Clinical trial NCT02035592: The Health Effects of Blueberry Anthocyanins in Metabolic Syndrome (the CIRCLES-study)
Official title: The Effects of Blueberry Anthocyanins on Insulin Resistance and Vascular, Lung and Cognitive Function in a Population With Metabolic Syndrome.
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Insulin Resistance
Metabolic Syndrome X
Lead sponsor: University of East Anglia
Sponsor class: OTHER
Collaborators: name: Harvard School of Public Health (HSPH)
First posted: 2014-01-14
Enrollment: 144
Sex: ALL
Minimum age (years): 50
Maximum age (years): 74
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

Brief summary: 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).


Eligibility criteria: 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)

Primary outcomes:
measure: Insulin resistance
timeFrame: Chronic (0 to 6 month)
Secondary outcomes:
measure: Insulin resistance
timeFrame: Chronic (0 to 6 month)
measure: Blood pressure and blood vessel regulation
timeFrame: Chronic (0 to 6 month)
measure: Lung function
timeFrame: Chronic (0 to 6 month)
measure: Cognitive function
timeFrame: Chronic (0 to 6 month)
measure: Liver fat and blood flow assessment
timeFrame: Chronic (0 to 6 month)
measure: Bio-availability
timeFrame: Chronic (0 to 6 month)
measure: Metabolite phenotype effects
timeFrame: Chronic (0 to 6 month)
measure: Acute +24 hour effect of single (26g) intervention intake, given with high fat challenge
timeFrame: Chronic (0 to 6 month)
Other outcomes:
Locations:
city: Boston
country: United States
facility: Harvard School of Public Health
state: Massachusetts
city: Cambridge
country: United Kingdom
facility: Addenbrooke's hospital
state: Cambridgeshire
city: Norwich
country: United Kingdom
facility: Norwich Medical School University of East Anglia
state: Norfolk
city: Norwich
country: United Kingdom
facility: Norfolk and Norwich University Hospital
state: Norfolk
Study officials:
affiliation: University of East Anglia
name: Aedin Cassidy, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Curtis PJ, Berends L, van der Velpen V, Jennings A, Haag L, Chandra P, Kay CD, Rimm EB, Cassidy A. Blueberry anthocyanin intake attenuates the postprandial cardiometabolic effect of an energy-dense food challenge: Results from a double blind, randomized controlled trial in metabolic syndrome participants. Clin Nutr. 2022 Jan;41(1):165-176. doi: 10.1016/j.clnu.2021.11.030. Epub 2021 Nov 27.
citation: Curtis PJ, van der Velpen V, Berends L, Jennings A, Feelisch M, Umpleby AM, Evans M, Fernandez BO, Meiss MS, Minnion M, Potter J, Minihane AM, Kay CD, Rimm EB, Cassidy A. Blueberries improve biomarkers of cardiometabolic function in participants with metabolic syndrome-results from a 6-month, double-blind, randomized controlled trial. Am J Clin Nutr. 2019 Jun 1;109(6):1535-1545. doi: 10.1093/ajcn/nqy380.