Research finds vision benefit to eating grapes daily

Oct. 12—It may come as little consolation for the local table grape industry after a brutal crop year like 2023, but a study out this month points to new health benefits from eating Kern's top-grossing ag commodity.

The scientific journal Food & Function recently published results from a randomized, controlled human study that found eating the equivalent of a cup and a half of grapes every day for four months improved signs of eye health in older people.

Paid for by the California Table Grape Commission, the study adds to evidence from earlier studies in mice suggesting that grapes protect against oxidation in the retina, specifically age-related macular degeneration.

It's the latest nutritional benefit to be associated with one of the county's leading specialty crops, such as almonds and pistachios, whose healthy qualities have been demonstrated in earlier research. Last year, studies in mice concluded grape consumption may extend lifespans and improve cognition.

Such studies further scientific understanding of nutrition at the same time as they make crops more marketable — an attractive possibility for a large local industry that lost a significant share of this year's harvest because of unseasonable precipitation in August.

President Kathleen Nave of the California Table Grape Commission said by email the new report in Food & Function builds on three prior studies showing benefits to the retina. One focused on the fruit's potential to reduce oxidative damage to the retina, while the other looked at how eating grapes helped protect blood vessel formation that can otherwise leak into and damage the retina.

Nave noted the grape commission has invested in health research for two decades in collaboration with universities and medical research facilities. She pointed out that other studies supported by the organization have shown eating grapes benefits heart and brain health, especially memory loss associated with Alzheimer's.

No particular color of grape — red, green, white or black — appears to offer a greater benefit than any other, she wrote, adding, "If everyone ate 1.5 cups of grapes a day, we would need a lot more vineyards to supply the demand."

Researchers in Singapore, including scientists at the National University of Singapore's Department of Food Science and Technology, divided 34 participants into two groups, one of which ate freeze-dried table grape powder every day for 16 weeks and the other ate a placebo powder.

The researchers measured the participants' macular pigment optical density every four weeks. At the end of the full term, they reported observing significant improvement in density, signifying lower risk of macular degeneration.

Age-related macular degeneration, often a result of oxidative stress, doesn't cut off all vision but makes it hard for people to see objects directly in front of them.

One of the report's authors, Dr. Jung Eun Kim, noted the study was the first to show that eating grapes improves eye health in humans, "which is very exciting, especially with a growing aging population."

"Grapes," she added, "are an easy, accessible fruit that studies have shown can have a beneficial impact in normal amounts of just 1 1/2 cups per day."