Abstract
Purpose: :
Dietary intake of lutein and zeaxanthin (LZ) is inversely related to the risk for developing age-related macular degeneration (AMD) and atherosclerosis. Lutein and zeaxanthin accumulate in various tissues, including the retina, where they may reduce disease risk by attenuating oxidative stress. The objective of the current project was to measure macular pigment optical density (MPOD) and C-reactive protein (CRP), biomarkers associated with risk for developing AMD and atherosclerosis, respectively, before and after carotenoid intervention.
Methods: :
Thirty-two individuals were assigned to one of four twelve-week treatments: one placebo pill p/day (PLACEBO); 30mg of lutein supplement p/day (SUPPLEMENT); 1/2cup of spinach, containing approximately 10mg of LZ, five days p/week (SPINACH); or one egg, containing approximately 960µg of LZ, five days p/week (EGG). Serum concentrations of LZ, determined by HPLC, serum CRP concentrations, determined by ELISA, and MPOD, measured psychophysically at 30-minutes eccentricity, were measured at baseline and after twelve-weeks of intervention (visit 2).
Results: :
MPOD significantly increased in the SUPPLEMENT (p=0.043), SPINACH (p=0.019) and EGG (p=0.011) groups, but not in the PLACEBO group (p=0.42). Significant changes in serum LZ (p=0.012) and CRP (p=0.043) concentrations were observed only in the SUPPLEMENT group. However, CRP was inversely related to MPOD at both baseline (p=0.049) and after twelve weeks of intervention (p=0.047). CRP at visit 2 was also related to LZ at visit 2 (p=0.006).
Conclusions: :
Tissue concentrations of lutein and zeaxanthin were significantly related to concentrations of CRP. The relationship between CRP and LZ at visit 2 suggests that increasing serum LZ, regardless of the treatment type, may not only increase MPOD, but decrease systemic inflammatory processes.
Keywords: macular pigment • nutritional factors