In the new study, over 4,000 people between ages 55 and 80 had their diets categorized by glycemic index—a measure of food’s blood sugar—raising effects. A high-glycemic-index diet raises blood sugar levels after a meal more than a low-glycemic-index diet does.
Compared with people with diets that measured lowest on the glycemic index, people eating the highest glycemic index foods were almost 1 1/2 times as likely to have features of macular degeneration. The higher the dietary glycemic index, the more severe the disease. Further, people with a higher than average glycemic index diet had a 49% increased risk of advanced macular degeneration.
“We estimate that 20% of cases of advanced macular degeneration would be eliminated if people consumed diets that have dietary glycemic index values below the median,” the study’s authors concluded.
Choosing unprocessed, whole foods appears to be a wise choice for eye health. The researchers noted, “Our results also suggest that the quality, not the quantity, of dietary carbohydrates influences the risk of macular degeneration.”
(Am J Clin Nutr 2007;86:180–8)