Nov 19, 2012

You Are What Your Grandpa Eats

Lars Olov Bygren, a professor at Umeå University in Sweden, grew up in a remote village north of the Arctic Circle. It wasn't an easy place to be a kid, and he has cold, hard data to back him up: book after book of facts and figures on the lives of generations of the town's residents, from their health to their financial success, to detailed records on the boom and bust years for crops. The numbers tell a story of wild swings in fortune -- feasts one year, harsh winters and famine the next. Looking at all those records, Olov realized he had a natural experiment on his hands. Along with Sam Kean, Olov explains the bizarre ripples through time that he discovered ... ripples that are totally unexpected, and honestly, sort of terrifying. 


"Why Your DNA Isn't Your Destiny," an article about Olov and his work in Time Magazine.

Pejk Malinovski paid a visit to the records in Sweden, and snapped a bunch of pictures:

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Announcer: Listener-supported WNYC Studios.

Director: And--

Jad Abumrad: And go. Hey, I'm Jad Abumrad.

Robert Krulwich: I'm Robert Krulwich.

Jad: This is Radiolab, and today?

Robert: It's inheritance today.

Jad: Yes, we're exploring questions of what can you pass down to your kids and their kids? What can't you? How much of you will echo into the future and how much of you won't? I've got say, I'm feeling pretty good about this show so far.

Robert: Because--

Jad: If a rat mother licking her baby can have such a profound effect, basically change the expression of the genes in the baby, that's hopeful.

Robert: So you think you can get deep down?

Jad: Look, in the end, what do I know, but I take it that we have more control over our destinies and our kids' destinies than we would've thought.

Robert: Let's not get too excited too fast because we have a story to tell and this tale leaves me a little queasy.

Olov Bygren: Oh, there was a contact.

Jad: Hello, hello.

Olov: Yes, it's me, Olov.

Jad: This is Olov.

Olov: Hi, Olov Bygren. I'm in public health.

Jad: He works at the Karolinska Institute in Sweden where he studies population data.

Olov: Looking for patterns in cardiovascular diseases, high blood pressure, and such.

Robert: But the story he told us begins around 25 years ago.

Sam Kean: Way up in northern Sweden.

Robert: That's Sam Kean again. He's the guy who told us about Olov's work.

Sam: In a little community called Överkalix.

Robert: What does it look like? Is it a big town? A little village?

Olov: It's a small forest area, very beautiful.

Sam: But this was a really, really tough place to grow up.

Robert: Very isolated and very cold. Are you near the Arctic Circle or--

Olov: North of it.

Robert: North of the Arctic Circle?

Olov: Yes. My home village was 10 miles North of polar circle. [chuckles]

Robert: You grew up in Överkalix?

Olov: Yes, yes. We had an expression here, "Dig where you stand." [chuckles]

Robert: It just so happens this town is a perfect place to dig.

Pejk Malinovski: Okay, I'm here. [unintelligible 00:02:25]. The kingdom archive.

Robert: Because there is more data, more information about the people of Överkalix going farther back into the past than you can find almost anywhere else on Earth?

Olov: Yes, we are really data-rich.

Pejk: This is the Överkalix church parish record.

Speaker 6: Yes, it is.

Jad: Because here's the thing, the churches up in Överkalix kept incredibly detailed records. We actually sent our friend, Pejk Malinovski, to the archives in Stockholm to check it out.

Pejk: It says "registrera", register.

Jad: In those books you can read everything about the citizens of Överkalix, going back hundreds of years.

Pejk: What's this name?

Jad: You know their names.

Speaker 6: Hans Olaf, Hanna Kaser, Heinrich Venvei.

Jad: What year they were born.

Speaker 6: 1814.

Pejk: 1881.

Speaker 6: She was born 1904 and this is--

Olov: Everything happening in the family--

Jad: Is in these books.

Speaker 6: Nelson, he was an idiot.

Pejk: He was an idiot. [laughs]

Speaker 6: Oh, sorry.

Pejk: What does that mean, he was an idiot? I guess retard.

Speaker 6: Yes, he was retarded. [foreign language]. He was miserable to look at.

Pejk: It's not very politically correct, huh?

Speaker 6: [chuckles] No.

Jad: [unintelligible 00:03:33] these books tell you when each of these folks died, how they died.

