Uriah

But the group that stands apart from their close neighbors in all these ways the most starkly are the Irish. However, they’re very different from the all populations mentioned so far: way up north, little sunlight, not much fish consumption now or in the past.

The primary clue to uncovering what’s happened is that the Irish represent a European extreme in two other ways: unexposed skin that is lighter than any European people, even Scandinavians, and a continent high frequency of hemochromatosis (iron overload).

Both of these distinctive features act to preserve bone health under conditions of very high rainfall and little sunlight. Those with light skin are able to produce more Vitamin D after exposure to sunlight than the competition: https://www.researchgate.net/profile/Etienne_Cavalier/publication/258054176_Skin_Color_Is_Relevant_to_Vitamin_D_Synthesis/links/544a06e60cf2ea65413426e5/Skin-Color-Is-Relevant-to-Vitamin-D-Synthesis.pdf …

I think Ireland and Iceland, both rain soaked and sunless, may be the only two places on earth where alcoholism was selected for because consumption linearly increases ferritin stores in blood. An old farmer may have found it easier to get a hold of booze than animal protein.

Icelanders don’t have problem drinking rates higher than other Europeans, but this is confounded by the fact that they enforced prohibition until NINETEEN EIGHTY-NINE. I don’t think they were just being sticklers: there is something funny going on here.

But circling back to the main point: In Coon’s The Races of Europe I believe the Irish are the only group singled out for the thickness of their bones and part of the mechanism has probably been a ruthless selection for both light skin and high baseline levels of Vitamin D.

D helps protect Irishmen against rickets and inflammatory diseases, but an expected benefit of the selection was this it provided them with a stronger immunity to schizophrenia than any other North European people. Psychotism is a plus if your body can handle it and they could.