Diet affects how we see

Health experts have long debated the role of nutrition in protecting against and slowing the progress of age-related macular degeneration, or AMD, a leading cause of vision loss among people over age 60. As the population ages, health experts predict that cases of AMD-related blindness in the U.S. will double to 3 million by the year 2020.

Dietary supplements and foods rich in antioxidants, such as vitamins C and E and other minerals have been researched as a way to stave off this widespread problem. New research is shifting the focus to another dietary area: refined carbs, abundant in white bread, white rice, most pasta, crackers and some cereals, for example. They have what is called a "high glycemic load," which causes blood sugar levels to spike.

Researchers at Tufts University found that 4,757 non-diabetic men and women with varying stages of AMD were 17 percent more likely to develop blinding AMD than those who consumed the least.

The study, published in this month's issue of the American Journal of Clinical Nutrition, comes on the heels of another Tufts finding: People older than 55 who ate above-average levels of refined carbs appeared to have a higher risk for both early and later stages of AMD.