[Applause]
growing up in the West of Ireland my
grandmother lived with us but it’s only
recently that I started to reflect him
how come she lives so long and so well
with all of her cognitive faculties in
place
was it genetics well longevity ran in
her family but more recently I started
to think that there could be something
else and I’d have a gut feeling that it
was and one of the things my granny used
to say is long before it became a TV
catchphrase she said you are what you
eat so eat well and indeed the quest for
finding this Fountain of Youth is
something that has fascinated mankind
for millennia none less than the famous
Russian immunologist elie metchnikoff
now Mexico worked in the Pasteur
Institute in Paris at the turn of the
last century and he won a Nobel Prize
for all of his famous work in immunology
but as often happens to famous
scientists later on in their careers
that can start coming up with some crazy
ideas and metchnikoff wasn’t short of
these and one of his crazy ideas was why
did people in parts of what is now
Bulgaria why do they live longer and he
put it down to the fact that they ate a
lot of fermented foods containing lactic
acid bacteria so you are what you eat
but mash the cuffs work also hinted at
something else what if you’re not just
what you eat but you’re what your
microbes eat and what’s important to it
to reinforce is that over the last two
decades we’ve began to really understand
that there is a very important
relationship between our microbes and
our overall physiology but first thing I
want to really reinforce is that
we are living in a microbial world these
trillions of bacteria that are that are
within us and honors are really shaping
a lot of what we do for example in terms
of genes we are 99% microbial it’s quite
humbling if you think of all of the
money we’ve spent on the Human Genome
Project well it’s less than 1% of our
genes now if I given this talk eighteen
months ago
I would have told you that we have 10
times more microbial cells than we do
human cells but this is a really fast
moving field with changes in technology
and mathematical models happening all
the time and so more recently this
ten-to-one has been downsized to one
point three to one
so we’re still more microbial but just
about so later when you go to the
bathroom and you shed some of these
microbes just think you are becoming
more human recently we’ve been
revisiting metchnikoff
ideas and we’ve shown that for example
in aged animals that there is a decline
in how this microbiome is working and
that we can carlay changes in the
microbiome with cognitive decline and
anxiety
moreover works from my colleagues in
Cork have shown a clear relationship in
an elderly population between the
composition and the diversity of the
microbiome with health outcomes with
elderly people with more diverse
microbes has much better indices of
frailty and cognitive health so you are
what you eat and you are what your
microbes eat and that would have been
interesting enough but they the Cork
researchers went one step further and
they showed that what was in they
investigated what was driving this
diversity and they put it down
– actually it was the diversity of the
diet with people who have a bland diet
full of processed food that was very
repetitive having a large shrinking in
their microbiome whereas those that are
much more diverse diet full of fruits
and vegetables having a much better
diversity in the microbiome so your are
what your microbes eat and this will
affect your overall health and one of
the big questions we have in this field
is how do microbes in your gut influence
your health in so many ways and what the
main thing I want to get across today is
that microbes are little factories
producing all sorts of weird and
wonderful chemicals that our bodies
would not make without them and these
chemicals depending on what foodstuffs
you take in can be really benefiting all
aspects of health so we can modify our
diets or we can actually modify the
microbes to actually shape this and
perhaps there is no better example of
this interaction between microbes and
diets than early in life in breast milk
human breast milk is is unique among
mammals in its complexity it contains a
lot of very specific sugars that is not
present in cow’s milk for example and we
know that these sugars are very good for
supporting gut health and immune
function but for me perhaps the most
startling thing is that these sugars
cannot be digested by the baby they are
as an exquisite example of coevolution
they are digested by the microbes
instead and so we we know that the
chemicals that these microbes make then
will support a lot of different aspects
of health including brain development
and this is probably underlying some of
the beneficial effects as seen with
breastfeeding
another component of breast milk are the
fatty acids and among fatty acids you
may have heard of Omega threes well
