Observational studies have suggested an inverse relationship between dietary or serum lutein and risk for age-related macular degeneration and cataracts. This evidence has stimulated interest in the biological and other characteristics of lutein, and also zeaxanthin, a structurally similar carotenoid; together, they comprise the macular pigment. Accurate interpretation of data linking dietary intake or serum concentrations of lutein and zeaxanthin and risk for eye disease in epidemiologic and clinical studies requires knowledge of biological and nondietary factors influencing these intake data or concentrations. The primary aims of this study were to identify the correlates of dietary lutein + zeaxanthin intake and the determinants of serum lutein and zeaxanthin concentrations in a heterogeneous community-based sample of adults aged 18-92 y, recruited and examined at three U.S. sites (n = 2786). An additional aim was to identify the determinants of change in serum lutein concentration from baseline to 1 y in a subset of 1368 study participants followed prospectively. Demographic characteristics (age, sex, race/ethnicity, education), body mass index and lifestyle factors (exercise, sun exposure, smoking, alcohol consumption) were significantly (P < 0.05) associated with dietary lutein + zeaxanthin intake. Demographic characteristics, dietary intake, serum cholesterol concentration, body mass index and smoking explained 24% of the variance in serum lutein concentration. Race/ethnicity, education level and smoking had the strongest associations with serum lutein concentration. Every 10% increase in dietary lutein + zeaxanthin intake was associated with a 2.4% increase in serum lutein concentration. Notably, however, the amount of variance in serum concentration that is explained by demographic characteristics, health-related behaviors and lifestyle factors remains substantial.
- Diet assessment
- Dietary intake