Lutein protects and perhaps improves the outlook on cancer of the colon and macular degeneration. It seems to protect the sporadic colonic cancer rather than the familiar type [American Journal of Clinical Nutrition; 2000: Feb; 71(2); pp.575-82]. It is an effective antioxidant in the body and is found in the region of the retina called the macula and in the lens of the eye. The macula is an area of the central retina responsible for clear reading and color vision. Lutein and its isomer zeaxanthin are the only two carotenoids found in the eye. Other carotenoids like, beta-carotene, and vitamin A are not found in the eye and are not associated with reducing age-related macular degeneration. Zeaxanthin is generally less available and the dose is 264mg a day. Naturally, Lutein is found in dark green vegetable leaves, spinach being the food with one of the highest amounts per serving.

Macular degeneration is a retinal disorder that obscures central vision among an estimated 4 million Americans and is the leading cause of blindness in people over age 60 . Persons with macular degeneration often have lower levels of Lutein and zeaxanthin in the macula. Zinc is also used in conjunction with Lutein. Currently, there are no effective treatments for macular degeneration and, therefore, ways to reduce the prevalence of the disease is critical, including the addition of Lutein to the diet or as a supplement. In addition, there is evidence indicating that Lutein and zeaxanthin reduce cataract formation.