we’ve recently shown that omega-3 fatty
acids can also affect the composition of
your microbes and if we deplete omega
trees and the diets and animals we can
really change the trajectory of brain
development and behavior so your brain
health depends on what your microbes are
eating another component of the diet
that is receiving a lot of attention are
the polyphenols now when I first heard
about polyphenol it sounded like some
sort of 70s disco Queen
but polyphenols are really important
dietary substances most talked about as
they’re found in dark chocolate and in
red wine let’s talked about is how
they’re also found in onions and grape
juice and green tea but polyphenols have
been shown to have really good
anti-aging properties and affect
learning and memory as well and more
recently it’s been shown that a lot of
polyphenols actually don’t get don’t get
absorbed but get down to your lower gut
and get acted upon by your microbes
moreover polyphenols will affect the
composition of these microbes so once
again you are what your microbes are
eating so Omega threes polyphenols could
we devise a diet that would be rich in
these that might have some beneficial
effects on our health well we don’t have
to go too far just to the Mediterranean
the Mediterranean diet has long been
known to have beneficial effects in
cardiovascular health and to lower the
incidence of stroke diabetes obesity and
heart disease so and it is a really rich
source of both polyphenols and Omega
threes and what about the Mediterranean
diet and brain health well just this
year a study was published from
Australia to show that adding a modified
Mediterranean diet to normal
psychotherapy or anti depressed
medication was was enough to have
profound effects on mood and these types
of studies are ushering in a whole new
discipline of nutritional psychiatry
where we can target mental health
through dietary means in a way going
back to Hippocrates where he said let
food be our medicine and perhaps the
missing part of this puzzle is or what
is the role of the microbes in mediating
these positive effects and that’s still
to be resolved but I really think that
they play a crucial part and why can I
be so confident well it goes back to
some of our studies in basic
neuroscience studies that we have in
animals now you don’t need to be a
neuroscientist to see here that when we
take microbes out of a system these are
germ-free mice they’ve never had any
microbes and these brains grow up
without any any gut microbes but you can
see clearly that there are marked
differences in this nerve cell from the
germ-free versus the control animal and
we’ve we’ve shown that almost all
aspects of brain health are dependent on
having microbes in our gut for example
in the last year we’ve shown that myelin
myelin is the key insulation in which
nerve cells communicate and that
myelination is totally regulated by
microbes in the gut and so if we can
develop diets that will target the
microbiome to support brain health at
crucial developmental windows we may
benefit a lot of people and where this
is going to be really important for
example is in areas of severe
malnutrition and under nutrition such as
in sub-saharan Africa where you have
lots of individuals with stunted growth
and cognitive decline
delay and neurodevelopmental problems
and so a lot of efforts are going in to
try and develop strategies for this now
up until now everything I’ve told you
has been about how diet affects our
microbes but could our microbes also
affect our diets and food choices and
that’s something that I find quite into
and again just this year a study came
from Lisbon where they used a lab fruit
fly to actually ask this now fruit flies
madhu Prive them a protein in their diet
and you give them a choice of yeast or
sugar with yeast for a fruit fly is kind
of like their steak so if they’re if
their protein deprived they’ll go right
after the yeast however if you put
microbes into the situation you can see
that the animal no longer chooses the
protein either actually gravitate
towards the sugar as well and if this
could be shown in other species it would
have huge implications for our drive we
have to take certain foods and perhaps
later the next time that you crave that
dark chocolate bar full of polyphenols
perhaps it’s your microbes that’s
telling you to go for it one of the best
ways that we have for studying microbe
diets interactions is looking at the
microbes of some of our ancestors and
scientists have gone out into the fields
and started to study what is going on in
communities that maintain ancestral like
diets and for example in the Hadza
hunter-gatherer community and in
Tanzania they’ve shown that this day
have diets very rich in fiber fiber is
key in this regard and in when they
looked at their microbiome they were
able to see a very very diverse
microbiome moreover we can chart the
influence of the introduction of
