*Norkus EP, Norkus KL, Dharmarajan TS, Schierle J, Schalch W. Serum lutein response is greater from free lutein than from esterified lutein during 4 weeks of supplementation in healthy adults. J Am Coll Nutr. 2010 Dec;29(6):575-85.
**Norkus et al., Serum lutein response is greater from free lutein than from esterified lutein during 4 weeks of supplementation in healthy adults. J Am Coll Nutr. 2010 Dec;29(6):575-85.