In the study, volunteers consumed the equivalent of three servings of whole grapes each day for two weeks. Researchers then analyzed gene expression in participants’ skin before and after grape consumption, both with and without exposure to low doses of UV radiation.

Grapes Changed Skin Gene Activity

The scientists found major differences in gene expression both between individuals and within the same individual over time. Each participant began the study with a unique pattern of gene activity in their skin.

Those patterns shifted after eating grapes and also changed following UV exposure. Additional changes appeared when grape consumption and UV exposure were combined. Even though every participant responded differently, researchers observed that grape consumption consistently altered gene expression in all subjects.

Stronger Skin Defenses and Less Oxidative Stress

After examining the data, the researchers identified common biological effects linked to grape consumption. The gene activity changes pointed toward increased keratinization and cornification, processes that help form the skin’s protective outer barrier against environmental damage.

The team also measured levels of malondialdehyde, a marker of oxidative stress, after exposing skin to low doses of UV radiation. Participants who consumed grapes showed lower levels of this marker, suggesting reduced oxidative stress in the skin.

Researchers Call Grapes a “Superfood”

“We are now certain that grapes act as a superfood and mediate a nutrigenomic response in humans,” said John Pezzuto, Ph.D., Professor and Dean of the College of Pharmacy and Health Sciences at Western New England University. “We observed this with the largest organ of the body, the skin. The changes in gene expression indicated improvements in skin health. But 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. This helps us to understand how consumption of a whole food, in this case grapes, affects our overall health. 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.”

The research was conducted by scientists from Western New England University in Springfield, Massachusetts, together with collaborators from Oregon State University in Corvallis, Oregon. Funding for the study was provided by the California Table Grape Commission.