Human: The World Within (2021) s01e03 Episode Script

1
- There's one ritual that happens
in every corner of the world.
Chances are, you did it today.
Over millennia
humans have turned eating
into culture
a way to celebrate
our roots
to bring us together.
But at the end of the day,
when you strip away
everything else
food is really just one thing
Fuel.
It's where you get the power
to live your life.
Even when you're sitting
completely still,
your body needs a lot of energy
to stay on.
But nowhere is the need
for fuel more apparent
than when you push yourself
to the absolute limit.
- As a Navajo distance runner,
we run for very specific things.
It's the celebration of life.
It's a form of prayer.
It's a teacher. It shows us how
to overcome obstacles in life.
And finally,
it's a form of medicine.
It helps heal us.
This is Navajo tea.
It's very hydrating.
On a cold morning like this,
it's the perfect way
to start a cold, long run.
Running in the Navajo culture
and the way that I was raised,
it's a part of life.
Whoo!
We get up, and we run
every morning to the East
to meet the Creator, at that
innocent time of the day,
the birth of that new day.
As we begin our run,
we start with a shout.
When we feel the connection
to the earth and to the sky
and to the Creator, we yell
Whoo!
and announce that we're
thankful for all those deities.
Our breath is breathing in
Father Sky.
The act of running is a prayer.
I'm Shaun Martin, I'm Navajo,
and I'm an ultra-marathon
runner.
- The marathon is considered
the ultimate test
of human endurance.
But an ultra-marathon
is in a whole other league
often upwards of 100 miles,
or four standard marathons
back to back to back to back.
These feats are only for
an elite class of athletes
and they send the body
to the edge of collapse.
See, the human body
is an amazing machine,
capable of feats that seem
impossible to most of us.
But like all machines,
it requires fuel.
Every one of our nearly
40 trillion cells
needs the juice to power on.
And for us, it comes
in one form glucose.
It's a sugar that allows cells
to create energy.
And it's locked inside
every plant and seed on earth.
The trick is extracting it.
Like how crude oil
has to be refined
to make the gas that we pump
our bodies contain a factory
that takes all the raw material
from food
and extracts glucose.
You know it as
the digestive system,
or more commonly, the gut.
It's a series
of connected organs
from your mouth,
through your intestines, and
all the way to the other end.
- When I think of the gut,
I think of three things
I think of an engine,
I think of a tunnel,
and I think of a strainer.
It's the engine because
it really is
where the food comes in,
and it gets processed
and digested,
and then it goes out to feed
all the other parts of the body.
It's a tunnel because
when you think about it,
it's a hollow tube
that divides the body,
so when something
is in your gut,
it's excluded
from the rest of the body.
And I like to think of it
as a strainer.
You dump something
into a strainer,
and the liquid goes through
into your little pot,
whatever you're
collecting it in.
And then all the debris
that's left gets dumped out.
- The liquid that goes through
the strainer is glucose.
And for an ultra-marathon runner
getting that fuel
is all about timing.
- Running, especially
long-distance,
is a really tricky challenge
when it comes to taking in the
right amount of food and water
to make sure you have
the sugar needed
to keep moving
without eating too much to the
point where you start cramping
because you can't
properly digest.
- So, this is what we call
blue corn mush.
In Navajo, it's called
Tóshchíín.
It's like a porridge.
The corn itself is really easy
on the stomach,
and then we add juniper ash
to the roasted corn,
and then with the ash mixed in,
it is a really good source
of energy
that'll last
for quite a long time.
- Starches like corn break down
into glucose in the gut,
and getting that sugar before
a run is crucial for Shaun.
But it doesn't happen instantly.
Luckily, a while ago,
humans discovered
how to jump-start the breakdown
before we ever take a bite.
- We don't know exactly when
hominids started using fire.
You know, it could have been
as long ago
as 2 million years ago,
2 1/2 million years ago,
perhaps longer than that.
But one of the major things
that it did for us
was to allow us to cook our food
and to unlock more nutrients.
