Sun-seeking behaviors while on vacation may affect the skin’s microbiome, new research suggests.

Prior to vacations to sunny destinations, which lasted at least seven days, the researchers analyzed participants’ skin. On day one, 28, and 84 post-holiday, participants’ skin microbiota was assessed again.

Additionally, each person was assigned a group based on individual tanning response. Eight out of 21 participants, who picked up a tan while on holiday, were deemed ‘seekers.’ The ‘tanned’ group was made up of seven individuals who already had a tan at departure and kept it throughout their holiday. These two groups were classified as ‘sun-seekers.’ The remaining six participants were deemed ‘avoiders;’ their skin tone was the same pre- and post-holiday.

“We have demonstrated that the development of a tan is associated with lower Proteobacteria abundance immediately post-holiday,” says study author Dr Abigail Langton of The University of Manchester in Manchester, UK, in a news release. “However, the microbiota of all holidaymakers was recovered a few weeks after they stopped spending extended time periods in the sun.”

Tanning response – even over a relatively short sunny period – can lead to an acute reduction in Proteobacteria abundance, which decreased skin microbiota diversity.

Despite the rapid reduction of Proteobacteria and the accompanying shift in skin microbiota diversity, the bacterial community structure had recovered 28 days after individuals had returned from vacation, the study found.

“Proteobacteria dominate the skin microbiota. Accordingly, it is not surprising that there would be rapid recovery of the microbiota to re-establish optimal functioning conditions for the skin,” Langton adds. The authors state that what might be more concerning is the rapid alteration of microbiota diversity, which has been linked to disease states. A decrease in skin bacterial richness, for example, has been previously associated with dermatitis. Fluctuation in Proteobacteria diversity specifically has been associated with skin problems like eczema and psoriasis.

Future studies should examine why Proteobacteria seem to be particularly sensitive to ultraviolet radiation and how this change in diversity impacts skin health in the longer term, the researchers noted. “Ideally, such studies will aim to increase the number of participants to allow further insights,” Langton says.

The study appears inFrontiers in Aging.