The acute effects of cocoa flavanols on cognitive control and response inhibition: A randomised crossover trial

In this pre-registered study, we investigated the effects of acute cocoa flavanol (CF) consumption on cognitive control and response inhibition processes, at two different dosage levels. This study was randomised, placebo-controlled, gender-balanced, double-blind, and utilised a crossover design. Participants consumed three different drinks across three separate sessions: A placebo drink with alkalised cocoa powder, a low dosage (415 mg), and a medium dosage (623 mg) of cocoa flavanols from flavanol-rich cocoa powder. Following the administration of these treatment conditions, participants were tested in the Flanker, Simon, and Go/No-go tasks in a counterbalanced order in each session. We analysed accuracy and response times from incongruent and congruent trials of the Simon and Flanker tasks, and commission errors, omission errors, and response times for the Go/No-go task. In addition to these main measurements, we considered interference and sequence effects, accounting for the influence of previous trials in Simon and Flanker tasks. The acute effects of CF on cognitive control and response inhibition were examined using (Generalised) Linear Mixed Model analysis, which included random intercepts, fixed effects, and random slopes. Analysis results revealed that neither dose of cocoa flavanols consumption acutely improved accuracies, interferences, errors, or response times in these three tasks. Furthermore, neither the gender of participants nor BMI scores predicted their cognitive control and response inhibition functions in addition to the treatment conditions. Our findings suggest that acute consumption of cocoa flavanols does not significantly enhance cognitive control or response inhibition in healthy young adults.