A Double-Blind, Placebo-Controlled Study on the Effects of Lutein and Zeaxanthin on Neural Processing Speed and Efficiency

• Published in: PloS one Vol. 9; no. 9; p. e108178
• Main Authors: Bovier, Emily R., Renzi, Lisa M., Hammond, Billy R.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 24.09.2014; Public Library of Science (PLoS)
• Subjects: Adolescent; Adult; Aging; Bioindicators; Biology and Life Sciences; Biomarkers; Brain; Carotenoids; Cognitive ability; Critical flicker fusion; Diet; Dietary Supplements - analysis; Double-Blind Method; Double-blind studies; Efficiency; Fatty acids; Female; Flicker fusion; Flicker Fusion - drug effects; Humans; Information processing; Laboratories; Lutein; Lutein - administration & dosage; Lutein - pharmacology; Macular Pigment - metabolism; Male; Medicine and Health Sciences; Memory; Motor task performance; Nervous system; Nutrition; Older people; Omega-3 fatty acids; Pigments; Reaction time; Reaction time task; Research and Analysis Methods; Retina; Retina - drug effects; Retina - physiology; Sensorimotor integration; Thresholds; Vision Tests; Visual pathways; Visual signals; Visual system; Young Adult; Zeaxanthin; Zeaxanthins - administration & dosage; Zeaxanthins - pharmacology; United States > US; Georgia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0108178

Lutein and zeaxanthin are major carotenoids in the eye but are also found in post-receptoral visual pathways. It has been hypothesized that these pigments influence the processing of visual signals within and post-retina, and that increasing lutein and zeaxanthin levels within the visual system will lead to increased visual processing speeds. To test this, we measured macular pigment density (as a biomarker of lutein and zeaxanthin levels in brain), critical flicker fusion (CFF) thresholds, and visual motor reaction time in young healthy subjects (n = 92). Changes in these outcome variables were also assessed after four months of supplementation with either placebo (n = 10), zeaxanthin only (20 mg/day; n = 29) or a mixed formulation containing 26 mg/day zeaxanthin, 8 mg/day lutein, and 190 mg/day mixed omega-3 fatty acids (n = 25). Significant correlations were found between retinal lutein and zeaxanthin (macular pigment) and CFF thresholds (p<0.01) and visual motor performance (overall p<0.01). Supplementation with zeaxanthin and the mixed formulation (considered together) produced significant (p<0.01) increases in CFF thresholds (∼12%) and visual motor reaction time (∼10%) compared to placebo. In general, increasing macular pigment density through supplementation (average increase of about 0.09 log units) resulted in significant improvements in visual processing speed, even when testing young, healthy individuals who tend to be at peak efficiency.