Abstract

Objective: Visual judgment has been shown to decline in healthy older adults. Previous research indicates higher levels of the nutrients lutein and zeaxanthin, naturally occurring carotenoids found in food, are associated with eye health due to antioxidant properties. We investigated the association between lutein level and brain activity during a visual judgment task. Method: Thirty-six community dwelling older adults ages 65–94 engaged in a modified judgment of line orientation task (JLO) while fMRI images were acquired. The JLO was controlled for using an active baseline during which participants indicated whether two lines were in the same horizontal plane or not. Lutein/zeaxanthin levels were measured using a standard Macular Pigment Ocular Density (MPOD) procedure (Hammond et al., 2013) and used as a covariate in the fMRI analyses. Data were processed using SPM12. Results: Increases in BOLD signal were seen in response to the JLO in areas traditionally associated with this cognitive process, including the bilateral occipital cortex, bilateral insula, and the bilateral middle frontal gyri (p < 0.01, family-wise error corrected). Covariate analyses indicated higher MPOD was associated with higher BOLD signal in the left middle frontal gyrus and right superior parietal lobe (p < 0.001, uncorrected). Lower MPOD levels were associated with increased right cingulate activation (p < 0.001, uncorrected). Conclusion(s): Data show the left middle frontal gyrus and the right superior parietal lobe are differentially activated in older adults with higher levels of lutein and zeaxanthin. Recruitment of these regions may help explain the mechanism by which these nutrients are associated with better visual integrity.