Effects of blackcurrant juice on pre-frontal cortical haemodynamics and cognition in healthy young adults.

Background: Evidence from randomised controlled trials demonstrates the modulatory effects of polyphenol consumption on the vascular system including improvements to cortical blood flow (CBF), microvascular blood flow, and large artery plasticity. Polyphenol-rich blackcurrants have been shown to inhibit monoamine oxidase, modulate brainwave spectral activity and modulate peripheral blood flow. This study assessed whether blackcurrant consumption can modulate blood flow in the shallow pre-frontal cortex, as measured using near infrared spectroscopy, during rest and under cognitive demand.

Methods: A randomised double blind, placebo-controlled balanced cross over design was used to assess the efficacy of a cold pressed blackcurrant juice drink (Blackadder cultivar, Neuroberry, Plant and Food Research Ltd.) standardised at 500 mg of total polyphenols upon attention and working memory and prefrontal cortical haemodynamics at rest and during cognitive load in 20 healthy young adults aged 18-35 years, following a 60-minute absorption period.

Results: Consumption of the Blackadder juice extract resulted in significant acute modulations of pre-frontal cortex haemodynamics during resting absorption and cognitive task performance as indicated by a decrease in deoxygenated haemoglobin [F(1,19) = 5.70, p = 0.027] and an increase in left hemisphere oxygenated haemoglobin during task performance [F(1.88,33.83) = 7.70, p = 0.002]. No effects on cognition were observed in this sample of healthy young adults.

Conclusion: Results from this trial outline the ability of a blackcurrant juice extract to increase cerebral blood flow during cognitive demand in healthy young adults. The effects of the juice extract in addition to other types of blackcurrant extracts upon acute and chronic brain function and blood flow deserve further investigation.Trial registration:ClinicalTrials.gov identifier: NCT01540123.