A specific dietary fibre supplementation improves cognitive performance-an exploratory randomised, placebo-controlled, crossover study

Rationale The impact of the microbiota on the gut-brain axis is increasingly appreciated. A growing body of literature demonstrates that use of dietary fibre and prebiotics can manipulate the microbiota and affect host health. However, the influence on cognition and acute stress response is less well understood. Objectives The objective of this study was to investigate the efficacy of a dietary fibre, polydextrose (PDX), in improving cognitive performance and acute stress responses through manipulation of the gut microbiota in a healthy population. Methods In this double-blind, randomised, placebo-controlled, crossover design study, 18 healthy female participants received 12.5 g Litesse (R) Ultra (> 90% PDX polymer) or maltodextrin for 4 weeks. Cognitive performance, mood, acute stress responses, microbiota composition, and inflammatory markers were assessed pre- and post-intervention. Results PDX improved cognitive flexibility as evidenced by the decrease in the number of errors made in the Intra-Extra Dimensional Set Shift (IED) task. A better performance in sustained attention was observed through higher number of correct responses and rejections in the Rapid Visual Information Processing (RVP) task. Although there was no change in microbial diversity, abundance ofRuminiclostridium5 significantly increased after PDX supplementation compared with placebo. PDX supplementation attenuated the increase of adhesion receptor CD62L on classical monocytes observed in the placebo group. Conclusions Supplementation with the PDX resulted in a modest improvement in cognitive performance. The results indicate that PDX could benefit gut-to-brain communication and modulate behavioural responses.