Lutein is a carotenoid found in a vast number of fruits and vegetables. Pure Encapsulations' free-form Lutein is structurally identical to the lutein found naturally in spinach and other leafy greens. Like other carotenoids, lutein has antioxidant activity in various tissues, but is one of only two that are stored within the retina, where lutein promotes the integrity and density of the macular pigment, a key component of ocular health. Multiple clinical studies suggest a direct relationship between lutein supplementation and macula lutein concentration. Lutein uptake reportedly occurs in the receptor layer of the eye through a soluble carotenoid-binding protein called tubulin. Clinical trials have indicated that lutein specifically supports vision health through a combination of pigment associated antioxidant protection and light screening mechanisms. Furthermore, a two-year, double-blind, placebo-controlled pilot study reported that lutein may support healthy visual function in older individuals more efficiently than alpha tocopherol.^‡