a little off topic but clarafication on previous post...
We share over 98% of the same DNA as chimpanzees and bonobos (old world primates) and in the wild they maintain serum levels of vitamin D in the 120 ng/ml range;
Dr. Reinhold Vieth presentation
You can see how the serum levels of lifeguards who better conform to the primative lifestyles of humans have serum levels of vitamin D akin to wild old world primates above.
Due to indoor lifestyles, sunscreen, and skin cancer scare campaigns modern humans have much lower serum vitmain D ranges and higher incidences of vitmain D deficiecny and vitamin D deficiency disease and disorders.
In regards to "trade-off" there is a sine-wave for natural serum vitmain D and new science is placing it in the 60-80 ng/ml, range but then most modern humans(%75) are below 30 ng/ml.
You can see what is considered "Normal" in Toronto, but then when you sample 1,000 people who are vitamin D deficient to begin with, the "normal" rating will obviously be a deficient number. This is the same problem with a fusion solar model. When you base your observaton in flawed thinking or basis your conclusions are wrong.
The serum levels of wild old world primates and lifeguards is empirical data that cannot be ignored.
I suspect those healthy range numbers will continually creep into the natural serum ranges exhibited by wild primates and humans with outdoor lifestyles exposing skin to sunlight.