Limiting Refined Carbohydrates May Stall Macular Degeneration

Limiting carbohydrates in the diet may help slow the progression of age-related macular degeneration (AMD), according to a recent study by researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. The study builds on a recent analysis that found that men and women older than 55 years who consumed diets with higher-than-average dietary glycemic index foods appeared to have an increased risk for early and later stages of AMD. Dietary glycemic index determines how quickly carbohydrates are broken down into glucose: Foods with a high glycemic index are associated with a faster rise and subsequent drop in blood sugar than those with a low glycemic index.

In the study, investigators analyzed diet questionnaires completed by 4,757 non-diabetic men and women participating in the nationwide Age-Related Eye Disease Study (AREDS), an eight-year study that included participants ages 55 to 80 with varying stages of AMD. They examined the participants' carbohydrate intake over one year and used the data to calculate the participants' dietary glycemic index. Results showed that those who consumed the greatest amount of refined carbohydrates were 17 percent more likely to develop blinding AMD than the group that consumed the least. Based on this data, the investigators believe that limiting dietary refined carbohydrates in at-risk elderly people could reduce the number of advanced AMD cases by 8 percent in five years. The authors note, however, that their findings warrant randomized controlled clinical trials.

SOURCE: Chiu CJ, Milton RC, Klein R, et al. Dietary carbohydrate and the progression of age-related macular degeneration: A prospective study from the Age-Related Eye Disease Study. Am J Clin Nutr 2007;86(4):1210-8.