- [Rhonda]: Welcome to another episode of
the FoundMyFitness podcast. Today, I'm
sitting here with doctors, Justin and
Erica Sonnenburg. Justin is an associate
professor at Stanford in the Department of
Microbiology and Immunology, and Erica is
a senior scientist at Stanford.
Together they run a lab where they study
the effects of diet on the hundred
trillion or so bacteria in the gut, and
how that impacts the health of the host
which in their case happens to be a
laboratory mouse. But this applies to the
general population, and so I'm really
excited because I'm convinced that the
health of the gut plays a very important
role in overall general health. So maybe
we can start by talking a little bit about
your research and
why the gut health is so important.
[Justin]: Sure. So the... I think we
became interested in the gut microbiota
from the stand point of just basic
pioneering research, trying to understand
this new microbial organ that we've
discovered inside of us that's incredibly
important and connected to some many
facets of our health. Over the course of
the past 10 years or so there's been this
transformation in understanding this
community and how fundamental it is. It's
not just quirky part of our biology. It
really is holding the key to health of our
immune system, our metabolism, there's a
brain-gut access so it's dictating mood,
behavior perhaps impacting things like
autism and neurodegeneration. So there's
really this profound impact, this
microbial community has on
our entire body.
[Erica]: Yeah, Just to throw some
interesting numbers out there. We're
actually by cell number, we actually
have 10 times more bacterial cells
associated with our body than human cells.
We even have a hundred times more
bacterial genes associated with our
collective genome than human genes.
So both by cell number and by gene
number we're actually more microbial than
we are human. So I think the research from
our lab and other labs in this area is
really redefining how we think of
ourselves as human beings. We're not just
this collection of human cells. We're in
fact more like a tube of human cells that
houses this incredibly complex and dynamic
ecosystem of microbes, and what we're
finding is that these microbes are wired
into pretty much all aspects of our
biology. They're really major players in
many aspects of our health.
- Yeah, in terms of how these bacteria in
our gut regulating health, one thing that
comes into my mind, in particular, is...so
this bacteria is in our gut and most of
it is in the distal part so in the colon.
It just so happens that our GI tract
happens to be also largest number of
immune cells. I don't think most
people...if you would ask them where? What
organ in the human body has the highest
concentration of immune cells? People
might say the thymus or the spleen. No,
it's actually the gut, and so that is
particularly where I have been interested
because there's a very complex interaction
between the bacteria in our gut and
the immune cells in out gut. And
you guys have a little bit of research on
how diet comes into play into that.
- Yeah, so there are two aspects of that.
I think one, it's a little bit daunting to
think of these microbes inside of us as
dictating so much of our biology, that
they actually are holding the reins to
some degree on our immune system on our
metabolism. On the other hand, our diet
directly impacts this community. Our
research and the research of others has
shown this over and over again. So,
really, we hold the reins on what's
happening inside out gut by controlling
what we eat and aspects of our lifestyle,
I think as we gain knowledge about this
community, it's possible for us to foster
a healthy microbiota to improve our health
in many dimensions.
Now, the immune system is really
interesting because there's really a
delicate balance between our microbiota
and our gut because living in close
proximity are these two entities that,
classically, in microbiology were thought
not to get along: bacteria and the host
immune system. What we realized is that
there's this incredible conversation
that's continually ongoing in our gut
between our immune system and the gut
microbes to maintain harmony in most cases
although this can go awry, but
there's a delicate balance in the gut, but
also the immune system can leave the gut,
those signals can leave the gut, and
influence our immune system throughout our
body. So really these microbes in our gut
are dictating the set point of our immune
system throughout our body. They can
impact things like respiratory infections,
how well we respond to a vaccine, how
rapidly autoimmune disease can progress.
So it's really...this insight that so much
of our immune system is in our gut is
really profound, and it's important to
recognize that this not only impacts
what's going on in the gut but
throughout our entire body.
- Absolutely, so the food that we put into
our body interacts with these gut bacteria
and if we feed them certain food or we
don't feed them certain foods this will
impact the immune system in the gut and
also in the rest of our body.
