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Completed

NCT Number: NCT04084457

Investigating the Effects of Daily Consumption of Blueberry (Poly)Phenols on Vascular Function and Cognitive Performance

Foods rich in certain (poly)phenols, particularly flavonoids, such as berries and cocoa, have been shown to improve measures of vascular function as well as cognitive performance in human intervention studies. This is a randomized, double-blind, placebo controlled, parallel trial investigating the effects of daily blueberry (poly)phenol consumption on vascular function and cognitive performance in healthy elderly individuals. The study will be conducted at King's College London, Franklin-Wilkins Building.

Eligible subjects will be healthy males and females aged 65-80.

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Key information

Conditions

Age range

65 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Franklin-Wilkins Building, King's College London

London, SE1 9NH, United Kingdom

About this study

To date no study has investigated whether daily blueberry consumption can induce an increase in cerebral blood flow, with subsequent improvements in vascular and cognitive function. In this study, the investigators aim to directly link daily blueberry consumption with improved vascular function, increased cerebral blood flow and positive cognitive outcomes in healthy elderly individuals. The investigators will use a large group of elderly individuals' representative of a healthy population, both males and females, aged 65-80 years to evaluate the health effects of daily blueberry consumption.

The main aim is to investigate whether improvements in vascular and cognitive function previously seen after blueberry consumption can be seen following 3-months daily consumption in elderly individuals, and whether enhanced cognitive performance is correlated with increased cerebral blood flow. The investigators hypothesise that daily consumption of an anthocyanin rich blueberry drink will improve cognitive performance and vascular function, increasing cerebral blood flow, in healthy older individuals.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Participants will include 60 healthy male and female volunteers, aged 65-80.
  • Volunteers will be able to understand the nature of the study and able to give signed written informed consent.
  • Subjects willing to maintain their normal eating/drinking habits and exercise habits to avoid changes in body weight over the duration of the study.

Exclusion criteria

  • Manifest cardiovascular diseases including coronary artery disease, cerebrovascular disease and peripheral artery disease.
  • Hypertensive, as defined as SBP superior or equal to 140 mmHg or DBP superior or equal to 90 mmHg.
  • Obese participants, defined as BMI superior or equal to 30.
  • Diabetes mellitus and metabolic syndrome.
  • Acute inflammation, terminal renal failure or malignancies.
  • Allergies to berries or another significant food allergy.
  • Subjects under medication or on vitamin/dietary supplements (within 2 weeks of baseline).
  • Subjects who have lost more than 10% of their weight in the past 6 months or are currently on a diet.
  • Subjects who reported participant in another study within one month before the study starts.
  • Subjects who smoke cigarettes irregularly.
  • MCI or dyslexic or unable to complete the cognitive function tasks for any reason such as visual impairments.
  • Subjects who require chronic antimicrobial or antiviral treatment.
  • Subjects with unstable psychological condition.
  • Subjects with history of cancer, myocardial infarction, cerebrovascular incident.
  • Any reason or condition that in the judgment of the clinical investigator(s) may put the subject at unacceptable risk or that may preclude the subject from understanding or complying with the study's requirements.

Treatment and study plan

Wild blueberry powder

Dietary Supplement

Powdered extract obtained from wild blueberries. A daily administration of 27g wild blueberry powder will be administered.

Placebo

Dietary Supplement

Identical formulation as the treatment matched for fibre and vitamin C

Primary outcomes

  1. Endothelial Function

    Time frame: Baseline and 12 weeks post-intervention

    Changes in flow-mediated dilation of the brachial artery (FMD) from baseline after 12-week consumption of blueberry vs control

  2. Cognitive function

    Time frame: Baseline and 12 weeks post-intervention

    Changes in cognitive function from baseline after 12-week consumption of blueberry vs control. Cognitive testing involves the participant conducting tasks administered on a tablet-style laptop. The participants will be conducting these tasks whilst cerebral blood flow measurements are taking place. The cognitive testing battery will consist of 4 tasks which are Auditory Verbal learning task, Corsi Blocks, Switching task and Serials 3's and 7's, including a mood assessment (PANAS).

