How to get some: About 20 minutes of daily sunshine on 40% of exposed skin produces ample vitamin D in general, but such estimates are gross generalities. Dark-skinned people need more exposure to produce the same amount of the vitamin.
Robert Roy Britt
Interesting, given so many people are probably vitamin D deficient. Question: given I live about as far north as you can get in the continental United States, does that 20 minutes of exposure count when we’re near the winter solstice and sunlight is very oblique?
Just wondering if my daily dog walking does the trick.