Lutein belongs to a class of antioxidant compounds called carotenoids. Lutein is the primary carotenoid found in the central area of the human retina (known as the macula). Consequently, lutein appears to be associated with protection from age-related macular degeneration, a leading cause of blindness in older adults.

At present, lutein is believed to function in two ways.

1. as a filter of high-energy blue and ultraviolet light
2. as an antioxidant that quenches light-induced free radicals and reactive oxygen species

While the roles lutein and zeaxanthin play in the physiology of the eye are not completely understood, the links between lutein and eye health are so strong that several national and regional health organizations have recommended increasing dietary lutein intake.

Lutein and zeaxanthin are found together in many food sources. Dark green leafy vegetables are the primary source, but they are also present in lesser amounts in other colorful fruits and vegetables, including broccoli, orange peppers, corn, peas, persimmons, and tangerines.

Unfortunately, most dietary surveys indicate that few people consume optimal amounts of lutein and zeaxanthin-rich foods.