Pejk: From disease.

Speaker 6: Heart disease. From pneumonia.

Pejk: Accident.

Speaker 6: She drowned.

Pejk: Oh my God.

Olov: A lot of diagnoses actually--

Pejk: Influenza.

Speaker 6: Cancer. Heart disease. Brain disease.

Robert: Interestingly, the church has also kept track of the farmers'--

Pejk: Crops and livestock.

Sam: How much they were growing each year.

Robert: Which turn out to be an interesting thing to look at it because the people in Överkalix who were farming--

Sam: Trying to eke a living out of the soil.

Pejk: Here we have how much they harvested.

Robert: They would experience these wild changes from harvest to harvest.

Jad: What you see in the records, is that one year?

Pejk: Potatoes.

Jad: Crops that do great.

Pejk: 100 liters. Oh, that's a lot of potatoes.

Robert: A few years later, there'd be a harsh winter.

Olov: The crops failed.

Sam: When the crops failed.

Olov: Famines.

Speaker 6: So sad.

Sam: -they basically starve. When you look at the records, you don't see huge spikes in mortality.

Olov: So they didn't starve to death.

Sam: They suddenly had to get by on a tiny fraction of the food that they were used to.

Olov: They didn't have grains. They didn't have porridge.

Sam: So they just had to hold on for the entire winter-

Robert: But then, a few years would pass, crops would bounce back.

Pejk: We have a lot more grain here.

Robert: And suddenly--

Olov: Plenty of food.

Robert: They could eat twice, three times as much.

Sam: But then--

Pejk: Oh, no.

Olov: Total crop failure.

Robert: Famine again, and these changes would just bounce back and forth; feast, famine, feast, famine, or feast again.

Jad: Looking at these swings in fortune, Olov realized what he had here--

Sam: Was a nice, natural experiment--

Jad: Because with all this data, he and his team could follow families forward in time, through the generations.

Robert: If they saw somebody who was starving as a kid in 1820, they could then see, "Well, when those people had children and grandchildren, did anything change? Were there any consequences?

Sam: They wanted to see basically the effects of starvation on multiple generations. What did you discover?

Olov: It was very interesting discovery.

Robert: It's a little odd, actually. Here's what Olov says he found in the data. If you were a boy in Överkalix between the ages of 9 and 12 years old, that's the window. 9 to 12, you're a boy, and then we have one of those terribly rough winters, and you're eating much less than normal. Assuming you can survive the ordeal and you grow up and you have kids of your own, the data seems to say that your kids will benefit from your suffering.

Olov: Yes.

Robert: They'll do better?

Sam: If you have a starving daddy, it turns out that the baby actually gets some health benefit.

Robert: Really?

Olov: Yes.

Sam: These effects, in fact, were so strong that you could trace it to the grandfather.

Jad: The grandfather? Two generations?

Sam: It seemed to have been passed down for multiple generations.

Robert: If you had a starving grandfather, you would be a healthier boy because you had a starving grandfather?

Sam: You got to help boost if you had a starving grandfather.

Jad: What health boost? Olov told us, take heart disease. He said, "If you were a boy, and you starve between the ages of 9 and 12, and then you went on to become a father then a grandfather, your grandkids--"

Olov: They were protected.

Robert: Meaning that they had less incidence of heart disease.

Olov: Much less.

Robert: How much less?

Olov: It's one-fourth [unintelligible 00:07:18] can we say.

Robert: One-fourth? Let me say this again. If you're a starving boy between 9 to 12 years old, it doesn't matter a whole lot what happens to you after this, your grandchildren will have one-quarter the risk of heart disease. If you were eating a whole lot between 9 and 12, one-quarter.

Sam: Not only that. Apparently, those grandkids were less prone to diabetes, they lived longer lives, something like 30 years on average.

Robert: 30 years?

Sam: This was a really, really big effect.

Robert: Instead of dying at 40, I'd live to 70? That kind of 30 years?

Sam: Yes, exactly.

Robert: It's such a surprising result. I wonder how much you believe in it.

Olov: The results are there. It's only the mechanisms are not so clear.

Robert: The results are very clear. The results are obvious to you.

Olov: The results are quite obvious.

Jad: Just to be sure, we asked Frances Champagne what she thinks of this data.

