Explained (2018–…): Season 1, Episode 15 - Can We Live Forever? - full transcript

[female narrator] Every life...

has a lifespan.

The C. elegans worm gets on average
14 days on Earth.

European lobsters get up to 50 years.

The Bristlecone pine tree,
as much as 5,000.

And humans?

We have a maximum lifespan of around 120.

As best we can tell, some people
throughout history made it past 100.

One tombstone of an ancient Roman soldier

states simply, "Vixit annis C."
"He lived 100 years."

But for most of human history, you were
pretty lucky to make it past five.



Just 200 years ago,

no country on Earth had
a life expectancy higher than 40.

But then, that number started ticking up.

City's engineered ways
to give people clean water.

We discovered that germs caused disease.

[man] The germs have to leave the body
of a sick person

and enter the body of one who is well.

[narrator] And started regularly
washing our hands with soap

Nutrition improved, and we invented
new ways to keep food safe.

We discovered antibiotics
and we developed vaccines,

knocking out some of the worst killers
mankind has ever known.

Since 1800, the average life expectancy
worldwide has more than doubled

to around 72 years.

And the biggest reason
is that you're now far less likely



to die of an infectious disease
before you reach old age.

But for people who reach old age,

their life expectancy
hasn't increased much at all.

In England and Wales in 1840,

a 70-year old could expect to live to 79.

Today, it's 86.

A hundred and eighty years
of scientific advancement

for just a seven-year bump.

If the human lifespan is 120 years,

why, even in developed countries,

do most of us only make it
two-thirds of the way there?

What is it about old age that kills us?

And is it treatable?

Today's drugs truly work medical miracles,
for young and older lives.

[man] It was only 1930.

You get a disease, you die.

And then suddenly, you take a pill
and you live.

[woman] Aging is only now
coming into its own.

I really think we could be on the eve
of a whole new era.

[man] The finiteness of life.

It forces me
to appreciate every sunrise.

[narrator] So, what is aging?

Some of its symptoms are hearing loss,

poor eyesight,

weakened muscles,

our heart rate slows,
our blood pressure rises,

and our brains become less nimble
and more inclined to forget.

Our ability to stay focused on a problem

declines with aging.

There's a series of problems,
all of which accumulate

such that the quality of life diminishes.

The amount that we can actually live
actively in the world goes down.

[narrator] And as we age,

our risk of dying from a chronic disease
skyrockets.

Aging is the major risk factor for death

for any one of those diseases
we're afraid from.

From cancer, from cardiovascular disease,

from Alzheimer, from diabetes.

Now, you might stop me and say,
"Just a minute!

For cardiovascular disease,
isn't it cholesterol?"

Well, cholesterol is a three-fold risk.

But aging is a 5,000-fold risk.

[narrator] In the US,
the majority of deaths

are now caused by a chronic disease
associated with old age.

The costs are extraordinary.

86% of healthcare spending in the US
goes towards treating chronic diseases.

Finding cures for these diseases
has been a fixation

of governments, and scientists,
and societies.

With a new moonshot,
America can cure cancer.

An incoming coalition government will
commit an additional 200 million dollars

to dementia research.

Heart disease is the number one killer
of women.

[narrator] But we haven't found one yet.

So some researchers have proposed
a different strategy,

focusing on what they see
as the underlying cause.

Aging.

Scientists have estimated
that if we cured all cancers,

that would only extend lifespan
by about four years on average,

because people would get sick
from some other disease.

And if we're successful
in finding the targets that drive aging

and we can slow aging down,

then that's going to affect
the rate of disease.

If you have a leaky faucet in your house
and you want to fix it,

there couple ways to do it. One is
you put a bucket under the faucet.

You have to empty that bucket
every week, and it's just a big hassle.

On the other hand, if you just go under
the sink and you find the part of the pipe

that is leaking and you fix that,

that gets rid of your whole issue.

And so what we think about
in the aging field

is how can we find the core problem

that is actually causing all these
downstream pathologies and fix that

and eliminate the chances of any of them
actually occurring in the first place? [narrator] Aging is the result
of the biological accumulation

of damage in our cells.

This damage actually starts
before we're born.

Soon after conception,
our cells start duplicating

so our tissue can grow and regenerate.

As our cells copy themselves,

they make errors
that cause molecular damage.

For about two decades,
we are able to repair those mistakes.

But by the time we are in our 30s,

aging is accelerated.

Fighting this process isn't a new idea.

We're constantly bombarded
with ads for products

promising to restore our youth.

