The relationship between retinal carotenoids and cognitive function in healthy and cognitively impaired elders

Abstract

Lutein (L) and zeaxanthin (Z) are incorporated into the neural retina as macular pigment (MP), which is a biomarker of L+Z distributed throughout the cortex. Cortical L+Z may have the ability to improve cognitive function. The purpose of this study was to determine whether or not MP relates to cognition in healthy elders and elders with mild cognitive impairment (MCI). 41 elders (M = 75.5 ± 6.3 years) participated. 15 of the 41 elders met criteria for MCI. MP density was measured psychophysically, and cognition was assessed via the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Visual processing speed was also measured. MP density was related to cognitive function in the visuospatial (r = 0.43, p < 0.05) and attentional (r = 0.47, p < 0.05) domains of the RBANS in elders with MCI, but not in unimpaired elders. Elders with MCI were also less sensitive to flicker. These results suggest that MP's relationship to cognition varies with cognitive impairment.