Lutein bioavailability is matrix‐dependent in powdered dietary supplements

Purpose Lutein (L) and zeaxanthin (Z) are the principal constituents of the macula lutea and have been associated with a reduction of risk for retinal diseases as well as improvements in visual function. Intake of L has also been reported to increase macular pigment levels, which are dependent on the bioavailability of the L source. External factors such as matrix composition and delivery system have a major impact on L absorption. A preliminary study in rats had indicated significant differences between the bioavailability of L formulated employing an alginate coating versus L embedded in a corn starch matrix. In order to evaluate these differences in humans, this comparative PK study was undertaken. Methods After a baseline period of 3 days, individual plasma responses to single doses of 20 mg unesterified L from product A or B were recorded in a randomized, double‐blind, two‐phase, cross‐over study enrolling 48 volunteers and conducted over 4 weeks for each cross‐over phase. Lutein plasma concentrations were determined by HPLC. Main PK parameters evaluated included the area under the curve, cmax, tmax, and elimination half‐time. Results A preliminary and blinded analysis showed striking differences, even though only the data of the first 7 out of the enrolled 48 subjects were available at the time of abstract submission. While the plasma level increase was minor with product A, product B almost doubled plasma concentrations on average (p<0.05). One of the seven subjects was a non‐responder to either product, but was still included in this initial analysis. Conclusion The drastic differences in apparent bioavailability between the two L forms emphasize the importance of matrix characteristics for the bioavailability of xanthophylls such as lutein.Commercial interest