DR. EMERAN MAYER: I'd like
to thank Liv and the team
here to invite me.
It's a great honor.
It's exciting to give
this presentation.
I should preface that
I'm not a nutritionist.
I'm not a dietary expert.
I'm really a hybrid between
a gastroenterologist
and a neuroscientist,
and have used these skill
sets during my career
to study the interaction
of the brain and the gut.
Let me start with a couple
of historical things.
I will walk you through--
well, let me say this.
You're not going
to come out of this
with a detailed
instruction of what I
want you to eat to be healthy.
For that, you can buy a lot of
books that are out there right
now.
Most of them are really
not the whole truth.
But I'm going to give you
the background for you
to look at your digestive
system and the brain-gut axis
in a totally different way.
And I think that will
change when you-- whenever
you eat something, you will have
a very different perspective
on what happens in your body.
I'm going to start with a
couple of historical slides.
This shows my grandfather
in 1895, I think.
He was one of many generations
of confectioners and chocolate
makers.
And that's the business that
I was supposed to take over.
It didn't turn out this way,
but I did stick with something
that appeals to the
tastes and which clearly
involves the brain and the gut.
Another historical
thing that I want
to mention-- 1929, the metaphor
of the digestive system
and the illustrator in Berlin,
Fritz Kahn, published his book,
"Man is Machine."
And the reason
I'm showing this--
it shows the paradigm that was
predominant for a long time--
actually, in some
people's minds,
it's still the paradigm--
that our digestive system
is this industrial-age machine
that you put things in.
It's a conveyor belt.
It grinds things.
Puts in chemicals, breaks it
down, and then eliminates it.
And that's quite different from
where we have arrived today.
So what I'm trying
to convince you,
and what I've done
in my book, is
that the model-- as
we always take models
from the technical world
to explain our bodies--
is limited.
But I think the
supercomputer model
is much closer to the way
we are understanding, now,
how the brain, the gut, its
microbes, and food interact,
generating, ultimately,
health and well-being.
Why did we come up with this
concept of the brain gut
microbiome supercomputer?
We've known for a
long time there's
close interaction between the
brain, the nervous system,
and the gut.
We knew this long before the
microbes-- the microbiome came
on the scene.
And let me show you how
far this has taken us.
On the left side, we now
know there's the human brain
connectome effort.
We know many of the
networks now in the brain.
There's no longer regions,
but the interconnectedness
of many of these systems
regulate not just
information goes out to
our skeletal muscles,
but it goes out-- through the
autonomic nervous system--
into the gut.
And on the right side, you
see what's been evolving,
in terms of the gut connectome.
Again, in my career, we
started with focusing
on individual cells.
Now we know they're
all interconnected
and they generate the
output that ultimately
is then picked up
by sensory nerves
and goes back to the brain.
So the brain gut axis is this
continuous circular movement
between things that
go on in our brain.
Emotions-- they're
always reflected
in a change in the
network in the periphery
and the output of this network
feeds it back to the brain.
So imagine you put
something in like food
into the lumen of your gut.
A lot of things will
happen at multiple levels
of this circular brain
gut communication.
A few years ago, some very
spectacular animal experiments
were published which
suggested that there
is an interaction
of the microbes
in our gut with the brain--
with the nervous system.
And in the meantime,
we have clearly
incorporated these microbes
and their signaling molecules
fully into this circular system
between the brain and the gut.
I'll show you a few
examples of this.
A few illustrations.
Some of you may have heard this.
This has almost become,
now, common knowledge.
The microbes-- there's 100
trillion of them in our gut--
if you put them together,
they will be larger
than either the
liver or the brain.
We can't see them, but if
you could compact them,
it would be a very large organ.
And some people have referred
to this as a forgotten organ
because we have really made
all our concepts about this
without taking this
into consideration.
It's amazing that
we could actually
come up with health
recommendations
by leaving more than half of
the system out of the equation.
So all the stuff that you
still read in textbooks--
because this has not made
into the GI textbook--
still has to be
re-conceptualized and
re-edited.
Why are the microbes
so important?
Not just because of the
100 trillion numbers.
Much more important
is that they have
the potential of doing a lot
of things that we can't do.
And if you compare the number
of genes that they have,
which allows them to produce a
lot of things, then between 350
and 500 times more genes.
So they can produce a lot
more substances and things
than any human being can do.
So we're just scratching
on the surface of this--
what this means for us.
The fact that they have
all these genes that
can be activated within
minutes of doing something,
either at your mind level--
changing your emotion--
or at your gut level, putting
something into your gut
that they will respond
to you immediately.
We, as humans, are much
slower and much more
limited in doing this.
There's a lot of things
that the microbes can do.
