Grapes may help prevent age-related blindness
Can eating grapes slow or help prevent the onset of age-related macular degeneration (AMD), a debilitating condition affecting millions of elderly people worldwide? Results from a new study published in Free Radical Biology and Medicine suggest this might be the case. The antioxidant actions of grapes are believed to be responsible for these protective effects.
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 result? Grapes proved to offer dramatic protection: 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,” said principal investigator Silvia Finnemann, PhD, Department of Biological Sciences, Fordham University in New York.
Dr. Finnemann noted that results from her study 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 RPE and retinal health and function.”
Age-related macular degeneration (AMD) is the leading cause of blindness among the elderly, and it affects more than 10 million Americans age 55 and older, according to the American Macular Degeneration Foundation. A recent study published in Free Radical Biology and Medicine looked to see if an antioxidant-rich diet would help sufferers ward of the condition for longer, and the results were surprising.
To test this, researchers studied mice because they are prone to developing retinal damage in old age in a similar fashion to humans. The mice were broken up into three groups, one ate a diet rich in grapes, a second group ate a diet with added lutein - a pigment found in plants known to support eye health, and the third group consumed a normal diet.
From the data, scientists found that the mice who ate the grapes were the most protected against the effects of AMD. The grapes worked to shield the mice’s eyes against oxidative damage of the retina and prevented blindness as well. The mice who ate a diet with added lutein also had benefits, though the grapes were far superior in providing overall protection.
Age-related macular degeneration 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. Aging of the retina is associated with increased levels of oxidative damage, and oxidative stress is thought to play a pivotal role in the development of AMD.
Age-related macular degeneration (AMD) is a disease associated with aging that gradually destroys sharp, central vision. Central vision is needed for seeing objects clearly and for common daily tasks such as reading and driving.
AMD affects the macula, the part of the eye that allows you to see fine detail. AMD causes no pain.
In some cases, AMD advances so slowly that people notice little change in their vision. In others, the disease progresses faster and may lead to a loss of vision in both eyes. AMD is a leading cause of vision loss in Americans 60 years of age and older.
In AMD, there is a known decline in the function of retinal pigment epithelium cells (RPE), which are the support cells for the photoreceptors in the retina that are critical to the process of converting light into sight. The RPE dysfunction is caused by 1) a build-up of metabolic waste products (known as lipofuscin) in the RPE itself and 2) an oxidation burden on the RPE that compromise important metabolic pathways. The resulting dysfunction, distress and often death of the RPE cells leads to AMD.
Who is at risk for AMD?
The greatest risk factor is age. Although AMD may occur during middle age, studies show that people over age 60 are clearly at greater risk than other age groups. For instance, a large study found that people in middle-age have about a 2 percent risk of getting AMD, but this risk increased to nearly 30 percent in those over age 75.
Other risk factors include:
Smoking. Smoking may increase the risk of AMD.
Obesity. Research studies suggest a link between obesity and the progression of early and intermediate stage AMD to advanced AMD.
Race. Whites are much more likely to lose vision from AMD than African Americans.
Family history. Those with immediate family members who have AMD are at a higher risk of developing the disease.
Gender. Women appear to be at greater risk than men.
This study showed that adding grapes to the diet prevented blindness in mice by significantly decreasing the build-up of lipofuscin and preventing the oxidative damage to the RPE, thus ensuring optimal functioning of this critical part of the retina.
“Preserving eye health is a key concern as we age and this study shows that grapes may play a critical role in achieving this,” said Kathleen Nave, president of the California Table Grape Commission. “This is good news for consumers of all ages who enjoy grapes, and adds to the growing body of evidence that grapes offer an array of health benefits.”
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The California Table Grape Commission was created by the California legislature in 1967 to increase worldwide demand for fresh California grapes through a variety of research and promotional programs.
The California Table Grape Commission prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable sex, marital status, familial status, parental status, or religion. The California Table Grape Commission is an equal opportunity provider and employer.
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Karen Brux
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California Table Grape Commission