A double blind placebo controlled study measuring the effect of two berry fruit extracts on mood, cognition and monoamine oxidase B inhibition in healthy young adults

Abstract

Berry fruit polyphenols have been shown to exert a number of physiological benefits in animal models suggesting a role in the prevention of a number of chronic human diseases and the augmentation of human brain function and cognition. This randomised, double-blind, placebo-controlled, crossover study investigated the effect of two berry extracts on cognitive performance and mood in 35 healthy young participants. Participants arrived 12-h fasted to provide baseline measurements, before consuming a powdered berry extract (521 mg polyphenols/60 kg body weight), juiced extract (528 mg polyphenols/60 kg) or placebo (all sugar and flavour matched). After a 60-min absorption period, participants completed a 70-min, mentally fatiguing, computerised cognitive assessment. Both berry extracts improved attention task performance when compared to placebo. The powdered extract increased accuracy during a rapid visual information processing task. The juiced extract improved reaction times during the digit vigilance task. Platelet MAO-B was inhibited by 96% ( n = 9) and a rapid decline in blood glucose levels was significantly attenuated over all time points following the juiced extract only, when compared to placebo. LC–MS analysis revealed that plasma anthocyanin levels were greater after supplementation of the powdered extract over all measured anthocyanins. This is the first illustration of a cognitive benefit of acute berry fruit supplementation in healthy young humans and the first description of a clinically significant inhibition of platelet MAO-B using a commonly consumed fruit.