Book Review: The Wild Life of Our Bodies by Rob Dunn
What if I told you that you:
This was a tough book for Dunn to organize. I'm going to mix it up in summary.
Chances are we began living and farming in communities in caves on cliffs. A full 50% of the species that grow in Hometown, USA started out on cliffs. The huge list includes: tulips, dandelions," most domestic crops from capers and agaves to almonds, carrots, cucumbers, and even wheat." Amazing. Also amazing, and perhaps necessary for hunter-gatherers, we have taste buds in our guts. I never knew! Bitter tastes are associated with poisonous things and tasting it in your stomach or small intestine can prompt projectile vomiting, the original stomach pump.
Cliff-living made sense given how often early humans were killed by predators, particularly snakes and big cats. Dunn says death by predation was 30 times more likely than is dying by cancer today! Getting killed by snakes so often influenced natural selection for decent eyesight and, even now, a disproportionately quickly-learned fear response to snakes. (Alone among primates, Madagascar's lemurs have crappy eyesight-- and Madagascar has no venomous snakes. Which is not proof--evolutionary biology has so little of that-- but pretty.) So, predation as a force shapes selection of people who have quickly-learned fear responses to new threats. Sadly, some people wind up too amped all of the time. Blame it on the sabertooth.
And disease. If you take someone's blood, have them look at images of sick people, and take their blood again, you will see a giant spike of cytokine action-- your immune system mobilizing for a threat. Not any threat will do, either. Violence in the photo does nothing; has to be sick folks, obese folks or old folks-- which Dunn thinks the body mistakes for sick. Dunn surmises that if your body physiologically changes when confronted with the possibiilty of disease, this might also be the case when confronted with "other people," who may carry diseases your group has no resistance to. Sure enough, in several world surveys, in places where there is a lot of disease, people form collectivist societies (where the needs of the tribe or group are on par with the needs of the individual), and in those societies, you see the most xenophobia. So if we can tame a bunch of diseases, we could all get along a lot better.
So, it's just 9-10,000 years ago and now we can see and defend ourselves pretty well against predators. We stay in big groups for safety, but then we deplete the hunting and gathering in our chosen refuges. Vermin build up. In Asia, Africa and the Amazon, we move every 15 years to escape the vermin and find new hunting and gathering. Eventually there are people already living where we want to go. Time to settle down. We try domesticating cows (then aurochsen), but early adult humans have no ability to digest lactose. So what do we do? Fart and have diarrhea until a mutation arises that doesn't turn off our ability to digest milk as adults. (Seems like an incomplete answer so I'll magic up another: I'd say, first of all we get bitten by a pest that bites the cows also, and we get some kind of parasite that has a hitchhiking microbe that digests lactose, and maybe it turns out our best defense against the microbe is having our own lactase production starve it out--maybe because we're ill and often ill, eventually our immune system sort of colludes with the microbe's fancy TAL effector to change our DNA. But it wasn't that fancy, because it happened at least four times since then, which suggests that any gene's on/off expression is pretty malleable, given the right trigger.... But enough Charlie the Unicorn.:D .) Agriculture makes us move down off the cliffs (unless it's goats we're farming). And we take all our plants from the cliffs with us.
Eventually we move into houses with indoor toilets. Some machinist's son gets convinced that germs are the reason thngs die and he spends thirty years building a germ free chamber and growing animals in it. Many die because germs do get in, or the diet is horrible. Eventually he creates the mice used in research today. For whatever reason, we go with the idea that germs are bad, ignoring that famous Pasteur guy who said no man or animal could live without germs. So we start dosing everything with lots of antibiotics and antibacterial wipes. And our immune systems start breaking down. People in developing countries have less autoimmune disease than we do. We get Crohn's Disease, ulcerative colitis, asthma, lupus, etc, a lot. They don't. People were very curious why. Then even researched whether or not it might be caused by germs in refrigerators (seriously).
They should have been looking at pronghorn antelope (seriously). Those suckers are so fast they make mountain lions seem like sloths. They have no predators other than man. Biologists asked why nature would waste such largesse of an adaptation. They stared at the problem until they were seeing ghosts-- cheetah ghosts. Sure enough, until very recently, the antelope's main predator was the American Cheetah, now extinct. That's why the antelope is that fast.
So, if our immune system is acting like a pronghorn, surging so far ahead of where it needs to be that it's attacking the body, is it perhaps also missing a predator? That's what a GI doc was wondering while editing a book on parasitical worms. So he ran the numbers. After 10 years of hygiene in a community, inflammatory disease skyrockets. AHA. So he gave folks worms to see what would happen. The words I read a lot of were: complete remission. Like, out of 29 Crohn's patients, 21 went into complete remission. And this was even for multiple sclerosis. It didn't work for everyone, every time, but the results are still rocking the medical world. There is still debate as to the mechanism. Do the worms sing to the autoimmune system so it doesn't attack anymore? (Yeah, I'm joking, but Dunn calls whatever the worms might produce "peacekeepers," which is equally silly.) Are the worms most effective at training the immune system if you're exposed once as a kid? Or do you need to have worms all the time? Nobody knows yet. But seriously interesting, stuff. The whole book. Highly recommended.
- still eat and are surrounded by plants that originated on cliffs?
