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  • A few years ago,

  • I always had this thing happening to me,

  • especially at family gatherings

  • like teas with aunts and uncles or something like this.

  • When people come up to you,

  • and they ask you, "So, what are you doing?"

  • And I would have this magical one-word reply,

  • which would make everybody happy:

  • "Medicine.

  • I'm going to be a doctor."

  • Very easy, that's it, everybody's happy and pleased.

  • And it could be so easy,

  • but this effect really only lasts for 30 seconds with me,

  • because that's then the time when one of them would ask,

  • "So, in what area of medicine?

  • What specialty do you want to go into?"

  • And then I would have to strip down in all honesty and just say,

  • "OK, so I'm fascinated with the colon.

  • It all started with the anus,

  • and now it's basically the whole intestinal tract."

  • (Laughter)

  • And this would be the moment when the enthusiasm trickled,

  • and it would maybe also get, like, awkwardly silent in the room,

  • and I would think this was terribly sad,

  • because I do believe our bowels are quite charming.

  • (Laughter)

  • And while we're in a time where many people are thinking about

  • what new superfood smoothie to make

  • or if gluten is maybe bad for them,

  • actually, hardly anyone seems to care about the organ where this happens,

  • the concrete anatomy and the mechanisms behind it.

  • And sometimes it seems to me

  • like we're all trying to figure out this magic trick,

  • but nobody's checking out the magician,

  • just because he has, like,

  • an embarrassing hairstyle or something.

  • And actually,

  • there are reasons science disliked the gut for a long time;

  • I have to say this.

  • So, it's complex.

  • There's a lot of surface area --

  • about 40 times the area of our skin.

  • Then, in such a tight pipe,

  • there are so many immune cells that are being trained there.

  • We have 100 trillion bacteria doing all sorts of things --

  • producing little molecules.

  • Then there's about 20 different hormones,

  • so we are on a very different level than our genitals, for example.

  • And the nervous system of our gut is so complex

  • that when we cut out a piece,

  • it's independent enough that when we poke it,

  • it mumbles back at us, friendly.

  • (Laughter)

  • But at least those reasons are also the reasons why it's so fascinating

  • and important.

  • It took me three steps to love the gut.

  • So today, I invite you to follow me on those three steps.

  • The very first was just looking at it

  • and asking questions like, "How does it work?"

  • and "Why does it have to look so weird for that sometimes?"

  • And it actually wasn't me asking the first kind of these questions,

  • but my roommate.

  • After one heavy night of partying,

  • he came into our shared-room kitchen,

  • and he said, "Giulia, you study medicine. How does pooping work?"

  • (Laughter)

  • And I did study medicine but I had no idea,

  • so I had to go up to my room and look it up in different books.

  • And I found something interesting, I thought, at that time.

  • So it turns out, we don't only have this outer sphincter,

  • we also have an inner sphincter muscle.

  • The outer sphincter we all know, we can control it,

  • we know what's going on there;

  • the inner one, we really don't.

  • So what happens is,

  • when there are leftovers from digestion,

  • they're being delivered to the inner one first.

  • This inner one will open in a reflex

  • and let through a little bit for testing.

  • (Laughter)

  • So, there are sensory cells

  • that will analyze what has been delivered: Is it gaseous or is it solid?

  • And they will then send this information up to our brain,

  • and this is the moment when our brain knows,

  • "Oh, I have to go to the toilet."

  • (Laughter)

  • The brain will then do what it's designed to do

  • with its amazing consciousness.

  • It will mediate with our surroundings,

  • and it will say something like,

  • "So, I checked.

  • We are at this TEDx conference -- "

  • (Laughter)

  • (Applause)

  • Gaseous?

  • Maybe, if you're sitting on the sides,

  • and you know you can pull it off silently.

  • (Laughter)

  • But solid --

  • maybe later.

  • (Laughter)

  • Since our outer sphincter and the brain is connected with nervous cells,

  • they coordinate, cooperate,

  • and they put it back in a waiting line --

  • (Laughter)

  • for other times,

  • like, for example, when we're at home sitting on the couch,

  • we have nothing better to do,

  • we are free to go.

  • (Laughter)

  • Us humans are actually one of the very few animals that do this

  • in such an advanced and clean way.

  • To be honest, I had some newfound respect

  • for that nice, inner sphincter dude --

  • not connected to nerves

  • that care too much about the outer world or the time --

  • just caring about me for once.

  • I thought that was nice.

  • And I used to not be a great fan of public restrooms,

  • but now I can go anywhere,

  • because I consider it more

  • when that inner muscle puts a suggestion on my daily agenda.

  • (Laughter)

  • And also I learned something else, which was:

  • looking closely at something I might have shied away from --

  • maybe the weirdest part of myself --

  • left me feeling more fearless,

  • and also appreciating myself more.

  • And I think this happens a lot of times

  • when you look at the gut, actually.

  • Like those funny rumbling noises that happen

  • when you're in a group of friends

  • or at the office conference table,

  • going, like, "Merrr, merrr..."