The most important one
is it breaks down--
that's probably why we
developed this-- they
break down indigestible
food products--
complex carbohydrates,
which are in plants--
into smaller molecules.
Some of these molecules
are being absorbed
and you can harvest
this additional energy
that otherwise would be lost.
So they help us, really,
to extract more energy out
of food.
The second one is-- and that's
kind of the most interesting
one-- that many of
the molecules that
arise from this breakdown
of these plant carbohydrates
are signaling molecules
that can talk not only
to the other microbes,
are also to our gut,
and through mechanisms,
back to our brains.
So probably this whole
thing arose mainly
because humans and
microbes found out
that they can benefit
from each other.
Humans mainly extracting
more calories out
of what they were eating.
Our hunter-gatherer ancestors
were obviously dependent
on that.
And there's a lot of
things-- it's just
showing a few examples here.
A lot of molecules that
are quite interesting.
They can affect virtually
every organ in the body.
The science is mainly
focused on metabolic
processes-- the
liver, fat tissue.
Our group has had
a primary interest
of which one of those molecules
actually can affect the brain?
Some of these
spectacular things that
have started this
interest in the brain
have been that it was
possible to transplant
behavioral traits, like
anxiety from a mouse that
was-- or the other way around.
From a timid mouse
into an outgoing mouse.
And this is obviously
anthropomorphic language.
And just by transferring
the microbes,
the behavior of that mouse
would change to the one
to the donor mouse.
And nothing else changed.
Whatever those microbes--
those substances
they produced changed the
behavior of the mouse.
Another one-- equally
interesting and important.
By just transplanting
the microbes
from an obese and a mouse
with a veracious appetite,
it changed a lean mouse
into one that not only
gained a lot of weight,
but also that had
the same abnormal eating
pattern of unrestricted eating.
Unfortunately, those
spectacular findings
have not been translated
into human studies.
A lot more difficult than
in these artificial mouse
experiments.
But certainly, it started
a lot of enthusiasm-- a lot
of potential-- for obesity
metabolic syndrome.
And there are many
studies going on
with fecal microbial
transplantation,
antibiotic treatment,
and so forth.
Why would these microbes
be able to talk to us?
Most people would think,
well, the microbes
learned it from us.
But in reality, over
billions of years,
microbes have
lived in the oceans
and have perfected-- developed
these 500 genes-- 500-fold--
so millions of genes,
really-- to synthesize
these communication
molecules that allow
them to talk to each other.
When they decided to settle
in the gastrointestinal tract
of the first primitive
marine animals,
the two found out that this was
a very beneficial relationship.
And that stayed for
the rest of evolution.
This symbiosis stayed there
for the rest of the time.
And the
neurotransmitters that we
have now in our gut-- in
our enteric nervous system
and in our brain--
really originated
from this genetic
information that the microbes
developed over a long time.
So we're intricately--
over millions
of years-- connected
to that world
of microbial communication.
And probably have a
lot to learn from it.
And very important to
say that I think we're
just really at
the very beginning
of understanding the
implications for our health
and for disease.
This just illustrates
the transition
of these very primitive
nervous systems
from the first marine
animals to our first gut,
which is really the gut in
our-- the brain in our gut.
Ultimately, into
our nervous system.
All this originates in this
vast experience and information
that the microbes
developed while they
were living without any
mammals or any humans around.
Let me say one thing about gut
reactions and gut feelings.
Everybody uses this term.
When I wrote this book, I
realized-- paying attention
to it-- there's not a
day goes by in the press
that people would
not talk about,
they made a decision with their
gut or they had a gut reaction.
It's present in every language.
So something very fundamental
that people have experienced.
Let me just give
you two examples.
The one is the top
down-- the gut reactions.
How the gut reacts when you are
in an emotional state or when
you're stressed.
If you don't have one
of those disorders--
these stress sensitive
disorders where
you get stomach pains when
you're stressed or anxious.
It happens all the time.
Your emotions are
reflected a mirror image
in your gut function.
The secretion, the
contractions, the blood flow,
and now, also the microbes.
We know that these signals
that go down from the brain,
specific for every
emotion and stress,
will directly talk
through this shared
language to your microbes
and will change what
they do to the food you eat.
So when you eat a meal
when you're angry, anxious,
or stressed, you will
process this food
very differently than if
you're relaxed, happy,
in a pleasant social context.
This is illustrated here.
Just like everybody
can tell if you're
angry or anxious by
looking at your face--
your facial muscles-- the gut
does exactly the same thing.
You may not feel it, but
it has a big impact on how
your gut processes the food.
The other way around is equally
intriguing, possibly more
intriguing.
And I've used in the
book this analogy
to the Google search engines.
