Short and intense exposure to the sun modifies the composition and diversity of the skin microbiota.
- Tanning over a relatively short sunny period is associated with a lower abundance of proteobacteria immediately after vacation.
- A few weeks after the stay in the sun, the structure of the bacterial community has recovered
- The rapid alteration in skin microbiota diversity may be linked to disease states, such as eczema and psoriasis.
The skin is home to a large number and wide range of microorganisms, namely bacteria, fungi and viruses, which protect us against pathogens. “Ultraviolet radiation can impact this skin microbiota through direct and indirect mechanisms,” said researchers from the University of Manchester (England). However, there is little research on the influence of individual behaviors on microbiota changes associated with UV radiation. This is why the scientists wanted to analyze the effects of sun exposure on the skin microbiota.
The skin microbiota is made up of three bacterial communities
In one study, researchers recruited 21 healthy people. Before their stay in sunny destinations, which lasted at least seven days, the team analyzed the participants’ skin. Then, skin samples were taken on the 28th and 84th day after their vacation. You should know that the microbiota of the skin is mainly made up of three surface bacterial communities: actinobacteria, proteobacteria and Firmicutes.
The volunteers were classified according to their tanning behavior. Eight of the 21 adults, who tanned while on vacation, were deemed to be sun-seekers. The “tanned” group was made up of seven people who were already tanned when they left and who kept it throughout their vacation. The other participants were considered people who avoided exposure to the sun. Their complexion was the same before and after the holidays.
Skin microbiota: rapid reduction of proteobacteria after sun exposure
“A significant change in microbial beta diversity was observed at 28e day after the holidays, compared to the starting situation, for all participants”, reported the researchers. Specifically, a rapid reduction in proteobacteria was seen immediately after vacation in adults who sought sun exposure.
According to the results, published in the journal Frontiers in Agingbacterial community structure recovered over time. “This indicates that UV exposure while on vacation has an acute effect on skin microbiota, but recovery is relatively rapid once the person returns to a less sunny climate,” said Thomas Willmott, author of the study, in a statement.
Disruption of skin microbiota can lead to health problems
“Proteobacteria dominate the skin microbiota. It is therefore not surprising that the microbiota quickly replenishes itself to restore the optimal functioning conditions of the skin”, explained Abigail Langton, co-author of the work. What could be of more concern, the team says, is the rapid alteration in microbiota diversity, which has been linked to disease states. “For example, a decrease in the bacterial richness of the skin has previously been associated with dermatitis. The fluctuation in the diversity of proteobacteria has been correlated with skin problems, such as eczema and psoriasis.”
