What exactly is lutein, and how does it work? If you have macular degeneration, is it wise to get more lutein?

R.R.

Lutein, a yellow-red pigment found in green, leafy vegetables and egg yolks, is one of an array of nutrients being studied as a possible weapon against macular degeneration, a progressive disorder that is the leading cause of irreversible blindness among elderly people in the United States. Macular degeneration affects the central vision, impairing or destroying people's ability to read, write and drive. Since this disease is so devastating, it is important for people to modify their risk factors to try to lessen their chance of developing blindness.

The strongest, modifiable risk factor for macular degeneration is smoking. So, reducing or eliminating tobacco is crucial to lowering one's risk of blindness. In addition, exposure to the sun's ultraviolet rays has been associated with a higher risk of vision loss from macular degeneration. Therefore, eye doctors recommend that people wear sunglasses with a ultraviolet-blocking coating when they go out in bright sunshine.

The effects of diet in modifying the risk of macular degeneration is much more controversial. Some experts hypothesize that the retina is prone to oxidation damage from naturally occurring chemicals called free radicals. This damage could theoretically be diminished by "antioxidant" nutrients, which include lutein and other members of the carotenoid family. Indeed, some well-designed studies have found a protective effect of diets that contain high levels of antioxidants. However, other research has failed to uncover such a link.

Experts who believe that antioxidant nutrients can reduce the risk of blindness with macular degeneration often point to a 1994 study in the Journal of the American Medical Association. In the study, people who ate high levels of foods rich in cartenoids, such as spinach and collard greens, had a lower risk of developing the severe form of macular degeneration than those who ate lower levels of such foods. This particular study did not specifically examine lutein. However, based on other research findings, supporters of antioxidants for prevention of macular degeneration recommend lutein as a nutrient that may be helpful.