How can you prevent age-related macular degeneration (AMD), a condition that will affect the vision of more than 10 million Americans this year? According to new research, you may want to lower the glycemic index (GI) of the foods you eat.

A study conducted by scientists from Tufts and Harvard universities showed that a low-GI diet could cut your risk of developing age-related maculopathy (ARM), an early form of AMD, by as much as 50 percent (American Journal of Clinical Nutrition, 2006, vol. 83, no. 4). Researchers followed 526 women for a decade. Those whose diets rated in the highest third for GI more than doubled their odds of developing ARM, compared with women whose diets rated in the lowest third. Low-GI diets tend to include a lot of whole grains, milk, legumes, fruits, and vegetables (except potatoes).

Other studies have linked diet and AMD, too. Diets high in antioxidants and fish have been shown to lower the risk of developing AMD. Obesity and high-fat diets, on the other hand, increase the risk. "The bottom line is that a healthy diet full of fresh fruits and vegetables that is low in fat but high in omega-3 fatty acids—along with healthy living habits such as not smoking, controlling your weight, and exercising—is your best bet [in preventing this disease]," says Bernard Godley, MD, PhD, professor and chairman of the department of ophthalmology and visual sciences at the University of Texas in Galveston.