- will be healthier with worms living in your gut?
- are still anxiety-ridden because your ancestors had to be to avoid being eaten?
- are still xenophobic because your ancestors avoided disease by being that way?
This was a tough book for Dunn to organize. I'm going to mix it up in summary.
Chances are we began living and farming in communities in caves on cliffs. A full 50% of the species that grow in Hometown, USA started out on cliffs. The huge list includes: tulips, dandelions," most domestic crops from capers and agaves to almonds, carrots, cucumbers, and even wheat." Amazing. Also amazing, and perhaps necessary for hunter-gatherers, we have taste buds in our guts. I never knew! Bitter tastes are associated with poisonous things and tasting it in your stomach or small intestine can prompt projectile vomiting, the original stomach pump.
Cliff-living made sense given how often early humans were killed by predators, particularly snakes and big cats. Dunn says death by predation was 30 times more likely than is dying by cancer today! Getting killed by snakes so often influenced natural selection for decent eyesight and, even now, a disproportionately quickly-learned fear response to snakes. (Alone among primates, Madagascar's lemurs have crappy eyesight-- and Madagascar has no venomous snakes. Which is not proof--evolutionary biology has so little of that-- but pretty.) So, predation as a force shapes selection of people who have quickly-learned fear responses to new threats. Sadly, some people wind up too amped all of the time. Blame it on the sabertooth.
And disease. If you take someone's blood, have them look at images of sick people, and take their blood again, you will see a giant spike of cytokine action-- your immune system mobilizing for a threat. Not any threat will do, either. Violence in the photo does nothing; has to be sick folks, obese folks or old folks-- which Dunn thinks the body mistakes for sick. Dunn surmises that if your body physiologically changes when confronted with the possibiilty of disease, this might also be the case when confronted with "other people," who may carry diseases your group has no resistance to. Sure enough, in several world surveys, in places where there is a lot of disease, people form collectivist societies (where the needs of the tribe or group are on par with the needs of the individual), and in those societies, you see the most xenophobia. So if we can tame a bunch of diseases, we could all get along a lot better.
So, it's just 9-10,000 years ago and now we can see and defend ourselves pretty well against predators. We stay in big groups for safety, but then we deplete the hunting and gathering in our chosen refuges. Vermin build up. In Asia, Africa and the Amazon, we move every 15 years to escape the vermin and find new hunting and gathering. Eventually there are people already living where we want to go. Time to settle down. We try domesticating cows (then aurochsen), but early adult humans have no ability to digest lactose. So what do we do? Fart and have diarrhea until a mutation arises that doesn't turn off our ability to digest milk as adults. (Seems like an incomplete answer so I'll magic up another: I'd say, first of all we get bitten by a pest that bites the cows also, and we get some kind of parasite that has a hitchhiking microbe that digests lactose, and maybe it turns out our best defense against the microbe is having our own lactase production starve it out--maybe because we're ill and often ill, eventually our immune system sort of colludes with the microbe's fancy TAL effector to change our DNA. But it wasn't that fancy, because it happened at least four times since then, which suggests that any gene's on/off expression is pretty malleable, given the right trigger.... But enough Charlie the Unicorn.:D .) Agriculture makes us move down off the cliffs (unless it's goats we're farming). And we take all our plants from the cliffs with us.
Eventually we move into houses with indoor toilets. Some machinist's son gets convinced that germs are the reason thngs die and he spends thirty years building a germ free chamber and growing animals in it. Many die because germs do get in, or the diet is horrible. Eventually he creates the mice used in research today. For whatever reason, we go with the idea that germs are bad, ignoring that famous Pasteur guy who said no man or animal could live without germs. So we start dosing everything with lots of antibiotics and antibacterial wipes. And our immune systems start breaking down. People in developing countries have less autoimmune disease than we do. We get Crohn's Disease, ulcerative colitis, asthma, lupus, etc, a lot. They don't. People were very curious why. Then even researched whether or not it might be caused by germs in refrigerators (seriously).
They should have been looking at pronghorn antelope (seriously). Those suckers are so fast they make mountain lions seem like sloths. They have no predators other than man. Biologists asked why nature would waste such largesse of an adaptation. They stared at the problem until they were seeing ghosts-- cheetah ghosts. Sure enough, until very recently, the antelope's main predator was the American Cheetah, now extinct. That's why the antelope is that fast.
So, if our immune system is acting like a pronghorn, surging so far ahead of where it needs to be that it's attacking the body, is it perhaps also missing a predator? That's what a GI doc was wondering while editing a book on parasitical worms. So he ran the numbers. After 10 years of hygiene in a community, inflammatory disease skyrockets. AHA. So he gave folks worms to see what would happen. The words I read a lot of were: complete remission. Like, out of 29 Crohn's patients, 21 went into complete remission. And this was even for multiple sclerosis. It didn't work for everyone, every time, but the results are still rocking the medical world. There is still debate as to the mechanism. Do the worms sing to the autoimmune system so it doesn't attack anymore? (Yeah, I'm joking, but Dunn calls whatever the worms might produce "peacekeepers," which is equally silly.) Are the worms most effective at training the immune system if you're exposed once as a kid? Or do you need to have worms all the time? Nobody knows yet. But seriously interesting, stuff. The whole book. Highly recommended.