There's constantly a huge
amount of information flow
from the gut, including all
the chatter of your microbes,
into centers of the brain.
And all these signals
are being stored.
You may not feel them.
You may not have the cramps.
But all these-- if you're in
a situation that is upsetting,
is threatening, you will store
this vast amount of information
at your brain
level and later, be
able to recall it by
accessing this vast database.
It's just like the
Google search engine.
Last year, I was at this
art exhibition in Venice,
the Biennale, and I saw
this interesting screen
where hundreds of these
little videos were playing,
and each person was
telling an emotional story
from their life.
And I thought, this
is the perfect analogy
to what happens in our brain.
We have billions of
these emotional moments
with their gut
sensations stored there.
And when we make a
gut-based decision,
our brain can access
them within milliseconds
without going through a
logical, linear attempt
to come up with a conclusion
or with a decision.
I can't prove this, but I think
it's a very tempting model,
or analogy, to understand that.
Food microbes and the brain.
As I mentioned
before, food interacts
with the microbes
with many sensors
in the gut and this information
makes it to the brain.
And then the brain responds
in a circular fashion
on the right side to influence
contractions and bowel
movements.
One signaling system is
particularly intriguing.
If anybody's in here who takes--
it's probably not the case--
but if anybody took an
antidepressant-- serotonin
reuptake inhibitor--
you would think
that this medication
acts on your brain,
on the serotonin system.
But we know now that only about
3% of your entire serotonin
is in the brain.
All the rest is in
the gut, in cells that
are influenced by the microbes.
The microbes actually
can influence
the synthesis of the substance.
And these cells, then, can
feed it back to the brain
into centers that deal with your
regulation of emotion, sleep,
appetite, and well-being.
So you have you on your own
Prozac factory in your gut
and the microbes play
a big role in this.
We're just at the beginning.
Psychiatrists have
refused to really look
at this for a long time.
Most of them still are not
aware of that collection.
But it, obviously,
opens up a lot
of intriguing
possibilities, not just
for pharmacological treatment
targeted at this gut system,
but also in terms of how
food and different food
components-- by
changing your microbes--
can influence that and generate
well-being and affect all
these other vital functions.
Another system of
great importance
are these inflammatory cells.
The circled type of cell
in the lining of the wall
are these dendritic cells.
They are immune cells and they
have these little tentacles
that stick out into the lumen
of the gut and their receptors.
The microbes talk
to those, as well.
So there's an
ongoing dialogue to
your gut-based immune system.
And immune cells, then,
signal this back up,
virtually of your organ,
particularly interesting,
to the brain.
Why would this be
important for diet?
The inflammation doesn't
occur because you
have a gastroenteritis, but
it's modulated to a large degree
by the food that you eat.
We know that food with a
high animal fat content
and with a high degree of
unsaturated fatty acids
will activate your microbes
to release a substance called
LPS-- lipopolysaccharide--
which increases
the leakiness of your
gut and then gets
into these immune cells and
triggers this whole cascade
of a systemic low-grade
immune activation,
including effects on the
central nervous system.
It's now believed that it's
not only your adipose tissue
that produces inflammation
through this mechanism.
Because the signals go to
the fat cells, as well.
But it's also the brain
and the chronic influence
of that low-grade
inflammation on the brain
may play a major role in
neurodegenerative diseases
such as Parkinson's disease
and Alzheimer's disease.
So that's a very intriguing
aspect that links--
and there's already now
studies, just recently published
from UCLA.
For example, that
a particular diet,
together with other
lifestyle factors,
can slow the development
of Alzheimer's
in high-risk patients.
So probably, that mechanism
is at the bottom of that.
The question that's
always being asked--
is there an optimal diet?
And this is not something that
people have asked just now,
in the last 10 or 20 years.
But this has been at
the center of attention
for many ancient
healing traditions.
The modern answer
to this question,
is there an optimal diet,
as you can see here.
You get these very
contradictory answers.
A clean gut versus
eating dirt, eating
fat to get thin versus
eating complex carbohydrates.
And then, "The Grain Brain,"
which basically recommended
all grains, which contain many
of those-- the whole grains--
many of these
complex carbohydrates
that microbes is food
for the microbes--
that this would cause all
kinds of diseases, including
brain diseases.
I had the pleasure
and the privilege
to participate some
30 years ago in a film
expedition to the
Yanomami Indians
in Venezuela on
the Orinoco River.
And I never thought that
that would come back
to me 35 years later, in
terms of optimal diet--
the question of optimal diet.
We lived with these people for
four weeks, ate the same things
that they ate.
We observed that they have
a very high, about 80%,
complex carbohydrate diet.
Very diverse.
They collect from the jungle.
