(dramatic piano music)
Downloaded from YTS.MX
- [Narrator] It's impossible to escape.
Official YIFY movies site: YTS.MX
Sweet and fatty foods surround us.
They're everywhere.
And for decades,
the body has not been handling these new eating habits well.
But what about the brain?
Do our mental health, our moods,
and our brain abilities suffer
when we eat badly?
- We know that junk food is making us fat
but science is telling us now
that it might also be shrinking our brains.
- [Narrator] Mind your manners
because scientists are at the dining table.
- Diets that are high in fat and sugar
in the long term lead to changes in part of the brain
involved in memory.
- [Narrator] This is a recent field of research,
a developing science
that spotlights a new facet of nutrition.
- Habitual intake of foods high in fat and sugar
result in a reprogramming of the brain.
- [Narrator] Your brain is affected
by what you put on your plate.
(gentle music)
Everything starts with the first meals,
even before birth.
The brain is built during pregnancy.
Later on, it's functioning depends
on how it has been nourished
by the expectant mother's diet over nine months.
The consequences of poor nutrition during gestation
have been known for a long time.
But in Australia,
scientists today are concerned with the effects of nutrition
on brain function.
Felice Jacka, a professor at the University of Melbourne,
is one of the best experts
on the link between nutrition and the brain.
She examined the behavior of babies
after tracking the eating habits of 23,000 pregnant women.
- We measured their intake of junk and processed foods.
We measured their intake of the healthful foods,
foods with lots of fiber and nutrients, et cetera.
And then we looked at the emotional health
of their children
over the first few years of life,
from 18 months to five years.
Of course, taking into account things such as education,
income, the mother's mental health, parenting practices,
these sorts of things.
And what we saw very clearly
was that mothers who ate more junk and processed foods,
so sweet drinks and salty snacks
and cakes, biscuits, during their pregnancy,
their children had more of these behaviors
such as aggression and anger and tantrums.
- [Narrator] This disquieting correlation
suggests that the mother
impacts the mental development of the baby,
though the link remains to be demonstrated
on the biological level.
In any case, Felice Jacka is convinced.
- So what we also saw in this large Norwegian study
is that the children's diets seemed to be important as well.
Independent of what mom ate,
if children were eating too much junk and processed foods
and/or not enough of the healthful foods,
they had more of these anger and aggressive type behaviors
but also sadness, anxiety, worry, nightmares.
- [Narrator] Since then, Professor Jacka's conclusions
have been confirmed
by studies in Spain, the Netherlands and Canada.
There is a link between dietary quality
and mood problems in children.
But what is the nature of this link?
How does food interfere with the functioning of neurons?
Excess fat and sugar
are now in the sights of scientists working on the brain,
both excesses and deficiencies.
Junk food often lacks nutrients,
so it leaves the body and neurons in particular
in a deficient state.
In this laboratory at the University of Bordeaux,
scientists are studying
the consequences of dietary deficiencies
on the brain of mice.
(mysterious music)
This experiment is used to measure anxiety.
The animal has a choice,
explore the lighted area
or hide in the shade.
A normal mouse takes the time to examine the lighted area.
But this mouse was deprived of omega-3 during its growth.
Omega-3 is a good fat well known for its benefits
to the heart and arteries.
Instead of exploring the environment,
the mouse takes refuge in a dark corner.
It's stressed, anxious.
This experiment has been reproduced many times
on dozens of mice.
For researchers, this strange behavior
can be simply explained.
Without omega-3's to build the brain,
it does not function normally.
That's because the gray matter is 90% fat,
so it cannot produce itself.
The brain is the organ after adipose tissue
that's the richest in polyunsaturated fatty acid or omega-3.
So omega-3 is indispensable
because the body cannot make it.
We have to ingest it.
It has to come from the diet.
Oily fish, organ meat, vegetable oils and seeds and nuts
like almonds have long been main sources
of omega-3 for humans.
But these foods have become scarce
in the cuisine of industrialized countries.
Sophie Laye wanted to go further
and understand what is wrong in the brain
of these anxious mice
that were deprived of omega-3.
She examined their neurons very closely
and under the microscope anomalies clearly appear.
- [Translator] Here the neurons
bloom with all these extensions.
But there's a reduction of the extensions
when there's a dietary deficiency of omega-3.
At a more precise level,
we see the connection between the neurons
which is represented by these small protuberances.
But these synapses are also diminished.
