One of my longstanding beliefs is that whenever a cheap and widely available therapy exists, the medical system is incentivized to bury it, as lucrative markets emerge once its benefits are no longer there. Natural light is one of the clearest examples of this. Despite over a century of research supporting it, a wide range of medical devices which work by putting specific wavelengths of light into the body (the most remarkable of which, ultraviolet blood irradiation, is discussed here https://www.midwesterndoctor.com/p/the-century-of-evidence-putting-light), and most importantly, people simply feeling better in natural light, its importance has been almost completely dismissed by the medical profession, and we have instead been subjected to ever increasing amounts of unhealthy light (often without any say in the matter).
Finish reading: https://open.substack.com/pub/amidwesterndoctor/p/the-hidden-harms-of-modern-lighting