Small amount of animal products.
And that they had several
hundred herbal medicines
that they used to
stimulate their-- used
for various diseases.
These are some of the few
remnants of hunter-gatherers
in the world.
Another entity are the
[? Hasta ?] in Africa.
Totally different environment,
but very similar dietary
habits.
The same kind of hunter
gatherer diet with small amounts
of meat, virtually no animal
fat, and large amounts
of complex carbohydrates.
Now, the reason I
got led back to this
was when a paper was
published by Gloria Dominguez
from NYU, where they
looked at the gut
microbes of those
Indians that lived very
close to the Yanomamis--
not identical,
but-- and the main
thing was they
and the [? Hasta ?]
have the greatest
diversity and abundance of
gut microbes of any known
human being in the world.
Several fold higher than
individuals in North America.
And that goes all the way
down to newborn infants
that already have, in this
country, the same depletion
of the microbial diversity.
This is obviously-- now
that we think that diversity
is one of the main
determinants for gut health,
and probably also
health, in general.
This obviously, is
a big warning sign.
What are we doing in
westernized societies?
What are we doing to
our diet, primarily,
in order to result
in this decimation
of our inner microbial world?
Another jump, not
expected-- but I
have found in my
travels and reading,
that there are diets--
not the extreme of vegan
or the diets free of
any natural grains--
but there are diets out
there that are actually not
that dissimilar in the
composition overall
of large amounts of very
complex carbohydrates
from plant-based food and small
amounts of animal products.
And both, mainly in terms
of chicken and fish,
which is the Mediterranean diet.
If you look at the field of
the pyramid based on that,
it's interesting.
To summarize what I
said, the biggest portion
are these plant-derived foods.
At the bottom, it's
important-- when
we talk about the mind brain
gut axis-- it's not just
what goes on or what you put
in, but also the state of mind
you are in.
So many investigators that
study the extensive health
benefits of this diet
not just on brain health,
which I was talking about--
the recent Alzheimer
study at UCLA-- but also
in metabolic health.
It was the social interactions
that these investigators
commented on that were a
major determinant in how
successful this diet was
in enhancing well-being.
Is this Mediterranean diet
beneficial for our gut
microbes?
Here are some reasons.
As I told you earlier,
one of the main reasons
we develop the microbes,
or this cohabitation,
is because the microbes break
down plant-based carbohydrates
and generate these
signaling molecules
to the rest of the body.
They also have
anti-inflammatory effects
against this low-grade
immune activation.
And then, clearly,
the Mediterranean diet
has something that is
not directly related
to the microbes-- this
high level of antioxidants
from olive oil and red
wine and nuts and berries.
Probiotics.
We are going to
have the pleasure
to taste some fermented food.
clearly that's been another
unique feature of the North
American diet that has,
until recently, completely
eliminated fermented
foods from the staples.
And there's been a lot of
hype now from animal studies.
Probably one the biggest
one is this psychobiotics--
that you may be able
to treat depression
and anxiety with the
intake of daily probiotics.
I can assure you that it's
almost certainly not the case.
There's a lot of work going on
in developing novel probiotics.
Some of them are engineered
to produce something
like an antidepressant.
Others are combinations
of human microbes
that produce short
chain fatty acids, which
are anti-inflammatory.
We're just at the beginning.
The ones that you currently can
buy-- and there are hundreds--
will not do that.
They will not act as
an antidepressant.
However, there's
pretty good evidence
that regular intake of
natural fermented food
contains different
types of lactobacilli
and bifidobacteria,
that it will benefit
the diversity of
your gut microbiome
and will make it,
because of that,
more resilient to perturbations
through infections or stress.
But just to summarize this now,
what I have tried to do here
is to get across a very
different way of thinking
about how our mind, environment,
the brain, and the gut,
and its internal environment
interact with each other.
It's clearly no longer
possible to have
these simple linear models.
I take one pill and that
gives me optimal health.
I think, really,
any intervention
has to involve strategies that
aim at the brain, at the mind,
and our internal ecosystem
to enhance and maintain
the diversity.
And we can do this through a
combination of relatively easy
lifestyle changes
that involve things
like mindfulness-based stress
reduction, healthy eating,
conscious eating, and sticking
to some fairly simple dietary
recommendations.
Hopefully, I gave
you some rationale
of why they might be beneficial.
Thanks for your attention.
LIV WU: Thank you.
[APPLAUSE]
Thank you so much.
Dr. Mayer, you are the director
of the Oppenheimer Center
for Neurobiology--
Neuroscience--
DR. EMERAN MAYER:
The Neurobiology
of Stress and Resilience.
LIV WU: Oh, stress
and resilience.
I want to go right there.
What does resilience look like?