This shows that there's an impact on the connectivity
between the neurons in the brain
and these omega-3 deficient mice.
- [Narrator] Without omega-3 available
in the development stage,
neurons have trouble communicating with each other
because the structure of the cells is changed.
- [Translator] The omega-3 that we consume
will enter the brain
and embed into the membranes of neurons.
This will give flexibility to the membranes of the neurons
and allow a better connection between them.
- [Narrator] The amount of omega-3 that enters the brain
is crucial for making brain cells more efficient
because when these fatty acids
are incorporated into the membranes,
they improve the electrical properties.
In omega-rich neurons,
the signal propagates faster.
The network is more efficient.
To deprive the brain of omega-3
is to take the risk that it will not function as well.
- [Translator] The general population
is deficient in omega-3.
We have insufficient intake of omega-3.
So it's important to pay attention to it,
especially in the prenatal, developmental period.
During this period, omega-3 embeds itself
in massive quantities into the brain.
Also in adolescents, when there's often a change of food,
and during aging
where the incorporation into the brain of omega-3
tends to be less effective.
So we must increase its intake.
- [Narrator] The first rule
for a brain to run at full speed, avoid deficiencies.
But it is still necessary
that the good nutrients are accessible
and that a varied diet is available.
What happens to neurons
when meals are poor
and above all, always the same?
The great hamster,
who has thrived for a long time
here in the planes of the Alsace region,
reveals his painful situation today.
- [Translator] Since the 1960's,
there's been a decline in the hamster population,
which is on the verge of extinction today.
And at the same time,
we've noticed an increase in the agriculture area
where corn is cultivated.
- [Narrator] Caroline Habold
wondered whether the collapse of the population
was linked to the sudden glut of corn.
So she did a laboratory experiment
by feeding the hamster this cereal exclusively.
- [Translator] During breeding,
we observed behavioral disturbances in females
which resulted in hyperaggression and hypersensitivity
as soon as there was noise in the room.
(comical music)
Above all, what we did not expect
is that these females would devour their young
the first day after birth.
This behavior was observed
in more than 80% of females.
- [Narrator] A poor diet
is enough to throw a hamster
into a murderous rage.
This calls into question a simple vitamin.
- [Translator] A vitamin B3 deficiency
is at the origin of the abnormal behavior.
When we supplemented them with vitamin B3
in addition to their corn-based diet,
they expressed quite normal behaviors
and they began to nurse their young,
to raise them in the same way
as the females that were fed a diversified diet.
- [Narrator] The deadly misadventure
of the hamster is disturbing.
Could a deficient, unbalanced diet
also trigger aggression and violent reactions?
(bombs exploding)
Archives from the last war in Holland
provide scientists with an opportunity
to study this question.
At the time, food deprivation
had a serious impact on the behavior
of an entire generation.
- [Translator] During the second world war,
there was a famine in the Netherlands.
Women who were pregnant suffered from hunger.
The children of these women
showed greater sociability problems
around 18 to 19 years later.
They had more of these issues
than other people at the same age born in another era.
- [Narrator] Impulsiveness, aggressive actions,
and recurrent violations of the law,
this generation has been particularly scarred.
Since then, many studies have linked violence
to the quality of daily food.
Ap Zaalberg is a doctor of psychology
and a political advisor
at the Ministry of Justice.
His specialty, nutrition and crime.
He is convinced that enriching the food with vitamins,
fatty acids and minerals
can reduce aggression.
(speaking in foreign language)
- [Narrator] It is difficult to test this hypothesis
in real life
because many factors and circumstances
can influence our behavior and our impulses.
In order to study food in almost ideal context
without the influence of many parameters,
he chose to go to prison.
Ap Zaalberg then launched an experiment
for which 221 detainees volunteered.
- [Translator] Here, in the Netherlands,
we conducted a study of young prisoners
in eight different prisons.
For three months, we gave them vitamins, minerals
and fatty acid supplements
and then we looked at the effect on their behavior.
We measured it in two different ways.
First, we asked the detainees how aggressive they were
and we asked the supervisors for their views on the issue.
Above all, we looked at the incident log,
the number of times detainees were punished
and we saw that solitary confinement
had fallen dramatically.
- [Narrator] In the group of inmates
whose meals were improved,
the number of incidents was reduced by one-third.
Similar studies conducted in British and Australian prisons
come to the same conclusion,
minerals, omega-3's and vitamins
added as dietary supplements
reduce violent behavior.