Secondary outcomes

  1. Cerebral blood flow velocity (CBFv)

    Time frame: Baseline and 12 weeks post-intervention

    Changes in cerebral blood flow velocity (CBFv) from baseline after 12-week consumption of blueberry vs control. Trans-cranial blood flow will be assessed by Non-imaging transcranial Doppler sonography (TCD). Variables measured include resting and active mean blood flow velocity (cm/s).

  2. Office systolic blood pressure

    Time frame: Baseline and 12 weeks post-intervention

    Changes from baseline office systolic blood pressure (mmHg) after 12-week consumption of blueberry vs control.

  3. Pulse wave velocity (PWV)

    Time frame: Baseline and 12 weeks post-intervention

    Determine the changes in Pulse wave velocity (PWV) from baseline after 12-week consumption of blueberry vs control.

  4. Augmentation Index (AIx)

    Time frame: Baseline and 12 weeks post-intervention

    Changes in augmentation Index (AIx) using a Sphygmocor device post consumption of a placebo or blueberry treatment

  5. 24-hour ambulatory systolic blood pressure

    Time frame: Baseline and 12 weeks post-intervention

    Determine the effect of the blueberry extract vs Placebo on 24-hour systolic blood pressure using a monitor, at 12 weeks post consumption. Variables include mean asleep, awake and total 24 h systolic blood pressure

  6. Mood

    Time frame: Baseline and 12 weeks post-intervention

    Assessment using a self-reported questionnaire using the Positive and Negative Affect Schedule (PANAS).PANAS (The Positive and Negative Affect Schedule) to measure mood, where the participants will need to answer 20 questions using a 5-point likert scale that ranges from (1) not at all to (5) extremely. Dependent variables are composite positive affect and negative affect scores obtained by summing responses to positive or negative PANAS items, respectively.

  7. Change in Blood lipids concentration (Total, HDL and LDL cholesterol, triglycerides)

    Time frame: Baseline and 12 weeks post-intervention

    Determine the effect of the blueberry extract vs Placebo on blood lipids (Total, HDL and LDL cholesterol, triglycerides), at 12 weeks post consumption.

  8. Plasma blueberry (poly)phenol metabolites

    Time frame: Baseline and 12 weeks post-intervention

    Measured by liquid chromotography- mass spectrometry (LC/MS) 0 and 2 hours post consumption

  9. Microbiome analysis

    Time frame: Baseline and 12 weeks post-intervention

    Stool sample collection involving an all-in-one kit for self-collection and stabilization of microbial DNA from faeces for gut microbiome profiling.

  10. Urine blueberry polyphenol metabolites

    Time frame: Baseline and 12 weeks post-intervention

    Collected over a 24 hour period. Measured by liquid chromotography- mass spectrometry (LC/MS) 0 and 2 hours post consumption

  11. Number of volunteers with treatment-related adverse events

    Time frame: Baseline and 12 weeks post-intervention

    The number of volunteers with treatment-related adverse events will be assessed by questionnaires and interviews.

  12. Pulsatility index (PI)

    Time frame: Baseline and 12 weeks post-intervention

    Changes in pulsatility index (PI) from baseline after 12-week consumption of blueberry vs control. Trans-cranial blood flow will be assessed by Non-imaging transcranial Doppler sonography (TCD). Variables measured include resting and active PI (cm/s.

  13. Office diastolic blood pressure

    Time frame: Baseline and 12 weeks post-intervention

    Changes from baseline office diastolic blood pressure (mmHg) after 12-week consumption of blueberry vs control.

  14. 24-hour ambulatory diastolic blood pressure

    Time frame: Baseline and 12 weeks post-intervention

    Determine the effect of the blueberry extract vs Placebo on 24-hour diastolic blood pressure using a monitor, at 12 weeks post consumption. Variables include mean asleep, awake and total 24 h diastolic blood pressure

Sponsors and collaborators

Lead sponsor

King's College London

Other

Collaborators

  • University of Reading

Registry information

Official study title

Randomised, Double-blind, Placebo Controlled, Parallel Trial Investigating the Daily Effects of Blueberry (Poly)Phenol Consumption on Vascular Function and Cognitive Performance in Healthy Elderly Individuals

Acronym: BluFlow

Important dates

Study start
2019
Primary completion
2020
Study completion
2020
First posted
Sep 10, 2019
Registry last updated
Jul 12, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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