Specifically, what comes into my mind is
the dietary fiber that can be metabolized
by certain bacteria in the gut into
something called short-chain fatty acids
that's like butyric acid, propionic acid,
acetic acid, lactic acid, anything else,
but...and how these short-chain fatty
acids provide signals to certain immune
cells to regulate their function
both in a positive or also in
suppressing your immune system from
becoming too active.
Can you explain a little bit about that?
- Sure. Well, so the dietary fiber we eat
is really the key for feeding this gut
microbial community, and the point that
the microbes in our digestive tract
primarily live at the end of the digestive
tract is really important because so much
of the food that we eat in the Western
world is laden in simple carbohydrates and
fats and all of those things gets
absorbed in the upper GI tract and leave
our microbes essentially starving; there's
no complex carbohydrate to feed this
community. In fact, going back to
traditional populations of humans that are
representative of how we evolved, it's
clear that we used to eat as humans much
more dietary fiber that we currently eat.
So there's really good evidence that in
the United States we're actually starving
our microbes.
So this is really important in many
respects. One is that when the microbes
receives these dietary carbohydrates,
these complex dietary fibers that we eat,
they make these compounds like short-chain
fatty acids. That's their metabolism
working. And these compounds, short-chain
fatty acids, are actually the bacterial
waste. The bacterial feces if you will.
And then we absorb these compounds and
they regulate a number of different
aspects of our biology in a positive way.
So they increase the number T regulatory
cells. These are cells that attenuate
inflammation, calm the immune system. So
if you're not eating dietary fiber it's
likely that your immune system is
operating in a hyper-inflammatory state.
This hyper inflammatory state, it's
believed it can drive a lot of different
Western diseases ranging from autoimmune
diseases, metabolic disorders.
Things like asthma, allergies. All of
these problems that we associate with the
Western world are really have excessive
inflammation as underlying mediator.
It's not too hard to imagine how Americans
that are not consuming dietary fiber not
producing a lot of short-chain fatty acids
have this hyperactive immune system
So dietary is really a key to feeding this
community and setting the immune system to
a proper set point so that it's not too
reactive. Now there's a really interesting
connection between lack of dietary fiber
and host mucus as well that, maybe,
Erica wants to talk about it.
- Yeah. So one thing I wanted to add ,
carbohydrates is such a loaded term in
our society now. People view carbohydrate
as something bad and you want to avoid.
But broadly speaking there are two types
of carbohydrates we need to be aware of.
The more simple carbohydrates, and like
Justin was saying, these are the ones that
are absorbed early in our GI tract so
these are things from highly refined
grains or packaged food types of simple
sugars that are so prevalent in much of
our Western diet, but then there's these
complex carbohydrates. The type of
carbohydrates that are found in dietary
fiber and these are things that you find
in whole grains, fruits, and vegetables,
and these are the carbohydrates that the
human genome is not very good at
degrading. So it actually makes all the
way down to our distal gut to our colon,
and then our microbes in our colon can
ferment these complex carbohydrates and
then produce the short-chain fatty acids
that you are talking about. So what we're
finding is that when we don't eat enough
of these complex carbohydrates found in
dietary fiber, these gut bacteria are
starving is so they really are forced to
rely on the mucus...the carbohydrates that
are found in the mucus layers that line
the our large intestine.
So as we don't consume enough dietary
fiber, these microbes become closer to our
mucus lining. They're eating that food
because that's all they have to eat, and
they inching ever closer to our own
epithelial cells, and that creates a
situation in which the human aspect of our
GI tract and the microbial aspect, that
fence that keeps them separated starts
thinning and setting up a scenario where
our immune system now can start
overreacting to these microbes encroaching
and these microbes potentially get a
little more aggressive because they're
lacking in the food that they require.
- And then, one thing that I just wanted
to add, there's a lot of focus on these
short-chain fatty acids that are these
major product of fiber degradation by the
microbiota in the distal gut, but there's
a variety of other interesting chemicals
that these microbes are producing.
