Skin exposure to sunlight: a factor modulating the human gut microbiome composition

Abstract

Background: The gut microbiome has been increasingly acknowledged as playing a pivotal role in human health. Therefore, a number of studies have focused on variables that impact its microbial structure and consequent functionality. A wide range of factors, such as diet, age, sex, life stage, behavior, ethnicity, and diseases have been considered, and strong links were set out. However, some aspects regarding the microbiome determinants are still under-explored. Discussion: Recently, Bosman et al. presented evidence that skin exposure to narrowband UVB light modulated the gut microbiome of a specific human cohort. This cohort presented an increase of biodiversity, Firmicutes and Proteobacteria, and a decrease of Bacteroidetes. Based on these findings, we revisited our data on a hunter-gatherer gut microbiome (Yanomami) and identified similarities in the gut microbiome of these two cohorts. Both presented a high abundance of Proteobacteria, which had been observed as a unique feature in the Yanomami gut microbiome, and based on Bosman et al study, could be associated with their natural sunlight exposure. Conclusion: In this commentary, we would like to point out that the human lifestyle concerning sunlight exposure should be considered as one force modulating the gut microbiome, highlighting, as proposed by Bosman et al, a novel skin-gut axis which is associated with health and disease.

Review of the relationship and underlying mechanisms between the Qinghai–Tibet plateau and host intestinal flora

“…After three rounds of ultraviolet radiation in a week, the alpha and beta diversities of bacteria in the intestinal tract of females increased, and the number of multiple bacterial genera changed ( Bosman et al, 2019 ). Furthermore, excessive ultraviolet radiation to the human body can lead to the emergence of intestinal flora in the thick wall of the phylum, increased deformation of the phylum, and a reduction in Bacteroides ( Conteville and Vicente, 2020 ). Ghaly et al (2018) found similar changes in the intestinal tract of mice exposed to high levels of ultraviolet light.…”

The aryl hydrocarbon receptor at the forefront of host‐microbe interactions in the skin: A perspective on current knowledge gaps and directions for future research and therapeutic applications

“…All barrier organs, and, in particular, the skin are continuously challenged by the exposome (or the collection of all environmental factors impacting human health) which also impacts the microbiome in its composition and metabolism, exemplified by dietary intake, 27 environmental pollution 28 , 29 and UV exposure. 30 , 31 Epidemiological and experimental studies on exposome‐associated AHR ligands (eg certain pollutants and dietary compounds, or UV radiation‐generated endogenous tryptophan metabolites) and signalling thus need to consider the additional influence of exposome‐mediated alterations in the microbiome and changes in microbial‐derived AHR ligands thereof.…”

The power and potential of BIOMAP to elucidate host‐microbiome interplay in skin inflammatory diseases

“…98 Narrowband UVB and natural sunlight exposure on the skin may even modulate the gut microbiome. 99,100 The skin, gut and household microbiome varies amongst populations living in regions with the same latitude, but varying levels of urbanization. These changes, particularly changes in the mycobiome, are associated with availability of household cleaning products and dwelling type.…”