The development of age-related macular degeneration (AMD) and nuclear cataract are associated with a high dietary glycemic index (GI), according to two separate studies published in the American Journal of Clinical Nutrition.1,2
The glycemic index is a measure of how quickly individual foods will raise the bodys blood sugar level. Foods with a high GI (i.e., simple carbohydrates) are rapidly absorbed and result in marked fluctuations in blood sugar levels.
The first study, in the April issue of the journal, looked at 1,036 eyes of 526 Boston-based women enrolled in the Nutrition and Vision Program at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. None of the women had an AMD diagnosis prior to enrollment.
Dietary data were based on information from an average of four food-frequency questionnaires collected over a 10-year period before an AMD assessment. Results showed that dietary glycemic index was related to the development of early age-related macular degenerationspecifically, retinal pigmentary abnormalities, though not drusen. Total carbohydrate intake was not related to either.
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| Optometrists need to talk to patients who have a high glycemic index about the quality of the carbohydrates they ingest and not just the quantity. |
The second study, in the May issue, looked at dietary information obtained from a food-frequency questionnaire given to 3,377 non-diabetic subjects (56% of whom were women) ages 60 to 80 years who were part of the Age-Related Eye Disease Study (AREDS).
Subjects were divided into three categories based on their dietary glycemic index or total carbohydrate consumption. Twenty-five percent of the subjects were placed in the highest intake category, 50% were placed in the middle intake category, and 25% were placed in the lowest intake category. This last category was used as the referent category, the researchers say.
Results showed that for those participants in the highest quartile, dietary glycemic index was linked with a higher incidence of all single and moderate nuclear opacities. The researchers surmise that foods containing a higher glycemic index may advance damage to the metabolically limited tissue of the lens by exposing this tissue to glucose for longer periods.
These studies suggest that we need to double our efforts against weight gain and obesity through prescribing adherence to the new and improved 2005 USDA Food Triangle, which emphasizes a reduction in simple carbohydrates, says optometrist Stuart Richer, associate professor of Family and Preventative Medicine at the Rosalind Franklin University of Medicine & Science in North Chicago. We need to talk to patients about the quality of the carbohydrates they ingest and not just the quantity. (See Put Your Patients On The Pyramid, December 2005.)
1. Chiu CJ, Hubbard LD, Armstrong J, et al. Dietary glycemic index and carbohydrate in relation to early age-related macular degeneration. Am J Clin Nutr 2006 Apr;83(4):880-6.
2. Chiu CJ, Milton RC, Gensler G, Taylor A. Dietary carbohydrate intake and glycemic index in relation to cortical and nuclear lens opacities in the Age-Related Eye Disease Study. Am J Clin Nutr 2006 May;83(5):1177-84.