Bacterial metabolism is something that's
really not studied well enough, and
there's...we can think of these...each
bacteria in our got has a little
unsupervised drug factory that's
constantly making interesting small
molecules and interesting chemicals. We
don't known the identity of most of these
compounds, we don't know how they effect
our biology. They're circulating in all of
our blood right now, they're slightly
different between me and you, and they
change in a single individual over the
course of the day. So, understanding how
these chemicals are impacting different
aspects for biology is one of the great
frontiers of research.
- Yeah. So about 10 different things came
to my mind as both of you guy spoke so I'm
going to try fire away, but as Erica was
saying it's really interesting you're
talking about how when you're starving
these gut bacteria in the colon, how they
start to eat away the mucus and of course
that's the gut barrier that is the mucus.
Most people know about the gut barrier
when that breaks down, you start to have
the immune cells which are usually not in
contact with all these bacteria in you
gut. So it starts to come in contact and
then they can start to have an immune
response. It's an interesting way because
I usually think about it as when you're
starving the bacteria of the fiber that
they need to make this short-chain fatty
acids as starving the gut epithelial cells
which rely on these short-chain fatty
acids for energy. I think I read somewhere
like between 60% to 90% of the goblet
cells which are the specialized cell in
the gut that produce mucin which is
actually the mucus. Slimy stuff that makes
up the gut barrier. They rely on that as
energy. It's almost like maybe there's a
double whammy going on where it's like he
bacteria are feeding on the mucin that's
breaking it down but at the same time, the
cells that make the mucin are being
starved of the energy substrates they need
to make that mucin. So you just got this
like double whammy compounded effect.
- Absolutely, yeah, that's a very
interesting point and I don't there's been
any systematic study to look at rate of
mucin production based on the fiber in
the diet, but this would be very
interesting because it's probably
correct what you're proposing.
It's a great hypothesis.
- Please look at it.
- That's a very good idea.
- Please look at it. The other thing that
came to mind was when Justin mentioned the
effects of some of the short-chain fatty
acids and other compounds that we have yet
to identify, possibly how they effect the
T regulatory cells. T regulatory cells as
you mentioned, they keep the immune system
in check, they make sure that you're not
having an hyperactive immune response
which leads to autoimmune diseases, and I
think I've read that type 1 diabetes,
rheumatoid arthritis, and multiple
sclerosis. All of which have an autoimmune
component to them have been linked to the
disruptions in the gut microbiome, and I
think there's direct evidence as well like
looking at animal models..
So I mean, you nailed it, right? These
diseases of the Western world, I mean, I'm
not sure if there's a complex interaction
between people that have gene polymorphism
that already predisposed them to a
hyperactive immune response, and then, on
top of that, having this unhealthy gut and
not being able to make as many Tregs is
like the perfect storm to create MS or
type 1 diabetes or any kind of that, but
at the very least, you can't control what
genes that you're born with but you can
control what you put in to your mouth and
what you put it to your gut.
- Yeah. So I think you're exactly right,
and actually, I would go as far to say
that I think all the focus on the human
genome and the polymorphisms that
predispose us to all different different
diseases is actually very misguided. I
think that's just overlaying normal human
genetic variation on something that's very
amiss in our environment, and namely, our
microbiota.
So and you named a few of the diseases
for which excessive inflammation is
thought to be driver, but it extends far
beyond that. I mean, many cancers are
driven by inflammation and heart diseases
driven by inflammation. All the metabolic
disorders are thought to be
inflammation-promoted now and certainly
all the autoimmune disease. So when you
look at...you're talking about tons of
disease that we have on the Western world
that largely aren't present in these
traditional societies that have a much
higher fiber consumption and also have a
much more diverse gut microbiota. So it
really... I think you know when you look
at all these things together and then the
mechanisms of how fiber degradation
attenuates inflammation. It really looks
like our lack of fiber in the Western
world and our diet is deteriorating the
microbiota, and this is predisposing us to
this tens of different diseases.
I think it's very unlikely that there tons
of different causes for these
diseases. I think that inflammation is the
common denominator in the microbiota and
our diet is really at the heart of this.