Let's just assume most of us
in this room are stressed,
let's say.
AUDIENCE: No.
LIV WU: No.
What does it look like?
If we are resilient, how are
we eating, how are we thinking,
how are we behaving?
DR. EMERAN MAYER:
Certainly, most
of the research over the years
has focused on the stress part
and the negative part
and the damage it can do.
It's gradually changing
in the scientific world.
Still very difficult
to get grants
on the positive
aspects-- resilience
and this whole ecological
perspective on health.
How do we-- starting
with something as focused
as the gut microbiome, how do
we optimize the resilience?
And the current concepts are
based on ecological theory.
The more diverse and the more
abundant the organisms are,
the more is it able-- the
system-- to bounce back
from a perturbation like an
infection or a major stressor
and even not being affected
to the same degree.
Keep in mind that the stress
I mention will always--
you may not notice
it, but it will always
affect your
gastrointestinal activities
and your microbial world inside.
About 10%-- I'm not sure--
Googlers are a very special
selection of people, so these
statistics may not apply.
But in the general population,
about 10% to 15% of people
have digestive issues that
are typically stress-related.
We have to assume
that their resilience
to those perturbations
is decreased.
And what we recommend-- when
I see patients like that
have the symptoms--
to really target
the brain, the mind part, and
dietary part of the gut part.
What can people do in here?
There are simple techniques.
One is clearly the healthy diet.
The anti-inflammatory
diet that prevents
these-- what I mentioned.
The worst thing that you could
do is to eat a high-fat diet
and be stressed.
It makes you feel better
temporarily-- the concept
of comfort food.
But in the long
term, it enhances
this inflammatory
reaction and has
detrimental effects
on your brain
health and general health.
So the dietary awareness.
And the second thing is-- I
would never leave the mind out
of this.
Mindfulness-based stress
reduction, abdominal breathing
are very simple
techniques that everybody
can use to enhance that
state of resilience.
LIV WU: We actually teach
mindful cooking and mindful
eating in this kitchen.
I hope all of you
will look into that.
When we're doing all-nighters
and putting out a product,
pizza and French fries
is not the thing to have.
DR. EMERAN MAYER:
It feels the best
because fat will--
this has been shown,
that particularly animal fat
will temporarily down regulate
your system in the brain.
But in the long term, it will
have the opposite effect.
It will lead to these long
term, low-grade changes
that will make you more likely
to be chronically stressed
and develop all kinds of things,
from the metabolic syndrome,
which is also a low-grade
inflammatory condition to heart
conditions.
So the challenging
thing is to be aware
that these comfort
foods are the worst
thing that you can do in
order to maintain or enhance
your resilience.
You're drawn towards them.
That's why companies-- you see
it on TV and in the evening.
It's all high-fat food.
But I think it's very
important, this concept
of this low-grade inflammation.
You don't want to have your
body in that state all the time,
day and night.
So I think if you only
take that message home--
I'm sure nobody has these
unhealthy eating habits here--
but a lot of people do.
And it's tempting.
Work late and let's get a pizza.
LIV WU: So what does
low-grade infection feel like?
Am I not sleeping well?
Am I likely to bite off the
head of somebody I work with?
What does it look like?
DR. EMERAN MAYER: It's low-grade
inflammation, not infection.
There's no organism involved,
other than the microbes
that produce these substances.
It's something that you
don't feel, unfortunately.
At some point, you may
feel exhausted, fatigued.
So chronic fatigue
syndrome would be
the end stage of that process.
But a lot of people
lose their vitality
and just don't feel right when
they wake up in the morning.
And keep in mind, it
starts a chain reaction.
Because exercise--
there's several factors
that influence that
low-grade immune activation.
One is you diet,
so very important.
Another one is risk.
Another one is physical
aerobic exercise,
which down regulates it.
And sound and
healthy sleep is also
a major factor to downregulate
this inflammatory state.
So I think what's
happening is we're slowly
developing a very comprehensive
model of health and well-being.
This system's view, with
the low-grade activation
of the immune system
being the common currency
for many of these influences.
If you only do one,
it may not harm you.
If you do more than
one, it will gradually
have this accumulating effect.
A lot of people-- if
you go out in the street
and see obese people-- they
don't feel it right away.
And some people
may be very healthy
even though they
have a high BMI.
But if several of these
factors come together,
then you clearly play
with your health.
LIV WU: Is the brain
the last thing to go?
I mean, is the fogginess or
I'm not thinking as straight
as I used to-- is
that an indicator?
And is that more a
final stage indicator?
DR. EMERAN MAYER:
It's not really
the-- I would say Alzheimer's
disease is a final stage.
But the brain fog--
a lot of people
have this and the loss
of vitality and sense
of exhaustion.
