Effects of Lutein/Zeaxanthin Supplementation on the Cognitive Function of Community Dwelling Older Adults: A Randomized, Double-Masked, Placebo-Controlled Trial

Abstract

<b>Background:</b> High levels of xanthophyll carotenoids lutein (L) and zeaxanthin (Z) in the central nervous system have been previously correlated with improved cognitive function in community-dwelling older adults. In this study, we tested the effects of supplementing L and Z on older men and women with a range of baseline cognitive abilities. <b>Objective:</b> The purpose of this study was to determine whether or not supplementation with L+Z could improve cognitive function in community-dwelling, older adults. <b>Design:</b> Double-masked, randomized, placebo-controlled trial. A total of 62 older adults were randomized into groups receiving either 12 mg L+Z or a visually identical placebo. Data from 51 participants (<i>M</i> = 73.7 years) were available for analysis. Retinal L+Z levels (macular pigment optical density, MPOD) were measured psychophysically using heterochromatic flicker photometry as a biomarker of cortical L+Z levels. Cognitive function was measured using the CNS Vital Signs computerized test platform. <b>Results:</b> Participants receiving the active L+Z supplement had statistically significant increases in MPOD (<i>p</i> < 0.03) and improvements in complex attention (<i>p</i> < 0.02) and cognitive flexibility domains (<i>p</i> < 0.04), relative to participants taking the placebo. A trend was also seen for the executive function domain (<i>p</i> = 0.073). In male participants only, supplementation yielded improved composite memory (<i>p</i> = 0.04). <b>Conclusions:</b> Supplementation with L+Z improved cognitive function in community-dwelling, older men and women.