The angi-aging industry is now worth
250 billion dollars

and growing.

[woman] It's clinically proven to give
ten years back to the look of skin.

[woman 2] With Olay, you age less.

[woman 3] Visibly younger-looking skin.
Youth is timeless.

[narrator] Most of the anti-aging market

is focused on the symptoms of aging
you can see, like wrinkles,

and marketed mostly to women. Not the wrinkles themselves.

They haven't been scientifically tested
to actually change the skin.

Forget looking younger.

Some people have tried
to cheat death entirely.

In the 1960s, we came up with cryonics,

freezing a person as soon as they die

with the plan of reviving them
in the future,

once science has figured out how.

I think cryonics

takes the human body
a little bit too seriously.

My inclination is the doubt
that simply saving the body

is going to be enough to make it possible
to resurrect a person.

And in particular, a person who's at all
like the person who died.

Because that's the other problem
if your brain has changed a lot.

[narrator] But some people believe
there's a solution for that:

preserving the brain
by uploading it to a machine.

Seems to me rather unlikely
that we can load up my consciousness

into a machine.

My consciousness, I think,
is deeply connected

with its biological existence in my brain.

And I assume that what people care about,
when they care about continuing,

is continuing as a conscious person.

[narrator] These are ideas to fight death.

But they don't fight
the biological process of aging.

Science has mostly accepted
that aging is a part of life.

If you look around
at different species of animals,

what you notice right off the bat
is very striking,

especially if you have had a dog,

is that the rate of aging
of different species is different.

So, a dog...

has a lifespan that's seven times
shorter than ours.

Aging could just sort of happen,

but why does it happen at such
a different rate in different species?

[narrator] Then in 1961, we found a clue.

Dr. Leonard Hayflick discovered
that many human cells

stopped dividing after about 50 divisions.

It seemed our cells had
death programmed into them at birth.

Then, in the 1980s,

we figured out the cause.

The chromosomes in our cells

had protective caps on them,
called telomeres,

and with every cell division
those caps got shorter.

When the telomeres couldn't protect
our chromosomes anymore,

our cells died.

The solution to that seems pretty clear.

We need to engineer our cells
so our telomeres don't get too short.

But as it turns out,

cells like that already exist.

Cancer cells.

Nobody's been able to solve
that puzzle yet.

But around the world,

a handful of communities seem to have
figured out a secret to living long.

In this cluster of Sardinian villages,
one in six hundred people make it to 100,

six times higher
than the national average.

And on the Greek island of Ikaria,
one in three people make it to 90,

living nearly a decade longer
than mainland Greeks.

All their lifestyles have a lot in common.

Daily exercise,

a rich social life,

and a mostly vegetarian diet,

washed down with a couple glasses
of red wine.

How you live clearly affects
how long you live.

But some things are out of your control,

and we know that

because of this worm.

The C. elegans worm
has an average lifespan of 14 days,

and both of these worms
are 13 days old.

But scientists mutated a gene
in the one on the left.

It isn't just acting younger,
its lifespan doubled.

It was such a striking result
that people didn't believe it,

when it first came out almost.

Scientists had knocked out a gene
called DAF-Two that regulates insulin,

which meant the worm absorbed
far fewer nutrients.

We basically tricked the worm's body
into thinking it was fasting.

If you eat a meal,
the tissues have little doors in them

and they'll take the food in,

but in order to do that,
they need the hormone insulin.

If you have less insulin,

or if you have a receptor for insulin
that doesn't work as well,

which is like the DAF-Two mutant receptor,

then the animal doesn't think
it has enough food. He thinks, "Uh-oh.

I'm headed for difficult times now.
I'm gonna be careful.

I'm gonna protect my cells,
gonna fold my proteins better.

I'm gonna make sure
my DNA doesn't get damaged."

So once the cells are
in that good taken-care-of state,

I think the animal can just live longer.

[narrator] Scientist mutated the same gene
in fruit flies

and their lifespan nearly doubled.

In mice, it extended their lives by 50%.

All these organisms not only lived longer,

but they were more resistant
to multiple chronic diseases.

If one gene, in one pathway,

can modulate the rate of aging,
we're in business.

It changed our field totally.

It took us from hope to promise.

[narrator] All the people through history
who lived to 100 or 110,

or 120, maybe they had a genetic mutation.

After that breakthrough, research
on lifespan extension took off.

Within the next few years, we're gonna add
ten to twenty years to life.

We know that this is achievable

because there are already humans
that lived to be past the age of 100.

They're called centenarians. These people aren't just lucky,

it's genetically controlled,

because their children are also
more likely to live past the age of 100.

