TEDxDanubia
Giulia Enders: The surprisingly charming science of your gut
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Ever wonder how we poop? Learn about the gut -- the system where digestion (and a whole lot more) happens -- as doctor and author Giulia Enders takes us inside the complex, fascinating science behind it, including its connection to mental health. It turns out, looking closer at something we might shy away from can leave us feeling more fearless and appreciative of ourselves.
Giulia Enders - Doctor, author
Giulia Enders is working to reveal how our gut is at the core of who we are. Full bio
Giulia Enders is working to reveal how our gut is at the core of who we are. Full bio
Double-click the English transcript below to play the video.
00:13
A few years ago,
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I always had this thing happening to me,
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especially at family gatherings
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like teas with aunts and uncles
or something like this.
or something like this.
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When people come up to you,
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and they ask you,
"So, what are you doing?"
"So, what are you doing?"
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And I would have
this magical one-word reply,
this magical one-word reply,
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which would make everybody happy:
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"Medicine.
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I'm going to be a doctor."
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Very easy, that's it,
everybody's happy and pleased.
everybody's happy and pleased.
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And it could be so easy,
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but this effect really only lasts
for 30 seconds with me,
for 30 seconds with me,
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because that's then the time
when one of them would ask,
when one of them would ask,
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"So, in what area of medicine?
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What specialty do you want to go into?"
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And then I would have to strip down
in all honesty and just say,
in all honesty and just say,
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"OK, so I'm fascinated with the colon.
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It all started with the anus,
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and now it's basically
the whole intestinal tract."
the whole intestinal tract."
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(Laughter)
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And this would be the moment
when the enthusiasm trickled,
when the enthusiasm trickled,
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and it would maybe also get,
like, awkwardly silent in the room,
like, awkwardly silent in the room,
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and I would think this was terribly sad,
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because I do believe
our bowels are quite charming.
our bowels are quite charming.
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(Laughter)
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And while we're in a time
where many people are thinking about
where many people are thinking about
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what new superfood smoothie to make
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or if gluten is maybe bad for them,
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actually, hardly anyone seems to care
about the organ where this happens,
about the organ where this happens,
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the concrete anatomy
and the mechanisms behind it.
and the mechanisms behind it.
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And sometimes it seems to me
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like we're all trying
to figure out this magic trick,
to figure out this magic trick,
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but nobody's checking out the magician,
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just because he has, like,
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an embarrassing hairstyle or something.
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And actually,
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there are reasons science
disliked the gut for a long time;
disliked the gut for a long time;
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I have to say this.
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So, it's complex.
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There's a lot of surface area --
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about 40 times the area of our skin.
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Then, in such a tight pipe,
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there are so many immune cells
that are being trained there.
that are being trained there.
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We have 100 trillion bacteria
doing all sorts of things --
doing all sorts of things --
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producing little molecules.
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Then there's about 20 different hormones,
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so we are on a very different level
than our genitals, for example.
than our genitals, for example.
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And the nervous system
of our gut is so complex
of our gut is so complex
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that when we cut out a piece,
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it's independent enough
that when we poke it,
that when we poke it,
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it mumbles back at us, friendly.
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(Laughter)
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But at least those reasons are also
the reasons why it's so fascinating
the reasons why it's so fascinating
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and important.
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It took me three steps to love the gut.
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So today, I invite you to follow me
on those three steps.
on those three steps.
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The very first was just looking at it
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and asking questions
like, "How does it work?"
like, "How does it work?"
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and "Why does it have to look
so weird for that sometimes?"
so weird for that sometimes?"
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And it actually wasn't me asking
the first kind of these questions,
the first kind of these questions,
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but my roommate.
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After one heavy night of partying,
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he came into our shared-room kitchen,
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and he said, "Giulia, you study medicine.
How does pooping work?"
How does pooping work?"
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(Laughter)
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And I did study medicine
but I had no idea,
but I had no idea,
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so I had to go up to my room
and look it up in different books.
and look it up in different books.
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And I found something interesting,
I thought, at that time.
I thought, at that time.
