Too bad that the 503 article didn't mention Vitamin D at all. Where exactly is the sweet spot? Leaving sun screen aside (as that seems to only prolong the time

Too bad that the 503 article didn't mention Vitamin D at all. Where exactly is the sweet spot? Leaving sun screen aside (as that seems to only prolong the time you need to stay in the sun for an effect, good or negative). I suspect the number of minutes you should stay in the sun per day is > 0. But how high is it?