Dietary intake of grapes may improve the skin’s resistance to UV radiation, a new study published in ACS Nutrition Science found.

In the study, volunteers consumed the equivalent of three servings of whole grapes each day for two weeks, in a freeze-dried, powdered form.

Researchers analyzed gene expression in the subjects both with and without exposure to low doses of UV radiation.

There were major differences in the gene expressions between individuals, and within the same individual over time. Each participant began the study with a unique pattern of gene activity in their skin.

These patterns shifted after eating grapes and also changed following UV exposure, and, when grape consumption and UV exposure were combined, additional changes appeared. While every participant responded differently, there were significant alterations in the gene expression of all subjects.

Consistent across all subjects was an increase in keratinization and cornification, processes that help form the skin’s protective outer barrier against environmental damage. Participants also showed lower levels of malondialdehyde, a marker of oxidative stress.

“We are now certain that grapes act as a superfood and mediate a nutrigenomic response in humans,” said John Pezzuto, PhD, 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 visualize complex matrices indicative of nutrigenomic responses.”