EFFECTS OF BERRY POLYPHENOLS ON COGNITIVE FUNCTION IN HUMANS

Abstract

A small number of epidemiological studies have suggested that increased polyphenol intake over the lifespan is beneficial for cognition. The mechanisms by which polyphenols could improve cognitive function include increased cerebrovascular blood flow, increased synaptic plasticity and modulation of neuronal signalling pathways. This systematic review examines the effect of consumption of berry polyphenols on cognitive function in humans. Method: inclusion criteria were berry polyphenol vs. control interventions which employed an objective measure of cognitive function. Participants were healthy or mildly cognitively impaired adults. Studies were excluded if clinical assessment or diagnosis of Alzheimer’s disease, dementia, or cognitive impairment was the sole measure of cognitive function. Results: five berry juice studies, one resveratrol study, and five epidemiological studies were identified. Three studies of regular berry fruit juice consumption over 12-16 weeks showed benefits for verbal memory whereas three acute studies failed to show cognitive effects. Four epidemiological studies demonstrated cognitive benefits associated with increased polyphenol intake over the lifespan. Conclusions: evidence from long term intervention studies in combination with epidemiological trials suggests that consuming additional polyphenols by including berries in the diet can lead to cognitive benefits, especially improvements in memory.