For Summer's First Full Day: The Science Of Skin Color And Vitamin D

discoverynews:

During a TED talk in 2009, anthropologist Nina Jablonski told her audience, “You have the evolution of the history of our species, part of it, written in your skin. Understand it, appreciate it, celebrate it. You are the products of evolution.”

It’s a beautiful thought, and an apt one to consider on this first full day of Vitamin D season, otherwise known as summer. To understand why there’s a diversity of skin colors in the world today does connect us to our evolution and illuminates some reasons for high levels of Vitamin D deficiency in some modern populations.

The human lineage originated, and first flourished biologically and culturally, in Africa. Evolutionarily, each of us is African; the first people had darkly pigmented skin and were thus well-adapted to handle the high levels of UVR (ultraviolet radiation) in equatorial regions.

As Jablonski explains in her talk, UVR has both benefits and costs for the human body. On the plus side, when it strikes the skin it catalyzes Vitamin D, which is essential for bone and immune health; on the minus side, it can cause DNA damage and skin cancers. In ancient Africa, melanin acted as a natural sun screen to protect people from the dangers while still allowing the benefits of Vitamin D synthesis from the sun.

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