The science behind lutein.

In humans, as in plants, the xanthophyll lutein is believed to function in two important ways: first as a filter of high energy blue light, and second as an antioxidant that quenches and scavenges photo induced reactive oxygen species (ROS). Evidence suggests that lutein consumption is inversely related to eye diseases such as age-related macular degeneration (AMD) and cataracts. This is supported by the finding that lutein (and a stereo isomer, zeaxanthin) are deposited in the lens and the macula lutea, an area of the retina responsible for central and high acuity vision. Human intervention studies show that lutein supplementation results in increased macular pigment and improved vision in patients with AMD and other ocular diseases. Lutein may also serve to protect skin from UV-induced damage and may help reduce the risk of cardiovascular disease. Crystalline lutein is readily absorbed from foods and from dietary supplements whereas, to enter the bloodstream, lutein esters require prior de-esterification by intestinal enzymes. Unlike the hydrocarbon carotenoids which are mainly found in the LDL fraction, xanthophylls like lutein and zeaxanthin are incorporated into both HDL and LDL. Today, lutein can be obtained from the diet in several different ways, including via supplements, and most recently in functional foods. Animal toxicology studies have been performed to established lutein's safety as a nutrient. These studies have contributed to the classification of purified crystalline lutein as generally recognized as safe (GRAS). The achievement of GRAS status for purified crystalline lutein allows for the addition of this form into several food and beverage applications. This achievement speaks directly to the quality and safety of purified lutein.