Abstract
Abstract: :
Purpose: Intake of dietary carotenoids may impact one’s risk for heart disease, various cancers, and age–related macular degeneration (AMD). Two carotenoids, lutein (L) and zeaxanthin (Z), are associated with AMD risk possibly due to their selective deposition in the macula. The macular carotenoids, referred to as macular pigment (MP), may inhibit the pathogenesis of AMD by reducing both light damage and oxidative stress. Our lab has previously demonstrated that L supplementation (30 mg) can significantly increase macular carotenoid concentrations, defined as macular pigment optical density (MPOD), at multiple retinal loci. Few researchers, however, have investigated the effects of Z supplementation. The aim of this study was to measure systematic changes in MPOD at four retinal loci during Z supplementation. Methods: Three male subjects consumed 20mg of Z per day for 70 days. MPOD was measured 3 to 4 days per week at 20', 30', 60' and 120' in the nasal hemiretina using heterochromatic flicker photometry. The test stimuli were presented in free–view with a Macular Metrics® densitometer. Blood samples were collected weekly for the first month, and in two–week intervals for the remainder of the study. High–performance liquid chromatography was used to analyze serum carotenoid concentrations. Results: Results for the 70 days of Z supplementation are compared to the same period of L supplementation. After 70 days of intervention, mean serum Z increased from 0.04 µg/mL at baseline to 0.89 µg/mL. In one subject, MPOD significantly changed from baseline at 20' and 30' eccentricity, increasing 0.06 and 0.04 log units, respectively (p<0.05). There were no significant changes from baseline in MPOD at other eccentricities or in other subjects. Following L supplementation, MPOD significantly changed from baseline at 20' in two subjects and 30' in one subject, increasing 0.08 and 0.06, respectively (p<0.05). Conclusions: The results suggest that supplementation with Z or L increases MPOD in some subjects but that the rate of deposition and distribution are different.
Keywords: macular pigment • carotenoids/carotenoid binding proteins • macula/fovea