Relation between dietary intake, serum concentrations, and retinal concentrations of lutein and zeaxanthin in adults in a Midwest population

Abstract

Background: Information on concentrations of retinal carotenoids (macular pigment, or MP) is of particular interest because MP protects against age-related macular degeneration, the leading cause of irreversible blindness in the United States. Objective: This study was designed to evaluate the relation between dietary intake, blood concentrations, and retinal concentrations of carotenoids in a large group of volunteers. Design: Two hundred eighty volunteers in the Indianapolis area completed health and diet questionnaires, donated a blood sample, and participated in MP density assessment to determine retinal carotenoid status. Dietary intake was assessed by food-frequency questionnaire. Serum concentrations of lutein, zeaxanthin, and β-carotene were measured by HPLC. MP optical density (MPOD) was determined psychophysically with a 460-nm, 1° test stimulus. Results: Average MPOD was 0.21 ± 0.13. Average intakes of lutein + zeaxanthin and β-carotene were 1101 ± 838 and 2935 ± 2698 μg/d, respectively. Although several key dietary intake variables (eg, lutein + zeaxanthin and β-carotene) differed by sex, no significant sex differences were found in either serum concentrations of lutein and zeaxanthin or MPOD. Serum β-carotene concentrations were significantly higher in women than in men. Serum lutein + zeaxanthin and dietary intake of lutein + zeaxanthin were significantly correlated and significantly related to variations in MPOD (r = 0.21, P < 0.001, and r = 0.25, P < 0.001, respectively). Conclusions: Retinal carotenoids can be measured in epidemiologic studies. In this study, MPOD was associated with lutein + zeaxanthin in the diet and the serum. Retinal concentrations, however, were influenced by other factors as well. To understand the effect of dietary lutein + zeaxanthin intake on the retina and risk of age-related eye disease, future studies should include measures of macular concentrations of these pigments.