A randomised controlled study to investigate the cognitive, mood, metabolic and anti-inflammatory effects of chronic oyster mushroom intervention in healthy older adults

Abstract

The Pleurotus ostreatus oyster species is a common edible mushroom, rich in ergothioneine, a bioactive that has previously shown preclinical benefits to cognition when administered in extract form. The OYSCOG study investigated the effects of a 12-week oyster mushroom intervention on cognition, mood, and serum markers in 80 healthy older adults aged 60-80 years. Participants consumed four portions per week of either oyster mushroom (OM) or placebo (PL). All measures were collected at baseline and 12-weeks post-intervention. EEG activity was recorded in a subset of participants (n=40) at rest and during a simple cognitive task. ANCOVA between baseline and 12-weeks revealed slower task switching reaction times, indicating decreased performance, in the PL group. Increases in negative mood, as indicated by PANAS-X ratings of fear, sadness, and shyness and DASS-21 anxiety ratings, were similarly observed in the PL group. Conversely, DASS-21 anxiety ratings and RAVLT delayed word recall and delayed word recognition were improved for the OM group, while serum levels of inflammatory markers (cyclo-oxygenase 2 and NADPH oxidase 2) were reduced. After 12-weeks supplementation, the OM group outperformed the PL group in RAVLT delayed word recall and delayed word recognition and displayed lower negative mood, as indicated by PANAS-X sadness, PANAS-X shyness and DASS-21 anxiety. Overall, the 12-week OM intervention, maintained mood and improved episodic memory in older adults compared to PL, alongside reducing markers of inflammation.