The effects of lutein and zeaxanthin on neural processing speed
Bovier, Emily Renee
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Lutein and zeaxanthin are found throughout neural tissue and have been shown to promote cellular communication. It has been hypothesized that nutritional modification with the xanthophylls may enhance neural efficiency. The goal of this study was to determine the relationship between macular pigment, a biomarker of total neural lutein and zeaxanthin, and temporal vision and visual motor reaction time. Changes in these outcome variables were also assessed after four months of supplementation with lutein and zeaxanthin. Consistent with past research, macular pigment accounted for a moderate amount of variance in critical flicker fusion (CFF) thresholds, temporal contrast sensitivity, and select measures of coincidence anticipation ability in a sample of college-aged subjects (N = 92). After four months of supplementation, macular pigment significantly increased for 54 subjects and was accompanied by improvements in temporal vision and reduction in visual motor reaction time. Comparatively, subjects in the placebo group (N = 10) did not have significant changes in CFF thresholds or visual motor reaction time, however increases in temporal contrast sensitivity were found. In general, findings related to CFF thresholds and reaction time were consistent with the predictions of the neural efficiency hypothesis of lutein and zeaxanthin function.