Lycopene and cognitive function

Abstract

Decreases in cognitive function related to increases in oxidative stress and inflammation occur with ageing. Acknowledging the free radical-quenching activ-ity and anti-inflammatory action of the carotenoid lycopene, the aim of the present review was to assess if there is evidence for a protective relationshipbetween lycopene and maintained cognitive function or between lycopene and development or progression of dementia. A systematic literature searchidentifiedfive cross-sectional andfive longitudinal studies examining these outcomes in relation to circulating or dietary lycopene. Among four studiesevaluating relationships between lycopene and maintained cognition, three reported significant positive relationships. Neither of the two studies reportingon relationship between lycopene and development of dementia reported significant results. Of four studies investigating circulating lycopene and pre-exist-ing dementia, only one reported significant associations between lower circulating lycopene and higher rates of Alzheimer’s disease mortality.Acknowledging heterogeneity among studies, there is insufficient evidence and a paucity of data to drawfirm conclusions or tease apart direct effectsof lycopene. Nevertheless, as low circulating lycopene is a predictor of all-cause mortality, further investigation into its relationship with cognitive longevityand dementia-related mortality is warranted.