Agriculture by looking at the microbiome
and the diets of people in rural Malawi
and Venezuela and you can clearly see
that it starts to be in decline in in
this microbiome and then in our Western
world what you see is with the
introduction of processed foods and
sweeteners and emulsifiers all of which
are having negative impact
the microbiome that we are more or less
extinguishing microbes that our
ancestors had the intriguing part of
this story is that if you look at
diseases like multiple sclerosis
inflammatory bowel disease diabetes
obesity these are not present in these
ancestral communities and a lot of
interest is now being put into
understanding the relationship that
these missing microbes have in driving
these diseases and we know little about
what’s going on in relation to brain
health and the contribution of this
depletion of microbes has two brain
cells but we do know is that in the
society that we’re living in which is
increases in stress and overuse of
antibiotics hyper cleanliness a huge
upsurge in births by cesarean sections
all of which will impact the composition
of the microbiome that we are
potentially having a public health
problem in our midst and this will also
potentially affect our brain and how we
deal with stress but how do we deal with
this and can we develop strategies
perhaps to target the microbiome for
mental health benefits and that brings
us to the whole concept of a term we
coined in Cork psycho bioethics and
these are targeted interventions that
will focus on our microbiome to actually
promote brain health and to date most of
the studies with psycho biotics have
been only at the preclinical stage in
animals but slowly we’re doing more and
more and around the world more and more
work is going into get evidence-based
for this whole new area and just paint
though your genome you can the genes
that you got from your parents and your
grandparents you can’t do an awful lot
with it
but your microbiome you can modify
potentially through diet prebiotics
probiotics and even fecal
plans eventually so there is a slow
psycho biotic revolution taking place
and changing how we met might consider
treating mental illness into the future
so in conclusion I guess my advice is
always trust the words of an Irish
granny eat well and perhaps some of that
wisdom comes from the trillions of
bacteria within your gut and I hope
that’s given you some food for toss
today thank you very much
[Applause]
growing up in the West of Ireland my
grandmother lived with us but it’s only
recently that I started to reflect him
how come she lives so long and so well
with all of her cognitive faculties in
place
was it genetics well longevity ran in
her family but more recently I started
to think that there could be something
else and I’d have a gut feeling that it
was and one of the things my granny used
to say is long before it became a TV
catchphrase she said you are what you
eat so eat well and indeed the quest for
finding this Fountain of Youth is
something that has fascinated mankind
for millennia none less than the famous
Russian immunologist elie metchnikoff
now Mexico worked in the Pasteur
Institute in Paris at the turn of the
last century and he won a Nobel Prize
for all of his famous work in immunology
but as often happens to famous
scientists later on in their careers
that can start coming up with some crazy
ideas and metchnikoff wasn’t short of
these and one of his crazy ideas was why
did people in parts of what is now
Bulgaria why do they live longer and he
put it down to the fact that they ate a
lot of fermented foods containing lactic
acid bacteria so you are what you eat
but mash the cuffs work also hinted at
something else what if you’re not just
what you eat but you’re what your
microbes eat and what’s important to it
to reinforce is that over the last two
decades we’ve began to really understand
that there is a very important
relationship between our microbes and
our overall physiology but first thing I
want to really reinforce is that
we are living in a microbial world these
trillions of bacteria that are that are
within us and honors are really shaping
a lot of what we do for example in terms
of genes we are 99% microbial it’s quite
humbling if you think of all of the
money we’ve spent on the Human Genome
Project well it’s less than 1% of our
genes now if I given this talk eighteen
months ago
I would have told you that we have 10
times more microbial cells than we do
human cells but this is a really fast
moving field with changes in technology
and mathematical models happening all
the time and so more recently this
ten-to-one has been downsized to one
point three to one
so we’re still more microbial but just
about so later when you go to the
bathroom and you shed some of these
microbes just think you are becoming
more human recently we’ve been
revisiting metchnikoff
ideas and we’ve shown that for example
in aged animals that there is a decline
