>nudist: Excellent idea! As for not so pretty, that's other people's problem, not yours. But in an indecent exposure trial, I think I would go with "freedom of religion" instead of "Seeking good health".

Some vitamins you just piss out any excess. I suppose too much Vitamin C could give you heartburn, but that would be several grams per day. Vitamins A and D are not like that. Beyond a certain point, more is bad, and way more is deadly. For example, humans can't eat much polar bear liver without dying from Vitamin A poisoning.

That doc who's blog I linked had a very interesting theory: When humans migrated North from Africa, they turned White. Why? Probably because the Black kids died from lack of Vitamin D. The lighter ones got enough and lived through epidemics. He couldn't think of any other evolutionary advantage of losing melanin. Of course some biologist looking at brightly-colored tropical birds found that being more attractive to potential mates can be a selective advantage. But the Vitamin D theory is a little more compelling than "Gentlemen Prefer Blondes".

The Hardy-Weinberg equilibrium says that the frequency of a particular gene in a population will remain stable unless there is some strong pressure to get rid of it. This is why we have different blood types, different eye color, etc. There has to be some very strong pressure for there to be essentially zero Black people in Nordic populations before we started traveling about in modern times. If it was weaker, you would expect a HW equilibrium point higher that zero.