- [Translator] The next step
is to test whether our scientific discoveries
can be put into practice.
We have several projects
with the prison system administration.
We will see if a change in diet
can be considered a way to regulate aggression.
- [Narrator] What we eat has the power to change our moods,
to stimulate certain impulses.
But could the food on our plate
also influence our decisions,
the ones we believe we make
with the most freedom in the world?
- [Translator] When people are asked
if they think that the food that they eat
has an impact on health, most answer yes.
But when asked if diet
can also influence thoughts and decisions,
very few people are willing to believe this is the case.
- [Narrator] However, in the very serious
Institute of Psychology
at the University of Lubeck in Germany,
Professor So Young Park has, for the first time, proven it.
His work reveals
the mechanism by which food could influence our thoughts.
And for that, the researcher has developed
a rather original experiment.
Imagine that you have to solve the following dilemma.
The money on the table
is to be divided into two sums
but it's your playing partner, a stranger,
who will decide on the distribution.
- I give you two Euros and I keep eight for me.
- [Narrator] If you accept this unfair offer,
you leave with a little money
but much less than him.
If you refuse, nobody wins anything.
So what would you do?
Do you accept the offer and take two Euros
even if you feel cheated
or do you refuse and leave with empty pockets
but keep your head held high?
Well, it turns out that taking or not taking the money
depends on a surprising condition,
what you just swallowed.
(mysterious jazz music)
- [Translator] We have prepared breakfast.
The only thing that is required
is to eat everything.
I will return later for the behavioral part.
Enjoy your meal.
- [Translator] As part of this study,
we followed 24 people
who came into the laboratory twice
to have two different breakfasts.
We found that the same person
made completely different decisions
based on what they ate in the morning.
- [Narrator] To this subject,
these two breakfasts look the same.
In reality, one is far more protein-rich than the other.
The ratio of protein to sugar
is the only parameter that is changed.
A few hours after the meal,
our subject then takes several tests on a computer.
Today, he tends to accept the offer.
His interest outweighs his annoyance.
He will leave with a little money in his pocket.
Last week, he had mostly refused
and had mostly gained nothing.
- [Translator] The subject,
having consumed a high protein breakfast in the morning,
was tolerant of unfair offers.
Conversely, the subject
who consumed a high carbohydrate breakfast
was less tolerant in the face of unfair offers.
- [Narrator] On average, the subject,
when we has had little protein,
rejects unfair offers twice as often.
But how to explain this surprising result?
To understand and provide biological evidence
for this observation,
scientists performed blood tests.
- [Translator] We will send the blood
to the laboratory for analysis.
We will measure the level of hormones
and amino acids in the blood.
For hormones, we are interested in insulin, cortisol,
adrenaline and adrenocorticotropic hormone.
And for amino acids, tryptophan and tyrosine.
(speaking in foreign language)
- [Narrator] On this list,
the most important is tyrosine.
It is an amino acid
that is part of the composition of a protein
that is key for brain function dopamine.
This molecule insures communication between neurons
involved in motivation and risk-taking.
The results of the analysis
show that subjects
who have a higher level of tyrosine in the blood,
are those who more easily accept the unfair offer.
- [Translator] We therefore assume
that increasing tyrosine in the blood
increases the amount of dopamine in the brain,
which in turn changes the behavior.
- [Narrator] In other words, after a few hours,
what we eat subtly alters the chemistry of the brain
and thus, the communication between neurons,
enough to guide some of our decisions.
At the Institute of Psychology in Lubeck,
experiments are continuing to confirm this result
because it is a first
and the implications are numerous.
- [Translator] Since we eat three times a day every day,
we realize that food has immense power,
that of modifying and shaping mankind.
So it's essential to think about how we can use food
to promote our wellbeing and optimize our mental state.
- [Narrator] Between dietary deficiencies
that soften the brain,
that disrupt moods,
and the diet that interferes with everyday decisions,
it's becoming increasingly clear
that food plays a preponderant role in our psychic life.
(sexy music)
But what about junk food
dripping with sugar and bad fat?
What would happen if we ate more of it?
This is the focus of research here in Australia
at the University of Sydney.
(mysterious music)
Margaret Morris runs the only laboratory in the world
where rats are fed junk food,
the stuff you find in supermarkets
and are served in cheap fast food restaurants.
