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Investigating the Acute Effects of Flavonoids in Blueberries on Cognitive Function.

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ClinicalTrials.gov Identifier: NCT01289860
Recruitment Status : Completed
First Posted : February 4, 2011
Last Update Posted : February 21, 2013
Information provided by (Responsible Party):
Jeremy Paul Edward Spencer, University of Reading

Brief Summary:

This study was a controlled, cross-over, acute flavonoid intervention trial with younger and older adults. Subjects consumed a blueberry beverage during one visit and a control beverage on another. Cognitive function pre drink was assessed, blood and urine samples were taken as well as blood pressure and a measure of vascular reactivity. These outcome measures were taken at 2 and 5 hours post drink.

It was predicted that the flavonoids in the blueberry drink would lead to improved performance on the cognitive tests and vascular reactivity measure compared to following the control drink. It was thought this could be due to increased vaso-dilation and improving blood flow to the brain which was investigated in an extension to the project where a sample of individuals underwent brain imaging in an MRI scanner pre and post a blueberry and a control drink.

Condition or disease Intervention/treatment Phase
Healthy Adults. Dietary Supplement: Flavonoids Dietary Supplement: Control Not Applicable

Detailed Description:

The control drink was matched to the blueberry drink for other bioactive compounds which may have affected cognition, specifically sugars and vitamin C. Volunteers were healthy, not on any medication, without high blood pressure, high cholesterol, high BMI, diabetes or other medical conditions. Older adults were aged 61-75 years and younger adults 18-26 years.

Blood and urine samples will be analysed for flavonoid levels and Brain Derived Neurotrophic Factor, a biomarker of memory and learning, flavonoids may lead to increased BDNF production through the ERK-CREB-BDNF pathway.

Flavonoids may also increase nitric oxide production and improve the flexibility of the blood vessels hence the measure of vascular reactivity using the Digital Volume Pulse machine. This can lead to increased vaso-dilation and blood flow to the brain, therefore an fMRI study was carried out the investigate this using arterial spin labeling following acute blueberry supplementation compared to a control drink.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 47 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single (Participant)
Primary Purpose: Basic Science
Official Title: A Controlled, Cross-over, Acute Intervention Study Investigating the Cognitive and Neuronal Effects of Flavonoids in Blueberries.
Study Start Date : May 2009
Actual Primary Completion Date : January 2013
Actual Study Completion Date : January 2013

Arm Intervention/treatment
Active Comparator: Blueberry drink
30g of blueberry powder (equivalent to 200g fresh blueberries) and 300ml of semi-skimmed milk
Dietary Supplement: Flavonoids
475g of anthocyanidins in 300ml of blueberry drink.
Other Name: Anthocyanidins, flavanols, flavonols.

Placebo Comparator: Control drink
29g of powder consisting of sugars and vitamin C, values of which were matched to that of the blueberry drink, with 1 g of citric acid to match for taste.
Dietary Supplement: Control
29g powder: sugars (glucose, sucrose, fructose), vitamin C and citric acid.

Primary Outcome Measures :
  1. Cognitive function [ Time Frame: pre drink, 2 hours and 5 hours post drink ]
    Extensive cognitive test battery including tasks measuring executive function such as updating, and memory tests such as free recall.

Secondary Outcome Measures :
  1. Bioavailability and pharmacology [ Time Frame: Pre drink and 1 hour post drink ]
    Flavonoid and BDNF levels in plasma and urine samples.

  2. Vascular Reactivity [ Time Frame: Pre and 1 hour post drink ]
    Measurements taken using Digital volume pulse equipment. Blood pressure also recorded.

  3. Neuronal effects [ Time Frame: Pre and 1 hours post drink ]
    Using fMRI to determine whether flavonoid supplementation leads to greater activation in brain regions associated with the cognitive abilities tested and to calculate cerebral blood flow before and after the blueberry compared to the control drink.

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Ages Eligible for Study:   18 Years to 75 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • No medical conditions
  • Not taking any medication or supplements (or willing to stop taking supplements for duration of study)
  • Not lactose intolerant
  • Willing to give blood and urine samples
  • Not partaking in frequent vigorous exercise
  • Not suffering from or history of depression

Exclusion Criteria:

  • On blood pressure medication, taking Aspirin or other blood thinning medication
  • BMI > 30
  • Cholesterol > 6
  • Diabetes or other serious medical condition
  • Lactose intolerant
  • Any learning difficulty e.g. dyslexia

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): NCT01289860

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United Kingdom
University of Reading
Reading, Berkshire, United Kingdom, RG6 6AP
Sponsors and Collaborators
University of Reading
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Principal Investigator: Jeremy PE Spencer, PhD University of Reading
Principal Investigator: Laurie T Butler, PhD University of Reading
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Responsible Party: Jeremy Paul Edward Spencer, Professor of Nutritional Medicine, University of Reading
ClinicalTrials.gov Identifier: NCT01289860    
Other Study ID Numbers: UReading_2010_01
First Posted: February 4, 2011    Key Record Dates
Last Update Posted: February 21, 2013
Last Verified: February 2013