Study Finds Grapes May Protect Skin From Sun Damage

Every summer, doctors and skin specialists repeat the same advice: use sunscreen, stay out of the intense midday sun and shield your skin from ultraviolet damage.

Although most people recognise these dangers, sun protection is commonly viewed as something applied to the skin, rather than something that may also be supported from within.

Emerging research indicates that diet could affect the way skin reacts to sunlight, with one familiar fruit attracting particular scientific interest.

A recent study by Western New England University suggests that consuming grapes may help human skin cope more effectively with sun exposure.

The researchers identified changes in genes associated with skin repair and protection, providing fresh evidence that food may influence skin health.

Grapes enter skin science

Grapes have long featured in nutrition studies, largely because they contain resveratrol, a plant compound frequently associated with healthy ageing.

Initial research generated enthusiasm about its possible benefits, yet subsequent studies found that resveratrol on its own did not fulfil many of the claims made for it.

Scientists consequently turned their focus from an individual compound to the whole grape.

Grapes provide hundreds of phytochemicals, which may act collectively in ways that isolated supplements cannot replicate.

Earlier studies showed skin benefits

Previous mouse research found that diets enriched with grapes lessened ultraviolet-radiation-related skin damage and delayed tumour development.

Later human trials indicated that regularly eating grapes made some participants more resistant to UV damage.

However, one question remained: did grapes genuinely have no effect on people who showed little outward improvement, or were more subtle biological effects being overlooked?

Testing human skin

To explore this issue, the researchers carried out an in-depth clinical study with 29 volunteers. For the first two weeks, participants followed a restricted diet.

They then took freeze-dried whole grape powder, equivalent to three daily servings of grapes, for a further two weeks.

The team assessed every participant’s minimal erythema dose, a measure of how much ultraviolet exposure the skin can withstand before it becomes red.

Results from skin biopsies

The researchers also took skin biopsies before and after grape consumption, from skin exposed to UV radiation as well as unexposed skin.

More than 100 skin samples were obtained, but many did not pass RNA sequencing quality-control checks.

Fully usable data were available from just four women, all of whom had the same skin type and had initially been labelled non-responders because their redness threshold had not increased.

Grapes lower hidden skin damage

The earliest indication came from malondialdehyde measurements. This marker is associated with oxidative stress and damage to cell membranes following UV exposure.

Malondialdehyde levels fell significantly after grape consumption across the wider participant group.

Oxidative damage was also reduced in all four apparent non-responders.

Their skin was therefore still being protected, even though conventional redness testing showed no clear improvement.

The result indicated that visible sunburn reactions may fail to reveal everything occurring within skin tissue.

Genes react differently

RNA sequencing revealed striking differences from one person to another. Even before the dietary intervention, each participant had hundreds of uniquely expressed genes.

Following grape consumption and UV exposure, gene activity changed differently in every participant. Initially, the findings appeared disordered, and statistical analysis found little common ground between individuals.

However, the scientists anticipated this variability, as nutrigenomic responses can be influenced by genetics, gut microbiota, age, diet and other biological factors.

Nevertheless, the study established an important point: grapes altered gene activity in human skin.

“We are now certain that grapes act as a superfood and mediate a nutrigenomic response in humans,” said Dr. John Pezzuto, a professor at Western New England University.

“We observed this with the largest organ of the body, the skin.”

The skin barrier strengthens

When the researchers compared each participant’s skin samples from before and after grape consumption, clear patterns began to appear. In three of the four women, genes related to forming the skin barrier became more active.

These included genes involved in keratinisation, epidermal development and cornification, processes that contribute to the skin’s protective outer layer.

Put simply, grapes seemed to prompt skin to strengthen its physical barrier against environmental stress.

Improved barrier function helps the body retain moisture and restricts damage from UV radiation, microbes and pollutants.

Lipids change too

One participant displayed a contrasting response focused on lipid metabolism. In her post-grape skin samples, genes associated with fatty-acid production and lipid droplets showed greater activity.

Scientists previously considered lipid droplets to be simple fat stores within cells. They are now understood to be active structures that help protect cells against stress, including UV damage.

Blood tests also identified changes in lipid profiles among all four women. Certain phospholipids rose considerably, while saturated fatty acids decreased and unsaturated fatty acids increased.

Many of these lipid shifts are linked to healthier skin barrier function and lower inflammation.

Skin defences become stronger

A further participant showed increased activity in genes connected with antioxidant protection and antimicrobial function.

The researchers observed higher expression of genes involved in breaking down hydrogen peroxide and detoxifying oxidants.

Antimicrobial proteins, including dermcidin, also increased after grape consumption. Normally released through sweat glands, dermcidin helps eliminate harmful bacteria from the skin.

Other proteins that reinforce the skin barrier and aid antibacterial protection likewise became more active.

While each participant used different biological routes, all reached comparable protective outcomes. The body appeared to tailor its response according to individual biology.

Gut bacteria affect skin response

The researchers think that the gut microbiome may account for much of this variation. Earlier work by the same study group found that grape consumption changed gut bacterial composition and metabolite production.

Their theory is that grape phytochemicals interact with gut microbes to create compounds that enter the bloodstream and affect distant organs, including the skin.

As every individual has a distinct gut microbiome, grape compounds may be processed differently from person to person.

This could help explain why nutrition studies frequently produce inconsistent outcomes among individuals.

Further studies are needed

The study has significant limitations. Only four women yielded usable sequencing data, and they all had similar skin types and background characteristics.

Bigger, more diverse studies remain necessary. The researchers also stress that grapes do not replace sunscreen or safe-sun practices.

The intervention used concentrated grape powder equivalent to several servings each day, rather than occasional grape snacking.

Even so, the findings are important because they show that a common food can bring about measurable genetic changes in human skin tissue.

Food may shape skin health

The results add support to the growing scientific understanding that nutrition influences the body in highly personalised ways.

“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,” Pezzuto said.

The team said the research is helping scientists understand more clearly how whole foods such as grapes may influence overall health, particularly as modern genetic tools enable researchers to monitor these changes more closely.