The $3 ‘superfood’ that can protect skin against sun damage and aging, according to a new study
Eating grapes daily changes how skin genes behave, helping protect against the aging and damaging effects of the sun.
New research found that eating three servings of grapes daily for two weeks changed gene activity in the skin, and the pattern was unique to each person.
One of the clearest effects was a drop in malondialdehyde, a marker of oxidative stress, after skin was exposed to ultraviolet (UV) light.
Less malondialdehyde means less cell damage from the sun. This finding shows that grapes provide protection at the biological level, even when no visible change in sunburn resistance is seen.
Grapes also boosted genes involved in skin barrier function. Specifically, the fruit enhanced genes related to processes that help the skin form a protective barrier against germs, chemicals and water loss.
This stronger barrier helps skin better handle environmental threats like UV radiation. Skin damage due to UV exposure is a leading cause of skin cancer, which affects nearly six million Americans annually.
Dr John Pezzuto, who led the research, said the same effect likely happens in other parts of the body, as well, calling grapes a superfood that trigger a nutrigenomic response, meaning food directly influences gene behavior.
The researchers believe the process starts in the gut as grape compounds interact with gut bacteria. This then send signals through the gut-skin axis to change how skin genes work.
Eating three servings of grapes daily for two weeks changed gene activity in everyone’s skin, boosted protective barriers and reduced signs of UV damage, even in people who didn’t get better at resisting sunburn (stock)
To figure out what grapes were doing to the skin, the researchers recruited 29 healthy volunteers for their study, which was published in ACS Nutrition Science.
For two weeks, the participants consumed a special freeze-dried grape powder that was the equivalent to three full servings of fresh grapes each day, equating to about three cups, or 45 to 60 grapes.
The scientists took tiny skin punch biopsies from a sun-protected area on the hip and a spot on the back that had been exposed to a low dose of ultraviolet light. They collected these samples both before and after the two weeks of grape eating.
The team then put those skin samples through a series of lab tests, measuring malondialdehyde, a chemical marker of UV-induced oxidative stress, using a special staining technique on the tissue.
They also extracted RNA from skin biopsies to analyze gene expression, comparing which genes turned on or off after grape consumption.
Then, they drew blood from the participants to analyze changes in hundreds of different fats in the bloodstream.
Even in the four volunteers who showed no visible improvement in sunburn resistance, eating grapes still reduced malondialdehyde after UV exposure.
Most notably, each person’s genetic activity shifted after eating grapes for two weeks. The changes were different from person to person, but they all pointed in a positive direction.
Grapes reduced UV skin damage in 26 volunteers. The taller yellow bar shows higher skin damage levels before eating grapes. The shorter pink bar shows lower damage levels after two weeks of daily grape consumption. Less damage means healthier skin.
In one volunteer, grapes turned on genes that help build a tougher, more resilient outer layer of skin.
Grapes boosted another volunteer’s skin barrier genes, but through different genetic control switches. And in another person, grapes activated genes that help skin fight germs and resist oxidative damage.
The researchers also found widespread changes in the study participants’ good blood lipid, or fat, levels. Nearly all measured lipids, which are essential structural components of skin cell membranes, increased after people ate grapes every day.
A rise in these fats helps skin cells stay strong, flexible and tightly packed together, creating a better seal against moisture loss and a stronger barrier against germs and chemicals.
Unsaturated fatty acids mostly went up, while some saturated fats went down. These lipid shifts are known to support skin barrier function and reduce inflammation.
Pezzuto said: ‘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.’
Staving off sun damage could help prevent millions of skin cancer diagnoses each year.
Repeated UV exposure damages DNA in skin cells and over time this accumulated damage, which appears as pigmented spots on the skin, can trigger uncontrolled cell growth that leads to skin cancer (stock)
When UV rays hit the skin, they do more than cause a sunburn. They also penetrate deep into skin cells and damage their DNA, which is the genetic instruction manual that tells cells how to grow and behave.
Most of the time, the body can repair this damage. But over years of repeated UV exposure, the damage accumulates.
Eventually, the DNA becomes so severely damaged that the cells begin to grow out of control.
This unfettered growth can take several forms. Some skin cancers, including basal cell carcinoma and squamous cell carcinoma, are very common — accounting for more than 90 percent of skin cancers — and are rarely fatal if caught early and removed.
However, the most dangerous form is melanoma, which affects roughly 112,000 Americans annually.
Melanoma grows in the cells that produce skin pigment and can spread quickly to other organs, including the liver, lungs and brain.
Once melanoma spreads, it becomes harder to treat and more likely to prove fatal. If caught early, around 95 percent of patients survive. That rate sinks to 35 percent once the cancer has spread.
Protecting one’s skin helps prevent those initial DNA errors from happening in the first place. Sunscreen, clothing and shade block or absorb UV rays before they ever reach the skin cells.