- Our experiments use a range of Western foods,
the type eaten by all of us.
So we feed our rats meat pies, chips, cakes and biscuits,
the sorts of foods that are readily available and cheap.
So we are modeling the Western world.
- [Narrator] First consequence,
the rat doubles his food rations.
The animal is never satiated.
But this is not the most surprising outcome.
- One of our chief interests
is the impact of this diet on the animal's memory.
And we can measure this easily in the rat
using a task known as the novel object
and novel place task.
- [Narrator] For this test,
the researcher places objects
in the environment of a rat.
This one comes immediately to examine them
because rodents are very curious by nature.
Once the animal has completed its exploration
and memorized its environment,
it is temporarily set aside.
- We then place the animal in the arena
with one object that's been shifted.
(mysterious music)
- [Narrator] When he returns,
the rat spends more time examining the object
that has changed places
because the rat already knows the other objects.
They are engraved in his memory.
The rat's supercharged on bad foods behave differently.
- What we observed
is the animals eating a high fat diet
or a high sugar diet
or the combined high fat, high sugar foods,
were less able to recognize, to remember,
that that object had moved.
They explored the two objects about the same.
That shows an impairment of their spatial memory.
- [Narrator] Not only do supercharged rats
have damaged spatial memory
but also other malfunctions
that are warning signals for scientists.
This tampers with the hippocampus,
a small region nestled in the heart of the brain,
essential for learning
and the consolidation of memories.
The latest studies show that in humans,
a diet that is too rich
also interferes with the hippocampus.
- We see, for example, that the quality of people's diets
is related to the size of their hippocampus,
to the size of their gray and white matter volume,
and there's starting to be intervention studies.
So for example, we see that only four days
on junk food type diet
will have an impact on cognitive functions
that are related to the hippocampus.
- You order a coke?
- It tastes good.
- You didn't care if it was a Coke, you just--
- No, I wanted a Coke.
I like the taste.
- Ooh!
- Can I get some fries with that?
- [Narrator] Is our memory,
and even our intellectual abilities
really threatened by this new way of eating?
It is still too early to be definitive about that.
But clues are piling up and worry scientists.
Margaret Morris now seeks to understand
how sugary and fatty foods
disrupt the brains of rats
to the point of affecting their effectiveness.
A hypothesis is in progress.
Eating too much fat and too much sugar
triggers an inflammatory reaction
that spreads to the neurons.
- So in response to these foods,
there's a general inflammatory response
all around the body.
This has been well described in obesity.
But it now appears to be quite an acute response as well.
And what we find is that inflammatory molecules,
such as cytokines,
are increased in response to the diet.
(mysterious music)
- [Narrator] An overly rich diet confuses the immune system.
It panics and triggers an inflammatory reaction,
especially in fatty tissues.
Our fat masses release molecules
that then propagate this inflammation throughout the body.
Neurons spared by the phenomenon
were thought to be safe behind the blood brain barrier,
the membrane that surrounds the blood vessels
and normally protects the brain.
- So there's increased inflammation in the whole of the body
and we think that this may spread to the brain.
That's because the blood brain barrier
which normally protects the brain
from inflammatory molecules
may be impaired, in fact, by the diet
and become leaky,
allowing traffic of molecules into the brain.
Importantly, we've seen changes in inflammatory molecules
within the brain of our animals in response to the diet
and these correlate with the memory loss.
- [Narrator] The inflammation that infiltrates the meninges,
then trigger a particularly surprising phenomenon.
In her laboratory, Sophie Laye
has shown in supercharged mice
that certain immune cells of the brain,
the microglial cells
begin to devour the neurons.
- [Translator] These microglial cells
within the brain are important
because they can eat dead neurons.
But when they're deregulated,
especially in a situation of unbalanced nutrition,
they start to eat neurons that are alive.
Therefore, by consuming these neurons in excessive numbers,
eventually, they will destroy
or participate in the destruction of neural networks.
That includes neurons that are alive
and that should be functional.
- [Narrator] The reaction of the microglial cells
was filmed in vitro.
These are the ones we see moving in these images.
In red, appears the fragments of neurons that they ingest.
In an obese mouse,
the activity becomes frenetic.
This phenomenon at the heart of neurons
is now suspected to significantly affect the functioning
of the brain.
- We've been saying to people for 30 years
don't eat these foods,
you might have a heart attack,
you might get cancer and diabetes.