- Well, yeah, inflammation is a driver of
aging. So you're talking about these
diseases which many are age-related. So
you're...it's a really...like you said
it's at the heart of all these diseases.
When I think that really is a driver of
the aging process itself. In terms of the
heart disease, that's the number one
killer in the United states, and as Erica
mentioned, when you're starving your gut
microbiome of this fiber, and the bacteria
starts to break down the mucin and gut
cells possibly aren't making as this much
mucin, then when those immune cells become
in contact with bacteria. They start to
kill it because that's what they're
programmed to do. Immune cells bacteria,
well, that's, I'm going to kill it.
So then what happens is they kill
bacteria, this releases lipopolysaccharide
endotoxin and what happens when you
release endotoxin, it gets released in the
bloodstream while your body has an
adoptive response to it. It produces more
cholesterol, the LDL, and the reason for
that is because there is binding sites the
LDL receptors on the LDL and also on HDL
cholesterol. Bind endotoxin is the way
stopping it up to protect your body. You
don't want to go into sepsis, and so
you're producing more cholesterol that's
why when you're in inflammed state you
produce more cholesterol. That's really a
link that I think between inflammation and
heart disease. It's also the reason why
you should always get your cholesterol
measured more than once because you maybe
sick or stress and you're inflamed and
then your cholesterol is really high, and
your doctor might go, "Whoa. Let's get you
on statins." So maybe that's not the best
scenario.
But I want to get back to the fiber
because you're talking about how important
it is to get fiber and how we don't get as
much fiber as our predecessors or whatever
you want to call it.
What kind of fiber? What kind of food
sources do you think are...do you think a
broad spectrum approach where you try to
get all types of fiber to because we don't
know what Justin mentioned, we don't know
what all these gut bacteria are producing.
So can you talk a little bit about the
types of fiber. How much fiber?
- Yes, if you look at the average American
is eating around 10 to 15 grams of dietary
fiber per day. The U.S. government
recommend that we eat more along the line
of 30 to 35. So just by that measure,
we're pretty fiber deprived. If you look
at these traditional populations that we
study in our lab. These hunter gatherers
that lived in Tanzania, they're eating on
the order of a 100 to a 150 grams of
dietary fiber per day. So it's clear that
the amount of fiber that we're consuming
as Americans is something that could be on
the order of 10 times less of what our
ancestors probably ate in the past. So
there's this issue of an amount of fiber
that we just have to increase that to
increase the food that's getting to our
gut bacteria, but then there's also this
issue of the diversity, the different
types of fiber. So some people say to us,
"Well can I just take a whole bunch
of Metamucil get my 35 grams,
and then I'm good." But what were finding
is that the diversity, the different types
of complex carbohydrate that are found in
dietary fiber are important.
So you could imagine if you ate just one
type of complex carbohydrate, there would
be, say, a handful of bacteria that are
really good at metabolizing of fermenting
that type of carbohydrate. Those who get
very about maybe at the expense of other
types of microbes, but if you're eating
many different types of carbohydrates,
complex carbohydrates, then you can foster
a community kind of an ecosystem that's
more rich and robust. So, if you are
eating, say, 20 different types of dietary
fibers then you're providing sustenance
from many different types of microbes that
might specialize in different types of
carbohydrate consumption.
And that appears to be important. This
having a diverse community of bacteria in
the gut, and so we think about it
sometimes ;like as a rainforest. You want
forest or this ecosystem tend to be more
stable when there's a lot of complexity of
life on them. If you have, say, just a
lawn of only grass then one small things
happens and that would harm that grass and
then everything dies or it's unstable. But
if you have an ecosystem that has grass
and trees and shrubs and all different
things then it's less likely to collapse
after just one event. So that's how we
like to think about it. You want a diverse
community of microbes in your gut and the
best way to foster that is to provide them
diverse amount of substrate. A diverse
amount of complex carbohydrates.
- So specifically, what foods would you
say would provide that diverse?
- So we think that foods so fruits,
vegetables, whole grains, and legumes are
all food that are high in dietary fiber
and so we tried to consume many different
types of each of those, and one sort of
easy way to do this is to eat seasonally.
