theory on why Europeans are so white

All meats have some vitamin D. Fish have very high amounts. But grains have no vitamin D at all. People who eat grains do not get vitamin D from food; they must get it from sunlight. This usually works out fine because grains grow only where it is warm. And this means only in latitudes with bright sunlight, with one exception. People who live in low latitudes, where they can live off grains, get plenty of sunlight. People who live in dim sunlight cannot grow grains, and so they get vitamin D from the meat and fish that they eat. The exception? There is only one spot on the planet where grains will grow despite sub-arctic sunlight. It is where the warm waters of the Gulf Stream wash ashore. The Baltic is the only place on earth where ocean currents keep it warm enough to grow grain despite dim sunlight. When the inhabitants of this region switched to grain about 6 KYA, they suddenly got insufficient vitamin D to survive. They had stopped eating mostly meat and fish in a place where sunlight was too dim to produce vitamin D in normally pigmented skin. And so they adapted by retaining into adulthood the infantile trait of extreme paleness.


taken from: http://knol.google.com/k/why-are-europeans-white-e1#




another interesting article:

http://www.npr.org/templates/story/story.php?storyId=100057939