Mounting research confirms that sun avoidance may be at the heart of a large number of health problems. Not only does your body produce vitamin D in response to sun exposure on bare skin, but sunlight also produces a number of other health benefits that are unrelated to vitamin D production.
In fact, humans appear to have a lot in common with plants in this regard — we both need direct sun exposure in order to optimally thrive, and while artificial lighting sources offering specific light spectrums may be helpful for various problems, ideally we need the full spectrum of light that natural sunlight offers.
