Serum Lutein Response Is Greater from Free Lutein Than from Esterified Lutein during 4 Weeks of Supplementation in Healthy Adults

Background: Current data suggest great variability in serum response following lutein ingestion from various sources. Objective: To compare the relative serum response during supplementation with free lutein (fL) and lutein esters (Le). Methods: 72 volunteers (23-52 years; body mass index [BMI] >20 and <30 kg/m(2); baseline serum lutein <20 mu g/dL [<352 nmol/L]) were identified. Subjects, matched for gender, age, and BMI, were randomly assigned to the fL or Le group. fL and Le capsules contained 12.2 mg of free lutein or 27 mg of lutein ester (equivalent to 13.5 mg free lutein), respectively. Fasting blood was obtained at baseline and after 7, 14, 21, and 28 days of supplementation. Supplements were consumed with standard portions of dry, ready-to-eat cereal and 2% cow's milk. Results: Absolute changes in serum lutein, per mg daily dose, were significantly greater in fL vs. Le after 21 days (p = 0.0012) and remained so after 28 days (p = 0.0011) of supplementation. Serum lutein Area Under the Curve [AUC((day 0-28))] response was 17% greater for fL vs. Le (p = 0.0187). Regression models were used and determined that (I) baseline serum lutein levels and (2) the form of lutein ingested (fL > Le) influence the serum lutein response during supplementation, while subject age, gender, BMI, and serum lipids do not affect serum response. Conclusions: These results suggest that the relative serum lutein response will be significantly greater from supplements containing free lutein than from supplements containing lutein esters. These findings should be useful for future clinical trials exploring the effectiveness of lutein supplementation in the prevention of or protection against age-related macular degeneration and/or cataracts.