ABSTRACT
We measured the blood uptake of meso-zeaxanthin (MZ) from a mixture of macular pigments since its bioavailability in man has not been studied. Volunteers (ten men and nine women) were recruited and received one capsule of Lutein Plus/d. Blood was taken at baseline, day 10 and day 22. One capsule contained 10.8 mg lutein, 1.2 mg (3R,3'R)-zeaxanthin and 8.0 mg MZ. Plasma lutein and total zeaxanthin concentrations were quantified using isocratic liquid chromatography and the eluting xanthophyll fractions were collected and re-chromatographed on a chiral column to assess the proportion of MZ. Plasma concentrations per mg dose at day 22 suggested that (3R,3'R)-zeaxanthin (0.088 micromol/l per mg) was about 50 % more actively retained by the body than lutein (0.056 micromol/l per mg) (although the difference was not significant in women) and 2.5-3.0 times more than MZ (0.026 micromol/l per mg). Concentrations of MZ at day 22 were 2.5 times higher in women than men. The plasma responses from lutein and (3R,3'R)-zeaxanthin in the Lutein Plus were lower than literature values for the pure substances. That is, their uptake into plasma appeared to be slightly depressed by the presence of MZ. Plasma concentrations of beta-carotene were depressed by about 50 % at day 10 and about 35 % at day 22. In conclusion, the lower plasma response to MZ compared with (3R,3'R)-zeaxanthin probably indicates that MZ is less well absorbed than (3R,3'R)-zeaxanthin but work with pure MZ will be needed to confirm that the lower plasma response was not due to the large amount of lutein in the Lutein Plus.
