The Health Effects of Blueberry Anthocyanins in Metabolic Syndrome (the CIRCLES-study)
CIRCLES
The Effects of Blueberry Anthocyanins on Insulin Resistance and Vascular, Lung and Cognitive Function in a Population With Metabolic Syndrome.
1 other identifier
interventional
144
2 countries
4
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).
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for not_applicable
Started Jan 2014
Typical duration for not_applicable
4 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
Study Start
First participant enrolled
January 1, 2014
CompletedFirst Submitted
Initial submission to the registry
January 10, 2014
CompletedFirst Posted
Study publicly available on registry
January 14, 2014
CompletedPrimary Completion
Last participant's last visit for primary outcome
November 7, 2016
CompletedStudy Completion
Last participant's last visit for all outcomes
November 7, 2016
CompletedSeptember 29, 2017
January 1, 2017
2.9 years
January 10, 2014
September 28, 2017
Conditions
Outcome Measures
Primary Outcomes (1)
Insulin resistance
Assessed, in the fasted state, via HOMA-IR calculation in all participants; indirect assessment.
Chronic (0 to 6 month)
Secondary Outcomes (8)
Insulin resistance
Chronic (0 to 6 month)
Blood pressure and blood vessel regulation
Chronic (0 to 6 month)
Lung function
Chronic (0 to 6 month)
Cognitive function
Chronic (0 to 6 month)
Liver fat and blood flow assessment
Chronic (0 to 6 month)
- +3 more secondary outcomes
Study Arms (3)
Full dose blueberry
ACTIVE COMPARATOR26g of freeze dried blueberry powder; equivalent to 2 portions of fresh blueberries per day. Frequency: 26g per day. Total duration: 6-month.
Half dose blueberry
ACTIVE COMPARATOR26g of freeze dried powder; containing 13g of freeze dried blueberry powder and 13g of placebo comparator material; equivalent to 1 portion of fresh blueberries per day. Frequency: 26g per day. Total duration: 6-month.
Control
PLACEBO COMPARATORMatched control powder; matched for appearance, taste and sugar content. Frequency: 26g per day. Total duration: 6-month.
Interventions
Full dose: 26g of freeze dried blueberry powder to be incorporated into the habitual diet. Dietary restrictions will be observed (i.e. avoidance of blueberry, and restricted intake of anthocyanin rich foods) for 21 days prior to the first assessment visit and throughout the study.
Half dose: 26g of freeze dried powder (containing 13g of freeze dried blueberry powder and 13g of placebo comparator material) to be incorporated into the habitual diet. Dietary restrictions will be observed (i.e. avoidance of blueberry, and restricted intake of anthocyanin rich foods) for 21 days prior to the first assessment visit and throughout the study.
Control: 26g of placebo comparator material to be incorporated into the habitual diet. Dietary restrictions will be observed (i.e. avoidance of blueberry, and restricted intake of anthocyanin rich foods) for 21 days prior to the first assessment visit and throughout the study.
Eligibility Criteria
You may qualify if:
- Men and postmenopausal women (≥ 1 year since last menstruation)
- to 75 years old
- BMI of ≥ 25 kg/m2
- 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
You may not qualify if:
- 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)
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- University of East Anglialead
- Harvard School of Public Health (HSPH)collaborator
Study Sites (4)
Harvard School of Public Health
Boston, Massachusetts, 02115, United States
Addenbrooke's hospital
Cambridge, Cambridgeshire, CB2 0QQ, United Kingdom
Norwich Medical School University of East Anglia
Norwich, Norfolk, NR4 7TJ, United Kingdom
Norfolk and Norwich University Hospital
Norwich, Norfolk, NR4 7UY, United Kingdom
Related Publications (3)
Curtis PJ, van der Velpen V, Berends L, Jennings A, Haag L, Minihane AM, Chandra P, Kay CD, Rimm EB, Cassidy A. Chronic and postprandial effect of blueberries on cognitive function, alertness, and mood in participants with metabolic syndrome - results from a six-month, double-blind, randomized controlled trial. Am J Clin Nutr. 2024 Mar;119(3):658-668. doi: 10.1016/j.ajcnut.2023.12.006. Epub 2024 Feb 6.
PMID: 38432713DERIVEDCurtis 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.
PMID: 34883305DERIVEDCurtis 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.
PMID: 31136659DERIVED
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Study Officials
- PRINCIPAL INVESTIGATOR
Aedin Cassidy, PhD
University of East Anglia
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- RANDOMIZED
- Masking
- QUADRUPLE
- Who Masked
- PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
- Purpose
- BASIC SCIENCE
- Intervention Model
- PARALLEL
- Sponsor Type
- OTHER
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
January 10, 2014
First Posted
January 14, 2014
Study Start
January 1, 2014
Primary Completion
November 7, 2016
Study Completion
November 7, 2016
Last Updated
September 29, 2017
Record last verified: 2017-01