Humans evolved to spend our days hunting and gathering in the great outdoors, getting plenty of exercise, excitement, camaraderie, fresh air and sun. Those were the good old days when the best things in life were free, including a flood of summer sunlight that created as much vitamin D as it penetrated our bare skin as we would need all year round.  But we moved further and further from the equator, where sunlight is most abundant, and began spending more and more of our lives indoors. We adopted a less healthy diet with fewer and fewer fresh fruits and vegetables with their antioxidants that protected us from potential damage by the sun, and medical authorities began recommending sun avoidance and sunscreens, the weakest of which (PF8) block 95% of the sun’s vitamin-D producing UVB rays. (See here on using the sun intelligently to still get free vitamin D.) Vitamin D deficiency is now so widespread that alternative doctors say virtually every new pa…