By Robin D. Schatz
March 26 (Bloomberg) — Cancer, diabetes and other life- threatening diseases may have evolved to help human beings survive other horrible fates — like succumbing to bubonic plague or freezing to death. That’s the bold hypothesis of geneticist Sharon Moalem in his new book, “Survival of the Sickest: A Medical Maverick Discovers Why We Need Disease.”
Moalem, who wrote his book with Jonathan Prince, says that understanding the evolution of these genetically based maladies may lead us to new cures and treatments. I spoke with the 33- year-old scientist, who is also a medical student at Manhattan’s Mount Sinai School, at Bloomberg’s New York offices.
Schatz: Why did you write this book?
Moalem: As a geneticist, I couldn’t understand one thing: why would diseases today still be common, and I mean the genetic variety. So one in particular that I looked at was hemochromatosis — 30 percent of people from western European descent carry genes that predispose them to that condition.
Schatz: What is hemochromatosis?
Moalem: It’s a condition where you absorb too much iron from the diet. The problem is, all of that iron that you’re absorbing from your diet ends up in organs, and rusting them out, essentially. So you can end up with diabetes and liver cancer.
So it didn’t make any sense to me: Why would such a high percentage of the population have something that appears to be negative? And the more I dug, I came to the conclusion, by putting different information together, that it probably protected past populations in Europe against the bubonic plague.
Schatz: Are you saying we need to view disease in a new context?
Moalem: Exactly. I think we’ve made the mistake of declaring war against disease. And when you use that conquer metaphor, and you don’t understand your enemy properly, you’re running the risk of failing miserably. We’ve declared war on cancer. We’ve declared war on obesity, on diabetes, without really stepping back and seeing if these conditions arose originally to protect to us.
Schatz: An example?
Moalem: Diabetes. People of a northern European descent are more at risk of type 1 juvenile diabetes. That’s the diabetes that is awful. It’s fatal, you need insulin and without treatment you die. But why northern Europeans? Well it’s pretty cold up in northern Europe. And I came across this frog called Rana sylvatica — it’s a wood frog — and it has the incredible ability of becoming diabetic every winter. It actually has reversible diabetes. And it does this to manage the cold.
It becomes so diabetic that it could actually freeze solid, its heart stops, its brain stops. It becomes like this frozen frogsicle. Come spring, it defrosts.
So now researchers are actually looking at a frog that can freeze solid in winter to find a new treatment for diabetes, and you would have never gotten to this point if you didn’t step back and ask these basic questions.
Schatz: What do we learn from fava beans?
Moalem: If you have a deficiency called G6PD — it’s a genetic condition — you lack the ability to break down fava beans, and a few beans can be deadly. It’s mainly people who hail from the eastern Mediterranean — southern Italy, Sicily, Greece, Turkey — who have this problem. Why? It didn’t make any sense to me, because these are the regions that love fava beans.
This G6PD deficiency makes your blood cells inhospitable to malaria. It turns out that even if you don’t have this mutation, if you eat a couple of fava beans it makes your red blood cells dirty and it makes them inhospitable for this malaria parasite to live within your red blood cells. So people were actually, in a way, probably almost treating their malaria by feasting on fava beans during the spring.
“Survival of the Sickest” is published by William Morrow (267 pages, $25.95).
(Robin D. Schatz is an editor for Bloomberg News. The opinions expressed are her own.)
To contact the writer of this story: Robin D. Schatz in New York at email@example.com .