Effects of formulation on the bioavailability of lutein and zeaxanthin: a randomized, double-blind, cross-over, comparative, single-dose study in healthy subjects

Lutein and zeaxanthin are macular pigments with a protective function in the retina. These xanthophylls must be obtained from the diet or added to foods or supplements via easy-to-use, stable formulations. The technique employed to produce these formulations may affect the bioavailability of the xanthophylls. Forty-eight healthy volunteers were randomized into this double-blind, cross-over study investigating the plasma kinetics of lutein provided as two different beadlet formulations. Subjects (n = 48) received a single dose of 20 mg of lutein as either a starch-matrix ("SMB", FloraGLO(A (R)) Lutein 5 %) or as a cross-linked alginate-matrix beadlet ("AMB", Lyc-O-Lutein 20 %) formulation. Plasma concentrations of lutein and zeaxanthin were measured at 0, 1, 3, 6, 9, 12, 14, 24, 26, 28, 32, 36, 48, 72, 168, and 672 h. The mean plasma AUC((0-72h)), AUC((0-672h)), and C (max) for total lutein and zeaxanthin and their all-E-isomers were significantly increased (p < 0.001) from pre-dose concentrations in response to SMB and AMB. There was no difference in lutein T (max) between the two test articles. However, by 14 h post-dose, total plasma lutein increased by 7 % with AMB and by 126 % with SMB. Total lutein AUC((0-72h)) and AUC((0-672h)) were 1.8-fold and 1.3-fold higher, respectively, for SMB compared to AMB. Both formulations were well tolerated by subjects in this study. These findings confirm that the bioavailability of lutein and zeaxanthin critically depends on the formulation used and document a superiority of the starch-based over the alginate-based product in this study.