Today, looking in the mirror, I realized that I'm not nearly as white as I should be, or that I remember being. I'm normally white as a ghost. "Why should this be?" I wondered. Why do I look darker than typical? Lately, for the past few months, I've gotten in the habit of taking vitamin supplements. Daily, I take a multivitamin and a few soft gels of fish oil. Could this have anything to do with it? Here's what I'm thinking. Black people have dark skin because the pigment protects the skin from the harmful effects of the sun. Blacks, like all humans, require vitamin D to survive; however, in the geography in which they evolved, the sun is very powerful and is strong enough to penetrate their skin so they can produce the needed vitamin D. The dark skin protects from skin damage as well as preventing their bodies from overproducing vitamin D. Whites and Orientals, however, evolved in a geography where solar radiation is less intense. The weaker sun doesn't provide enough power to promote vitamin D production for people with dark skin, so naturally, the skin color lightened. People with dark skin, regardless of geography, will be more resistant to sun damaged skin/skin cancer. However, it's a trade-off between protection from cancer and the ability to produce vitamin D. Obviously, vitamin D is important enough, because white people exist. But what about those whom the trade-off doesn't apply to? What about the people who get vitamin D from their food, such as the Inuits and Yupik? Those people live in very light-deprived places, and yet their skin colors are dark. Their dark skin protects them from the sun, and they don't need light skin to help with vitamin D production because they already get it from the food they eat. Now, here's what I'm getting at. We know that for humans, being exposed to the sun for a duration will have the effect of darkening the skin, regardless of the ethnicity. Yes, even black people can get tans. Whites, Orientals, Hispanics, blacks--all people get darker skin when exposed to the sun for a duration. But does it go the other way as well? Can you get a tan, not due to exposure of sunlight, but due to a diet with increased quantities of vitamin D? Works on the same idea, really. People get tans due to increased exposure to sun because they do not need as much sun as they're getting to produce the requisite vitamin D and it also protects the skin. If you increased your dietary intake of vitamin D, your skin might darken for the same reason. Your body doesn't need as much vitamin D, and the dark skin will still protect the skin from dangerous rays--even if the body is exposed to only a little light. I've heard of tans you can get by ingesting a pill. Maybe that works on a similar principle. Thoughts?