Eat Right to Beat Eye Disease

Healthnotes Newswire (September 6, 2007)—A new study shows that age-related macular degeneration—the most common cause of blindness in people over age 65—might be avoided by replacing refined carbohydrates with whole grains.

As the Western world’s population continues to live longer, problems like macular degeneration are becoming more common. The disease attacks the part of the eye responsible for central vision. In its early stages, macular degeneration may make straight lines appear wavy or make objects look fuzzy. As it progresses, reading, driving, and performing other activities that require sharp vision become more difficult.

Researchers have found a relationship between certain dietary factors and macular degeneration risk. Antioxidant nutrients like beta-carotene, zinc, and vitamins C and E may play a protective role. Less is known about the connection between foods and macular degeneration risk.

The Age-Related Eye Disease Study (AREDS) gathered dietary information from 4,099 people ages 55 to 80. Their diets were categorized by glycemic index—a measure of the blood sugar–raising effect of foods. A high-glycemic-index diet raises blood sugar levels after a meal more than a low glycemic index diet does.

The participants’ eyes were examined for evidence of macular degeneration. Compared with people with the lowest glycemic index diets, people with the highest glycemic index diets were almost 1.5 times as likely to have features of macular degeneration. The higher the dietary glycemic index, the more severe the disease. Further, people with a higher than average glycemic index diet had a 49% increased risk of advanced macular degeneration.

“We estimate that 20% of cases of advanced macular degeneration would be eliminated if people consumed diets that have dietary glycemic index values below the median,” the study’s authors concluded in the American Journal of Clinical Nutrition.

Examples of high glycemic index foods include white bread, sugar, white rice, and potatoes. Foods that have not undergone processing to remove the fiber-rich portions of the plant have lower glycemic indexes; these include whole wheat flour, brown rice, and legumes (beans, lentils, and peas). High-glycemic-index diets are implicated in many chronic diseases such as diabetes, heart disease, and cancer.

While the researchers were not able to make specific dietary recommendations, it seems wise to eat fewer high glycemic index foods. “Our results also suggest that the quality, not the quantity, of dietary carbohydrates influences the risk of macular degeneration,” they commented. Most grocery stores offer whole grain versions of many carbohydrate-rich foods—whole wheat pasta, brown rice, and multigrain breads abound. If you’re looking for a healthier way to sweeten your coffee or tea, stevia is a natural sweetener that has a value of zero on the glycemic index.

(Am J Clin Nutr 2007;86:180–8)

Kimberly Beauchamp, ND, earned her bachelor’s degree from the University of Rhode Island and her Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. She cofounded South County Naturopaths in Wakefield, RI. Dr. Beauchamp practices as a birth doula and lectures on topics including whole-foods nutrition, detoxification, and women’s health.

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