Eating grapes is good for the eyes and could reduce the risk of going blind later in life, according to new research.
The fruit protects against a chemical process known as oxidative stress, which releases harmful molecules called free radicals into the retina. Grapes are rich in antioxidants that protect healthy cells from DNA damage and it is believed these compounds are behind the eyesight benefits.
The retina is the part of the eye that contains cells that respond to light, known as photoreceptors. Degenerative diseases of the retina can cause blindness.
“Adding grapes to the diet actually preserved retinal health in the presence of oxidative stress in this study,” says Professor Abigail Hackam, of the University of Miami in the U.S., which carried out the research.
Elevated oxidative stress is strongly associated with retinal disease and has been widely studied in the development of age-related macular degeneration and other eye conditions.
During the research, mice were fed either freeze-dried whole grape powder – the equivalent of about three servings a day for humans – a diet with the same level of sugar, or a standard research control diet. The results showed that both retinal structure and function were preserved in the group eating the grape-enriched diet.
Mice in this group maintained their retinal thickness, the quantity of photoreceptors and the amount of photoreceptor activity, despite high oxidative stress. In the non-grape eaters, retinas were damaged, displaying holes and lesions, and there was a significant decrease in thickness.
There was also a 40 per cent reduction in photoreceptors and significant loss of photoreceptor activity.
Previous research by scientists at the University of Glasgow found that the antioxidant benefits of drinking purple grape juice could also reduce the risk of heart disease, cancer and Alzheimer’s disease.
Another study, by scientists at Washington State University, found that eating grapes can help prevent weight gain.
They contain a compound called resveratrol – also found in blueberries, strawberries, raspberries and apples – that converts bad, white fat in the body into good ‘beige fat’, which burns up calories.