It hasn't worked to change people's behavior.
We hope that if people understand
that what they put in their mouth
is actually really essential
to the health of their brain
and that of their children,
that might have a more profound impact
on people's dietary choices.
- [Narrator] Awareness that certain eating habits
are harmful to the brain is one thing.
But how to resist temptations.
Desires are often stronger than willpower.
Junk food, especially sugar, which is glucose,
constantly tempt us to make bad choices.
The masterful manipulator, sugar,
leads our neurons by the nose.
(goofy music)
Microscope, mini manipulator and ultrasensitive recorder,
Xavier Fioramonti is at the helm
of a machine capable of recording
the electrical activity of a single neuron.
The principle is simple,
a slice of mouse brain is washed in a liquid
that keeps it alive.
Meticulously, the researcher approaches it
with an electrode.
The operation is particularly delicate.
- [Translator] Here, I go down the pipette
in the slice of brain.
And now we will approach this recording pipette
near the neuron to make contact.
That's it, we made contact.
And now we will be able to measure
the electrical activity of the neuron.
(machine beeping)
The upward peaks that we see
are potential areas for action.
This is how neurons encode information.
- [Narrator] The time that elapses
between each peak forms the message sent by the neuron.
- [Translator] Now, we will increase
the glucose concentration in the both
and we will see if this cell
responds to this increase in concentration of glucose.
As it can be seen here,
this cell responds to the increase
with more electrical activity.
There is more potential for action
than what could be seen here
before the increase in glucose concentration.
- [Narrator] Here is the signal
of that single cell.
In the brain, neurons are all connected to each other.
Scientists suspect that glucose
has the ability to modify the activity
of entire brain areas,
those that control emotions and pleasure.
Is this how sugar ensures its grip on our will?
This is for the moment, only a hypothesis.
But today, sugar addiction is the subject
of intense research in laboratories.
And what appears more and more obvious
is that the power of sugar
is similar to that of a drug.
Serge Ahmed was one of the first to bring proof
with a very simple experiment.
Step one, he raised rats
by giving them cocaine and sugar.
Then after weeks of this diet,
he presented the animals with a choice.
(speaking in foreign language)
- [Translator] We have a situation
in which the animal has the choice
between a lever that is connected to a syringe
that contains drug solution,
and the drug in question is a hard drug
like cocaine and heroine,
and on the left, a lever allows him to control a syringe
that contains a sweet drink.
And there we see
the animal chooses to take the sweet drink.
- [Narrator] Rats selected the sugar water
four times more often that the drugs.
It's not a glucose overdose,
but the irrepressible desire is there.
- [Translator] So this experiment simply shows
that sugar has more addictive potential
than we had imagined
and it is perhaps even stronger
than the pull of hard drugs,
such as cocaine and heroine.
(dramatic music)
Today, we live in a food environment that's a little crazy.
We find sugar in a lot of foods,
as we would expect, in sugary drinks.
But we also find sugar in foods
that are not meant to be sweet,
such as ham or soup.
We could cite other examples
but it's adding sugar to these foods
that contributes to the fact
that we make people addicted to it
without them knowing it.
(dramatic music)
- [Narrator] So are we actually addicted to candy bars
and the sugar hidden in most supermarket products?
Does the addictive power
that draws in rats also trap humans?
(ominous music)
The influence of sweet food on the human brain
is being studied here at the Oregon Research Institute.
- [Eric] What this program of research has revealed
is that habitual consumption of energy-dense food
alters your neural circuitry
in exactly the same way of consumption of drugs of abuse.
- [Narrator] Eric Stiche recruited
about 100 students,
half of which are used
to stuffing themselves with ice cream,
while the others never eat it.
They all came to his laboratory
to sip a milkshake inside an MRI machine
and deliver the secret of their brain activity.
- Great Casey.
So what we're going to do today
is give you chocolate milkshake
and record the brain activity in your entire brain
as you receive and anticipate receiving chocolate milkshake
to look at the neural basis
of consuming energy-dense foods.
- [Female] Doing okay there?
- [Casey] Mmhmm.
- [Female] All right, I'm gonna move
to the other room again.
- [Casey] Okay.
- This is very simple.
We're going to basically
give you several tastes of chocolate milkshake
and all you have to do is stay very still
and after the milkshake's delivered into your mouth,
wait five seconds and then swallow
and we'll repeat that sequence several times.
