The Philadelphia Inquirer on Sunday printed one of the best stories to date explaining in anthropologic terms why humans tan and why sunlight is natural and intended.
“At the beginning of anthropologist Nina Jablonski’s lecture yesterday at the Wagner Free Institute of Science, it appeared her audience of about 100 was composed of several different races,” the Inquirer wrote. “By the end of the free lecture, titled ‘The Evolution of Human Skin Color,’ the Pennsylvania State University professor had made a case that we are all just people with varying levels of melanin.”
The Inquirer continued, “As author of the book Skin: A Natural History, Jablonski has studied all aspects of skin, perhaps none more important than why it appears in such a puzzling array of hues. It all comes down to the planet’s uneven distribution of sunlight and the universal human need for two vitamins, she explained. This knowledge was very recently acquired. ‘Only in the last decade or so has our data allowed us to crack open the mystery,’ Jablonski said as she began her lecture at the 152-year-old science museum near Temple University.”
Joblonski’s lecture brought into focus one of Smart Tan’s major points: That tanning is no accident and is a natural and intended part of natural life under the sun.
The Inquirer article continued, “Nature has painted human skin using one major brown pigment, melanin, which evolved in many species. ‘It’s a natural sunscreen,’ she said, which is important because humans have a troubled relationship with the sun. Since we are relatively hairless creatures, our skin gets bombarded by ultraviolet light, which can burn us, destroy the DNA in skin cells, and lead to cancer. Hence an advantage of dark skin.”
“But there is more to melanin than protection from skin cancer and sunburn. Scientists recently realized that ultraviolet rays penetrating skin destroy the B-vitamin folate. With too little folate, or folic acid, men cannot make adequate sperm and women cannot start healthy pregnancies. So in very sunny places, any genetic mutations that created light skin would likely die out with their owners. But with melanin offering so many advantages, the question was why anyone would evolve light skin.Lighter shades came about because humans need some sunlight to penetrate skin and trigger a chemical reaction that produces vitamin D.”