Cocoa flavanols increase cerebral haemoglobin levels acutely during cognitive task performance in healthy young adults

Crystal Haskell, Philippa Jackson, Joanne Forster, Bryce Laverick, Katie Sutherland

Research output: Contribution to conferencePoster


Introduction: Consumption of cocoa flavanols (CF) has been shown to increase flow-mediated vasodilation, and cerebral blood flow/velocity as measured by arterial spin labelling and transcranial doppler acutely at rest. Acute effects on cognition following ingestion of CF have also been shown during performance of mentally demanding tasks. Objectives: The present randomised, placebo-controlled, double-blind, counterbalanced-crossover study investigated the acute effect of CF consumption on cognition, mental fatigue and cerebral blood flow during completion of a 30 minute version of a mentally demanding paradigm. Method / Design: Twenty healthy, young, adults consumed a cocoa drink containing 500 mg CF or a matched control in a counterbalanced order. Cognition and mental fatigue were assessed with a shortened version of the Cognitive Demand Battery previously shown to be sensitive to CF supplementation in its 60 minute form. Tasks were completed at baseline and following a 60 minute absorption period. Changes in oxygenated and deoxygenated haemoglobin were monitored throughout via near infrared spectroscopy (NIRS), with their combined total providing a proxy for cerebral blood flow (CBF). Results: Compared to placebo, the consumption of 500 mg CF significantly increased deoxygenated and total haemoglobin levels throughout a 60 minute absorption period and during task completion, with more pronounced elevations during cognitive tasks. No effects on cognition or mental fatigue were observed. In addition, no positive correlations between CBF and behaviour were observed following CF. Conclusions: These findings demonstrate the ability of CF to increase CBF during performance of cognitive tasks. Replication of previously identified cognitive effects was not achieved. The present results suggest that previously demonstrated improvements to cognition and mental fatigue following CF consumption may not be related to increases in CBF parameters. It is also possible that behavioural effects may only become apparent following prolonged task completion, when neural resources are depleted.
Original languageEnglish
Publication statusPublished - Oct 2015
Event12th European Nutrition Conference (FENS) - Berlin, Germany
Duration: 1 Oct 2015 → …


Conference12th European Nutrition Conference (FENS)
Period1/10/15 → …


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