabolic syndrome. We will also examine acute post-prandial effects of blueberry intake (at baseline and at 6-months).

Inclusion Criteria:

• Men and postmenopausal women (≥ 1 year since last menstruation)
• 50 to 75 years old
• BMI of ≥ 25 kg/m2
• 3 characteristics of metabolic syndrome i.e: Waist circumference ≥ 102 cm for men, ≥ 88 cm for women; Triglycerides ≥ 1.7 mmol/L (or drug treatment for elevated triglycerides); HDL-cholesterol < 1.0 mmol/L for men, < 1.3 mmol/L for women (or drug treatment for low HDL-cholesterol); Blood pressure ≥ 130 mm Hg systolic and/or ≥ 85 mm Hg diastolic blood pressure; Fasting blood glucose ≥ 5.56 mmol/L
• Successful biochemical, haematological and urinalysis assessment at screening

Exclusion Criteria:

• Current smokers, or ex-smokers ceasing < 6 months ago
• Existing or significant past medical history of vascular disease or medical conditions likely to affect the study measures
• Fructose intolerance or known allergies to the intervention treatments
• On therapeutic diets or having experienced substantial weight loss within 3 months of screening
• Taking flavonoid containing supplements (and unwilling to cease intake during, and 1 month preceding the trial)
• Planning on altering consumption of vitamin supplements / fish oil capsules during the course of the study.
• Prescribed hypoglycaemic, vasodilators or HRT medication.
• Unsatisfactory biochemical, haematological or urinary assessment at screening, or measures considered to be counter indicative for the study
• < 3 characteristics of the metabolic syndrome.

NB: REC approved NoSA granted to include those on anti-hypertensives (29JUL2014)