Investigating the Acute Effects of Flavonoids in Blueberries on Cognitive Function.
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 Design:||Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single Blind (Participant)
Primary Purpose: Basic Science
|Official Title:||A Controlled, Cross-over, Acute Intervention Study Investigating the Cognitive and Neuronal Effects of Flavonoids in Blueberries.|
- 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.
- Bioavailability and pharmacology [ Time Frame: Pre drink and 1 hour post drink ]Flavonoid and BDNF levels in plasma and urine samples.
- Vascular Reactivity [ Time Frame: Pre and 1 hour post drink ]Measurements taken using Digital volume pulse equipment. Blood pressure also recorded.
- 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.
|Study Start Date:||May 2009|
|Study Completion Date:||January 2013|
|Primary Completion Date:||January 2013 (Final data collection date for primary outcome measure)|
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.
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.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01289860
|University of Reading|
|Reading, Berkshire, United Kingdom, RG6 6AP|
|Principal Investigator:||Jeremy PE Spencer, PhD||University of Reading|
|Principal Investigator:||Laurie T Butler, PhD||University of Reading|