Low glycemic index diet may cut risks for age-related eye disease

Researchers at Tufts University have found that switching from a high-glycemic, high-sugar food environment to one less blood sugar-spiking may help slow the development of a debilitating age-related eye disease.
Earlier studies suggested that type 2 diabetes may be associated with early age-related macular degeneration (AMD), but the underlying processes for why the two tend to be linked remained to be determined.
This new research suggests that a high-glycemic environment, meaning the intake of foods that cause sudden dramatic increases in blood sugar levels, may play a role.
The study, which was conducted on mice, saw significant reductions in risks after changing the animals’ diet from a high-glycemic diet composed of white bread to a low-glycemic diet made of starches found in whole grains.
The hypothesis tested by researchers was that even when carbohydrate intakes are matched, low-glycemic diets release sugar into the bloodstream less rapidly than their higher-glycemic counterparts.
For people with type 2 diabetes, this means more gradual variations in blood sugar levels and therefore more control and time to anticipate these changes.
The team of researchers from Tufts’ Jean Mayer USDA Human Nutrition Research Centre on Aging compared a 45% carb diet in two groups of mice for six months with one group placed on the high-glycemic diet and the other on its low-glycemic equivalent.
These were old mice to start with that may or may not have gone to develop AMD from natural causes. The researchers followed them for six months, a follow-up equivalent to 34 human years to see if either diet slowed or accelerated AMD onset.
The research revealed that a high-glycemic diet resulted in the development of many AMD features, including the loss of function of cells at the back of the eye called retinal pigmented epithelial atrophy (RPE).
RPE leads to the typical blurred vision seen in early stages of AMD. Cells that capture light, called photoreceptors, were also affected with this diet. A low-glycemic diet did not trigger such changes and actually stopped the damage to the retina due to aging.
“We hadn’t anticipated that dietary change might repair the accumulated damage in the RPE so effectively,” lead author Sheldon Rowan told a Science Daily reporter.
Rowan and his colleagues believes that a low-glycemic diet is effective as it reduces Advanced Glycation End Products (AGEs) that are formed in large numbers on higher-glycemic diets and are a factor in AMD.
Low-glycemic diets are also well-known to lower inflammation and inflammation in the body accelerates the onset of many age-related diseases. These results suggest that these types of diet are beneficial to eye health in people predisposed to AMD.