Can Grapes Reduce Your Chances of Sunburn?

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Scientists have studied grapes to see if they can help with UV damage. Carlos Ciudad Photos/Getty Images
  • A new study has found that grapes can reduce the chances of sunburn for some people.
  • The cause of sunburn—UV radiation from the sun—is involved in the development of skin cancer.
  • The study suggests that microbiome differences may explain why grapes reduce some people’s sensitivity to UV exposure and not others.

Some people become less sensitive to the harmful effects of the sun’s ultraviolet (UV) rays after eating grapes, according to a new human study.

A third of the study’s participants became less prone to skin redness from UV rays after two weeks of eating three portions of powdered grapes daily.

For some individuals, the protective effect lasted a month after grape consumption ended.

The difference between those who were less likely to get sunburned and others appeared to be differences in them microbiome and metabolomes. This suggests an interesting connection between the gut and UV resistance.

The study is published in Antioxidants.

It was partially funded by the California Table Grape Commission, which had no other involvement in the research. One of the authors was a member of their scientific advisory committee.

According to the Skin Cancer Foundation, more than 9,500 cases of skin cancer are diagnosed daily in the US. More than two people die from skin cancer every hour.

Excessive exposure to UV radiation is the cause of approximately 90% of non-melanoma cancers—including basal cell and squamous cell cancers—and is considered a major factor in melanoma. Non-melanoma cancers can typically be managed.

If you burn your skin five or more times in the sun, your risk of melanoma doubles. One burning sunburn in childhood or adolescence can also double your risk.

The American Cancer Society predicts 97,610 new melanoma diagnoses in the US this year, and that 7,990 people will die from the disease. Early detection of melanoma increases the chances of survival.

The latest on UV damage from LED nail dryers

Recent research also suggests that LED UV nail polish dryers can alter skin cells at the molecular level, potentially leading to fingertip skin cancer. Reports of such cancers in people using gel polish prompted the investigation.

Dermatologist dr. However, Beth G. Goldstein, who was not involved in this research, said it “clearly documents damage to the cell lines that caused extensive oxidative damage and leads to cellular markers seen in skin cancer.”

While dr. Goldstein said that while further epidemiological study is needed to fully understand the risk of nail polish dryers, it may be a good idea to use them less often:

“Infrequent use a few times a year is probably not that much of a concern, maybe, [as] used every two weeks, which is not unusual.”

“There are alternative nail products, such as dipping powder, or options that do not require UV light for curing, and will not cause skin damage, as one might think can happen with these devices,” said Dr. Goldstein said.

In 2021, approximately 6.05 million tons of grapes were produced in the US. Grapes have been shown to play a positive role in “atherosclerosis, inflammation, cancer, gastrointestinal health, central nervous system effects, osteoarthritis, urinary bladder function and vision,” according to the new study.

Lead author of the study, dr. John Pezzuto, a professor and dean at Western New England University in Springfield, Massachusetts, explained his interest in the study of grapes to Medical News Today.

“Many years ago I had a seminal paper describe the potential of resveratrol to mediate anti-inflammatory activity and prevent skin cancer in model systems,” he recalls.

“In addition to relatively low amounts of resveratrol, grapes contain numerous additional phytochemicals, so it is reasonable to investigate the health benefits of the grape as a whole food,” he added.

Studies of grapes’ role as a protector against skin cancer date back a decade or more, with the first human trials conducted in 2021. The new study is an extension and confirmation of this earlier work.

For the current study, 36 people were enrolled, of whom 7 (19%) dropped out, leaving 29 participants with complete data. Thirteen were female and 16 male – their ages ranged from 24 to 55.7 years.

The group was mainly white (21 people), and the rest were Hispanic. The authors report that 25 participants had a type III, while the rest had type II.

The trial began with a two-week restricted diet period. This was followed by a two-week study period during which individuals prepared two 36-gram packets of freeze-dried, crushed and seedless red, green and black grapes each day. This is the equivalent of three portions of grapes (378g in total).

The participants provided fecal, urine and blood samples to researchers at the end of the restricted diet period, the end of the grape eating period and one month after. The researchers also applied UV radiation sensitivity tests at each of these times.

The resulting analysis found that nine participants showed reduced sensitivity to UV exposure at the end of the grape eating period. For three of them, the effect was still present a month later.

The findings of the study were similar, but not the same, as the 2021 study. The authors speculate that differences in Fitzpatrick skin types are responsible and that people with lighter skin types may obtain greater UV protection from grapes.

The researchers looked for differences in the samples from the people on whom grapes had no effect, the people who developed short-term resistance to UV radiation, and those who maintained resistance longer. They hoped to explain why participants reacted differently.

“People who showed greater resistance to UV radiation showed the most profound differences in their microbiome,” Dr. Pezzuto said.

The study says that the nine people who achieved UV resistance “were clearly distinguished from the remaining 20 volunteers by metabolomic analyzes as well as microbiomic analyses.”

Dr. Pezzuto added that, for example, there was a perfect correlation between resistance to UV radiation and a reduction in a urinary metabolite indicative of UV-induced skin damage.

While he noted that it is impossible to establish a cause-and-effect relationship with this study, “this strong correlation appears to be more than a coincidence. Additional research would be important.”

Dr. Pezzuto cautioned that his study “does not suggest that people should be careless and, for example, avoid using sunscreen.”

“The broader significance of this work, in my opinion, is the ability of human grape consumption to strengthen our cellular systems that defend us against free radicals and reactive oxygen species that can lead to adverse effects.”
– Dr. John Pezzuto