It's definitely
not the end stage.
It can come fairly early.
It can come before
somebody starts overeating
or have other health issues.
And it probably depends on
the genetic vulnerability.
Some people are more vulnerable
to one organ over the other.
If you have a genetic
predisposition for Alzheimer's
disease and a lot of
relatives with it,
then I'll be particularly
worried about the brain being
affected by these
factors than if you
don't have these risk factors.
Same-- family history
for heart disease,
family history for obesity.
So the human genes
set the stage of where
the damage occurs first.
Some people get the full
hit that all organ systems
are affected.
In others, it's selective.
And in others, they're so
resilient that they will not--
there's a lot of people with
very unhealthy lifestyles
and being stressed and will
not get the full damage
that you would expect in
a situation like that.
LIV WU: I'm not sure I-- you're
asking how the genetic material
and what you feed your gut
interact with each other?
AUDIENCE: Number one, what's
the significance of that?
DR. EMERAN MAYER: Yeah.
So I can answer this, too.
LIV WU: What's the
significance of that?
DR. EMERAN MAYER: First of all,
the options that the microbiome
has to adapt to
new situations, be
it signals coming from the brain
or coming through nutrition
or they have been able to
adapt to eating seaweed.
Most people in the world
don't have microbial capacity
to break down the
carbohydrate of seaweed.
But in Japan, they
have developed it
through eating seaweed
on a regular basis.
There are other examples.
What microbes also do-- they
break down many of our drugs,
so-called xenobiotics.
These are substances that have
never occurred in evolution.
And the microbes, through this
combinatorial possibility,
can develop strategies to break
them down and inactivate them.
They also, through
these-- probably
people are familiar with
this concept of epigenetics.
They can influence
our own cells--
the immune system-- during
development, the first three
years of life.
There's a lot of interactions
and clearly the microbes
have much more to
say because they
have a lot more capacities
to talk to our immune system
and to our nervous system.
I didn't get to this in
my talk, but I believe
and quite a few
investigators believe
that the biggest influence
of these microbes
is early in life-- prenatally
and the first three
years of life, where
many of these systems
are being established
and set up.
Once they're programmed, both
the brain and at the gut level,
they remain fairly constant.
They vary in a
certain bandwidth,
but you don't change
them fundamentally.
So I think the main interests--
including the probiotics
and nutrition-- it should really
focus on these first three
or four years of life,
starting during pregnancy.
I think that's most
data suggest that.
LIV WU: Yes.
AUDIENCE: On that vein, my
first introduction to this topic
was in New York.
The Museum of Natural
History had a big exhibit
on the microbiome.
And they mentioned the
importance of, for example,
vaginal birth and breastfeeding
on introducing that microbiome
to an infant.
I'm wondering what is
your thoughts on how--
as C-sections increase in our
population and, let's say,
bottle feeding increases
in our population--
how can we introduce these
really important microbiomes
to our infants and our children?
DR. EMERAN MAYER: Yeah.
This would be a the
topic for a whole talk,
really, because it
starts during pregnancy.
There's the stress
of the mother.
Fix the mother's
microbes, including
the microbes that live in the
vaginal canal of the mother.
The baby is born.
It goes through this canal.
It's the first
contact with microbes.
And it's been shown
in animal studies
that a stressed
mom will transmit
a different set of
microbes to the infant
and these mice have
different brain development.
So it starts-- the
stress-- the nutrition
of the mother-- the metabolites
get towards the infant.
Breast milk is a huge component.
There is the so-called human
milk oligosaccharides, or HMOs,
that are contained in breast
milk, which are specifically
targeted at feeding
the microbes.
We cannot-- humans cannot absorb
those or do anything with them.
So breast milk produces those
to target the evolving gut
microbiome of the infant.
If that's altered, the
whole program will be off.
And I've talked to
experts in this field.
They say that-- but it's
not just the breast milk.
The breast milk, for example,
of these Yanomami Indians
and moms in North America
is fundamentally different.
Because the nutrition of the
mother really affects that.
So this whole-- what we
see also with the diversity
of the microbiome
starts, really,
with the diet of the
mother that affects
the breast milk and that
affects this human milk
oligosaccharides.
So it's a major conflict.
I personally think
in 10 years from now,
the microbiome field and
the probability field
will mainly focus
on this period.
AUDIENCE: Is there
anything that can
be introduced for children who
aren't breastfeeding that can--
DR. EMERAN MAYER: Well, I think
the only thing that you can do
is the same thing
that you would do
as an adult-- non-pregnant
adult. To eat a healthy diet
and learn to deal
with stress better.
I often see it with our
postdocs who get pregnant.
