Transcripts

Dr. Sharon Moalem:
Could they be protective? Could they be an evolutionary compromise? Could they be offering us a window into our evolutionary past?

Dr. Sharon Moalem, author of the book Survival of the Sickest, says this discussion began about fifty years ago when researchers looked at sickle cell anemia, which is most common in people of African descent.

You know researchers at the time were saying, "Could it be that this is protective against malaria?" Because doctors on the ground started noticing people who had sickle cell seemed to be somewhat protected against the ravishes of malaria. If you kind of step back and ask those questions... you know why would something that is so detrimental be so common unless it's an evolutionary compromise? Perhaps choosing illness over death.

Another example is a condition Dr. Moalem has called hemachromatosis.

Having this condition your body hides the iron out of the blood system so it takes the iron and it stores it away in the organs. And by doing that, it prevents organisms that need it to survive that infect you such as one that causes the plague. The plague loves iron it grows on it.

So it's thought that people in Europe with hemachromatosis were protected from the bubonic plague. The downside is, it puts you at risk for heart disease and liver cancer.

But you tend to get those things when you're past the age of fifty and most people weren't living that long. So this is actually a pretty good compromise. The only problem is, today with longer life expectancies these conditions may not be such a good deal anymore.

Tomorrow, why many Asians can't drink alcohol - I'm Mike Carruthers and that's Something You Should Know.