Lutein and Zeaxanthin in Red Blood Cells as a Measure of Their Status in Humans

Abstract

BackgroundIntake of lutein and zeaxanthin (L+Z) may reduce age‐related macular degeneration (AMD) risk. Plasma L+Z, which reflects short‐term intake, is often used to assess status. Red blood cell (RBC) level may reflect long‐term intake. Use of RBC to assess status has not been explored. Macular pigment (L+Z in retinal tissue) is considered reflective of long‐term L+Z status. Evaluation of relationships of L+Z in plasma and RBC with macular pigment density (MPD) may be useful.ObjectiveTo determine the relationship between L+Z in plasma and RBC with MPD.MethodsBlood and MPD were obtained from 15 healthy adults. Extraction and measure of L+Z in plasma and RBC were performed with standard lipid extraction methods and reverse‐phase, gradient HPLC. MPD was measured with a psychophysical method at a 1‐deg target and a 7‐deg parafoveal reference. Pearson correlation coefficients were used to measure relationships with MPD.ResultsPlasma and RBC levels of L+Z were significantly related to MPD (p = 0.050 and 0.018, respectively). The correlation was greater for RBC than plasma (r = 0.622 and 0.532, respectively).ConclusionsA greater correlation of RBC L+Z with MPD may be due to RBC and MPD reflecting long‐term intake and plasma reflecting short‐term intake. Measures of L+Z in RBC in studies examining the relationship between L+Z status and AMD may be useful. Support: USDA grant# 58‐1950‐7‐707