If too much exposure to the sun causes cancer, how are there still any fair-skinned people on earth? For the vast majority of human history, we didn’t have sunblock. Shouldn’t we gingers be extinct by now?

Question

If too much exposure to the sun causes cancer, how are there still any fair-skinned people on earth? For the vast majority of human history, we didn’t have sunblock. Shouldn’t we gingers be extinct by now?

In: Biology

Answer 1

Fair skinned people produce more vitamin D then dark skinned people when exposed to the same levels of sunlight. So the same way that fair skinned people have a higher risk of cancer by living in the low latitudes dark skinned people have had a traditionally higher risk of vitamin D deficiency by living in the high latitudes.