Disease is Good?

I always wake up late in the morning to the Diane Rehm show. Fascinating discussion always, but especially today. In the second hour of the show, Dr. Moalem speaks about how many diseases may actually be protecting us from worse ailments. Apparently there are some instances in which diabetes is good for us. Could bloodletting delay the onset of alzheimer's? Also, It was just the other day that I was wondering how we end up getting vitamin D from sunlight. Coincidentally, the answer came to me in this show today. Sunlight converts cholesterol into it. So people in climates with less sun require higher amounts of cholesterol.

When I was a kid my family moved from Illinois to Louisiana. My brothers and I all developed asthma with varying degrees of severity, and within three years my family had moved back up north as a result. Today I'm reminded of this, and I'm thinking that there is so much more we have to learn about how we adapt to our environment, and what happens when we remove ourselves from one set of conditions for another.

(Link to Diane Rehm)
(Link to Dr. Moalem's book, "Survival of the Sickest")