Survival of the Sickest by Dr Sharon Moalem

SO interesting. DID YOU KNOW... that hemochromatosis is protective against malaria? that sickle-cell anemia is protective against HIV?  Type 1 diabetes is most common among those with Northern European ancestry? that the pituitary gland's production of melanin is triggered by the optic nerve's perception of sunlight--so wearing sunglasses can make you more prone to sunburn (since melanin is protective against sunburn)?

This is the kind of stuff that is so interesting to me! And it comes neatly packaged in a fast-moving narrative that is accessible in its explanations. This book provided a wonderful introduction to epigenetics for the layperson.

An interesting example: Vitamin D, folate, and cholesterol... Did you know that when we are in UVB sunlight, our skin converts cholesterol to Vitamin D? Ultraviolet light, however, ALSO destroys folate in the body. The darker a person's skin color, the less ultraviolet light they absorb. Thus, darker skin is protective against loss of folate, but also puts one at risk for Vitamin D deficiency. So darker skinned people, it would follow, should have low Vitamin D levels--and they would, except for a gene (ApoE4) which is found in darker-skinned people, which increases the amount of blood cholesterol. More cholesterol available in the bloodstream means increased conversion to Vitamin D. Of course, this protection against Vitamin D deficiency also comes with all the risks of higher blood cholesterol!

A note on evolution: of course, Dr Moalem speaks from an evolutionary perspective. So all of these amazing findings are attributed to the "brilliance of mother nature" or something like that. He tries to talk in a passive voice when refering to these feats of our hardwiring. It certainly strikes me as odd, since I believe that the intricacies of our bodies and world are created by a wise, loving God. Seems outrageous to ME that his closing sentences are, "The more we learn about the unbelievably complex, immensely varied, and yet simultaneously simple origin and development of life on earth, the more it looks like a miracle, and one that is still unfolding.  The miracle of evolution" (208). It serves as a reminder to me that, even though our world denies holding to absolute truth and purports inquisitiveness and discovery, every scientific finding is assimilated into the worldview that one already has.

Still, all of this piques interest and inspires further reading. I want to further investigate-- therapeutic use of low Iron levels (low H&H) to prevent infection? I want to read-
*M.J. Blaser. 1998. Passover and the plague. Perspect Biol Med. 41(2): 243-256.
*Exposing the Hidden Dangers of Iron: What Every Medical Professional Should Know about the Impact of Iron and the Disease Process (Nashville, TN: Cumberland House, 2004) (and of course, some counter-points).
*Gaia Vince, "Pregnant Smokers Increase Grandkids' Asthma Risk," New Scientist, April 11, 2005.
*G Riddihough and E Pennisi. 2001. The evolution of epigenetics. Science293(5532)1063.
*E Jablonka and M. J. Lamb. 2002. The changing concept of epigenetics. Ann N Y Acad Sci 981:82-96.