The more you think about sickness and health, the trickier it gets to draw a clean line between them. We tend to think of ourselves as being prepared by nature for a good life. If we can just keep bacteria and viruses from killing us, and avoid walking into open elevator shafts, we’ll live a long, healthy life.
But we are actually the products of evolution, and evolution can’t give us perfect health. It has endowed us with powerful immune systems, thank you very much. And it has endowed us with quick reflexes that can, in some cases, keep us out of open elevator shafts. But evolution doesn’t automatically march to perfection. It stops short, leaving us with grave imperfections.
We have lots of defenses against cancer, for example, but they weaken as we get old. That’s a recipe for heartbreak in millions of families. But in the game of evolution, that’s a winning formula. Natural selection strongly favors defenses against cancer that threaten our ability to survive to adulthood and have kids. But if we die of cancer at age sixty, our kids are well on their way, carrying out genes down to the next generation.
This evolutionary perspective could change the way we think about our health in many ways. Take allergies. They affect millions of people, causing everything from hay fever to anaphylactic shock. One of the world’s leading immunologists, Ruslan Medzhitov, is convinced that allergies are actually adaptations we use to defend ourselves from noxious chemicals. As awful as allergies can get, we wouldn’t want to live without them.
I’ve written a profile of Medzhitov. It appeared today originally in Mosaic, but it’s now propagating through the Internet. You can also find it on Ars Technica, Discover, Gizmodo, Digg, and elsewhere. Check it out at the outlet of your choice. And good luck this pollen season!
Go Further
Animals
- How can we protect grizzlies from their biggest threat—trains?How can we protect grizzlies from their biggest threat—trains?
- This ‘saber-toothed’ salmon wasn’t quite what we thoughtThis ‘saber-toothed’ salmon wasn’t quite what we thought
- Why this rhino-zebra friendship makes perfect senseWhy this rhino-zebra friendship makes perfect sense
- When did bioluminescence evolve? It’s older than we thought.When did bioluminescence evolve? It’s older than we thought.
- Soy, skim … spider. Are any of these technically milk?Soy, skim … spider. Are any of these technically milk?
Environment
- Are the Great Lakes the key to solving America’s emissions conundrum?Are the Great Lakes the key to solving America’s emissions conundrum?
- The world’s historic sites face climate change. Can Petra lead the way?The world’s historic sites face climate change. Can Petra lead the way?
- This pristine piece of the Amazon shows nature’s resilienceThis pristine piece of the Amazon shows nature’s resilience
- Listen to 30 years of climate change transformed into haunting musicListen to 30 years of climate change transformed into haunting music
History & Culture
- Meet the original members of the tortured poets departmentMeet the original members of the tortured poets department
- Séances at the White House? Why these first ladies turned to the occultSéances at the White House? Why these first ladies turned to the occult
- Gambling is everywhere now. When is that a problem?Gambling is everywhere now. When is that a problem?
- Beauty is pain—at least it was in 17th-century SpainBeauty is pain—at least it was in 17th-century Spain
Science
- Here's how astronomers found one of the rarest phenomenons in spaceHere's how astronomers found one of the rarest phenomenons in space
- Not an extrovert or introvert? There’s a word for that.Not an extrovert or introvert? There’s a word for that.
- NASA has a plan to clean up space junk—but is going green enough?NASA has a plan to clean up space junk—but is going green enough?
- Soy, skim … spider. Are any of these technically milk?Soy, skim … spider. Are any of these technically milk?
Travel
- Could Mexico's Chepe Express be the ultimate slow rail adventure?Could Mexico's Chepe Express be the ultimate slow rail adventure?
- What it's like to hike the Camino del Mayab in MexicoWhat it's like to hike the Camino del Mayab in Mexico