Today's post from "Sham vs. Wham: The Health Insider" may be of
interest here. Google the site for original text and links on the
subject.

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New research supports the belief that people consuming diets with a
higher glycemic index than average are at greater risk of developing
advanced age-related macular degeneration (AMD). This new study from
Tufts University suggests that 20 percent of cases of advanced AMD
might have been prevented if individuals had consumed a diet with a
glycemic index below average.

In the July issue of the American Journal of Clinical Nutrition, Dr.
Allen Taylor and colleagues of the Laboratory for Nutrition and Vision
Research at Tufts University confirmed earlier findings linking
dietary glycemic index with the risk of developing AMD. Here's how
Taylor describes this work, and the lessons learned from his research:

   "Men and women who consumed diets with a higher glycemic index
than average for their gender and age-group were at greater risk of
developing advanced AMD," corresponding author Taylor says. "The
severity of AMD increased with increasing dietary glycemic index."

   Glycemic index is a scale applied to foods based on how quickly
the carbohydrates in foods are converted to blood sugar, or glucose.
Foods like white rice, pasta and bread are examples of foods with a
high-glycemic-index, meaning that these foods are associated with a
faster rise and subsequent drop in blood sugar. Whole wheat versions
of rice, pasta and bread are examples of foods that have a low-
glycemic-index. These foods are often considered higher quality
carbohydrates because they are associated with a slower and less
dramatic rise and fall of blood sugar.

   In this study, Taylor and colleagues analyzed data from 4,099 men
and women participating in the nationwide Age-Related Eye Disease
Study (AREDS). Detailed dietary histories were obtained at the start
of the study when participants were 55 to 80 years of age and had
varying degrees of AMD.

   "Although carbohydrate quality was not the main focus in the
AREDS, we were fortunate that the investigators had collected the
dietary carbohydrate information we needed to do our analyses," says
Taylor. "Our findings suggest that 20 percent of the cases of advanced
AMD might have been prevented if those individuals had consumed a diet
with a glycemic index below the average for their age and gender,"
notes Taylor.

   AMD typically occurs after middle age, although the events which
cause it may begin earlier. A leading cause of irreversible blindness,
AMD results from the gradual breakdown of light-sensitive cells in the
central region of the eye's retina, called the macula. Although there
is no effective therapy for AMD, dietary intervention may delay its
progress. Identifying modifiable risk factors for AMD is becoming
increasingly important as the population ages. As Taylor and
colleagues point out, the number of people in the US with visually
impairing AMD is expected to double and reach three million by 2020.

   Taylor speculates that carbohydrates that comprise a high-
glycemic-
index diet may provide eye tissue with too much glucose too quickly,
and overwhelm the ability of the eye cells to use the carbohydrate
properly. "It is possible that the type of damage produced by poor
quality carbohydrates on eye tissue is similar in both diabetic eye
disease and AMD."

The risk for AMD may be diminished by improving dietary carbohydrate
quality, as defined by dietary glycemic index. This may be achieved by
relatively simple dietary alterations, such as replacing white bread
with whole grain bread.

D.