I was fascinated when a friend of mine went back to India for a month. He is a medium/dark I guess you would say average skin toned person of that area of the world. He was living in St. John's Newfoundland which if you don't know is 10+- miles from the most eastern point of North America. They have 3 types of weather there, rain, drizzle and fog. I remember seeing months where the amount of sun for an entire month of June (summer there) was reported as 90 hours in the local newspaper. He had been there for about 2-3 years, so he was starting to look like a honky
Anyways when he got back to St. John's he was telling about his trip there and he went on about how he had a bad sunburn just after arriving there.
That was a shock to me that a dark skinned person got sunburns. Another theory shattered.
Getting back to the subject of sun exposure, this year I have been walking around in my shorts with no shirt and no shoes or socks. I started the raw diet last December and I started sungazing last July (year ago) so I am not sure which thing is the cause of the change, but for instance on my skin, I used to have spots up to slightly less that 1/4 inch. Not everywhere and it's a family tradition. They have been slowly disappearing. They almost fall off at times or if I scratch them they come off. It's quite amazing! I also had bumps on my skin here and there, most were not noticeable except to myself. They are slowly disappearing. (BTW I am 57)
In those books I quoted, the authors tell about treatment for TB that took place in Switzerland and Norway in the 1800s and early 1900s that was essentially exposure to sunlight and fresh air high in the Alps where it was felt that the sun's rays did not have to travel through the atmosphere as far so the rays were stronger in the appropriate wavelengths to bring about the return of health to the patients. This treatment modality was prevalent right up to the start of the start of the use of antibiotics and vaccinations and was apparently quite effective if you had the money and time to travel to Switzerland, plus a spare pair of leather shorts. Course you buy the shorts and the long horn once you got there.
The patients were put into the sun in measured periods of time according to a treatment concept they worked up. Of course the nice sunny fresh air environment of the Alps didn't hurt either.
I strongly believe that sun exposure and raw diet are critical to health.