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Effects of Blackberry-derived Polyphenols on Cardiovascular Risk in Adults (Cardio-Rubus)

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ClinicalTrials.gov Identifier: NCT02355444
Recruitment Status : Completed
First Posted : February 4, 2015
Last Update Posted : February 27, 2017
Sponsor:
Information provided by (Responsible Party):
Dr. Alice Lucey, University College Cork

Brief Summary:
Cardiovascular disease (CVD) is the most common cause of death in Ireland, accounting for 33% of all deaths. Hypertension or elevated blood pressure, is also a significant health problem, however, it is one of the major controllable risk factors associated with CVD. While increased consumption of fruit and vegetables is associated with reduced risk of CVD, evidence is accumulating that consumption of berry fruits in particular, may promote cardiovascular health. Blackberries have a favourable nutritional profile, in that they are rich in dietary fibre, vitamins C, K and folate but low in dietary fat and kilocalories. In addition, blackberries are a rich source of antioxidants, and contain numerous phytochemicals including polyphenols. The aim of this study is to investigate the potential beneficial effects of blackberry consumption on cardiovascular health, in particular, effects on blood pressure.

Condition or disease Intervention/treatment Phase
Hypertension Dietary Supplement: blackberry polyphenol enriched beverage Dietary Supplement: blackberry beverage with minimal polyphenol concentrations Not Applicable

Detailed Description:

Dietary factors play a significant role in the prevention and/or treatment of hypertension and significant efforts are being put in to the development of functional foods with antihypertensive activity. Blackberries and their intrinsic polyphenols, consumed as part of a healthy diet, may be of functional interest in both the treatment and prevention of hypertension and dyslipidaemia. The Cardio-Rubus study presents healthy adults with an opportunity to participate in a human nutrition study that will assist in identifying biological effects of blackberry-derived components establishing further the value of berries as a nutritious, health conducive food.

It is proposed to carry out a crossover, randomized double-blind 18-week supplementation study in 100 men and women aged 45-70 years with a systolic blood pressure of 130-149 mmHg but who are otherwise in good health. The proposed sample size is based on systolic blood pressure data derived from baseline values of 700 adults who participated in RCTs that we have conducted at UCC over the last 6-7 years. The calculation for sample size is based on observational data of systolic blood pressure in older pre-hypertensive adults, which showed a mean (SD) SBP of 135 (3) mmHg. The proposed study is powered to detect a mean drop of 2 mmHg systolic blood pressure at 85% power and with a significance level of 5%. The calculations support the recruitment of 100 participants in total (n = 41 per group, rounded up to 50 to account for a 20% attrition rate).

Potential study participants will be recruited by researchers at the School of Food & Nutritional Sciences and all study visits will take place at the Human Nutrition Studies Unit, UCC. In addition to the provision of written information, the study protocol will be clearly and comprehensively discussed with each potential participant prior to enrollment and their provision of informed written consent. Participants will initially complete a 2-week run in period which involves refraining from the consumption of specified foods items (predominantly berries and other fruits) until the end of the study. Each participant will be randomly assigned to receive one of two beverages (either a high dose or low dose blackberry polyphenol enriched beverage) for a period of 6-weeks (study phase 1) and then after a 2-week wash-out, the participant will receive the opposite treatment to that which was provided during study phase 1 for the next 6-weeks (study phase 2). After completion of study phase 2 there will be a 2-week wash-out followed by a final visit to UCC. Thus, after screening and enrolment on to the study, there will be a further 5 visits to UCC (at the baseline and endpoint of each study phase and at the end of the final washout phase). All 5 visits will be fasting morning visits where the nurse will take a small blood sample which will be analysed for blood lipids, fasting glucose and biomarkers of endothelial function. Brachial and central blood pressure will be measured as well as an assessment of arterial stiffness by pulse wave velocity analysis. Body weight, BMI and waist circumference will also be measured. Each participant's body composition (% body fat & lean mass) will be assessed by DXA scan.

All information collected is strictly confidential. Samples and questionnaires will be labelled with a unique identifying code, and participant's names will not be used at any stage during data collection, database construction or data analysis. Data will be archived by the principal investigator. In any publications or other documents, participants will not be identified by name or code numbers. Group summary data will be presented in place of individual data, further ensuring confidentiality.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 83 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Dietary Intervention to Investigate the Effects of Blackberry-derived Polyphenols on Cardio-metabolic Risk Factors in Adults
Actual Study Start Date : May 2015
Actual Primary Completion Date : October 2016
Actual Study Completion Date : October 2016

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Experimental: High-dose blackberry polyphenol beverage
Each participant will consume a blackberry beverage with high-dose blackberry polyphenols (250mL/day for 6 weeks).
Dietary Supplement: blackberry polyphenol enriched beverage
Double-blind intervention study, cross-over design with one 250 mL bottle of high-dose blackberry polyphenol beverage per day or placebo (blackberry beverage with minimal polyphenol) in Phase one followed by cross-over in Phase two.
Other Name: Rubus Fructicosus

Placebo Comparator: Low-dose blackberry polyphenol beverage
Each participant will consume a blackberry beverage with minimal blackberry polyphenols (250mL/day for 6 weeks).
Dietary Supplement: blackberry beverage with minimal polyphenol concentrations
Double-blind intervention study, cross-over design with one 250 mL bottle of high-dose blackberry polyphenol beverage per day or placebo (blackberry beverage with minimal polyphenol) in Phase one followed by cross-over in Phase two.
Other Name: Rubus Fructicosus




Primary Outcome Measures :
  1. Blood Pressure [ Time Frame: 42 days ]
    A change between baseline blood pressure and endpoint blood pressure within the intervention group versus the control group.



Information from the National Library of Medicine

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Ages Eligible for Study:   45 Years to 70 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Adult Caucasian men and women (ratio men: women, 70:30)
  • Good general health
  • Systolic blood pressure: 130 - 149 mmHg
  • Body mass index (BMI): 25.0 - 35.0 kg/m2
  • Signed consent form

Exclusion Criteria:

  • Current smokers
  • Diagnosed hypertension
  • History of cardiovascular events such as stroke, myocardial infarction or peripheral vascular disease
  • Diagnosed medical illness including diabetes mellitus (Types 1 & 2), chronic kidney disease and gastro-intestinal diseases
  • Medications that may affect any of the study outcome measures: anti-hypertensive medications and lipid lowering therapies e.g. statins.
  • Suspected hypersensitivity or allergy to berries.
  • Intolerance for aspirin or salicylate acid.
  • Current consumption of nutraceuticals, botanical extracts or other polyphenol-rich supplements.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02355444


Locations
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Ireland
Human Nutrition Studies Unit, School of Food & Nutritional Sciences, UCC
Cork, Ireland
Sponsors and Collaborators
University College Cork
Investigators
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Principal Investigator: Mairead Kiely, PhD School of Food & Nutritional Sciences, University College Cork.
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Responsible Party: Dr. Alice Lucey, Research Fellow, University College Cork
ClinicalTrials.gov Identifier: NCT02355444    
Other Study ID Numbers: Cardio-rubus 13F539
First Posted: February 4, 2015    Key Record Dates
Last Update Posted: February 27, 2017
Last Verified: February 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided
Additional relevant MeSH terms:
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Hypertension
Vascular Diseases
Cardiovascular Diseases