So if you eat foods that are in season,
you are more likely to eat over the span
of a year a diverse collection of fruits
and vegetables.
I don't know if you have some other.
- I mean, the other piece of advice that I
would give is just to avoid foods that
comes in wrappers or packages. I mean, I
just think that processed food
manufacturers have not caught on to the
importance of dietary fiber in health, and
if you go to most of these processed
foods, if they do claim high fiber it
usually a single type of fiber that
they're supplementing with. Either inulin
or celium husk or chickory or something
like that, and it doesn't provide the
breadth of fiber that you would get if you
were to go to a produce
section and pick a
handful of vegetables to cook.
So I just think that until the processed
food people get on board with the
importance of fiber, it's good just to
avoid food that comes in packages.
- So a couple things come to mind. One is
that maybe even prebiotics aren't the
magic pill either, but the other thing is
the effect of processed food on the gut
bacteria. Have you guys looked in to
specifically any or do you anyone else in
terms of mechanisms, what happens, how it
effects the gut bacteria. I remember
reading a paper, I believe it was
published in Nature not too long ago on
the effect of artificial sweeteners like
aspartame. Are you familiar with that?
- Yeah, absolutely, yeah. So there's a
variety of compounds in processed foods
now that seem to be problematic for the
microbiota. The artificial sweeteners is a
good example, and although, the mechanism
wasn't well delineated and how this is
impacting the microbiota. It certainly
appeared that artificial sweeteners and
they looked at three different classes of
artificial sweeteners. All affect the
microbiota and go on and impact insulin
resistance in the host. So a measure of
diabetes in metabolic syndrome.
Similarly, emulsifiers recently have been
looked at. These are chemicals that are
found in processed foods quite commonly,
and it was shown that emulsifiers actually
can break down the mucus layer lead to
bacteria getting closer to a host tissue
and induce inflammation, and that also
leads to a metabolic problems. So I think
there's a...the other thing that processed
foods do in addition to not providing
dietary fiber is that they provide all
these other compounds that just
haven't....in most cases, haven't been
well studied.
And in the cases where they have been
studied, it appears that they're
problematic. This is... I guess somewhat
intuitive when you consider that our body
hasn't adapted to a lot of these chemicals
that we're exposed to in process food. It
doesn't know how to handle them, and
therefore, potentially problematic to our
long term health.
- So it's not just a lack of fiber, but
it's also they're doing something actively
bad in addition to that. Again, one of
those compound it affects.
So the other thing that comes to mind is
when you're talking about these compounds
that our gut isn't used to, antibiotics.
That's obviously, antibiotics have their
place if it's a life or death situation
prescribing antibiotics. But, the problem
is that they are prescribed in many not
life or death situation. In fact, they're
very over prescribed for just things that
are not necessary. Sinus infection or
cold, common cold. What effect does just
even having like a single dose of
antibiotics have on your gut microbiome,
and how can we recover from that? Like
what are the best ways we can
recover from that.
- Yes, I think we have to realize that
when antibiotics were developed there was
no thought placed on gut microbes. These
are not drugs designed in any way to spare
the bacteria that live in our gutmost.
Antibiotics that we take are in fact
designed to be in broad spectrum to kill a
wide variety of microbes so that they can
be used for many different types of
infection. What we're finding is that
these antibiotics do wreak havoc
in our guts. So many of the
microbes that are beneficial that inhabit
us are killed by these antibiotics, and
what we're finding is that often the
microbiota....there is or it is able to
rebound, but often it is not able to
rebound exactly as it was before.
From studies done, others in Stanford,
not us, but a colleague of ours, David
Relman. They showed that with multiple
rounds of antibiotics, with each
additional round there is another sort of
hit that the microbiota takes that makes
it less likely to recover. So with each
additional round of antibiotics, they saw
like an increase deterioration of the
bacterial community that was there in a
way that it was not able to go back to the
state that it was before. We don't know
exactly what that means but there's a lot
of evidence that, for example, children
that go on multiple rounds of antibiotic
are more likely to develop a lot of these
autoimmune diseases like asthma and
allergies, and so there's evidence that
this lot of antibiotic use is detrimental
for our health. Then children that takes
antibiotics but, say, have a family pet.
