Sun, skin, vitamin D and the gut flora

https://www.frontiersin.org/articles/10.3389/fmicb.2019.02410/full

This is the first study that reports changes in the human gut microbiota in response to UVB light. As decreased exposure to UVB light and subsequent decreased vitamin D production has been suggested to take part in the current rise in chronic inflammatory diseases, the fact that gut microbiota composition could also be a piece in this puzzle opens new avenues for research that needs to be validated in larger cohorts.

https://onlinelibrary.wiley.com/doi/full/10.1111/imm.12939