Flavonoids, Blood Pressure and Blood Vessel Function
- Conditions
- Cardiovascular Disease Risk Reduction
- Interventions
- Dietary Supplement: Flavanone - supplementDietary Supplement: Anthocyanin - supplementDietary Supplement: Isoflavone - supplementDietary Supplement: Flavan-3-ol - supplementOther: Anthocyanin - foodOther: Flavanone - foodOther: Isoflavone - foodOther: Flavan-3-ol - foodOther: Flavanone - placeboOther: Isoflavone - placeboOther: Anthocyanin - placeboOther: Flavan-3-ol - placeboDietary Supplement: Isoflavone - metabolite supplement
- Registration Number
- NCT01530893
- Lead Sponsor
- University of East Anglia
- Brief Summary
The primary aim of this placebo-controlled study is to determine whether flavonoids beneficially affect markers of cardiovascular disease risk in healthy subjects at elevated cardiovascular risk.
The underlying mechanisms of action of flavonoids will be assessed on blood biomarkers and we will assess the effects of the food matrix, and aspects of isoflavone metabolism.
- Detailed Description
The study population will be healthy males (aged 50-75 years) at elevated risk of cardiovascular (CV) disease.
A target of 60 participants will be required to complete the study and a total of 70 subjects will be targeted (n=70 subjects \* \~85% anticipated completion rate = 60 subjects to complete the study).
This placebo-controlled study will test the relative efficacy of 4 different flavonoid sub-classes ((i) flavan-3-ol, (ii) anthocyanin, (iii) flavanone and (iv) isoflavone).
Accordingly, subjects will be randomised to one of the four flavonoid study groups ((i) to (iv) outlined above), and then will consume each of the following treatments in random order:
1. dietary flavonoid + placebo supplement
2. placebo food + commercially available/produced flavonoid supplement
3. placebo food + placebo supplement
Additionally, an isoflavone metabolite will be fed to establish potential vascular effects.
Each sub-class will be assessed separately and a 1 week wash-out period between treatments will be observed.
At each assessment visit, vascular function will be assessed pre- and post-intervention, with subsequent assessments made to coincide with anticipated peak plasma concentrations.
Dietary intake will be monitored during the study and participants will be required to adhere to a range of dietary and lifestyle restrictions within 3 days of each assessment to reduce potential confounding of the data assessment of interest.
A standard battery of vascular function tests will be performed on all intervention groups, with each assessment visit performed in an identical manner.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- Male
- Target Recruitment
- 64
- Males
- 50 to 75 years old
- At elevated risk of CV disease
- Screening blood pressure of < 160/90mmHg (at rest)
- Successful biochemical, haematological and urinalysis assessment at screening (as judged by clinical advisor)
- Current smokers, or ex-smokers ceasing < 3 months ago
- Subjects with existing or significant past medical history of vascular disease or medical conditions likely to affect the study measures (as judged by clinical advisor)
- Those with known allergies to the intervention treatments
- Those unprepared to adhere to dietary restrictions during the trial
- Parallel participation in another research project which involves concurrent dietary intervention and/or sampling of biological fluids/material
- Having vaccinations (excluding the flu vaccination) or antibiotics within 3 months of start of trial, and those with vaccinations scheduled for during the trial
- Taking flavonoid containing food / dietary supplements likely to affect the study results
- Prescribed lipid lowering, hypertension, vasodilators (e.g. Viagra) or antibiotic medication
- Unsatisfactory biochemical, haematological or urinary assessment at screening, indicating abnormal; renal or liver function, full blood profile, impaired glucose handling, deranged lipids or measurements considered to be counter indicative of the study by the clinical advisor
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- FACTORIAL
- Arm && Interventions
Group Intervention Description Intervention group A: flavanones Flavanone - supplement All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest. Intervention group B: isoflavones Isoflavone - metabolite supplement All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest. Intervention group D: Anthocyanins Anthocyanin - food All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest. Intervention group A: flavanones Flavanone - food All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest. Intervention group B: isoflavones Isoflavone - food All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest. Intervention group C: Flavan-3-ols Flavan-3-ol - food All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest. Intervention group D: Anthocyanins Anthocyanin - supplement All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest. Intervention group A: flavanones Flavanone - placebo All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest. Intervention group B: isoflavones Isoflavone - placebo All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest. Intervention group B: isoflavones Isoflavone - supplement All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest. Intervention group C: Flavan-3-ols Flavan-3-ol - supplement All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest. Intervention group D: Anthocyanins Anthocyanin - placebo All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest. Intervention group C: Flavan-3-ols Flavan-3-ol - placebo All experimental days will be exactly the same. All volunteers will attend the clinical research and trial unit in a fasted state. Prior to test administration, baseline vascular function will be assessed and biological samples taken by a trained and qualified research nurse. Subsequently, assessments will be repeated at times corresponding to anticipated peak plasma concentration of the flavonoid of interest.
- Primary Outcome Measures
Name Time Method Change from baseline in blood vessel control (pressure and endothelial function) at time points coinciding with postprandial [anticipated] peak plasma flavonoid concentration. acute postprandial; up to 24 hours, dependent on flavonoid sub-classification studied Assessment of vascular function
- Secondary Outcome Measures
Name Time Method Differences in effects of flavonoids introduced by food matrix acute postprandial; up to 24 hours dependent on flavonoid sub-classification studied
Trial Locations
- Locations (1)
Department of Nutrition, Norwich Medical School
🇬🇧Norwich, Norfolk, United Kingdom