in how this microbiome is working and
that we can carlay changes in the
microbiome with cognitive decline and
anxiety
moreover works from my colleagues in
Cork have shown a clear relationship in
an elderly population between the
composition and the diversity of the
microbiome with health outcomes with
elderly people with more diverse
microbes has much better indices of
frailty and cognitive health so you are
what you eat and you are what your
microbes eat and that would have been
interesting enough but they the Cork
researchers went one step further and
they showed that what was in they
investigated what was driving this
diversity and they put it down
– actually it was the diversity of the
diet with people who have a bland diet
full of processed food that was very
repetitive having a large shrinking in
their microbiome whereas those that are
much more diverse diet full of fruits
and vegetables having a much better
diversity in the microbiome so your are
what your microbes eat and this will
affect your overall health and one of
the big questions we have in this field
is how do microbes in your gut influence
your health in so many ways and what the
main thing I want to get across today is
that microbes are little factories
producing all sorts of weird and
wonderful chemicals that our bodies
would not make without them and these
chemicals depending on what foodstuffs
you take in can be really benefiting all
aspects of health so we can modify our
diets or we can actually modify the
microbes to actually shape this and
perhaps there is no better example of
this interaction between microbes and
diets than early in life in breast milk
human breast milk is is unique among
mammals in its complexity it contains a
lot of very specific sugars that is not
present in cow’s milk for example and we
know that these sugars are very good for
supporting gut health and immune
function but for me perhaps the most
startling thing is that these sugars
cannot be digested by the baby they are
as an exquisite example of coevolution
they are digested by the microbes
instead and so we we know that the
chemicals that these microbes make then
will support a lot of different aspects
of health including brain development
and this is probably underlying some of
the beneficial effects as seen with
breastfeeding
another component of breast milk are the
fatty acids and among fatty acids you
may have heard of Omega threes well
we’ve recently shown that omega-3 fatty
acids can also affect the composition of
your microbes and if we deplete omega
trees and the diets and animals we can
really change the trajectory of brain
development and behavior so your brain
health depends on what your microbes are
eating another component of the diet
that is receiving a lot of attention are
the polyphenols now when I first heard
about polyphenol it sounded like some
sort of 70s disco Queen
but polyphenols are really important
dietary substances most talked about as
they’re found in dark chocolate and in
red wine let’s talked about is how
they’re also found in onions and grape
juice and green tea but polyphenols have
been shown to have really good
anti-aging properties and affect
learning and memory as well and more
recently it’s been shown that a lot of
polyphenols actually don’t get don’t get
absorbed but get down to your lower gut
and get acted upon by your microbes
moreover polyphenols will affect the
composition of these microbes so once
again you are what your microbes are
eating so Omega threes polyphenols could
we devise a diet that would be rich in
these that might have some beneficial
effects on our health well we don’t have
to go too far just to the Mediterranean
the Mediterranean diet has long been
known to have beneficial effects in
cardiovascular health and to lower the
incidence of stroke diabetes obesity and
heart disease so and it is a really rich
source of both polyphenols and Omega
threes and what about the Mediterranean
diet and brain health well just this
year a study was published from
Australia to show that adding a modified
Mediterranean diet to normal
psychotherapy or anti depressed
medication was was enough to have
profound effects on mood and these types
of studies are ushering in a whole new
discipline of nutritional psychiatry
where we can target mental health
through dietary means in a way going
back to Hippocrates where he said let
food be our medicine and perhaps the
missing part of this puzzle is or what
is the role of the microbes in mediating
these positive effects and that’s still
to be resolved but I really think that
they play a crucial part and why can I
be so confident well it goes back to
some of our studies in basic
neuroscience studies that we have in
animals now you don’t need to be a
neuroscientist to see here that when we
take microbes out of a system these are
germ-free mice they’ve never had any
microbes and these brains grow up
