Macular Pigment and Serum Response to Dietary Supplementation with Meso-zeaxanthin

Abstract

Abstract: : Purpose: To determine the effect of oral supplementation with meso-zeaxanthin on the serum concentration of this carotenoid and on macular pigment (MP) density in human subjects. Methods: Ten subjects were given gelatin capsules that provided a daily dose of ~16 mg of meso-zeaxanthin and 4 mg of lutein. The supplementation period was 120 days. Prior to supplementation, the subjects received an eye exam to ensure that no abnormalities were present. Blood samples were obtained prior to dosing and at 2 weekly intervals during the dosing period. Serum concentrations of zeaxanthin and lutein were determined by HPLC. MP optical densities for the central 1.5° were obtained by heterochromatic flicker photometry at least 4 times prior to dosing and twice per week during the dosing period. An inclusion criterion for the study was a subject's ability to provide repeatable results. Results: Two females and 8 males with an average age of 30.5 ± 10.9 (range 21 to 58) were admitted to the study. Average serum levels (µg/ml)of zeaxanthin rose from 0.058 prior to dosing to a plateau of 0.156 during dosing. Similarly lutein (µg/ml) rose from 0.148 to 0.204. The average increase of zeaxanthin was 165% and that of lutein was 38%. MP optical density levels increased in both eyes of 4 subjects, in one eye only of 5 subjects, and in neither eye of 1 subject. The average rate of increase for both eyes of all 10 subjects was 0.56 mAU/day (range 0 to 2.2 mAU/day), corresponding to a 120 day increase of 0.07 AU. No adverse events occurred during the dosing period. Conclusions: The average rate of increase in MP optical density is very similar to the value of 0.53 mAU/day observed in an earlier supplementation study where subjects took 20 mg/day of lutein. At 20 mg/day, the predominantly meso-zeaxanthin-based supplement was capable of increasing MP density by an average of ~18% in 120 days. It therefore shows promise as a potential preventative against age-related macular degeneration.

Keywords: macular pigment • carotenoids/carotenoid binding proteins • retina