  • This is not because we're hungry.

  • This is because our small intestine is actually a huge neat freak,

  • and it takes the time in between digestion to clean everything up,

  • resulting in those eight meters of gut -- really, seven of them --

  • being very clean and hardly smelling like anything.

  • It will, to achieve this, create a strong muscular wave

  • that moves everything forward that's been leftover after digestion.

  • This can sometimes create a sound,

  • but doesn't necessarily have to always.

  • So what we're embarrassed of is really a sign

  • of something keeping our insides fine and tidy.

  • Or this weird, crooked shape of our stomach --

  • a bit Quasimodo-ish.

  • This actually makes us be able to put pressure on our belly

  • without vomiting,

  • like when we're laughing

  • and when we're doing sports,

  • because the pressure will go up and not so much sideways.

  • This also creates this air bubble

  • that's usually always very visible in X-rays, for example,

  • and can sometimes, with some people,

  • when it gets too big,

  • create discomfort or even some sensations of pain.

  • But for most of the people, is just results

  • that it's far easier to burp when you're laying on your left side

  • instead of your right.

  • And soon I moved a bit further

  • and started to look at the whole picture of our body and health.

  • This was actually after I had heard

  • that someone I knew a little bit had killed himself.

  • It happened that I had been sitting next to that person the day before,

  • and I smelled that he had very bad breath.

  • And when I learned of the suicide the next day,

  • I thought: Could the gut have something to do with it?

  • And I frantically started searching if there were scientific papers

  • on the connection of gut and brain.

  • And to my surprise, I found many.

  • It turns out it's maybe not as simple as we sometimes think.

  • We tend to think our brain makes these commands

  • and then sends them down to the other organs,

  • and they all have to listen.

  • But really, it's more that 10 percent of the nerves that connect brain and gut

  • deliver information from the brain to the gut.

  • We know this, for example, in stressful situations,

  • when there are transmitters from the brain that are being sensed by our gut,

  • so the gut will try to lower all the work,

  • and not be working and taking away blood and energy

  • to save energy for problem-solving.

  • This can go as far as nervous vomiting or nervous diarrhea

  • to get rid of food that it then doesn't want to digest.

  • Maybe more interestingly,

  • 90 percent of the nervous fibers that connect gut and brain

  • deliver information from our gut to our brain.

  • And when you think about it a little bit,

  • it does make sense, because our brain is very isolated.

  • It's in this bony skull surrounded by a thick skin,

  • and it needs information to put together a feeling

  • of "How am I, as a whole body, doing?"

  • And the gut, actually, is possibly the most important advisor for the brain

  • because it's our largest sensory organ,

  • collecting information not only on the quality of our nutrients,

  • but really also on how are so many of our immune cells doing,

  • or things like the hormones in our blood that it can sense.

  • And it can package this information, and send it up to the brain.

  • It can, there, not reach areas like visual cortex or word formations --

  • otherwise, when we digest,

  • we would see funny colors or we would make funny noises -- no.

  • But it can reach areas for things like morality,

  • fear or emotional processing

  • or areas for self-awareness.

  • So it does make sense

  • that when our body and our brain are putting together this feeling

  • of, "How am I, as a whole body, doing?"

  • that the gut has something to contribute to this process.

  • And it also makes sense

  • that people who have conditions like irritable bowel syndrome

  • or inflammatory bowel disease

  • have a higher risk of having anxiety or depression.

  • I think this is good information to share,

  • because many people will think,

  • "I have this gut thing, and maybe I also have this mental health thing."

  • And maybe -- because science is not clear on that right now --

  • it's really just that the brain is feeling sympathy with their gut.

  • This has yet to grow in evidence until it can come to practice.

  • But just knowing about these kinds of research

  • that's out there at the moment

  • helps me in my daily life.

  • And it makes me think differently of my moods

  • and not externalize so much all the time.

  • I feel oftentimes during the day we are a brain and a screen,

  • and we will tend to look for answers right there

  • and maybe the work is stupid or our neighbor --

  • but really, moods can also come from within.

  • And just knowing this helped me,

  • for example, when I sometimes wake up too early,

  • and I start to worry and wander around with my thoughts.

  • Then I think, "Stop. What did I eat yesterday?

  • Did I stress myself out too much?

  • Did I eat too late or something?"

  • And then maybe get up and make myself a tea,

  • something light to digest.

  • And as simple as that sounds,

  • I think it's been surprisingly good for me.

  • Step three took me further away from our body,

  • and to really understanding bacteria differently.

  • The research we have today is creating a new definition

  • of what real cleanliness is.

  • And it's not the hygiene hypothesis --

  • I think many maybe know this.

  • So it states that when you have too little microbes in your environment

  • because you clean all the time,

  • that's not really a good thing,

  • because people get more allergies or autoimmune diseases then.

  • So I knew this hypothesis,

  • and I thought I wouldn't learn so much

  • from looking at cleanliness in the gut.

  • But I was wrong.

  • It turns out,

  • real cleanliness is not about killing off bacteria right away.