- Cooking releases about 80%
more energy than raw food.
That's great news
for an endurance runner,
especially because
exercise actually
makes digestion slow down.
- Running and digestion are both
really active processes
in the sense that they both
require a lot of blood flow.
So somebody
who's an endurance runner,
a lot of blood flow
gets diverted away
from other parts of the body
and, in particular,
the digestive system
and gets diverted to
the large muscles in the body.
- One of the things
I had to learn really early
in running these distances
was to be able to eat enough
to have enough energy and fuel
during the long runs,
but at the same time,
not too much
to feel heavy and bogged down.
Scoop in there.
When I have blue corn mush
before a morning run,
I like to have it
at least an hour before
just so my body has time
to digest a little bit
and absorb
some of the nutrients.
Yep. That's what
I was raised on.
- Digestion really consists
of six distinct phases.
The first is ingestion
Just taking the food in.
- When you eat, mouth saliva
breaks food down
and binds it into a single mass,
ready to be swallowed
into the esophagus.
Through a process of relaxing
and contracting muscles,
the esophagus pushes
the food on its way.
The pulses are so powerful
that you could hang upside-down
and still move food against
gravity into the stomach.
The stomach is basically
a vat of acid,
so strong it can dissolve metal.
The juices kill off
dangerous bacteria,
and enzymes turn the solid mass
into liquid,
and then it's onto
the small intestine.
It's here where glucose
is finally extracted
and then absorbed
into the gut's lining,
where it then
enters the bloodstream.
Now it is ready
to refuel the body.
But glucose can't reach
hungry cells all by itself.
It needs to be carried
through the blood
by a hormone called insulin.
- Insulin is hugely important
in glucose metabolism.
What do we mean?
When you're eating,
you need insulin to come out
and ferry that sugar
and those carbohydrates
where they're needed
to convert it to energy.
Most of us know someone or have
heard of someone with diabetes.
Those are people
who have problems
with their insulin system,
so they have trouble
controlling their sugar levels.
- But how does glucose
actually become fuel?
Well, your cells have doors,
and insulin opens those doors.
Once the glucose is inside,
it burns into raw energy
and heat.
Usually that requires oxygen.
But some cells, like muscles,
can do it without
which tells us
that this chemical process
evolved even before
the atmosphere had oxygen.
Under normal circumstances,
insulin keeps the amount
of sugar in your blood in range,
and levels drop
as glucose gets burned for gas.
But for a marathon runner,
things work
a little differently.
- During exercise, there is
the suppression of insulin
which lowers blood sugar
so that we see in people
who are doing intense activity,
their sugar levels can rise
to almost diabetic levels,
because their bodies know
that they need that sugar
to do the intense activity.
- And on the flip side, the cells
of elite endurance athletes
are also much more sensitive
to insulin
three times more, in fact.
Glucose floods in
so an ultra-marathoner's body
can get more raw fuel
to cells faster.
During an ultra
is one of those times
muscles have to burn glucose
without oxygen.
When you're out of breath,
you can bet your cells are, too.
The upshot
is that you can keep running,
but there are byproducts.
As you push on, lactic acid
builds up, which means soreness.
At a certain point,
even the most efficient bodies
start to break down.
- As I'm running, I'm paying
attention to overall effort,
how my body's feeling inside,
what the muscles
are feeling like,
little aches and pains,
tightness all over the body.
As you go further
in an ultra-marathon,
those little, tiny
aches and pains
have the potential
to turn into something bigger
that could ultimately
end your race early.
- All runners have felt
muscle aches and exhaustion.
But marathoners have to face
hitting the wall.
It usually happens
at about mile 20.
That's when the body's
natural glucose reserves
are totally dried up.
The gas tank is empty.
A fog settles in,
and focusing becomes
increasingly difficult.
Some runners get cramps,
and others just can't
continue the race
unless they refuel.
- About every 15 to 20 minutes,
I like to take a gel
or blue corn mush.
- Every body is different,
and some people feel
that during the run,
they need to take a small amount
of carbohydrates or sugar
as they're running.
