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A study this year confirms earlier findings
linking high consumption of fast-acting carbs over time with age-related
macular degeneration (AMD). Above, top: a simulation of AMD-related vision loss
compared to (bottom) normal vision.
Images courtesy
National Eye Institute,
National Institutes of Health.
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Fast-Acting Carbs May Hasten Vision Loss Over
Time
By Rosalie Marion
Bliss
October 29, 2007
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. Scientists
supported by the Agricultural Research Service (ARS) and grants reported the findings this
year in the
American Journal of Clinical
Nutrition.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.
The study was led by Chung-Jung Chiu with
Allen
Taylor, both at the Jean Mayer USDA Human Nutrition Research Center on
Aging (HNRCA)
in Boston, Mass. Taylor is director of the
Laboratory
for Nutrition and Vision Research at the HNRCA.
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 carb" 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 carb" 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.
Consuming a diet high in fast carbs 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 carbs could be
similar in both AMD and diabetic eye disease.
At this time, there is no effective cure for AMD, so finding modifiable risk
factors is important. While it's too soon to recommend dietary slow carbs as a
preventive strategy for AMD, replacing fast carbs with whole grains may soon
prove to be an early dietary intervention to slow its progression.