[narrator] People who live past 100
get sick much later in life

and for a shorter period of time
than people with a more average lifespan.

If we can find out what these secrets are,
then we can develop drugs that mimic them

for the rest of us, so we can all
live longer and healthier.

Investors have started betting serious
money on finding what those secrets are,

funding a flurry

of new companies
focused on the science of longevity.

[woman] We test different drugs
at Insilico,

in order to see how they can change
the difference between young and old.

[man] The goal at Human Longevity INC.,
is to change the face of aging.

[man 2] Elysium is sparking
new discoveries

and bringing the science
of living healthier for longer to you.

[narrator] One promising lead
with a lot of money behind it?

Senescent cells.

Sometimes when a cell stops dividing,
it doesn't die.

It keeps sending out chemical signals.

And these zombie cells
build up in our bodies as we age.

Clearing out those cells in mice

significantly improved
their health and lifespan.

These startups are racing to create
the first proven anti-aging treatment.

But there's a chance they might be beaten
by a drug that already exists.

The field of aging has been fascinated

by the fact that there are drugs
on market today

which potentially impact human aging
that were approved for other diseases.

[narrator]
And for a lot of people in the field

the great hope now is
the anti-diabetes drug metformin.

The active ingredient in metformin
comes from the plant Galega officinalis,

also known as goat's rue,

false indigo, professor-weed,

French lilac,

Spanish sainfoin,

and Italian fitch.

One major UK study showed that 78,000
diabetes patients taking metformin

lived a little bit longer
than non-diabetics.

People with diabetes who take metformin
compared to other drugs

have 30% less cardiovascular disease.

People with diabetes who are on metformin
have 30% less cancers.

[narrator] Remember the worm
and how we mutated its DAF-Two gene?

Metformin actually acts
on the human version of that same gene,

regulating insulin.

And works through other molecular
mechanisms we don't totally understand.

The US Federal Drug Administration
approved a metformin trial

as a possible treatment
for age-related diseases,

not for aging itself,

because the FDA doesn't recognize aging
as something that's treatable.

But if the results come back positive,

that might change,
opening the floodgates for more research.

I'm very optimistic
that this is going to be accelerated,

and that the next decade is really going
to be the turning point to target aging.

One of the exciting things for me is
it could be the case

that none of this translates to humans,
that's a possibility.

But if any of it works,
it changes the paradigm completely.

This is the beginning of a new way
to think about medicine.

[narrator] But we may not even want
a world where everyone lives to 120.

I've never heard anyone say
they want to, like, be the winner,

they want to beat the odds and live longer
than anyone ever has lived.

It's typically that you want to be able
to have good years for as many as you get.

One hundred and twenty?
As long as you can be healthy.

No asthma,

no heart trouble, you know,

and no bad legs.

That'd be wonderful.

Then it brings up other questions, like,

do I have enough money
to survive that way?

Part of aging is you might outlive
your money.

Why do cells age, why do organisms age,
why do organisms age and die?

That's a great puzzle to solve.
It's a challenging puzzle to solve.

But that doesn't mean solving it
and getting a therapy for it

is gonna be a good thing
for planet Earth.

[narrator] Centenarians might be healthier
than other people in old age,

but they're still old.

They're probably not going to work a job,
and they'll need some care,

and that has a cost.

And these costs are hard to cut back.

Caring for the elderly in many societies
is seen as a moral imperative.

If you look at countries that have
very long life expectancies like Japan,

what ends up as you have
a lot of old people

who are very isolated and lonely.

And you got frequent reports in Japan
of people dying and no one noticing.

[narrator] And we still haven't finished
the project we began two centuries ago:

getting every child to make it to old age
in the first place.

Once you're past 75,

getting it to 85 or 90
should not be our goal.

What our goal should be
is to get everyone to 75.

[narrator] If older people live longer,

the ratio of elderly to the young shifts,

and that changes society.

Studies have shown that
when a population becomes more elderly,

countries become less entrepreneurial.

And if a population doesn't die at all,
we might stop doing much of anything.

As that wonderful Star Trek episode shows,

you would run out of things that you could
possibly think were worth doing

if you had infinite time.

There's nothing left to say.

Can't you see, Captain?

For us, the disease is immortality.

The fact that my life has a beginning,
a middle, an end

is a really important part of what frames
the questions about what I'm doing.

In fact...

living with limitations is precisely
what gives life meaning.

Life's meanings derives
from the challenges we face.

And taking away all challenge
makes life completely uninteresting.