Frances Champagne: I believe it.

Jad: Oh, you do.

Jad: Michael Meaney as well.

Michael Meaney: I think the Swedish data are really, really strong, and very reliable.

Jad: Everybody we talked to seems to think there's something really interesting going on here. What exactly-- Maybe you can explain this to me, Robert. What exactly happens between 9 to 12 that makes this big difference?

Robert: Here's the thing. How old are your boys right now?

Jad: Three and eight months.

Robert: Here's what you're going to notice. Your boys will first grow taller and taller for the next few years, and when they get to be about 9, 10 years old, they're going to stop growing just for a few years.

Sam: This is what's called the slow growth period.

Robert: Just for those years. That's 9, 10, 11.

Olov: Just before puberty.

Robert: They won't grow much on the outside, but on the inside--


Olov: That is the time where the sperms are developing.

Sam: What's happening during this time is that you're setting aside a stock of cells that you're going to draw on in the future to make sperm cells.

Olov: They are pre-exposed.

Robert: The thought is when those little boys in Överkalix were really, really hungry. Their hunger started a chemical process that reached all the way down to the DNA inside the boy's sperm.

Olov: Something happens on the molecular level.

Jad: What exactly?

Olov: The DNA, the RNA, micro-RNAs, histone.

Jad: Hey, wait. That you're just renaming it.

Olov: Methylations, phosphorylation [unintelligible 00:09:49].

Jad: [unintelligible 00:09:50], that's all this is.

Olov: [chuckles]

Robert: Because we don't know precisely how this happens but somehow the experience of starvation marks the DNA. Maybe like those [unintelligible 00:10:01] things we were telling you about with the rats, telling some genes to turn off now, other genes to turn on. The incredible thing is, those marks stick around.

Sam: The sperm carries these marks to the next generation.

Jad: Then the next one after that.

Sam: Right.

Robert: Somehow by some chemical mechanism, starving grandpa back when he was about 9 to 12 years old, turned out to be a good thing.

Jad: It's like grandpa's struggle is jumping forward and giving me a leg up?

Robert: That's the good news, but unfortunately there is some bad news here. If your grandpa didn't starve, instead he lived through great times. He stuffed himself silly; 9, 10, 11 years old, so he's a happy grandpa, you the grandson, you then would have.

Olov: Higher frequencies of heart attacks. As to diabetes, it was a four-fold risk.

Robert: Four-fold. 400% greater?

Olov: Yes.

Jad: I got to say this is spooky. This is spooky because it's like--

Sam: It does get--

Jad: It means what if grandpa has a bad day, suddenly you're marked.

Robert: Frankly, this makes being 9, 10, 11, 12 like a rather crucial.

Sam: At a time when you're not making the best decisions anyway.

Jad: Yes, because grandpa's just nine.

Sam: I should add too. They have found very similar effects for smoking, for instance. If you start smoking when you're 10, 11 something like that, you end up having children with more problems.

Jad: I initially felt very hopeful and excited about this research because it seems to suggest that one body can respond to an environment and change and be flexible in a way we didn't think was possible. This stuff you're telling me about Sweden feels very grim in a certain way.

Robert: Although, sometimes that your grandfather's suffering helps you.

Jad: Even if it helps, it's horrifying. [unintelligible 00:11:56] makes me claustrophobic.

Sam: You feel hemmed in by what your grandfather did?

Jad: A little bit.

Sam: I guess the way I would look at it is that you can change your environment a lot more easily than you can change your genes.


Robert: I think what's weird here is that we started trying to make a difference in our children and now we're a surprise attack for our grandparents.


Jad: I tell you what I'm going to do though. When Emil gets to be eight, I'm cutting him off. He's not even eating at all.

Robert: "This may hurt you my son, but I'm doing it for my grandchildren."


Jad: Thanks to Olov Bygren, reporter Pejk Malinovski and--

Speaker 6: [unintelligible 00:13:00] and I'm a senior archivist at the National Archive in Marieberg in Stockholm.

Sam: Hello, this is Sam Kean.

Jean Kean: My name is Jean Kean. I'm Sam Kean's dad.

Sam: Radiolab is produced by WNYC.

Jean: And distributed by NPR.

Speaker 7: Bye. Bye.


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