This is going to make me sound like someone from a travel series where, say, the actor Stanley Tucci convinces CNN to fund his sumptuous eating tour of Italy, but nevertheless: Modern science teaches us that when you eat grapes, grapes change you.
Researchers have confirmed that the simple act of eating about three daily servings of grapes for just two weeks can alter the expression of genes inside human skin cells, at least, as sampled from four human volunteers. This grape-induced genetic activation, according to their new study, was “ubiquitous and variable” but uniformly aided in these volunteers’ ability to withstand skin damage from ultraviolet (UV) radiation in sunlight.
Biochemist John Pezzuto and his coauthors found that somatic cells from the volunteers’ skin displayed enhanced skin keratinization, a natural process whereby skin cells form a UV-protective layer by flattening out and accumulating fibrous keratin proteins. Sampled skin cells also showed signs of cornification, a similar UV-protective process in which a defensive layer of skin is produced via so-called programmed cell death, among other genetic responses the researchers identified via Gene Ontology (GO) enrichment analysis.
All this gene expression got results, according to Pezutto’s team. Across the 30-day period of study, volunteers’ skin produced less malondialdehyde—a chemical marker of oxidative stress from UV damage—sometimes with two- or three-fold reductions compared to control group skin samples.
Why, exactly, however, remains something of a mystery. “The mechanism responsible for this grape-induced diminution of malondialdehyde generation remains to be characterized,” the team noted.
Amazing grapes
Pezzuto, dean of the College of Pharmacy and Health Sciences at Western New England University, said in a statement that he was “now certain” that grapes “mediate a nutrigenomic response in humans.” Nutrigenomics is the study of how foods and nutrients interact with genes to influence health.
The new research builds on his years-long interest in the health benefits of grapes. A prior study involving 29 participants who ate 2.25 cups of grapes per day for a similar two-week period found that 31% of them developed an increased resistance to UV exposure. But Pezzuto’s new study, published this May in the journal ACS Nutrition Science, suggests that the skin protection afforded by grapes might benefit everyone.
The researchers selected their four volunteers at random from the 29 who had volunteered to undergo their two-week grape-eating regimen.
Previously, Pezzuto had also investigated the cancer-fighting benefits of resveratrol, a bioactive molecule found in both grapes and grape products like red wine. He has described this work as elevating the humble grape to “superfood” status on par with trendy, antioxidant-rich produce like açai berries, blueberries, and broccoli.
“Much of the attention received by grapes stem from our research,” as Pezzuto told NPR’s The Academic Minute this past August. “But importantly, grapes contain more than 1600 natural compounds and they all function together in complex ways.”
Grape expectations
“Beyond skin, it is nearly certain that grape consumption affects gene expression in other somatic tissues of the body, such as liver, muscle, kidney, and even brain,” Pezzuto said. “This helps us to understand how consumption of a whole food, in this case grapes, affects our overall health.”
Perhaps crucially, the new study was supported financially by the California Table Grape Commission, a public group established by the California state legislature in 1967 to “protect and enhance the reputation of California fresh grapes.” Pezzuto and one of his coauthors, pharmacologist Richard B. van Breemen at Oregon State, both also serve on the commission’s scientific advisory committee.
Regardless of the researchers’ clear investment in the nourishing and restorative power of grapes, Pezzuto noted that he was optimistic that further hard proof would be coming via future Gene Ontology analyses. “It’s very exciting to be working in the post-genomics era where we can finally start to employ functional genomics and actually visualize complex matrices indicative of nutrigenomic responses,” he said.
