Healthy Adults. Clinical Trial
Official title:
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.
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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Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Single Blind (Subject), Primary Purpose: Basic Science