Survival of the Sickest: A Medical Maverick Discovers Why We Need Disease

Why would you take a drug that is guaranteed to kill you in forty years? One reason, right? It's the only thing that will stop you dying tomorrow.

By the way, the next time you get your cholesterol checked, make a note of the season. Because sunlight converts cholesterol to vitamin D, cholesterol levels can be higher in winter months, when we continue to make and eat cholesterol but there’s less sunlight available to convert it.

far as to say that white-skinned people are actually black-skinned mutants who lost the ability to produce significant amounts of eumelanin. Redheads, with their characteristic milky white skin and freckles, may be a further mutation along the same lines. In order to survive in places with infrequent and weak sunlight, such as in parts of the U.K., they may have evolved in a way that almost completely knocked out their body’s ability to produce eumelanin, the brown or black pigment.

connection between skin color and sunlight. The results were as clear as the sky on a cloudless day—there was a near-constant correlation between skin color and sunlight exposure in populations that had remained in the same area for 500 years or more. They even produced an equation to express the relationship between a given population’s skin color and its annual exposure to ultraviolet rays. (If you’re feeling adventurous, the equation is W = 70-AUV/10. W represents relative whiteness and AUV represents annual ultraviolet exposure. The 70 is based on research that indicates that the whitest possible skin—the result of a population that received zero exposure to UV—would reflect about 70 percent of the light directed at it.)

There is one notable exception to Jablonski and Chaplin’s equation—and it’s the exception that proves the rule. The Inuit—the indigenous people of the subarctic—are dark-skinned, despite the limited sunlight of their home. If you think something fishy’s going on here, you’re right. But the reason they don’t need to evolve the lighter skin necessary to ensure sufficient vitamin D production is refreshingly simple. Their diet is full of fatty fish—which just happens to be one of the only foods in nature that is chock-full of vitamin D. They eat vitamin D for breakfast, lunch, and dinner, so they don’t need to make it. If you ever had a grandmother from the Old World try to force cod liver oil down your throat, she was onto something for the same reason—since it’s full of vitamin D, cod liver oil was one of the best ways to prevent rickets, especially before milk was routinely fortified with it. IF YOU’RE WONDERING how people who have dark skin make enough vitamin D despite the fact that their skin blocks all those ultraviolet rays, you’re asking the right questions. Remember, ultraviolet rays that penetrate the skin destroy folate—and ultraviolet rays that penetrate the skin are necessary to create vitamin D. Dark skin evolved to protect folate, but it didn’t evolve

In evolutionary terms, that means we asked for it.

The great Irish poet Seamus Heaney wrote that once in a lifetime hope and history can rhyme. Evolution is what happens when history and change are in rhyme.

if there’s fire on the mountain or lightning and storm and a god speaks from the sky. That means someone is hearing the outcry and the birth-cry of new life at its term.

Coincidence? Probably not. Pregnancy isn’t the only time folate is important, of course. A lack of folate is also directly linked to anemia, because folate helps to produce red blood cells. THE SKIN, AS you’ve probably heard, is the largest organ of the human body. It’s an organ in every sense of the word, responsible for important functions related to the immune system, the nervous system, the circulatory system, and metabolism. The skin protects the body’s stores of folate, and it’s in the skin that a crucial step in the manufacturing of vitamin D takes place.

Recent scientific sleuthing reported in the prestigious journal Science goes so