bTeam Scientists have demonstrated that excessive sun exposure can have a negative impact on the short-term diversity and composition of the skin’s bacterial community. The skin, being the body’s largest organ, hosts a wide array of bacteria, fungi, and viruses that collectively constitute the skin microbiota. These microorganisms play a crucial role in defending against harmful pathogens and contribute to maintaining skin health. Despite the known risks of extended ultraviolet (UVR) exposure, such as DNA damage, skin inflammation, and premature aging, many individuals still actively seek out sun exposure.
Given the scarcity of research addressing how individual behaviors affect UVR-induced shifts in the skin’s microbiota and their implications for skin health, a group of researchers in the UK conducted a study to investigate the impact of sun-seeking behaviors on the skin’s microbiota composition in holidaymakers. Dr. Abigail Langton, the lead investigator at the University of Manchester and the corresponding author of the study published in Frontiers in Aging, stated, “Here, we demonstrate that the sun exposure behavior of holidaymakers significantly influences the diversity and composition of their skin microbiota. We found that the development of a tan is associated with reduced abundance of Proteobacteria immediately after the holiday, but the microbiota of all holidaymakers returned to normal a few weeks after their sun exposure ended.”
Before embarking on vacations to sunny destinations lasting at least seven days, the researchers analyzed the participants’ skin microbiota. The skin microbiota primarily consists of three bacterial groups on the skin’s surface: Actinobacteria, Proteobacteria, and Firmicutes. The researchers assessed the participants’ skin microbiota on day one, day 28, and day 84 after their holidays.
The participants were categorized into three groups based on their tanning responses. Eight out of 21 participants who developed a tan during their vacation were classified as ‘seekers.’ The ‘tanned’ group consisted of seven individuals who already had a tan before their vacation and maintained it throughout. These two groups were collectively labeled ‘sun-seekers.’ The remaining six participants, whose skin tone remained the same before and after the holiday, were labeled ‘avoiders.’
Dr. Thomas Willmott, the study’s first author and a researcher at the University of Manchester, explained, “This study was conducted with real-life holidaymakers and offers valuable insights into how sun exposure, even over a relatively short period, can lead to a significant reduction in Proteobacteria abundance and a decrease in skin microbiota diversity.” Despite the rapid decrease in Proteobacteria and the resulting change in skin microbiota diversity, the bacterial community structure had returned to normal 28 days after individuals returned from their vacation. Willmott continued, “This suggests that UV exposure during a holiday has an immediate impact on the skin microbiota, but recovery is relatively quick once the person returns to a less sunny environment.”
The authors of the study noted that the rapid alteration in microbiota diversity is of particular concern, as it has been linked to various skin conditions. A decrease in bacterial richness on the skin’s surface, for example, has been associated with dermatitis. Changes in the diversity of Proteobacteria specifically have been linked to skin issues like eczema and psoriasis.
The researchers emphasized the need for future studies to explore why Proteobacteria appear to be particularly sensitive to UVR and how these diversity changes affect long-term skin health. Dr. Langton noted, “Ideally, such studies should involve a larger number of participants to provide further insights.”
It’s worth mentioning that this study was funded by the No7 Beauty Company.
