Diet affects eye disease progression

BOSTON, July 6 (UPI) -- A study of U.S. twins finds diet can significantly influence the course of the eye disease macular degeneration, researchers say.

Dr. Johanna M. Seddon, director of the Epidemiology and Genetics Service at Tufts Medical Center and professor of ophthalmology at Tufts University School of Medicine, and colleagues used data from the study of identical twins from the U.S. World War II Twin Registry.

Seddon, the lead researcher, says the study involved identical twin pairs in which one twin had early age-related macular degeneration and the other had late stage age-related macular degeneration.

By examining identical twins who share the same genes but whose disease was at different stages, the researchers say they were able to identify environmental and behavioral factors that may contribute to severity of the disease.

The study, published in the journal Ophthalmology, found that twins whose macular degeneration was at the early stages tended to consume more vitamin D from dietary sources such as fish or milk than their twin.

Seddon says vitamin D may reduce the risk of macular degeneration because of its anti-inflammatory properties or it may block the formation of new blood vessels that can grow under the macula, leaking blood and causing vision loss during the more severe stages of the disease.

In addition, the study, published in the journal Ophthalmology, found the twin who was the heavier smoker tended to have the more severe case of macular degeneration.