In high-latitude environments with less intense sunlight, darker skin can result in vitamin D deficiency, especially when the diet no longer provides adequate vitamin D from animal sources (as it would have for hunter-gatherers eating abundant fish, meat, and fatty foods).

When agricultural populations shifted to grain-based diets that were lower in vitamin D, the selection pressure for lighter skin increased, and over several thousand years, lighter skin genes became increasingly prevalent in European populations.

Ötzi, living in the Copper Age, predated much of this evolutionary transition.

He was darker-skinned than the popular image suggested — darker, in fact, than many modern Europeans.

His appearance would likely have been striking and unfamiliar to those accustomed to picturing an ancient Alpine man as a light-skinned proto-European.