Abstract

Objective: Previous research suggests higher levels of the nutrients lutein and zeaxanthin, naturally occurring carotenoids found in food, are associated with cognitive health due to their role as antioxidants and anti-inflammatory agents. As these nutrients are preferentially taken up into neural tissue, we investigated the association between lutein level and brain activation in response to learning and memory processes. Method: Thirty-five community dwelling older adults ages 65–94 engaged in an fMRI adapted verbal paired associates (VPA) task learning novel word pairings, viewing a distractor, and later recalling the second word of the novel word-pair following exposure to the first word. Tasks were repeated to facilitate learning and recall of the word-pairs. The distractor task was used as the imaging contrast for the learning and recall tasks. Lutein/zeaxanthin levels were measured using a standard Macular Pigment Ocular Density (MPOD) procedure (Hammond, et al, 2005) and used as a covariate in the fMRI analyses. Data were processed using SPM12. Results: Increased BOLD activation during learning and recall was seen in the left middle frontal and inferior frontal gyri, left middle temporal gyrus, and other areas associated with verbal memory (p < 0.01, family-wise error corrected). Covariate analyses indicated higher MPOD was associated with higher BOLD signal in the postcentral gyrus bilaterally (p < 0.001, uncorrected). Lower MPOD levels were associated with increased activation in the left superior frontal gyrus, left precentral gyrus, and right insula (p < 0.001, uncorrected). Conclusion(s): These results suggest that individuals with less lutein may have compensatory neural mechanisms to help them engage in learning and recall processes.