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So it turns out, we don't only have
this outer sphincter,
this outer sphincter,
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we also have an inner sphincter muscle.
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The outer sphincter we all know,
we can control it,
we can control it,
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we know what's going on there;
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the inner one, we really don't.
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So what happens is,
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when there are leftovers from digestion,
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they're being delivered
to the inner one first.
to the inner one first.
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This inner one will open in a reflex
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and let through a little bit for testing.
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(Laughter)
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So, there are sensory cells
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that will analyze what has been delivered:
Is it gaseous or is it solid?
Is it gaseous or is it solid?
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And they will then send
this information up to our brain,
this information up to our brain,
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and this is the moment
when our brain knows,
when our brain knows,
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"Oh, I have to go to the toilet."
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(Laughter)
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The brain will then do
what it's designed to do
what it's designed to do
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with its amazing consciousness.
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It will mediate with our surroundings,
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and it will say something like,
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"So, I checked.
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We are at this TEDx conference -- "
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(Laughter)
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(Applause)
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Gaseous?
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Maybe, if you're sitting on the sides,
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and you know you can pull it off silently.
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(Laughter)
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But solid --
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maybe later.
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(Laughter)
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Since our outer sphincter and the brain
is connected with nervous cells,
is connected with nervous cells,
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they coordinate, cooperate,
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and they put it back in a waiting line --
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(Laughter)
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for other times,
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like, for example, when we're at home
sitting on the couch,
sitting on the couch,
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we have nothing better to do,
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we are free to go.
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(Laughter)
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Us humans are actually one
of the very few animals that do this
of the very few animals that do this
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in such an advanced and clean way.
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To be honest, I had some newfound respect
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for that nice, inner sphincter dude --
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not connected to nerves
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that care too much about
the outer world or the time --
the outer world or the time --
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just caring about me for once.
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I thought that was nice.
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And I used to not be a great fan
of public restrooms,
of public restrooms,
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but now I can go anywhere,
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because I consider it more
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when that inner muscle puts a suggestion
on my daily agenda.
on my daily agenda.
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(Laughter)
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And also I learned
something else, which was:
something else, which was:
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looking closely at something
I might have shied away from --
I might have shied away from --
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maybe the weirdest part of myself --
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left me feeling more fearless,
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and also appreciating myself more.
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And I think this happens a lot of times
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when you look at the gut, actually.
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Like those funny rumbling
noises that happen
noises that happen
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when you're in a group of friends
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or at the office conference table,
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going, like, "Merrr, merrr..."
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This is not because we're hungry.
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This is because our small intestine
is actually a huge neat freak,
is actually a huge neat freak,
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and it takes the time in between digestion
to clean everything up,
to clean everything up,
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resulting in those eight meters
of gut -- really, seven of them --
of gut -- really, seven of them --
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being very clean
and hardly smelling like anything.
and hardly smelling like anything.
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It will, to achieve this,
create a strong muscular wave
create a strong muscular wave
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that moves everything forward
that's been leftover after digestion.
that's been leftover after digestion.
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This can sometimes create a sound,
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but doesn't necessarily have to always.
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So what we're embarrassed of
is really a sign
is really a sign
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of something keeping
our insides fine and tidy.
our insides fine and tidy.
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Or this weird, crooked shape
of our stomach --
of our stomach --
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a bit Quasimodo-ish.
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This actually makes us be able
to put pressure on our belly
to put pressure on our belly
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without vomiting,
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like when we're laughing
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and when we're doing sports,
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because the pressure will go up
and not so much sideways.
and not so much sideways.
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This also creates this air bubble
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that's usually always very visible
in X-rays, for example,
in X-rays, for example,
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and can sometimes, with some people,
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when it gets too big,
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create discomfort
or even some sensations of pain.
or even some sensations of pain.
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But for most of the people,
is just results
is just results
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that it's far easier to burp
when you're laying on your left side
when you're laying on your left side
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instead of your right.
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And soon I moved a bit further
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and started to look at the whole picture
of our body and health.
of our body and health.
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This was actually after I had heard
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that someone I knew a little bit
had killed himself.
had killed himself.
