COLUMBUS, Ohio Scientists have identified the protein responsible for transporting nutrients to the eye that are believed to protect against the development of age-related macular degeneration, a leading cause of vision loss in elderly Americans.
The research sought to illuminate the process by which compounds called lutein and zeaxanthin move from the bloodstream to the eye. Various studies have suggested that high concentrations of these two dietary compounds in particular, known as xanthophylls, have properties that can prevent macular degeneration.
These two nutrients are not made by the body and must be obtained through the diet. They are commonly found in green, leafy vegetables, such as kale, spinach, broccoli, zucchini and peas, and in yellow or orange fruits and vegetables, such as carrots, papaya, squash and peaches.
According to the study, the protein SR-B1, or scavenger receptor class B, type 1, plays a central role in transporting these nutrients from the bloodstream to cells in the eye.
"Our research to understand this mechanism might provide a greater appreciation for how one could intervene to possibly slow macular degeneration," said senior study author Earl Harrison, Dean's Distinguished Professor and chair of human nutrition at Ohio State University.
An estimated 10 million Americans have age-related macular degeneration, which gradually destroys sharp, central vision. The macula is located in the center of the retina, the light-sensitive tissue at the back of the eye that sends nerve signals to the brain. Deterioration of the macula blurs the central field of vision needed to drive and read. Treatment can slow vision loss, but does not restore vision, according to the National Eye Institute.
The research appears in the August issue of the Journal of Lipid Research.
Xanthophylls are a class of carotenoids, naturally occurring pigments that absorb blue light and sometimes
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Ohio State University