Scientists see new benefits to grapes – staving off blindness

In some people, eating grapes might slow or help prevent the onset of age-related macular degeneration, a debilitating condition affecting millions of elderly people worldwide, says the California Table Grape Commission, citing a new study.

The antioxidant actions of grapes are believed to be responsible for these protective effects, says the study, based at Fordham University and published in Free Radical Biology and Medicine, the Fresno-based commission says.

Funding was provided by the National Eye Institute of the National Institutes of Health and the California Table Grape Commission.

The study compared the impact of an antioxidant-rich diet on vision using mice prone to developing retinal damage in old age in much the same way as humans do. Mice either received a grape-enriched diet, a diet with added lutein, or a normal diet.

The study found that the grape-enriched diet protected against oxidative damage of the retina and prevented blindness in those mice consuming grapes. While lutein was also effective, grapes were found to offer significantly more protection.

“The protective effect of the grapes in this study was remarkable, offering a benefit for vision at old age even if grapes were consumed only at young age,” says principal investigator Silvia Finnemann, of the Department of Biological Sciences at Fordham University in New York.

Ms. Finnemann says that results from her study also suggest that age-related vision loss is a result of cumulative, oxidative damage over time. “A lifelong diet enriched in natural antioxidants, such as those in grapes, appears to be directly beneficial for retinal health and function,” she writes.

“We’re not suggesting that you need to eat grapes like crazy, but that a life of having a healthy diet of natural anti-oxidants makes a difference to changes in the human eye,” says Ms. Finnemann.

Her three-year study also showed that, in order to be effective, eating anti-oxidant-rich foods should begin before the onset of advanced age, preferably in youth or young adulthood.

Mice who were not fed a grape and lutein-rich diet until they were the equivalent of a human age of 60 showed little or no improved retinal function, she says.

“Once the changes have started to happen, it may be too late to reverse them,” she says.

AMD is a progressive eye condition, leading to the deterioration of the center of the retina, called the macula. It is the leading cause of blindness in the elderly. Oxidative damage and oxidative stress are thought to play a pivotal role in the development of AMD.