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It happened that I had been sitting
next to that person the day before,
next to that person the day before,
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and I smelled that he had very bad breath.
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And when I learned
of the suicide the next day,
of the suicide the next day,
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I thought: Could the gut have
something to do with it?
something to do with it?
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And I frantically started searching
if there were scientific papers
if there were scientific papers
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on the connection of gut and brain.
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And to my surprise, I found many.
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It turns out it's maybe not as simple
as we sometimes think.
as we sometimes think.
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We tend to think our brain
makes these commands
makes these commands
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and then sends them down
to the other organs,
to the other organs,
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and they all have to listen.
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But really, it's more that 10 percent
of the nerves that connect brain and gut
of the nerves that connect brain and gut
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deliver information
from the brain to the gut.
from the brain to the gut.
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We know this, for example,
in stressful situations,
in stressful situations,
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when there are transmitters from the brain
that are being sensed by our gut,
that are being sensed by our gut,
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so the gut will try to lower all the work,
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and not be working
and taking away blood and energy
and taking away blood and energy
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to save energy for problem-solving.
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This can go as far as nervous vomiting
or nervous diarrhea
or nervous diarrhea
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to get rid of food that it then
doesn't want to digest.
doesn't want to digest.
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Maybe more interestingly,
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90 percent of the nervous fibers
that connect gut and brain
that connect gut and brain
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deliver information
from our gut to our brain.
from our gut to our brain.
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And when you think about it a little bit,
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it does make sense,
because our brain is very isolated.
because our brain is very isolated.
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It's in this bony skull
surrounded by a thick skin,
surrounded by a thick skin,
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and it needs information
to put together a feeling
to put together a feeling
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of "How am I, as a whole body, doing?"
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And the gut, actually, is possibly
the most important advisor for the brain
the most important advisor for the brain
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because it's our largest sensory organ,
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collecting information not only
on the quality of our nutrients,
on the quality of our nutrients,
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but really also on how are so many
of our immune cells doing,
of our immune cells doing,
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or things like the hormones
in our blood that it can sense.
in our blood that it can sense.
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And it can package this information,
and send it up to the brain.
and send it up to the brain.
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It can, there, not reach areas
like visual cortex or word formations --
like visual cortex or word formations --
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otherwise, when we digest,
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we would see funny colors
or we would make funny noises -- no.
or we would make funny noises -- no.
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But it can reach areas
for things like morality,
for things like morality,
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fear or emotional processing
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or areas for self-awareness.
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So it does make sense
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that when our body and our brain
are putting together this feeling
are putting together this feeling
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of, "How am I, as a whole body, doing?"
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that the gut has something
to contribute to this process.
to contribute to this process.
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And it also makes sense
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that people who have conditions
like irritable bowel syndrome
like irritable bowel syndrome
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or inflammatory bowel disease
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have a higher risk of having
anxiety or depression.
anxiety or depression.
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I think this is good information to share,
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because many people will think,
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"I have this gut thing, and maybe
I also have this mental health thing."
I also have this mental health thing."
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And maybe -- because science is not
clear on that right now --
clear on that right now --
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it's really just that the brain
is feeling sympathy with their gut.
is feeling sympathy with their gut.
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This has yet to grow in evidence
until it can come to practice.
until it can come to practice.
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But just knowing about
these kinds of research
these kinds of research
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that's out there at the moment
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helps me in my daily life.
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And it makes me think
differently of my moods
differently of my moods
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and not externalize so much all the time.
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I feel oftentimes during the day
we are a brain and a screen,
we are a brain and a screen,
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and we will tend to look
for answers right there
for answers right there
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and maybe the work is stupid
or our neighbor --
or our neighbor --
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but really, moods can also
come from within.
come from within.
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And just knowing this helped me,
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for example, when I sometimes
wake up too early,
wake up too early,
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and I start to worry and wander
around with my thoughts.
around with my thoughts.
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Then I think, "Stop.
What did I eat yesterday?
What did I eat yesterday?
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Did I stress myself out too much?