So there's an example of bringing microbes
back into our world by having an animal
that those children are somewhat protected
from the antibiotic effects just through
increased environmental
microbial exposure.
So there is kind of this too we're killing
microbes with the antibiotics, but if we
can reintroduce more microbes so in cases
where you really do need antibiotics, we
need to think about ways of repopulating
that community in a beneficial way to kind
of mitigate the effects that antibiotics
have on our gut.
- I think it's important to recognize that
antibiotics are wonderful drugs if they
are used appropriately, and I think the
problem is that for many years they were
used without recognition that there's a
cost associated. I think the first cost
that was recognized was the idea of
antibiotic resistance, and if antibiotics
are overused you can actually get
pathogens that are resistant to these
drugs that then are very difficult to
eradicate.
I think there's a second wave recognition
for reasons to limit
antibiotic use which is that there is a
cost associated with harming our resident
microbes. I think, from a very practical
sense, just talking people that worked in
our lab and other people that are in field
of microbiota research.
If you have a conversation with your
physician, and let them know that you
don't expect antibiotics every time you
get sick. If the wait-and-see approach is
appropriate, that you're comfortable with
that. A lot of times, physicians will not
prescribed antibiotics when they otherwise
would. We've heard of physicians that
would say thing like, "I thought you
wanted antibiotics. I'm fine with not
giving you any." So I think it's just
important for people to understand that
every time they take antibiotics, they're
harming this really important part of
their biology, and if they can avoid it
that's certainly
a better course of action.
- Yeah, so if it is necessary for like let
say in the case of a surgery or something,
after the antibiotic course then...just
eating the fiber, if you've deplete
those...if you've killed off those
beneficial bacteria often called commensal
bacteria that are producing all these
compounds, short-chain fatty acids,
if you kill it off and eating dietary
fiber only can do so much, right so. What
about repopulating it with the bacteria
itself. Probiotics, food that contain
probiotics. Are they ways that you think
are better than others?
- Yeah. This is something that really
hasn't been explored experimentally in
great detail. The best way to recover
after some major perturbation whether it's
antibiotics or preparation for a
colonoscopy or food poisoning, diarrhea or
something like that. If you look at trials
that have been performed, probiotics
certainly have a place in recovery from
this major perturbation. It's clear that
probiotics, either in supplement form or
in fermented foods.
Things like yogurt can actually shorten
duration of antibiotic associated diarrhea
or make it less common in people taking
probiotics. So this really suggest that
probiotics are doing something beneficial.
Now, that mechanism isn't well understood
but it's fairly well recognized that these
organisms that you can buy as supplements
or you find in fermented foods don't take
up permanent residence in the gut
typically but they do something as they're
passing through this community. It's known
that they can be viable, they're alive,
and they can actually have interactions
either with the microbiota or the host's
immune system. So I think, a nice way to
think of it is just using probiotics as
place holders while your microbiota is
recovering using those organisms that are
present in fermented foods for instance
can actually help to prevent pathogens,
bad bacteria from taking up residence
during that time.
- I've read a few studies with a probiotic
called VSL 3 which I use myself. I
definitely use it if I have to take our
kids over a round of antibiotics but it's
got like 450 billion bacteria which is
like 10 times more than anything else in
the market. If you think about, you take a
probiotic not to mention comes
shipped cold, a lot of these probiotics
in the market I think also are dead.
They're dehydrated dead bugs. So, there's
been like 25 published studies, clinical
trials and also animal studies where I've
seen, it's actually effective, It does
increase certain amounts of commensal
bacteria, it does lower inflammation. In
fact, it also increases brain drive
neurotrophic factors in the brain. So it's
having an effect in the brain. But I did a
personal trial myself where I took VSL 3
for 30 days, and I measured...
Well,
I I didn't specifically measure it, I used
Ubiome, a company allows you to send in a
little sample of your poop and they'll
tell you what sort of bacteria are in it.
