Assessment of lutein and zeaxanthin status and dietary markers as predictors of the contrast threshold in 2 age groups of men and women.

Lutein and zeaxanthin (L + Z) status is associated with the macular pigment (MP). The relationship between MP and visual function is controversial. We hypothesized that, within the framework of nutrition, visual function was related to MP and nutritional and/or/dietary factors influencing it. A cross-sectional study was performed in 108 volunteers divided into 2 age groups (20-35 years; 45-65 years), each 27 women and 27 men, to assess the relationship between MP optical density (MPOD) and contrast threshold (CT), considering the influence of L + Z and, fruit and vegetable (F + V) intake. MPOD, L + Z in serum and dietary intake were determined using heterochromatic flicker photometry, high-performance liquid chromatography and 3-day food records, respectively. CT was measured with the CGT-1000 Contrast Glaretester at 6 stimulus sizes, with and without glare. Spearman correlation coefficient and a generalized linear model were used for the statistical study. MPOD and CT were higher and lower, respectively in younger than in elder individuals (P < .000) and were correlated only in the older group. CT were higher under glare conditions, at the intermediate and smaller visual angles, with greater differences in the older (P < .003) than the younger group (P < .014). In the total sample, CT correlated inversely with MPOD (correlation coefficients and P values ranging from -.245 to -.152 and from .000 to .026, respectively) and directly with F + V intake (correlation coefficients and P values ranging from -.265 to -.176 and from .000 to .010, respectively). As predictors of CT in the total sample, MPOD, F + V (every 100 g/d) and sex were identified (β coefficients ranged from -0.01 to -1.86; from 0.01 to 0.08 and from 0.01 to 0.40, respectively). CT revealed age-specific nutritional predictors: MPOD and serum lutein in the 45- to 65-year group, and F + V intake in the 20- to 35-year group.