I was listening to the radio the other day and caught a news item about Vitamin D deficiency in kids in certain parts of the world because they are spending far too much time indoors, studying, watching TV or playing computer games and therefore not getting their three hours of daylight every day. I mentally classified it into the “obesity in kids, world going to hell in a handcart” category of news, i.e., so far, so yawn. Well okay, I am pretty sure I am not getting three hours a day either and I idly wondered if I should look into the requirements for adults, but apart from that, so far, so yawn.

But then it occurred to me that really, there is a different point here, a point that is specific to Vitamin D as against other vitamins. The point is that time in the sun is something that evolution took so much for granted that the human body has simply been programmed to expect it. In that time it does some magical chemistry to produce a compound we call Vitamin D, and the poor old human body really gets into trouble when it doesn’t get enough Vitamin D. So much trouble that evolution even took some special care to avoid Vitamin D deficiency – as we migrated out of the sunny land of Africa to higher latitudes our skin lightened and we were still able to make enough vitamin D with much less sun.

But the point also is that as we have moved further and further away from how our ancestors lived, we are failing ourselves and failing the magic wrought by evolution. All it takes is cholesterol (which most of us seem to have enough of, and then some) and sunlight, et voila, vitamin D. But what evolution would have considered by far the more easily available ingredient – sunlight – is what has gone missing, and without that the algorithm fails. What strikes me is that the failure is at such a fundamental level – lack of sunlight is something that the algorithm is just not designed to handle.

I am reminded of a book I heard of recently, on the occasion of Earth Day. It is by David Abram, titled Becoming Animal: An Earthly Cosmology. I haven’t read it, but a central thesis seems to be a fact that we have apparently forgotten: We are of the earth, and in a very physical sense, we are animals. Our existence is embedded into the natural world as firmly as that of mosses and sycamores, sparrows and snakes. It seems to me that civilization has made us forget this and an increasing incidence of vitamin D deficiency is just one consequence.

I am also reminded of Richard Feynman’s childhood conversation with his father, described in Surely You’re Joking, Mr. Feynman.

It was the kind of thing my father would have talked about: “What makes it go? Everything goes because the sun is shining.” And then we would have fun discussing it:
“No, the toy goes because the spring is wound up,” I would say.
“How did the spring get wound up?” he would ask.
“I wound it up.”
“And how did you get moving?”
“From eating.”
“And food grows only because the sun is shining. So it’s because the sun is shining that all these things are moving.” That would get the concept across that motion is simply the transformation of the sun’s power.

Indeed. We are of the earth, and we belong under the sun.