Others get cramps from doing it.
Some people get diarrhea.
It all depends on the body.
- It's not about
replacing calories.
It's about getting sugar
into the blood
as quickly as possible to start
reviving those overworked cells.
The trick is to refuel 
before
you run out of gas.
Our bodies can be pushed
to extremes
as long as we know
how to support them.
The record for longest run
stands at 350 continuous miles.
- When I finish an ultra,
I usually feel really good.
As a Navajo distance runner,
it's an enormous amount
of connection
thinking about our loved ones,
thinking about our ancestors,
and it's very emotional.
- Chances are you don't eat
with the same precision
as an endurance athlete.
Most of us eat
when we're hungry,
a few times a day.
But is inhaling food
every few hours
actually what's best for us?
- Today, we have access
to foods year-round
that we wouldn't
have had access to
through most of our
evolutionary past.
Our bodies are adapted to
dealing with periodic scarcity
that we don't encounter now.
- We evolved in a world
where sometimes
you just didn't catch dinner,
or frost killed the plants.
And obviously, we survived.
Hunger is a part of our DNA.
So while long-term
starvation is bad,
choosing not to eat
sometimes might
actually be good.
- Food is a huge part of my life
in every way.
It's sustenance.
You know, it keeps me going,
and it keeps me alive.
Food is also a part of my work,
and food is also meditation
for me.
My name is Deepti Sharma.
I am a practicing
spiritual Hindu.
Growing up, Hinduism was
a pretty big part of my life,
so I fast as part
of my religious practice.
I've tried to incorporate
those different beliefs
and rituals
into my everyday life today.
Hindus fast for a lot
of different reasons.
It's a form of discipline.
It's a form of cleansing,
to remember family members
that have passed away.
I grew up fasting
for those reasons,
and I continue to
because I believe
it's just a wonderful tradition.
- Fasting is a test of will.
That's probably why
it's part of so many religions.
But it also has powerful
physical effects
inside the body.
- Digestion uses up a lot
of resources from the body,
a lot of blood flow.
So when you fast, you basically
allow your digestive tract
to take a break.
- And it benefits
the rest of the body, too,
because of our
evolutionary past.
- Research actually suggests
that fasting might help
our cognition, memory,
ability to learn,
and be better for our bodies.
- If you're eating
three meals a day,
your body relies on glucose
for energy.
Whatever isn't immediately used
by cells goes to the liver.
It's the body's
energy reservoir.
When you're not eating,
the liver burns that sugar
and releases it into the blood.
But when you fast,
all that changes.
After about eight hours
of no food,
the liver runs out of sugar
to burn,
so you got to tap
into a new resource fat.
Under the skin,
around internal organs,
and in between muscles
are pockets of fat.
Fat cells travel to the liver,
and it breaks them down
into acids called ketones.
Ketones can be used
in the same way as glucose
by the brain, blood,
and muscles to power on.
And they're actually a more
efficient source of energy.
- Fasting seems to promote
an increased production
of a protein called brain-
derived neurotrophic protein,
and this seems to be something
that increases new cells
being laid down,
both in the digestive tract,
as well as in the brain.
- I'm a working mother.
I'm an entrepreneur.
My schedule
is all over the place,
as in each day
is very different for me.
So, a day of fasting for me
is I usually try
to eat one meal a day.
If in between, I feel sluggish
or exhausted,
I try to consume
a piece of fruit,
and I drink water
throughout the day,
because, for me,
it's really hard.
- What Deepti does is called
intermittent fasting,
and it can take
a couple different forms.
Some people don't eat
for a full 24 hours.
Others just seriously
limit their calories
once or twice a week.
- I try to adapt to what works
for me and my lifestyle,
because it's important
to take care of my body,
my health, my sanity,
most importantly.
As I am spending time
with other people
talking to them about work,
what I do, and what they do,
I started a company, FoodtoEat,
where we partner
with immigrant-, women-,
and minority-owned restaurants
in New York City.
We love coming into restaurants,
getting to know the owners.
