Age-related macular degeneration (AMD) is the leading cause of blindness among older adults in Western countries, and a major study has shown that antioxidants and zinc supplements may slow its progression. But last year, after poring through data from that study, the U.S. government-funded Age-Related Eye Disease Study (AREDS), Tufts University protein chemist Allen Taylor found preliminary evidence suggesting another way to stop this vision killer: Cut your intake of dietary carbohydrates. White bread and other foods with a high glycemic index, he argues, contribute to AMD by destroying proteins in the retina and lens and making them less able to remove damaged tissue. Taylor is a long way from winning over his colleagues. "He's identified an interesting association that needs to be replicated. But it could be only an epi [secondary] phenomenon," says Frederick Ferris, clinical director of the National Eye Institute, which funded AREDS and is about to launch a follow-up to test the value of other nutrients in slowing the progression of the disease. Such skepticism is normal for human nutrition studies, which are notoriously hard to interpret. That's no problem for Taylor, head of the vision lab at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. The center is the only U.S. research facility focused on the intersection of nutrition and older adults, and the financial support from the U.S. Department of Agriculture (USDA), combined with outside grants, helps Taylor and his colleagues pursue the type of long-term studies needed to unravel these complex relationships. It's also the product of the first major modern congressional earmark for basic science.
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