- [Narrator] Using a simple tube,
the subject sips the milkshake without moving his head.
- What we found out
is that the people who never eat ice cream,
you could trace the reward circuitry,
everything lit up just beautifully
and it activated things very strongly
but in contrast, the people who ate ice cream every day,
showed a very diminished response,
there was hardly any activation whatsoever,
illustrating that regular intake of energy-dense foods
really reduces the pleasure you experience
when you consume those foods.
- [Narrator] The reward circuit is a brain region
that controls the feeling of pleasure.
It is particularly responsive to sugar consumption
but eating too much
ends up weakening its responsiveness.
At equal doses, the pleasure sensations are reduced.
- What's very interesting about these findings
is that people who do cocaine or other drugs of abuse
on a very regular basis
show a very similar pattern
that they have to escalate how much cocaine
they do on a regular basis
to experience the same hedonic pleasure
and that's because of this decreased response
of reward circuitry
when you do something
that's hedonically pleasurable too much.
- [Narrator] In other words,
it takes more and more to be satisfied.
As in rats, sugar acts on our brain like a drug.
But is its addictive power
as powerful in humans?
The question still divides the scientific community.
But Eric Stiche's experiment
reveals another more subtle,
and maybe even more pernicious effect,
the brain after a diet too rich in sugar,
becomes hypersensitive to images of food.
- The more and more you eat ice cream,
the less and less the reward circuitry is recruited
when you consume ice cream
but the more your reward circuitry is activated
when you see cues that say you might get ice cream.
So your reward circuitry fires up
when you see an ice cream store
as you're driving down the street
or you see a commercial for ice cream on the television.
The reward circuity activities much more
for people who eat ice cream all the time
than it does for people who don't.
And that prompts eating in the absence of hunger
that drives obesity and weight gain.
- [Narrator] The direct influence
of food on our brain
plays a crucial role in what we choose to eat each day.
Feeding behavior turns out to be
an extremely complex phenomenon.
Public health issues push scientists
to study all aspects
that govern the choices we make on a daily basis.
(crying)
(slapping)
What is really going on in the brain
when choosing a dessert rather than a starter,
fish rather than red meat?
Who is really pulling the strings?
Carlos Ribeiro's laboratory
leads research on food choices.
- What we really want
is to find all the components,
all the genes, the molecules, the neurons,
which direct feeding decisions.
And for that we have to be able
to look at very fine and small effect.
- [Narrator] The simplicity of this model, the fly,
makes it possibly to explore new avenues, new hypotheses.
To understand the feeding behavior of the fly,
Carlos Ribeiro has just developed a machine
that follows in detail
the choices made by the insect
when it goes to the table.
- When it's touching the food,
which is in the other electrode,
with its tongue, the proboscis,
then we can measure that with the sensor here
which is the same sensor
which you use on you iPad and your iPhone
to detect touch on the screen.
Just that here, we don't detect the touch on the screen
but the touch of the food.
And so we can really now dissect and analyze
the choice of the fly,
if she eats protein or sugar,
but also when she's eating from the different foods
how it eats, how much it eats,
how fast it eats, how often it eats,
and really dissect all the details of the decisions
which are controlled by the brain.
- [Narrator] Thanks to this technique,
Carlos has proven that the main reason for choosing food
is first and foremost deficiencies.
Naturally, protein-lacking flies
prefer protein-rich food.
But as Ribeiro looked more closely,
he observed that that is not always the case.
- Sometimes actually we had some flies
which didn't have this strong urge to eat protein.
And then we were wondering why that was the case, right,
and so when we looked at it,
it turned out that the flies
which had no craving for protein
had gut microbes.
And so following up on many experiments,
we could show that there are two specific gut microbes
which when they are in the fly,
they suppress protein appetite
and therefore these two microbes
have a very important influence
on protein cravings in flies.
- [Narrator] Flies, when choosing their diet,
are influenced by the bacteria in their gut.
This unexpected discovery
obviously raises an important question,
does the bacteria in our own intestinal flora,
that which scientists call microbiota,
also work on our brains?
Do they play a role in our food preferences?
At Cork University in Ireland,
John Cryan pioneers microbiota research.
He has managed to prove that in mammals
the bacteria of the gut
intervene in certain behaviors.
- When you take microbes from highly anxious mice,
and transplant them to normal anxious mice,
they become much more anxious and vice versa,
that even when you take them from normal,
you can normalize the stress response and the anxiety.