So I did this before and after 30 days of
VSL 3. I was very interested to see that I
was expecting just to have an increase in
some of this commensal bacteria that were
in the probiotic, but what I found to my
surprise was that I have new strains of
bacteria that weren't identified
previously cropping up. I am not sure if
that's because the commensal bacteria are
making more of these compounds which were
feeding other types of bacteria that
couldn't be detected. Now they are
flourishing or what, but that was sort of
surprising to me to see, but I think that
in terms of recovering from something like
antibiotic use or even people that have
inflammatory bowel disease or colitis,
eating these fermented foods, eating the
fiber, broad spectrum fiber, and possibly
doing a round of the VSL 3 maybe a good
thing to do after any sort of procedure.
- Yeah. I think your story is really
interesting in a couple of respect. So,
the first is that I think it really
reinforce this idea that we have this
complex ecosystem, like a rain forest,
inside of us, and you could imagine that
adding a bunch of new species had high
numbers to a rainforest doesn't just
result in those new species being there,
but could lead to an entirely different
chain of interactions and ecology that
would crop up over a certain period of
time. So it's not hard to believe that you
would new species flourishing in the
presence of this new community members
added at high numbers. I think the other
to be aware of is, and I think you're
insinuating this with talking specifically
about VSL 3 that the supplement market is
a mess.
It's not regulated. There are a lot of
really poor products out there. Many of
which don't have the viable organisms that
they suggest they have in their label.
Many of them don't have the actual species
that they say that they do on their label
or they have contaminants that are
present. So I think it's really important
if people want to go the route of
probiotic supplements to make sure that
you go with a company that you trust.
There are independent organizations that
can verify the contents of probiotics
supplements. So USP is a symbol that you
can look for in probiotic supplements as
an independent verificatoin of the
contents. Not efficacy but of the
contents. I think fermented foods are
really great way to go just because you
get this diversity of microorganisms, and
we really don't know which ones are best
for different individuals. So, it really
requires that each person take a
personalized approach to this becomes
systematic in testing what appears to work
well. Be compatible with your system and
isn't causing problematic Side effects. So
that's just kind of a personal journey
that each person to go on.
- Now, that's really a good insight and
advice. Another thing I wanted to just
touch on briefly because I know that you
guys have talked about something that has
to do with the origin of our microbiome,
starting from when we are born. So, I'm
not sure actually if you guys know about
the development of it in uterus at all or
if it's known at all how that works in
terms of what the mom's eating or doing
etc. So starting from conception in utero
development to giving birth. Can you talk
a little bit about that and the
development of the microbiome.
- Yeah. So I think for many years, it was
largely thought that the, while the baby
was in the womb that that was a
largely...an environment that was largely
devoid of bacteria.
And now there's starting to be some new
studies that looks like maybe there are
some bacteria in the amniotic fluid but
it's clear that even if that pans out to
be true that these are not major
contributors to the initial colony that
forms in the new born infant. So when
you're, you are born with gut largely
sterile and what happens at that point is
that there is this land rush by microbes
to colonize this new habitat. What we've
seen is that children depending if they're
born by C-section or vaginally will have
very different
initial microbial communities.
So children born vaginally got microbiota
that looks more like that of their
mother's colon or vagina. Whereas children
that are born by C-section actually have
microbes in their gut that are more...the
type of microbe that we find more on skin
and not necessarily the mother's skin,
maybe the doctor or nurse's skin. So that
initial colonization is dependent on the
method of birth, but there's all these
other things that happen initially in a
child's life that really dictate how the
community goes. So whether a child is
breast fed or formula fed has a huge
impact on the microbes.
So this is the baby's diet and diet we
know is the basically, one of the major
levers to control this community. So
babies that are fed formula, their
mircrobiota looks very different than
breast mil. Actually, what we see is
breast milk has a component of it, one of
the major component of breast milk is this
type of carbohydrate called human milk
oligosaccharides or HMOs. For a long time
it was really a mystery why those
molecules where there because we knew that
humans can digest human milk
olisaccharides. So why would a mother put
so much effort into creating these
compounds and putting them in our milk if
her baby can't even digest it.
