Sunbathing Could Ruin Your Skin Microbiome

Throughout the summer, we are constantly reminded of the cancer risks and accelerated aging brought on by spending too much time in the sun. But did you know that sun exposure can also disrupt your skin's microbiome?

In a recent study, published in the journal Frontiers in Aging, researchers from the University of Manchester in the U.K. demonstrated that a week-long vacation in the sun can significantly impact the delicate balance of microbes on our skin's surface that is important to skin health.

"Skin is colonized by a diverse microbiota that play essential roles in the maintenance of skin homeostasis [balance], protecting skin against invading pathogens and coordinating the innate and adaptive arms of the cutaneous immune system," Abigail Langton, who led the study, told Newsweek.

"Microbiota colonisation of the skin begins at birth and its composition is determined by several intrinsic and extrinsic factors—[like] lifestyle, hygiene routine, cosmetic use, antibiotics, geographical location, climate, and seasonality."

In the recent study, Langton and her team analyzed the skin microbiomes of 21 healthy volunteers before and after they went on vacation. The volunteers were divided into three groups—those who were tanned before the vacation and continued to tan throughout their trip; those who picked up a tan while on vacation; and those who avoided tanning and going into the sun.

The microbes present on the participants' skin were measured prior to the vacation and then 1, 28 and 84 days post-vacation.

Those who developed a tan while on vacation showed lower levels of "good" skin bacteria after returning home. Specifically, there was a reduction in Proteobacteria, a group of microbes commonly found on healthy skin.

"[Proteobacteria are] particularly interesting because a disturbed Proteobacteria microbiota has been previously associated with skin conditions such as psoriasis, eczema and diabetic foot ulcers," Langton said.

"Those individuals that avoided developing a tan ('sun avoiders') were the only ones that maintained a diverse skin microbiota post-holiday," Langton said, adding that it remained unclear why Proteobacteria were particularly sensitive to ultraviolet radiation.

Luckily, the skin microbiomes of these participants returned to normal fairly rapidly, after about 28 days post-vacation. "However, during this 28-day post-holiday period of recovery, skin may have reduced health making it more susceptible to infection or irritation due to the loss of Proteobacteria and the overall change in skin microbiota balance," Langton said.

This particular study was conducted on white British holidaymakers, but Langton said that they hoped to extend the project to explore the impacts of sunlight on the skin microbiome for a wider range of skin tones.

Ultimately, protecting your skin from the sun is important no matter your skin tone. "Practising sun safety is important for everyone including wearing broad-spectrum sunscreen and finding some shade whenever possible, but especially in the middle of the day, between 11 a.m. and 3 p.m., when the sun is at its strongest," Langton said.

When it comes to protecting your skin microbiome, your skincare routine matters.

"The most important thing for healthy skin is to maintain your skin barrier by avoiding overly harsh ingredients or overuse of products such as exfoliants and retinoids," Langton said. "These products can strip the skin and break down the barrier rather than building it up. Barrier-supporting ingredients such as ceramides, hyaluronic acid, and squalene are particularly useful to help improve overall skin health and keep the microbiome in balance."