Sun, Skin & Melanin - it all began in Africa!

Why did we actually need to protect ourselves from the sun?

Once upon a time, roughly 2 million years ago, we were a hairy race- mostly lots of fur with potentially pale skin beneath. But as we expanded to hunt out in the African savannah, especially in the day, the fur was not comfortable, and we experienced overheating. Following this, a new system of heat regulation came in, which made us lose our fur. Without fur, we needed something else to protect us from sunlight.

Enter melanin, an advanced photoprotection system, which made it possible for humans to hunt under the sun more efficiently, which made us increase in numbers, thanks to better access to resources, food essentially.

However, this also meant more competition, and some of us had to migrate away to colder places with lesser UV. Also, some of the melanin had to be dropped along the way, to continue to maintain skin physiological functions such as Vitamin D and folate metabolism with lesser UV inputs. Result: lighter skinned humans, in regions with lower UV radiation.

There are several versions and twists to the above plot, including one that states that everything started with one fair skinned ancestor, but most of us go with the vitamin D storyline. Now that we have mentioned Vitamin D, do sunscreens cause vitamin D deficiency? We will get to the answer soon!