Like, where are you guys from?
Like, why did you
start this restaurant?
We essentially
help these local restaurants
be able to book more catering
opportunities
at large corporate offices.
So, our clients
are, like, The Skimm,
Microsoft, Warby Parker.
- Wow.
- We love to get them to think
about diversity and inclusion.
But before we onboard
these restaurants,
we taste their food.
- The first dish
is a soup dumpling.
- Wow. Wow.
- Wow. Look at that.
- That looks amazing.
Those look so good.
But I will not be eating today,
because I'm Hindu,
and I'm actually fasting.
- Wow.
- Yeah.
- The fact that fasting
is mostly mind over matter
is particularly tough,
considering how hardwired
that connection is
between our stomach
and our brain.
- Digestion begins long before
the food actually hits the gut.
In fact, the thought of food
or the smell of food
can actually stimulate the
release of digestive enzymes.
- When we see
something appetizing,
receptors in the brain
fire signals
for the mouth
to start producing saliva
to help break down that food
before we even swallow it.
Within our saliva is an enzyme
that kick-starts
the chemical part of digestion,
preparing the body
for the task ahead.
- So I always bring somebody
along with me
who gets to enjoy the food
more than I do, I guess.
- Give feedback.
- Yeah, give feedback.
- I'm eating for two.
- Okay.
- Where should I start?
- Here you go.
- There you go. Wow.
- I'm so hungry.
I haven't eaten anything.
This is definitely torture.
- The stomach is
really fascinating
in how it can tell your brain,
"I'm full," or, "I'm hungry."
Our brains actually get a signal
when our stomach
is stretched out
saying, "Oh, my gosh.
I'm full. Don't eat any more."
And on the other hand,
when our stomachs are empty,
this also triggers our brain
in saying, "Eat and fill me up."
Our guts can directly affect
our moods and vice-a-versa.
- While scientists
have connected fasting
with an increase
in mental flexibility,
they've also found an increase
in hanger,
the irritable,
hot-tempered feeling
that comes along with hunger.
When we aren't eating,
and glucose levels drop,
adrenaline and
cortisol levels rise.
These chemicals in the brain
that trigger for hunger
are the same ones
that trigger for anger, rage,
and other emotions.
- We refer to the gut
as the enteric nervous system,
and we have about five times
as many neurons in the gut
as we have in the spinal cord.
90% of serotonin, the feel-good
hormone, is produced in the gut,
and we know that many
other neurotransmitters
are also produced in the gut.
So it really has a whole
separate system in there
that is helping to regulate mood
and feelings, et cetera.
- I can't wait to come back
and to eat for real,
'cause that looks great.
When I'm fasting, my body
definitely feels it.
There's a difference
than when I'm stuffing my face.
My body does feel
a little sluggish
and a little weaker.
It's a lot of discipline
of, like,
what you're able
to push yourself through.
But there is this energy,
this power
that comes from within.
- The fact that a lack of fuel
might make you healthier
isn't the only irony
lurking in the gut.
It's also home to a giant
population of bacteria
that, instead of
making you sick,
might actually be the key
to a strong immune system.
See, despite being
in the middle of our body,
the gut is our most
direct connection
to the outside world.
Food brings with it
pieces of nature,
and nature makes itself
at home inside us.
There's a symbiotic relationship
between our own cells
and foreign ones,
an alien universe
that runs right through us.
- The microbiome
essentially describes
the bacteria living in our gut.
Scientists estimate we have over
10 trillion bacteria in our gut,
which are playing a great role.
They help us break down food,
reabsorb nutrients and vitamins,
and even play
a really critical role
in keeping out the bad bacteria.
- The gut is a diverse
environment where our own cells,
food from outside,
and the bacteria that live
within us all coexist.
And because bacteria and human
cells are constantly touching,
it's a perfect place for
the body to learn what's safe
and what's dangerous.
- Where is your immune system?
It's in your gut.
- The thin mucus barrier
that protects the gut
is home to 80% of all
the immune cells in the body.