Well come to find out it's actually the
gut microbes that are digesting these
HMOs. So in breast milk there's just not
food for the baby in form of lactose and
fat, but these HMOs that are food for the
baby's growing microbiota so the mother's
feeding the baby and also her baby's
growing microbiota. These HMOs are very
specific for human milk and so far have
not been able replicated in formula. So
that, we think is a large reason why the
communities are so different.
Then of course, antibiotics the average
American child is on a round of
antibitiotics every year, and we know that
that's a huge makes a huge impact on that
growing community. So all these things
that happen early in life could really set
a child on a trajectory potentially for
having potetially very good, healthy,
robust microbiota or potentially one that
isn't as good. So I think as parents
especially of new children, we need to be
mindful of the choices that we make early
in a child's life because many of these
microbes that we have by the time, say,
the age of five, many of these microbes
would be with us throughout our entire
lives so we really want get that community
started in the best possible way.
- So very interesting in terms of the
giving a vaginal delivery then do you
think that having...the mother
having...making sure that her bacteria in
the vagina is populated with the right or
good types bacterias, something she can do
during pregnancy or before that may help
with that? Are there certain...
- Yeah. I don't think that that's been
studied extensively. I mean, I think just
common sense wise, you would imaging that
foods that are healthy for the mother's
microbiota so...which would be coming from
a diet that's high in dietary fiber,
fermented foods that that would be a good
community to pass on to a child but that
hasn't been looked at very carefully.
- Yeah, Yeah, I mean, that would make
sense logically, and the breast milk,
obviously very important. Do you know why
certain mother choose to use formula? Is
there a reason for that?
- I think there are probably many reasons
I mean, I personally breast fed to of my
two children, and I can say as a working
mother, it was a challenge. I mean, a lot
of work environment don't make it so easy
to pump milk and provide breast milk for
your child. It's a huge choleric load so I
think a lot of mother don't realize that
you require more calories for generating
breast milk that you did during pregnancy.
So that's a huge work load for the mother
at a time when her infant is young and
isn't sleeping well. I mean, there's a lot
of reasons why women choose not to breast
fed, and unfortunately, this is a whole
society issue that I think we need to
address just on making that easier for
mothers especially for working mothers
because we know it appears to be so
important for the health of our child.
- Perhaps, now knowing the effect on
microbiome and setting them up for life is
probably a good motivating factor to do
extra work if you can. But this has been a
very interesting conversation. There is so
much more I wanted to talk about in terms
of obesity, transplanting gut bacteria
from lean mice into obese, making them
lean and vice versa, and the brain, but I
think we're running out of time. So people
that want to learn about your research,
you guys wrote a book. If you want to talk
about that, where can they
find those things.
- Yeah. So we do research at Stanford, and
our lab website is
sonnenburglab.stanford.edu and this gives
an overview of all the various things
we're studying in the lab. I think our
background is researches. There is a
really interesting intersection between a
research impacting our own personal life.
- We realize we were racing our kids
differently, we were eating a different
diet because of this research that we are
doing on the gut microbiota and then we
started talking to the other scientist in
our field and realizing that they were
making the same changes to their lifestyle
that we were making. Then we talked to
other scientist, to other friends that
didn't know about the gut microbiota, and
they weren't doing these things. It really
struck us that shouldn't be just the
scientist studying this field that had the
access to the information to make changes
to lifestyle and diet and so that really
prompted us to try to get this message out
there and our first step in doing this has
been writing a book called "The good gut
taking control of your weight, your mood,
and your long term health" and this is
available on Amazon, and it goes over the
science very broadly but it also attaches
that science to practical advice. How we
changed our lifestyle and how we think
provides insight into how you can change
what you're eating and what you're doing
to positively impact you gut microbiota,
and it even has short section of recipes,
examples of how we feed our family.
- Yeah, and the other thing that I would
add is that we have a Facebook page
facebook, com/thegoodgut where post things
like interesting studies that have come
recently that are a broad appeal to lots
people so we post in
there couple times a week.
- Great. Awesome guys. Well, check
out the Sonneburgs.
