Surprised no one is mentioning vitamin D. As I understood it, sun exposure is one of the few ways the body is supplied with this vitamin in a usable form. Vita

Surprised no one is mentioning vitamin D. As I understood it, sun exposure is one of the few ways the body is supplied with this vitamin in a usable form. Vitamin D is essential for the immune system so a correlation between a lack of sun exposure and ill-health seems almost so obvious it's a wonder it needs studying. What would be useful is the exact parameters around sun exposure/vit D metabolism.