As we digest, these cells
learn to tell the difference
between friend and foe.
They know that what we eat
is fuel,
even though it comes
from the outside.
And anything that can hurt us
provokes a response.
- An intact intestinal membrane
is really essential
for protecting us from toxins
and keeping us healthy.
- But when these cells
malfunction,
fuel can suddenly become poison.
- Hey, guys.
- Hi.
- Okay, I have some cream cheese
and carrots, your favorite.
- Oh, yay.
- Do I use this for that?
- Mm-hmm, you can dip it.
It's all allergy-friendly.
Is that good?
- The carrots are really hard.
-My name is Ava,
and I'm 11 years old.
I'm allergic to dairy,
wheat, soy,
fish, shellfish,
nuts, tree nuts,
and I don't know if I said egg,
but egg.
It is kind of scary
to have all these allergies,
but, like, as long as you
stay away from them,
they can't really hurt you.
I can be near dairy.
I can be near nuts.
I just can't eat it or touch it.
- For a variety of reasons
we don't quite understand,
some people are more predisposed
to having allergies than others.
What happens in these people
is the immune system
will see certain types of food
as dangerous,
attach onto it,
and trigger this huge cascade.
- Whenever I have dairy
or some other allergens,
then I'll probably
start vomiting,
and I have to stay home
from school,
but I'm anaphylactic to nuts,
so they could
potentially kill me
if I didn't get
the right treatment time.
It's really terrible when you go
into anaphylactic shock,
'cause you start, like, grabbing
at your throat.
It's like you're underwater,
but you can't get out.
- The health of the G.I. tract
is one of the main factors
that's involved
in allergic reactions
and why we're seeing
so many people
who are having food allergies
and food sensitivities.
- An allergy is basically a case
of mistaken identity,
where the immune system
sees food as toxic.
There are a lot of different
immune cells
involved in
an allergic reaction,
but there's one special type
of cell that starts it.
They're called dendritic cells.
And they live on the top layer
of the gut's lining.
They're the messengers
of the immune system,
and their job
is to spot threats.
When you eat something,
dendritic cells eat, too,
in a way.
They try a piece
of what's passing through
to find out
whether it's safe or not.
Underneath this outer layer,
deep in the gut's lining,
are other immune cells
that can be activated fast.
Let's say these cells
absorb milk or a nut
and decide it's dangerous.
They raise the alarm
for other cells to go to war.
They release chemicals
that attack the food.
One of the most common
is called Immunoglobulin E.
- Now, IgE historically
was used to hunt down
parasites in our body.
But in some people,
for whatever reason,
the IgE will see food
as foreign, which can cause
all the symptoms
we see with food allergies.
- You may throw up
or break out in hives
classic signs of the body
trying to get rid of poison.
When the reaction happens once,
it will likely happen again.
Often, it starts early on.
- When Ava was born, she had
a lot of feeding issues.
She would vomit every thing
that ever went into her mouth.
- We know that one
of the contributors
to developing food allergies
is whether we've been exposed
to a lot of germs early on.
- From the moment we're born,
bacteria starts
putting down roots in the gut.
- Breast milk encompasses
the exact ratio of protein,
carbohydrates, and fat
needed to give Baby nutrition,
but it also contains antibodies
to promote healthy
gut bacteria growth
and to prevent the growth
of some bad bacteria.
- Our infant immune system
interacts with these bacteria,
and if all goes well,
this training makes it easy
for us to process fuel.
But if the body doesn't
get exposed to enough germs,
the immune system may never
learn to fight the right stuff.
And instead, the body
could end up attacking food.
Without the trillions of foreign
organisms living inside us,
we're more susceptible
to disease.
There are other effects, too.
The microbiome is also
directly responsible
for keeping us energized.
- We are completely animated
by our microbes.
We are really just the hive,
but without our microbes,
we are an empty hive.
The microbes are the worker bees
that are doing all the work.
They're synthesizing
the vitamins.
They're breaking down
the toxins.
They are digesting the food.
- They also play a role
in fat storage
and helping us
with our blood sugar.