- [Narrator] Scientists are even beginning to understand
how these bacteria interact with neurons.
- Here we go.
Okay, so we take out the organs.
This uncovers the Vagus nerve.
See here in yellow,
this is the long wandering nerve
that communicates with all of the organs,
all the way down into our intestine.
And this is really one of the key pathways
for communication between our gut and our brain.
And what we've shown some years ago
with our colleagues in Canada in a mouse model
that when we cut the Vagus nerve,
all of the effects
that we've seen with a certain microbe were gone.
So this tells us that the Vagus
is one of the key pathways of communicating
from our gut all the way to our brain.
We still need to figure out
well what happens when it gets to the brain
and comes to a region in deep in the brain stem
and then from there the signals get to the key circuits
that underpin complex behavior like food intake
and that's something we're working on right now.
- [Narrator] The influence of bacteria
on our food preferences
remains to be demonstrated.
On the other hand, it is established
that these preferences act on mood and anxiety.
Scientists now even consider the microbiota
to be a kind of intermediary,
a link between food and our brain.
- The main factor that influences
the composition of these microbes
is the food we take.
Diet and the diversity of the diet
is really important
from the moment we're born until we die
in shaping the composition of the microbes.
And so we're beginning to realize the importance
that what we eat has on what's in our microbes
and how that's influencing what's going on in our brain.
- [Narrator] One way or another,
our wellbeing depends on our microbiota.
A good diet for our mood
is a diet that is suitable for bacteria
in our intestines first.
This has led to the idea
of using food to pamper one's brain
and maintain one's mental health.
And for this, it is the famous Mediterranean diet
that seduces scientists.
- The traditional Mediterranean diet
is really high in a diverse range of plant foods.
So lots of different leafy greens
and different colored vegetables
but also fruits,
very importantly legumes,
so this is your beans and lentils and chickpeas,
nuts, nuts and seeds, fish
and of course olive oil.
Olive oil is a very important component
of the Mediterranean diet.
And we think that that diversity
leads to more diversity in the gut microbiota,
the microbiota that live in our gut.
And that diversity in the gut
has been linked to good health outcomes.
We ran the first study last year
where we recruited 67 people with major depression,
they received dietary support with a clinical dietician.
Now over a three month period this trial took place,
and at the end of that
when we measured their depression again,
we saw that the degree of change in their diet
correlated with the degree of change in their depression.
So the more they moved towards a Mediterranean diet,
the more their depression improved.
- [Narrator] Placing the kitchen
at the surface of your brain
is an idea that's catching on.
Scientists are now exploring ways to do that.
Spices praised for centuries
by traditional Indian medicine
are now studied in laboratories
for their virtues related to the mind.
Red fruit and berries
also have high expectations.
The polyphenols they contain
have the ability to reinvigorate neurons on the decline.
- [Translator] These polyphenols,
especially those from red fruits,
are found to reverse the cognitive decline
in aging mice.
That is to say,
these animals are protected
with any memory problems they may have.
And this leads us to human trials.
In this case,
a very recent study was conducted
on more than 200 subjects, age 65 and over.
In the group, some were healthy
but facing normal decline due to age.
To rebound their health,
they consumed large doses of polyphenols.
- [Narrator] Are red fruits, berries and spices,
the miracle ingredients for eternally young neurons?
It is still premature to proclaim it.
Science is just beginning
to uncover the secrets of this unexpected relationship
between diet and the brain.
The ideal menu for strengthening the brain
remains largely a mystery today.
But it seems that a diversified, balanced diet,
low in processed food and sugar
and favoring fruits and vegetables,
is the best way to preserve one's mental faculties.
- My grandmother said you are what you eat so eat well.
And what we're realizing now
is that science is beginning to understand
how true she was.
- And I think in the next few years,
we'll start to really get to a point
where we can understand maybe personalized nutrition,
personalized medicine,
and a very clear understanding of how
food interacts with the brain.
- [Translator] If we limited the deficiencies,
would that reduce crime?
Too early to say.
What we do know is that when you bet on healthy eating,
it has effects on behavior.
- The more we overeat Snickers bars,
we become hypervigilant to Snicker cues
and then we eat a lot of Snickers.
And we create that monster in ourselves.
So the best thing to do if you have kids
is feed 'em healthy foods
and not get 'em used to eating this kind of crap.
I can't believe I just said crap, sorry.
(mysterious music)