A sunscreen can help prevent sunburn and a healthy skin can be preserved when exposed to the sun, a new study finds.
The findings, published in the journal Nature, could lead to a safer and more effective sunscreen, which can also reduce the risk of skin cancer.
Researchers from Columbia University in New York City and the University of California, Berkeley, recruited more than 2,000 healthy adults who had never been diagnosed with sunburn or skin cancer, and gave them a sunscreen for five days before the study began.
After the sun exposure, the participants were asked to apply a 10- to 20-minute application of either a natural or synthetic sunscreen.
The study also tested the effectiveness of sunscreen in preventing skin cancer by measuring levels of the sunscreen in their skin.
The researchers found that the sunscreen applied for five consecutive days after the sun protection had stopped produced lower levels of UV-A and UV-B, which are the types of harmful UV rays that cause sunburn.
“The findings suggest that a sunscreen applied five days after sun exposure can help to reduce the risks of skin cancers and may also prevent sun damage in skin cells,” said the study’s lead author, Dr. John R. Farrar, a professor of dermatology and skin science at Columbia.
Farsolv also noted that the study was the first to find that sunscreen applied in the morning, after sun protection was gone, produced less UV-D, which is harmful to human skin.
“This study is important for two reasons,” said Farsalov, who was also an author of the previous study.
“First, the sunburn protection we observed for this study lasted longer than the typical time between sun exposure and skin damage, which means that this protection is much longer lasting than sun exposure alone.”
The second reason, he said, is that the sun-protecting effect lasted longer and produced less skin damage than when sun protection is done at night, which may have been the intention of the researchers.
The sun-protective effects were also more pronounced in women, who have higher levels of circulating vitamin D. A study published last year found that vitamin D protects against UV-induced damage to human cells.
“We know that vitamin A and vitamin D are both needed to protect cells from UV-radiation, and they protect cells when they are exposed to UV-R wavelengths, but they do not protect cells during the day,” said Dr. David B. Stegner, a dermatologist and director of the department of dermatologic research at Children’s Hospital Los Angeles.
“It’s not a simple question, but the idea that vitamin C can protect cells against UV rays is very plausible.”
Farser said it was important to look beyond sun protection alone to determine whether a sunscreen was more effective.
“I think it’s really important to think about whether a sun-protected person has a higher exposure to UV, and if so, to look at their daily exposure,” he said.
“Sun protection, in particular, can be a very good source of vitamin D, which protects cells from damage and is essential for maintaining a healthy immune system.
Vitamin D plays a key role in controlling UV-related damage to the skin and may prevent skin cancer.”
Dr. Stebner said sunscreen use was not limited to people with cancer, although that was the case for some participants in the current study.
He said he was “surprised” that participants in this study were still reporting sunburn after they stopped using sunscreen.
“There’s a lot of evidence that there are many things that we know about sunscreen that can be used to prevent sun exposure in people with skin cancer,” he told ABC News.
“But if you have an inflammatory skin condition that’s affecting your skin and you’re exposed to sun, you may want to consider using sunscreen as a first line of defense.”
There is no evidence that using sunscreen during a sunburn episode reduces the risk for sunburn in people without skin cancer who are already well protected from UV,” he added.
“As you age, the skin becomes more sensitive to UV radiation. “
If we really are concerned about the safety of the sun in this day and age, we need to start thinking about the consequences of using sunscreen, and the health benefits of sunscreen,” he explained.
“As you age, the skin becomes more sensitive to UV radiation.
The more UV-protected your skin, the more UV radiation you can absorb.”
Farrasol said the current findings showed that the protective effects of sun protection could be seen even for people who had not developed skin cancer or had skin cancer in the past.
“A sunscreen can be really good for the skin, but it can also be harmful,” he suggested.
“In this study, the results show that if you are using sunscreen every day and have a