Eating Grapes Reshapes Skin Gene Expression

Clinical trials have previously shown that consuming grapes can boost the resilience of skin to UV irradiation in about 30-50% of subjects. New research published in ACS Nutrition Science indicates that the effect on human skin health extends much further—most likely affecting everyone who eats them.

For the investigation, human volunteers consumed the equivalent of three servings of whole grapes each day over a two-week period. Researchers measured gene expression in skin before and after grape consumption, both with and without exposure to low doses of UV irradiation.

The findings revealed inter- and intraindividual differences in gene expression. From the outset, gene expression in each volunteer's skin was different. That expression shifted when participants consumed grapes or when their skin was exposed to UV irradiation, although each individual still differed from the others. Additional unique changes appeared when UV exposure was paired with grape consumption.

In short, while gene expression varied from one person to another, every participant's gene expression changed after consuming grapes

In searching for a functional commonality behind these shifts, investigators interpreted the data as indicative of enhanced skin keratinization and cornification—processes that build a barrier against environmental damage. The interpretation was reinforced by exposing skin to a low dose of UV irradiation and measuring the generation of malondialdehyde, a marker of oxidative stress. Levels of malondialdehyde were reduced when subjects ate grapes. 

"We are now certain that grapes act as a superfood and mediate a nutrigenomic response in humans," said senior author John Pezzuto. "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."