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

A Controlled, Cross-over, Acute Intervention Study Investigating the Cognitive and Neuronal Effects of Flavonoids in Blueberries.

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.

Study Overview

• Status: Completed
• Conditions: Healthy Adults.
• Intervention / Treatment: Dietary supplement: Flavonoids; Dietary supplement: Control

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.

• Study Type: Interventional
• Enrollment (Actual): 47
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Berkshire
    • Reading, Berkshire, United Kingdom, RG6 6AP
      • University of Reading

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / 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 Names: 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cognitive function	Extensive cognitive test battery including tasks measuring executive function such as updating, and memory tests such as free recall.	pre drink, 2 hours and 5 hours post drink

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Bioavailability and pharmacology	Flavonoid and BDNF levels in plasma and urine samples.	Pre drink and 1 hour post drink
Vascular Reactivity	Measurements taken using Digital volume pulse equipment. Blood pressure also recorded.	Pre and 1 hour post drink
Neuronal effects	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.	Pre and 1 hours post drink

Collaborators and Investigators

• Sponsor: University of Reading
• Investigators: Principal Investigator: Laurie T Butler, PhD, University of Reading

Study record dates

Study Major Dates

• Study Start: May 1, 2009
• Primary Completion (Actual): January 1, 2013
• Study Completion (Actual): January 1, 2013

Study Registration Dates

• First Submitted: February 3, 2011
• First Submitted That Met QC Criteria: February 3, 2011
• First Posted (Estimate): February 4, 2011

Study Record Updates

• Last Update Posted (Estimate): February 21, 2013
• Last Update Submitted That Met QC Criteria: February 20, 2013
• Last Verified: February 1, 2013

More Information

Terms related to this study

• Other Study ID Numbers: UReading_2010_01