The first two articles I get from that search looks at vitamin d and the older population, and the third[1] suggests that even in sub-arctic elevations "Adequate levels were found in 79.2%, more often in women (82.7%) than in men (75.6%). Only 0.7% of the population were vitamin D3–deficient but 23.1% of men and 17.1% of women had insufficient levels." That doesn't seem too damning.
At the end of the day I don't know enough, so I'm not making the claim about Vitamin D quantities, but isn't the evidence that there was at least some form of adaptation evident based upon skin tone alone?