Metabolism of Anthocyanins and Heart Health
- Conditions
- Healthy
- Interventions
- Other: Freeze dried blueberry powderOther: Anthocyanin free, sugar-matched placebo
- Registration Number
- NCT03869086
- Lead Sponsor
- University of East Anglia
- Brief Summary
This study aims to find out if consuming a single dose of blueberries, rich in anthocyanins, within an energy dense meal, improves blood vessel function and biomarkers of heart health. The study specifically aims to confirm if differences in how individuals process the bioactive compounds in blueberries, called anthocyanins, has an influence on heart health. The investigators will assess the effects of eating one portion of blueberries on vascular health over a 48hour period, and will track the breakdown compounds within blood and urine, to see if health effects are related to metabolism.
- Detailed Description
The primary aim of this cross-over designed, placebo controlled, acute dietary intervention study, is to prospectively recruit participants on the basis of anthocyanin metabolism profiles (based on profiles confirmed in our previous studies) following a 'blueberry challenge'. Acute cardio and metabolic function responses will be assessed (by metaboliser profile), following an energy dense test meal with/without the addition of blueberries.
Participants will be healthy, but overweight and obese (BMI inclusion: ≥ 25kg/m2) men and women (aged 50 y to 80 y), who will initially undertake a 'blueberry challenge' by consuming a single dose of freeze dried blueberries. Anthocyanin metaboliser type will be profiled from the analysis of metabolites within urine, collected for 48h following the 'challenge'.
A total of 70 participants will complete the intervention (n=35 FAST and n=35 SLOW metabolisers) which consists of two, test meal periods (separated by at least 7d and allocated in random order); 1) energy dense test meal plus freeze dried blueberries, 2) energy dense test meal plus an isocaloric matched placebo material. Urine samples and ambulatory blood pressure measures will be collected for 24h prior to, and then over the 48h period which follows the test meal intake. Further assessment of vascular and metabolic function will be made at pre-defined times over the 48h postprandial period. Dietary restrictions to abstain from blueberries and reduce the anthocyanin intake level, will be applied for 5d before each test meal intake. In addition, all food and drink will be provided for a 4d period (2d before and during the 48h following the energy dense test meal) to further control the intake of flavonoids and to standardise the influence of background diet on metabolism profile.
Recruitment & Eligibility
- Status
- TERMINATED
- Sex
- All
- Target Recruitment
- 49
- BMI >= 25 kg/m2
- Adults aged 50 - 80 years old
- Successful biochemical, haematological, and urinalysis assessment at screening
- 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 or lactose intolerant subjects or known allergies to intervention treatments
- Those unprepared to adhere to dietary instructions
- Parallel participation in another research project involving dietary intervention and/or sampling of biological fluids/material
- Those on therapeutic diets or having experienced substantial weight loss within 2 months of screening.
- Those taking flavonoid, nitrate / nitrite containing or fish oil containing supplements (and unwilling to cease intake during, and 1 month preceding the trial) or unwilling to maintain existing intake of other supplements.
- Prescribed hypoglycaemic, anti-hypertensive, vasodilator or hormone replacement therapy (HRT) medication.
- Unsatisfactory biochemical, haematological or urinary results or measurements considered to be counter indicative for the study
- Undiagnosed hypertension (elicited at screening; i.e. ≥ 180 / 110mmHg) at a level requiring immediate referral back to general practitioner for follow-up
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description SLOW anthocyanin metabolisers Anthocyanin free, sugar-matched placebo Participants will be prospectively recruited to the SLOW anthocyanin metaboliser group, following a pre-intervention screen (blueberry challenge). Participants in this arm will consume (in random order) blueberry and placebo interventions (both consumed with an energy dense meal) in a cross-over manner. At least 7 days washout will be observed between the two treatments. SLOW anthocyanin metabolisers Freeze dried blueberry powder Participants will be prospectively recruited to the SLOW anthocyanin metaboliser group, following a pre-intervention screen (blueberry challenge). Participants in this arm will consume (in random order) blueberry and placebo interventions (both consumed with an energy dense meal) in a cross-over manner. At least 7 days washout will be observed between the two treatments. FAST anthocyanin metabolisers Freeze dried blueberry powder Participants will be prospectively recruited to the FAST anthocyanin metaboliser group, following a pre-intervention screen (blueberry challenge). Participants in this arm will consume (in random order) blueberry and placebo interventions (both consumed with an energy dense meal) in a cross-over manner. At least 7 days washout will be observed between the two treatments. FAST anthocyanin metabolisers Anthocyanin free, sugar-matched placebo Participants will be prospectively recruited to the FAST anthocyanin metaboliser group, following a pre-intervention screen (blueberry challenge). Participants in this arm will consume (in random order) blueberry and placebo interventions (both consumed with an energy dense meal) in a cross-over manner. At least 7 days washout will be observed between the two treatments.
- Primary Outcome Measures
Name Time Method Brachial artery endothelial function assessed at 0, 1.5, 3, 6, 24, 48 hours after intervention intake percentage maximum dilatation assessed via flow mediated dilation (%FMD): (diametermax-diameterbaseline) / diameterbaseline×100.
- Secondary Outcome Measures
Name Time Method Bioavailability - serum Measured prior to, and then at +20, +40, +60, +90, +120, +180, +270 and +360 minutes, +24 hours and +48 hours following the energy dense meal intake. Assessment of flavonoid and metabolite levels in blood samples
Postprandial Insulin response Measured prior to, and then at +20, +40, +60, +90, +120, +180, +270 and +360 minutes, +24 hours and +48 hours following the energy dense meal intake. Assessment of postprandial insulin control
Total cholesterol Measured prior to, and then at +20, +40, +60, +90, +120, +180, +270 and +360 minutes, +24 hours and +48 hours following the energy dense meal intake. Assessment of blood cholesterol
Office blood pressure Assessed at 0, 3, 6, 24, 48 hours after intervention intake. Measurements of blood pressure
Trial Locations
- Locations (1)
Quadram Institute Clinical Research Facility; a partnership facility of the NHS, UEA and QIB
🇬🇧Norwich, Norfolk, United Kingdom