And then they work on a grant
to one week before delivery
and come back a week later.
This is really insane.
When you think about it,
the potential consequences
of that-- now that we know
many of these connections--
is definitely not worth it.
AUDIENCE: Do you
vegetarian or vegan diets
reduce the diversity
of the microbes
in our stomach in
a negative way?
DR. EMERAN MAYER: No.
No.
As I said a few times, the
main food for the microbes
and why they evolved is to use
these complex plant-derived
carbohydrates-- these complex
molecules-- that we, as humans,
can't absorb.
Many mammals can't
do that either.
I think humans have gotten
better since they developed--
discovered the fire to
be able to cook things,
so they easily break down.
But even cooked food will still
have a very high percentage
of those substances.
So if you want to do something
to feed your microbiome,
a vegetarian diet-- can't really
compare vegan and vegetarian
in that respect.
But the main thing is
this high percentage
of these plant-derived foods.
I think that is
the key, also, when
I made this huge jump
from the Yanomami
to the Mediterranean diet.
It's the common principle
that underlies them.
AUDIENCE: Since I was a little
girl, and I'm sure a lot of you
have also heard the same,
we've heard this phrase,
you are what you eat.
But as I've gotten
older and I've
seen family members in the
hospital or in hospice,
or I've talked to friends
who've gone to medical school,
nutrition and food isn't
discussed or it's skimmed over.
And they look at me like
I'm crazy when I'm talking
to them about probiotics.
Why do you think there
is such a big disconnect?
Why are my grandparents
being fed horrible food
when they're trying to
recover from illnesses?
And why am I getting ice
cream in the hospital?
DR. EMERAN MAYER: This
is an excellent question.
And I've been trained as a
gastroenterologist at UCLA
and have never been
exposed to-- we deal
with gastrointestinal
disorders--
never been exposed
to a single minute
to anything that had
to do with nutrition.
And so it's the
expo-- I'm not sure
why we have developed--
there's two things in medicine.
One is medicine, basically,
has not paid attention
to the brain and the mind.
This whole
mindfulness revolution
is really taking traditional
medicine by surprise
because they never
paid attention to it.
And nutrition is
the other aspect.
It's still, today-- I would
say in most training programs
for health professionals, it's
not a mandatory component.
The good news is-- I was
mentioning this earlier--
some of the UC campuses have
really started these campaigns.
Some of what you do here in this
kitchen-- this healthy campus
initiative with a healthy food
component and a healthy mind
component-- it's extremely
popular among students.
I think there's a phenomenal
involvement in both UCSF
and UCLA.
The goal is to become
the healthiest campuses
in the world.
That's the mission statement.
That's almost
starting a revolution,
but it's outside of medicine.
It's amazing.
It comes-- even though
all these data come now
from medical science,
the practice in medicine
has not changed, really.
AUDIENCE: Can you say
anything about glyphosates
and the impact on the gut
and implications of that?
DR. EMERAN MAYER: Yeah.
The glyphosates?
This is this substance
in the Roundup, which
is a genetically modified food.
Mainly, it's modified
in order that you
can kill off everything
else but not the crop
that you want to have.
And it's fascinating
when you read over
how this was approved.
It was approved on the lack
of effects on human cells
in a test in a Petri dish
on a short term basis.
So this was done long, long
before the whole microbiome
science came onboard.
And it has not
really been repeated.
So these early
experiments suggested
that humans do not metabolize
that substance, so do not
get the toxic effects--
the cells, at least.
But now we know
that the microbes
can break it down
into-- can activate it
into a substance that
is really harmful to us.
So not only is it bad
for some of the microbes,
but also for our own gut health.
And it's been interesting to me
that this whole GMO debate has
always been about the potential
harm of the genes, which
I'm not so sure
if they are really
that dangerous to humans.
To the environment,
they are, probably.
But the main danger, I, think
comes from these chemicals that
are being given at
higher and higher doses
because there's
resistance developing.
And without ever having studied
the impact on the microbiome,
now, with all the
things we know.
So it's really
amazing that people
will not-- I had a venture
capitalist coming down once who
asked me this question
and said, would you
be willing to do a
study to look at that?
And what would this cost?
And so we talked this
through and you probably
have tremendous
resistance at every level
to do a study like this.
At this multibillion
dollar business,
like the tobacco industry.
I think the reason there
is no research is probably
for that reason.
People are afraid
to get into this.
AUDIENCE: Hi.
What are your
thoughts on fasting?
DR. EMERAN MAYER: Fasting
is an interesting thing.
First of all, there's
a diurnal rhythm
to what microbes do, both their
numbers and what they produce.
So when they sleep and no
food gets into your intestine,
it's a completely different
set up than when you are awake.
