Lutein and zeaxanthin are carotenoids in the macular region of the retina of the eye (macular pigment), and thus lutein has been studied for its use in treating cataracts, preventing macular degeneration and retinal degeneration. Lutein and zeaxanthin also have antioxidant capabilities as well as the ability to trap short-wavelength light. The potential for carotenoids, including lutein, to play a preventing role in cardiovascular disease and cancer was recognized in the 1990s.
Most of the information surrounding lutein is based on blood and/or dietary intakes of lutein compared with disease states (e.g. cancer, eye disorders, lung function, muscle soreness, obesity, and pre-eclampsia). More evidence is needed before recommendations can be made in these fields.