Professor Tim Spector

Yeah, so most people, if you ask people to point to the gut, they always think of their stomach.

That's not your stomach, you see.

They're the intestines.

So your stomach is up here.

It will take away your liver.

Yeah.

If you imagine we've got a body here, mouth, food goes in there through the esophagus, which is a tube that leads to the stomach.

And this is the stomach here, which is highly acidic.

And that leads into the duodenum through a little valve and that leads.

is where food starts getting mushed around into little balls, and it goes into the small intestine here, which is badly named because the small intestine is really the largest bit of the gut.

And it's endless coils of guts.

There are lots of crypts.

There's little nooks and crannies everywhere.

And so the surface area is really huge.

It's several tennis courts if you laid it out, just one area.

in one human and that's because that's where most of the nutrients get absorbed they get extracted from the food and absorbed that way so that all the trace elements and things we're recycling we're like a recycling factory and then from the small intestine it then goes into the large intestine which is also called the colon and that's where most of the gut microbes are

So 99% of the gut microbes are in that final part, the large intestine, which is a couple of meters long and varies widely between people.

And this is the spot where fiber goes, things that hasn't been digested in the early part of the gut.

And that's because the microbes mainly feed off fiber.

And so that's where they do the good.