October 30, 2007

Age Related Macular Degeneration – The Link to Fast-Acting Carbohydrates

Age Related Macular Degeneration – The Link to Fast-Acting Carbohydrates. A study this year confirms earlier findings linking high consumption of fast-acting carbohydrates over time with age-related macular degeneration (AMD).

Scientists funded by the Agricultural Research Service (ARS) reported this month that consuming a "high glycemic-index" diet over a long period of time is associated with a higher risk of developing the early stages of a major eye disease, age-related macular degeneration, or AMD.

Consuming higher-than-average amounts of carbohydrates that cause blood sugar levels to spike and fall rapidly could be a risk factor for central vision loss with aging.

The study was led by Chung-Jung Chiu and Allen Taylor at the Jean Mayer USDA Human Nutrition Research Center on Aging in Boston, Mass., and is part of the Nutrition and Vision Project, a substudy of the federally funded Nurses' Health Study.

The researchers analyzed dietary intake and other data from more than 4,000 men and women aged 55 to 80 participating in the Age-Related Eye Disease Study, or AREDS.

Diets high in carbohydrates that are quickly digested and absorbed, resulting in a rapid rise in blood sugar levels, are considered high-glycemic-index diets. Examples of such "fast carbohydrate" foods are white bread, rice, potatoes and pasta, and also sugars and corn syrups.

Carbohydrates leading to a more gradual rise and fall in blood sugar levels comprise low-glycemic-index diets. Such "slow carbohydrate" foods include whole-grain versions of bread, rice and pasta.

Central vision loss is one of the first signs of age-related macular degeneration (AMD), a disease that is one of the leading causes of blindness among the elderly.

The macula is a yellow pigmented spot, one-eighth-inch wide, in the center of the retina toward the back of the eye. AMD is one of the leading causes of irreversible vision loss among those aged 40 or older in the United States.

Study participants were 526 women aged 53 to 73 years who did not have a history of age-related maculopathy, the early form of AMD. The scientists assessed the participants for macular disease and classified the results. They then compared the results with long-term dietary information that had been collected using questionnaires over a 10-year period prior to the macular disease assessment.

When ranked into three groups from highest to lowest in terms of dietary glycemic index, the participants who were ranked highest were well over two times more likely to have macular pigment abnormalities as those ranked lowest. An abnormal level of macular pigment is an early indicator of macular degeneration. The macula is responsible for the maximum ability to receive light and distinguish images.

Consuming a diet high in fast carbohydrates is also suspected of being involved in the vision loss that sometimes occurs in people with diabetes. The researchers theorize that the type of damage to eye tissue produced by fast carbohydrates could be similar in both age-related macular degeneration and diabetic eye disease.

Replacing fast carbohydrates with whole grains may soon prove to be an early dietary intervention to slow its progression.

The study was published in the April issue of the American Journal of Clinical Nutrition.

Related articles:

The Glycemic Index: Good Carb, Bad Carb

The Dangers of Diabetes Patients Not Understanding Disease Risks

Adapted with permission from New Findings on Link Between Diet (April 27, 2006 ) and Vision Loss and Fast-Acting Carbs May Hasten Vision Loss Over Time (October 29, 2007), By Rosalie Marion Bliss, United States Department Of Agriculture, USDA, Agricultural Research Service (ARS)


Chung-Jung Chiu, Larry D Hubbard, Jane Armstrong, Gail Rogers, Paul F Jacques, Leo T Chylack, Jr, Susan E Hankinson, Walter C Willett, and Allen Taylor. Dietary glycemic index and carbohydrate in relation to early age-related macular degeneration. Am. J. Clinical Nutrition, Apr 2006; 83: 880 - 886.

Chung-Jung Chiu, Roy C Milton, Gary Gensler, and Allen Taylor. Dietary carbohydrate intake and glycemic index in relation to cortical and nuclear lens opacities in the Age-Related Eye Disease Study. Am. J. Clinical Nutrition, May 2006; 83: 1177 - 1184.

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