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Did I eat too late or something?"
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And then maybe get up
and make myself a tea,
and make myself a tea,
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something light to digest.
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And as simple as that sounds,
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I think it's been
surprisingly good for me.
surprisingly good for me.
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Step three took me further
away from our body,
away from our body,
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and to really understanding
bacteria differently.
bacteria differently.
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The research we have today
is creating a new definition
is creating a new definition
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of what real cleanliness is.
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And it's not the hygiene hypothesis --
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I think many maybe know this.
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So it states that when you have
too little microbes in your environment
too little microbes in your environment
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because you clean all the time,
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that's not really a good thing,
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because people get more allergies
or autoimmune diseases then.
or autoimmune diseases then.
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So I knew this hypothesis,
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and I thought I wouldn't learn so much
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from looking at cleanliness in the gut.
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But I was wrong.
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It turns out,
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real cleanliness is not about
killing off bacteria right away.
killing off bacteria right away.
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Real cleanliness is a bit different.
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When we look at the facts,
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95 percent of all bacteria on this planet
don't harm us -- they can't,
don't harm us -- they can't,
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they don't have the genes to do so.
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Many, actually, help us a lot,
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and scientists at the moment
are looking into things like:
are looking into things like:
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Do some bacteria help us clean the gut?
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Do they help us digest?
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Do they make us put on weight
or have a lean figure
or have a lean figure
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although we're eating lots?
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Are others making us feel more courageous
or even more resilient to stress?
or even more resilient to stress?
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So you see, there are more questions
when it comes to cleanliness.
when it comes to cleanliness.
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And, actually, the thing is,
it's about a healthy balance, I think.
it's about a healthy balance, I think.
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You can't avoid the bad all the time.
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This is simply not possible;
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there's always something bad around.
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So what really the whole deal is
when you look at a clean gut,
when you look at a clean gut,
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it's about having good bacteria,
enough of them,
enough of them,
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and then some bad.
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Our immune system needs the bad, too,
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so it knows what it's looking out for.
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So I started having this different
perspective on cleanliness
perspective on cleanliness
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and a few weeks later,
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I held a talk at my university,
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and I made a mistake by 1,000.
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And I went home and I realized
in that moment,
in that moment,
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I was like, "Ah! I made
a mistake by 1,000.
a mistake by 1,000.
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Oh God, that's so much,
and that's so embarrassing."
and that's so embarrassing."
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And I started to think about this,
I was like, "Ugh!"
I was like, "Ugh!"
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And after a while I said,
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"OK, I made this one mistake,
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but then I also told so many
good and right and helpful things,
good and right and helpful things,
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so I think it's OK, you know?
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It's a clean thing."
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And then I was like, "Oh, wait.
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Maybe I took my perspective
on cleanliness further."
on cleanliness further."
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And it's my theory at the moment
that maybe we all do.
that maybe we all do.
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Take it a bit further than just
cleaning our living room,
cleaning our living room,
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where maybe we make it
to sort like a life hygiene.
to sort like a life hygiene.
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Knowing that this is about
fostering the good
fostering the good
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just as much as trying to shelter
yourself from the bad
yourself from the bad
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had a very calming effect on me.
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So in that sense,
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I hope today I told you
mostly good and helpful things,
mostly good and helpful things,
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and thank you for your time,
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for listening to me.
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(Applause)
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ABOUT THE SPEAKER
Giulia Enders - Doctor, authorGiulia Enders is working to reveal how our gut is at the core of who we are.
Why you should listen
Giulia Enders is a medical doctor and author from Germany. In 2012, her presentation "Darm mit Charme" ("Charming Bowles") won her first prize at the Science Slam in Berlin and went viral on YouTube. Shortly after that she was asked to write a book which turned out a great success in Germany and around the world. Her bestseller Gut: The Inside Story of Our Body's Most Underrated Organ has sold more than four million copies and has been published in over 40 countries. Today Enders is doing research for her medical doctorate at the Institute for Microbiology in Frankfurt and has continued to communicate science in TV and museum projects.
Giulia Enders | Speaker | TED.com