Lutein is an important carotenoid that protects the eyes, lungs and arteries from free radical damage. Lutein has been found to play an important role in protecting our eyes from the deterioration that comes with aging, sun damage, and eyestrain. A study conducted on 480 individuals by the University of Southern California showed that lutein supplementation can help reduce hardening of the arteries. Over the course of 18 months, the people with the highest lutein blood levels had almost no additional arterial plaque in their sample. The original study appeared in the Journal of the American Heart Association.