Enhancement of Macular Pigment Optical Density and Contrast Sensitivity Following Supplementation with Supercritical Fluid Extraction -Based Lutein Ester Products: Evidence from a Randomized, Double-Blind, Placebo-Controlled Study in Healthy Adults

Abstract

Introduction: Macular pigment optical density (MPOD) is an important marker of macular carotenoid status and visual function. Although lutein supplementation can increase MPOD, comparative clinical evidence on different lutein-ester delivery formats remains limited. This study compared three supercritical fluid extraction (SCFE)-based lutein ester formulations: a conventional lutein ester preparation (LE), a true oil solution of lutein ester (LETOS), and a self-emulsifiable lutein ester formulation (LEU).
Methods: In this randomized, double-blind, placebo-controlled, parallel-group study, 128 healthy adults with baseline MPOD values of 0.20–0.35 were randomized equally to LE, LETOS, LEU, or placebo for 90 days. MPOD was assessed by heterochromatic flicker photometry at baseline and Days 15, 30, 60, and 90 at 0.25°, 0.5°, and 1° eccentricities in both eyes. Secondary outcomes included contrast sensitivity, visual processing speed, intraocular pressure, and Schirmer test results. Serum lutein concentration was assessed on Day 15 as an exploratory outcome.
Results: All three lutein ester groups showed significant improvements in MPOD compared with placebo from Day 30 onward (p < 0.05), with Day 90 increases ranging from approximately 28.5% to 45.1%. Contrast sensitivity also improved in the active groups, whereas no consistent treatment-specific effect was observed for visual processing speed or intraocular pressure. LETOS showed the largest observed improvement in MPOD among the active formulations.
Conclusion: Ninety days of supplementation with the tested lutein ester formulations increased MPOD and improved contrast sensitivity in healthy adults with relatively low baseline MPOD. LETOS produced the largest observed MPOD response, although direct formulation comparisons should be interpreted in the context of the different lutein-equivalent doses used. No clinically meaningful safety concerns were identified during the study.