So compromised sleep, which
means compromised fasting,
because many people get
up and eat something--
usually fatty and sweet things.
The other thing has not
really been studied so well.
I've always had this philosophy
if something has been around
for a long period of time, like
the fasting tradition and all
the fasting practice and all
the major healing traditions,
there must be something to it.
I would imagine it's a
reduction-- it's clearly--
one is the reduction of the
numbers, which is temporary.
The other one is that
the microbes-- there's
another source of food
for the microbes, which
is the mucus layer of the gut.
So when you don't feed them,
they go after the mucus layer
and use that as a substitute.
And so it will definitely affect
that layer that separates us
from the lumen from the inside.
That mucus layer is a big
part of the leaky gut concept.
It's not just holes in the
wall, but it's this mucus layer.
If this strengthens the
barrier function of the gut,
I would say, most likely,
it has a health benefit.
I would not dismiss that.
Not enough research on
that topic, unfortunately.
AUDIENCE: Question.
Is their proof that eating
probiotic food increase
the amount of the bacteria
in digestive system?
DR. EMERAN MAYER: Yes.
There's a couple things to it.
The first person who
propagated probiotic yogurt
was the scientist Mechnikov,
who also got a Nobel
Prize more than 100 years ago.
But he realized that he
had to eat it continuously
in order to have the benefits.
And that's one limitation if you
are the occasional yogurt eater
or if you go and buy your pills
when you don't feel right.
If you change your
dietary habit chronically,
or constantly, I think
that's really required
to get the health benefit.
I don't think by going on
a two-week course of taking
your probiotic pills will really
have any significant effect.
We have done a study
where we looked
at the changes in the
microbial architecture
with a four-week intake of
a probiotic-enriched yogurt.
And there was no change in the
architecture, in the players.
But the signaling molecules
that they produced changed.
But only as long as you took it.
The minute you--
it would stop it.
I think-- I mentioned
this earlier.
Probiotics, really, in the
first three years of life
and during pregnancy probably
have a very big impact.
The same impact-- and this
is just my personal opinion.
There's no science on it.
If you are on a diet that's
enriched in fermented foods,
you will have a
sustained benefit.
But you have to
stay on that diet.
It's not like let's go
once a week in a restaurant
and eat a kimchi or
a sauerkraut dish.
It has to become-- like
in the Korean culture,
it's really integrated.
And that's also
been interesting.
When I was working on
the book, to realize
how important that that is.
I think there was a time
during the war where
Korean soldiers
would refuse to fight
because there was
a threat that they
wouldn't have their kimchi.
That shows how dependent
they became on this, possibly
through some changes
within their brain
or they just feel different.
But the key thing is
the regular intake.
It cannot be the occasional
breakfasts-- yogurt and--
AUDIENCE: Thanks so much.
So what can we-- rather
than taking probiotics,
what can we eat--
complex carbohydrates,
it sounded like--
what can we eat
to nurture our gut bacteria?
You've talked several
times about a healthy diet.
You've mentioned the
Mediterranean diet.
Can you say a little bit more?
What can we do to
nurture our gut biome?
DR. EMERAN MAYER: If you take--
there's a lot of these-- a lot
of diets, nowadays,
recommend what you can't eat.
I'm always amazed.
You buy something,
a drink and it
has five-- no gluten,
no sugar, no-- I
think you really have to think
much more about the other way
around-- what should we eat?
Plants, in general.
A high variety-- one
is the high variety
because each plant has
a different composition
of these molecules.
A larger amount, which is not
just good for the microbes,
but it also has a lower caloric
density and glycemic index,
so your insulin won't go up.
And all the
plant-based oils, which
are generally low in these
saturated fatty acids.
On top, probably the
olive oil is probably
on top of all these.
But avocados-- anything
that has fat in it
and comes from a
plant has a-- doesn't
have the inflammatory
effect that you
get with the animal fats.
So I don't think you have to
pick any particular vegetable
or any particular--
it's variety and it's
the relative proportion of
the overall food intake.
So it's different,
clearly, than what
you would get from any
specialized cookbooks,
that you have to eat
this particular thing.
There's other substances, which
goes beyond the microbiome more
into this low-grade
inflammatory state.
Turmeric, for example, has these
anti-inflammatory properties.
And I'm sure there's other--
I said in the beginning,
I'm not a nutritionist.
I can't really give
you this in detail.
But there's a lot
of plant-based foods
that have these
anti-inflammatory properties.
And so that's another thing.
AUDIENCE: So more plants.
DR. EMERAN MAYER: More plants.
A lot of more plants.
LIV WU: Thank you very much.
DR. EMERAN MAYER: Thank you.
[APPLAUSE]
