New Research Supports Grapes’ Benefits to Eye Health
Compounds found in grapes may help protect against eye disease, according to new research led by researchers at the Bascom Palmer Eye Institute at the University of Miami Miller School of Medicine. The study, published in the journal Nutrition, showed that a diet supplemented with grapes was able to counter damage from oxidative stress and preserve retinal structure and function in a laboratory model of retinal degeneration.
“Adding grapes to the diet actually preserved retinal health in the presence of oxidative stress in this study,” said Abigail S. Hackam, Ph.D., associate professor of ophthalmology at the Miller School, and lead investigator of the study. “These results are very exciting and build on the growing evidence that suggests a compound in grapes is beneficial to eye health.”
Natural components in grapes that help promote antioxidant activity are thought to be responsible for these beneficial effects, in keeping with previous studies that indicate grape-derived compounds are biologically active in the retina. The retina is the part of the eye that contains the cells that respond to light, known as photoreceptors. There are two types of photoreceptors: rods and cones. Retinal degenerative diseases cause progressive photoreceptor death and irreversible vision impairment, including blindness, and affect millions of people in the U.S. Elevated oxidative stress is strongly associated with retinal disease and has been widely studied in the development of age-related macular degeneration and other retinal degenerations.
In this new study, which was funded by the California Table Grape Commission, researchers investigated whether a diet supplemented with grapes, in the form of whole grape freeze-dried powder, would protect the photoreceptors of the retina from degeneration induced by acute oxidative stress. Mice were fed the grape-supplemented diet (corresponding to about three servings per day for humans), a sugar-matched control diet, or a normal chow control diet.
The results showed that both retinal structure and function were preserved in the mice consuming the grape-enriched diet. Animals in the grape-consuming group maintained their retinal thickness, the quantity of photoreceptors, and the amount of photoreceptor activity, despite the elevated oxidative stress conditions.
Conversely, in the non-grape consuming group, retinas were damaged, displaying holes and lesions, and with a significant decrease in thickness. Because the mice were treated identically except for their diet, the researchers concluded that the protective effect to the retina came from compounds in the grapes.
Hackam focuses her research on the cellular mechanisms of retinal development and degeneration.