So any alteration
in our microbiome
can actually increase our risk
of obesity or diabetes,
and we can alter
our gut bacteria
through lifestyle changes,
diseases, antibiotics.
Research is still out on
how we can go backwards, then,
and fix our gut bacteria
to make ourselves healthy.
- Alright, so, eat, homework,
and then off
to basketball practice.
- We kind of live through life
feeling like
there's this monster out there
that could get her.
So in order to make life normal,
we make sure that Ava
has all the safe alternatives.
Take the flaxseed milk and
mix it in with the rice flour.
- Whether allergies
can be completely reversed
is a question
we have yet to answer.
But it's no surprise
that the solution might lie
in restoring balance
to the microbiome.
But let's rewind.
Now that we know allergies
and the gut are connected,
here's another question
What hurts the gut
in the first place?
- We're seeing so many people
who are having food allergies,
and one of the main factors
is we're exposed
to so many things that really
are microbial disruptors,
that can affect our G.I. system
and that healthy ecosystem
of bacteria.
We are exposed to so many
pesticides and chemicals
through our food supply.
The average American child will
have 18 courses of antibiotics
before their 18th birthday.
That's a time when we should be
really stuffing our kids
full of vegetables
and trying to get them
to avoid antibiotics.
Our microbiome ages with us
as we age,
but the good news is
that it becomes more resilient.
- Oh, that looks so good!
I hope they make
more foods for me,
like coconut whipped cream.
It's delicious.
- Oh, that's a big bite.
What makes me hopeful
is that she's capable.
As much as she's tempted,
she won't try food
that may make her sick.
- I double-check the labels
for all the food
and just make all safe stuff.
That way, I'm not hurt at all.
- Most broad-spectrum antibiotics
will remove 1/3
of your gut bacteria.
So it's such a balancing act
trying to figure out
how can we establish practices
that can keep us safe
from diseases,
but at the same time,
not going too far
so that we're endangering
our health and our microbiome
because we have
super-sanitized ourselves.
- But a sanitized environment
doesn't totally decide
your gut's fate.
We're also learning
that it's much more dynamic
than other parts of the body.
- Based on a variety of factors,
from environmental
and lifestyle factors
to genetics,
our gut microbiome is changing
constantly, all day, every day.
- It's like a microbial
impression of your past
and present,
more unique than a fingerprint.
And it's not just bacteria.
There might be upwards
of a trillion viruses
roaming through our bodies
at any given time.
The microbiome is a living,
breathing organism,
much like a garden,
which means
that we can cultivate it.
- There are definitely
some negative processes
in the outside world
that I think parallel
what's going on
in our digestive systems.
Just as we're destroying
the external environment,
we're destroying
our internal environment
by being over-medicated
and not paying attention
to the food we're eating.
- The microbiome is like a moss
that sits on top of the lining
that separates the gut
from the rest of the body.
It's one of the most
diverse ecosystems on Earth,
controlled by more than
300,000 genes.
Human DNA by comparison
comes from a pool
of only 20,000 genes.
But if we deprive our microbes
for too long,
the moss goes barren
and bad bacteria spread.
That makes it easier for other
toxins to slip into the body.
The same goes for farmland.
When the soil is depleted
by deforestation
and pesticides,
disease creeps in.
- So how do we restore
a landscape that's been damaged?
- The really optimistic message
about the microbiome
is we can change it.
I like to think about gut health
as sort of threefold
remove, replace, and restore.
Remove all the things that are
potentially causing problems,
and that would be
a lot of medications
that are not
absolutely necessary.
Replace What can we do
to replace gut bacteria?
We could eat fermented food.
We can roll in the dirt.
We can get a dog.
We can open a window.
We can be exposed to nature.
And lastly, restore How can
we restore our microbiome?
We really get most of our gut
bacteria from the food we eat.
In conservation ecology,
rewilding means
reintroducing species
into a landscape
where they've become extinct,
and we can apply those
same principles to our gut.
- Whether they're in your gut
or in the ground,
good bacteria
need fuel to thrive.