without any any gut microbes but you can
see clearly that there are marked
differences in this nerve cell from the
germ-free versus the control animal and
we’ve we’ve shown that almost all
aspects of brain health are dependent on
having microbes in our gut for example
in the last year we’ve shown that myelin
myelin is the key insulation in which
nerve cells communicate and that
myelination is totally regulated by
microbes in the gut and so if we can
develop diets that will target the
microbiome to support brain health at
crucial developmental windows we may
benefit a lot of people and where this
is going to be really important for
example is in areas of severe
malnutrition and under nutrition such as
in sub-saharan Africa where you have
lots of individuals with stunted growth
and cognitive decline
delay and neurodevelopmental problems
and so a lot of efforts are going in to
try and develop strategies for this now
up until now everything I’ve told you
has been about how diet affects our
microbes but could our microbes also
affect our diets and food choices and
that’s something that I find quite into
and again just this year a study came
from Lisbon where they used a lab fruit
fly to actually ask this now fruit flies
madhu Prive them a protein in their diet
and you give them a choice of yeast or
sugar with yeast for a fruit fly is kind
of like their steak so if they’re if
their protein deprived they’ll go right
after the yeast however if you put
microbes into the situation you can see
that the animal no longer chooses the
protein either actually gravitate
towards the sugar as well and if this
could be shown in other species it would
have huge implications for our drive we
have to take certain foods and perhaps
later the next time that you crave that
dark chocolate bar full of polyphenols
perhaps it’s your microbes that’s
telling you to go for it one of the best
ways that we have for studying microbe
diets interactions is looking at the
microbes of some of our ancestors and
scientists have gone out into the fields
and started to study what is going on in
communities that maintain ancestral like
diets and for example in the Hadza
hunter-gatherer community and in
Tanzania they’ve shown that this day
have diets very rich in fiber fiber is
key in this regard and in when they
looked at their microbiome they were
able to see a very very diverse
microbiome moreover we can chart the
influence of the introduction of
Agriculture by looking at the microbiome
and the diets of people in rural Malawi
and Venezuela and you can clearly see
that it starts to be in decline in in
this microbiome and then in our Western
world what you see is with the
introduction of processed foods and
sweeteners and emulsifiers all of which
are having negative impact
the microbiome that we are more or less
extinguishing microbes that our
ancestors had the intriguing part of
this story is that if you look at
diseases like multiple sclerosis
inflammatory bowel disease diabetes
obesity these are not present in these
ancestral communities and a lot of
interest is now being put into
understanding the relationship that
these missing microbes have in driving
these diseases and we know little about
what’s going on in relation to brain
health and the contribution of this
depletion of microbes has two brain
cells but we do know is that in the
society that we’re living in which is
increases in stress and overuse of
antibiotics hyper cleanliness a huge
upsurge in births by cesarean sections
all of which will impact the composition
of the microbiome that we are
potentially having a public health
problem in our midst and this will also
potentially affect our brain and how we
deal with stress but how do we deal with
this and can we develop strategies
perhaps to target the microbiome for
mental health benefits and that brings
us to the whole concept of a term we
coined in Cork psycho bioethics and
these are targeted interventions that
will focus on our microbiome to actually
promote brain health and to date most of
the studies with psycho biotics have
been only at the preclinical stage in
animals but slowly we’re doing more and
more and around the world more and more
work is going into get evidence-based
for this whole new area and just paint
though your genome you can the genes
that you got from your parents and your
grandparents you can’t do an awful lot
with it
but your microbiome you can modify
potentially through diet prebiotics
probiotics and even fecal
plans eventually so there is a slow
psycho biotic revolution taking place
and changing how we met might consider
treating mental illness into the future
so in conclusion I guess my advice is
always trust the words of an Irish
granny eat well and perhaps some of that
wisdom comes from the trillions of
bacteria within your gut and I hope
that’s given you some food for toss
today thank you very much
[Applause]
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