Serum lutein and its dynamic changes during supplementation with lutein in Chinese subjects.

Observational epidemiological studies have shown that a high consumption of lutein-containing foods is associated with decreased risk of chronic diseases. However, results are inconsistent, suggesting the possibility that confounders may impact serum lutein concentration after consumption. The present study aimed to determine the factors affecting serum lutein status and to characterize dynamic changes of lutein concentration in serum during lutein supplementation in healthy Chinese subjects. After baseline characteristics were determined, thirty-seven healthy participants were randomized to receive 6 mg lutein/d, 12 mg lutein/d, or placebo for 12 weeks, as well as to be observed for 6 additional weeks after the cessation of supplementation. Serum levels of lutein and beta-carotene were measured by HPLC at weeks 0, 1, 3, 6, 9, 12 and 18. Dietary intake was estimated by food-frequency questionnaires. No significant sex differences were found in serum concentration of lutein. Serum lutein level positively correlated with dietary lutein, retinol equivalents, vitamin C, vitamin E, beta-carotene and fat intake after adjustment for caloric intake, but not with BMI. After 12-weeks of supplementation, lutein levels increased approximately 1.8-fold and 2.3-fold for the 6-, and 12-mg dose groups respectively, approaching a plateau at week 9, and then decreased to baseline values at week 18. No adverse events or reductions in serum beta-carotene were observed throughout the study. Our findings indicate that increasing the consumption of lutein-rich fruit and vegetables can be considered as a long-term, sustainable and safe approach to reach and maintain high serum levels of lutein.