On Georges' land, that fuel
comes from an unlikely source.
- The same fundamental building
blocks of the physical world
that make up the food that
ultimately becomes the energy
that fuels our mind and body
are also in our waste products.
- All organic matter can be
turned into energy.
It's a cycle, which means
that waste can become fuel
under the right conditions.
- For most of us,
stool is toxins, waste matter,
passing out of the body,
and it's mostly dead
red blood cells and bacteria.
And it's the dead red blood
cells that tend to give it
that brownish, nice, beautiful,
chocolate color.
- And so what we do at SOIL
is we try to think about,
how can we use
the example of nature
to create a system
whereby the nutrients
that we consume,
instead of going into the water,
where they pollute
aquatic ecosystems,
actually get back onto the soil
so that they can
produce more food?
And we do that
by taking human poop
and turning it into
incredible, fertile soil.
- Even though
it's organic matter,
if it's not treated properly,
human waste can be deadly.
- 99% of human waste in Haiti
is going untreated
into the environment.
Those pathogens are making
their way into the water
that people use to drink,
and that's why waterborne
disease continues to be
one of the leading
causes of death in Haiti.
But if you know
how to treat it well,
then you can actually
transform it
and harvest the amazing
nutrients that it has within it.
- Human waste on its own
would not reach the temperatures
to treat the pathogens,
but when you mix it
with agricultural waste,
that's when you get
that perfect mixture.
- Over time, the waste
breaks down into compounds
that can be put back
into the ecosystem.
- If you really want
a healthy forest environment,
the best way to do that is to
actually leave the forest alone.
How can we sort of stand back
and allow this ecosystem
to really blossom on its own?
If you want a really healthy
gastrointestinal track,
the best thing to do
is to really limit
what you're putting in there
and limit it to food.
- The health of Georges' crops
is actually more connected
to your own gut
than you might think.
Because just like plants
need good soil to thrive,
the microbiome needs plants.
- Healthy bacteria like
a lot of plant fiber.
And plant fiber
is mostly indigestible,
and it's indigestible
because it's really
not there to feed
us.
It's there to feed
our gut bacteria.
When the fiber gets broken down
by gut bacteria,
it's fermented into substances
that are really important
for the health of the gut.
- After they break down fiber,
gut bacteria release
something called
short-chain fatty acids
basically microbial poop.
Short-chain fatty acids
strengthen the lining
of the colon.
This not only prevents disease,
it helps the departure
of our own waste.
So you could say that the gut
is doing its own recycling.
- What does a healthy gut
look like?
A great example is a bacteria
called
Faecalibacterium
prausnitzii.
It's protective against
colon cancer,
heart disease, and diabetes.
But you can't just sort of
transport them in.
Just like when you're trying
to rewild land,
you have to figure out, how do
I create the right environment
to really encourage a growth
of these indigenous species?
If you're not feeding
the
F. prausnitzii
a high-fiber plant diet,
they're not going to repopulate
and recolonize your gut
in a sufficient number
to be helpful.
- I like to sometimes say
not we are what we eat,
but rather, we are
what our cells eat.
I think it would be healthy
for us as humans
to think about what they need.
When we think about what it
takes to be a good gardener
watering those plants,
giving them sun
we forget that our own bodies
are also like a garden.
- What we know about this system
is changing more rapidly
than any other.
- What excites me about our gut
is that
it's almost a symphony
between a half-dozen organs,
a ton of bacteria,
hormones, and chemicals.
It's more than just breaking
down and digesting food.
If you strip away everything,
we all feel
the exact same thing.
We go through the exact same
physiologic struggles.
- It's more than just an engine.
It's a unique footprint
and an entire universe.
- It is influenced
by so many things
by the food we eat,
by the places we've lived,
the experiences we've had.
In fact, we refer to the gut
as the second brain.
It reflects everything about us.
It's the hub. It's the center.
-To order "Human:
The World Within" on DVD,
visit shopPBS.org
or call 1-800-PLAY-PBS.