How Did Vikings' Gut Worms Create Today's Lung Disease?

Intestinal parasites that plagued our ancestors seem to have led to a genetic adaptation that's causing emphysema and COPD today. Learn more in this episode of BrainStuff, based on this article: https://health.howstuffworks.com/diseases-conditions/respiratory/viking-toilet-investigation-emphysema.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of I Heart Radio, Hey
brain Stuff Lauren Bolga bomb here. A thorough inspection of
an old Viking latrine in Denmark has confirmed what we've
all sort of suspected. The lives of early Scandinavians were
not especially sanitary. These otherwise hardy people were crawling with

(00:24):
intestinal parasites, mostly due to the food they ate and
because they lived in close quarters with their livestock. The
outpousing question was active a thousand years ago, but recent studies,
including one published in twenty six and the journal Nature
Scientific Reports, show that the genes of some modern people
are still haunted by the ghosts of those Viking parasites.

(00:47):
They may even contribute to the reason why lung diseases
like chronic obstructive pulmonary disease and emphysema are so prevalent worldwide,
affecting around three hundred million people, nearly five percent of
the global population. Of course, these types of diseases are
most common in smokers, but there is one heritable risk factor.

(01:08):
It's genetic. It leads to your body having a deficiency
of this protein called alpha one ant trips in or
A one a T that deficiency is caused when your
body makes slightly different forms of A one A T
than normal. These deviant forms of A one A T
are particularly common in Scandinavian populations, and for years researchers

(01:30):
have been stumped as to why the deviant forms exist
at all. But these new studies show that they can
be traced back to the way vikings adapted over generations
to being completely overrun by parasites. It's a weird answer,
for sure, and it's a big deal because in your body,
A one AT normally protects your lungs and your liver

(01:53):
from these enzymes called proteases. Basically, proteases are enzymes that
break stuff down. Your immune system produces them as part
of its normal functioning, But in your lungs and liver,
your immune systems proteases can break down healthy tissue, leading
to diseases like emphysema, and those alternate forms of A

(02:13):
one A T don't help protect you like they should.
It turns out that what they do help with is
protecting you against parasitic worms. Okay, in your body, when
something like a parasitic worms sets up shop, your immune
system creates antibodies to try and kick them out, but
the worms have counterattacks. They produce proteases that break down

(02:37):
those antibodies. And it turns out that those alternate forms
of A one A T are really good at teaming
up with, or more specifically, binding to, your antibodies and
preventing them from being broken down so your body can
clear the parasites. Useless for protecting your lungs, great for
protecting you from parasites. And because Viking didn't smoke tobacco

(03:01):
and lived relatively short lives anyway, your average Viking would
have been unbelievably fortunate to make it to the age
of fifty. The fact that the deviant forms of A
one A T didn't protect them as effectively from lung
disease wasn't as important as the fact that they helped
them deal with their worms. These days, however, things are different.

(03:22):
Some people do smoke tobacco, We've got a decent grasp
on food safety, better practices for animal handling. We regularly
live past the age of fifty. We need A one
A T to prevent proteases from corroding our lung tissue.
Yet some of our bodies are still living in the
Viking age. Today's episode is based on the article Viking

(03:46):
toilet worm investigation that finds genetic clues to emphasemas. Origins
on how stuff works dot com, written by Deslin Shields.
Brain Stuff is production by Heart Radio and partnership with
how stuff works dot Com, and it's produced by Tyler Klang,
a four more podcast. It's from my heart Radio, visit
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