A Taste of Wellness for Savoury and Snacks
Givaudan
Writing in the American Journal of Clinical Nutrition, researchers from Tufts University, the AREDS Coordinating Center, and the University of Wisconsin report that consuming a diet with a low glycaemic index may lead to significant reductions in the risk of AMD.
"Based on our data, limiting refined carbohydrate intake, such as by limiting sweetened drinks or exchanging white bread for whole wheat, in at-risk elderly could reduce the number of advanced AMD cases by eight per cent in five years. This can equate to saving the sight of approximately 100,000 people," said lead researcher Allen Taylor from.
Age-related macular degeneration (AMD) occurs when the macula, the area at the back of the retina that produces the sharpest vision, deteriorates over time. It is the most common cause of blindness among the over-50s.
According to the researchers, the prevalence of the condition is likely to increase as the population ages. While there is currently no known way of preventing the condition, more and more research is focusing on potentially modifiable risk factors and nutrient-based approaches, most notably on the carotenoids lutein and zeaxanthin.
The new research adds to the science linking dietary habits to the development of the condition. The researchers used data from the Age-Related Eye Disease Study (AREDS) for 3977 men and women (age range 55 to 80, 58 per cent women). The data allowed the researchers to calculate the dietary glycaemic index (dGI) using a weighted average of GIs.
The glycaemic index measures how quickly certain foods release carbohydrates into the body, which then raise consumers' blood glucose levels. High GI foods, including white bread, white rice, many prepared breakfast cereals and concentrated sugar, cause blood sugar levels to rise more rapidly. Low GI foods include most vegetables, fruits, beans and unprocessed grains.
The researchers then classed the 7232 eyes without advanced AMD into three groups: group 1 (nonextensive small drusen), group 2 (intermediate drusen or extensive small drusen), or group 3 (large drusen or extensive intermediate drusen). Drusen are accumulations of material from outside the cell (extracellular) in the eye.
After an average of 5.4 years of follow-up, the researchers report that high dGI was associated with higher risks of AMD progression for each group, compared to a low dGI.
"The risk of progression for groups 1, 2, and 3 eyes was five, eight and 17 per cent greater, respectively," they said.
"The latter gives an estimate that 7.8 per cent of new advanced AMD cases would be prevented in five years if people consumed the low-dGI diet."
"Our data showed those people in the high-glycemic-index group were at greater risk of AMD progression, especially those already in the late stages," said lead author Chung-Jung Chiu.
The authors called for randomised, controlled clinical trials to further test the observation that low dGI may reduce the risk of AMD progression or prevent AMD development.
Source: American Journal of Clinical Nutrition
October 2007, Volume 86, Number 4, Pages 1210-1218
"Dietary carbohydrate and the progression of age-related macular degeneration: a prospective study from the Age-Related Eye Disease Study"
Authors: Chung-Jung Chiu, R.C. Milton, R. Klein, G. Gensler and A. Taylor