- [rhonda]: welcome to another episode ofthe foundmyfitness podcast. today, i'm sitting here with doctors, justin anderica sonnenburg. justin is an associate professor at stanford in the department ofmicrobiology and immunology, and erica is a senior scientist at stanford. together they run a lab where they studythe effects of diet on the hundred trillion or so bacteria in the gut, andhow that impacts the health of the host which in their case happens to be alaboratory mouse. but this applies to the general population, and so i'm reallyexcited because i'm convinced that the health of the gut plays a very importantrole in overall general health. so maybe
we can start by talking a little bit aboutyour research and why the gut health is so important. [justin]: sure. so the... i think webecame interested in the gut microbiota from the stand point of just basicpioneering research, trying to understand this new microbial organ that we'vediscovered inside of us that's incredibly important and connected to some manyfacets of our health. over the course of the past 10 years or so there's been thistransformation in understanding this community and how fundamental it is. it'snot just quirky part of our biology. it really is holding the key to health of ourimmune system, our metabolism, there's a
brain-gut access so it's dictating mood,behavior perhaps impacting things like autism and neurodegeneration. so there'sreally this profound impact, this microbial community has onour entire body. [erica]: yeah, just to throw someinteresting numbers out there. we're actually by cell number, we actuallyhave 10 times more bacterial cells associated with our body than human cells.we even have a hundred times more bacterial genes associated with ourcollective genome than human genes. so both by cell number and by genenumber we're actually more microbial than we are human. so i think the research fromour lab and other labs in this area is
really redefining how we think ofourselves as human beings. we're not just this collection of human cells. we're infact more like a tube of human cells that houses this incredibly complex and dynamicecosystem of microbes, and what we're finding is that these microbes are wiredinto pretty much all aspects of our biology. they're really major players inmany aspects of our health. - yeah, in terms of how these bacteria inour gut regulating health, one thing that comes into my mind, in particular, is...sothis 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 ofimmune cells. i don't think most
people...if you would ask them where? whatorgan in the human body has the highest concentration of immune cells? peoplemight say the thymus or the spleen. no, it's actually the gut, and so that isparticularly where i have been interested because there's a very complex interactionbetween the bacteria in our gut and the immune cells in out gut. andyou 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 asdictating so much of our biology, that they actually are holding the reins tosome degree on our immune system on our
metabolism. on the other hand, our dietdirectly impacts this community. our research and the research of others hasshown this over and over again. so, really, we hold the reins on what'shappening inside out gut by controlling what we eat and aspects of our lifestyle, i think as we gain knowledge about thiscommunity, it's possible for us to foster a healthy microbiota to improve our healthin many dimensions. now, the immune system is reallyinteresting because there's really a delicate balance between our microbiotaand our gut because living in close proximity are these two entities that,classically, in microbiology were thought
not to get along: bacteria and the hostimmune system. what we realized is that there's this incredible conversationthat's continually ongoing in our gut between our immune system and the gutmicrobes to maintain harmony in most cases although this can go awry, butthere'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 ourbody. so really these microbes in our gut are dictating the set point of our immunesystem 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 isreally profound, and it's important to recognize that this not only impactswhat's going on in the gut but throughout our entire body. - absolutely, so the food that we put intoour body interacts with these gut bacteria and if we feed them certain food or wedon't feed them certain foods this will impact the immune system in the gut andalso in the rest of our body. specifically, what comes into my mind isthe dietary fiber that can be metabolized by certain bacteria in the gut intosomething called short-chain fatty acids that's like butyric acid, propionic acid,acetic acid, lactic acid, anything else,
but...and how these short-chain fattyacids provide signals to certain immune cells to regulate their functionboth in a positive or also in suppressing your immune system frombecoming too active. can you explain a little bit about that? - sure. well, so the dietary fiber we eatis really the key for feeding this gut microbial community, and the point thatthe microbes in our digestive tract primarily live at the end of the digestivetract is really important because so much of the food that we eat in the westernworld is laden in simple carbohydrates and fats and all of those things getsabsorbed in the upper gi tract and leave
our microbes essentially starving; there'sno complex carbohydrate to feed this community. in fact, going back totraditional populations of humans that are representative of how we evolved, it'sclear 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 starvingour microbes. so this is really important in manyrespects. one is that when the microbes receives these dietary carbohydrates,these complex dietary fibers that we eat, they make these compounds like short-chainfatty acids. that's their metabolism working. and these compounds, short-chainfatty acids, are actually the bacterial
waste. the bacterial feces if you will.and then we absorb these compounds and they regulate a number of differentaspects of our biology in a positive way. so they increase the number t regulatorycells. these are cells that attenuate inflammation, calm the immune system. soif you're not eating dietary fiber it's likely that your immune system isoperating in a hyper-inflammatory state. this hyper inflammatory state, it'sbelieved it can drive a lot of different western diseases ranging from autoimmunediseases, metabolic disorders. things like asthma, allergies. all ofthese problems that we associate with the western world are really have excessiveinflammation as underlying mediator.
it's not too hard to imagine how americansthat are not consuming dietary fiber not producing a lot of short-chain fatty acidshave this hyperactive immune system so dietary is really a key to feeding thiscommunity and setting the immune system to a proper set point so that it's not tooreactive. now there's a really interesting connection between lack of dietary fiberand 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 carbohydrateas something bad and you want to avoid. but broadly speaking there are two typesof carbohydrates we need to be aware of.
the more simple carbohydrates, and likejustin was saying, these are the ones that are absorbed early in our gi tract sothese are things from highly refined grains or packaged food types of simplesugars that are so prevalent in much of our western diet, but then there's thesecomplex carbohydrates. the type of carbohydrates that are found in dietaryfiber 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 atdegrading. 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 andthen produce the short-chain fatty acids
that you are talking about. so what we'refinding is that when we don't eat enough of these complex carbohydrates found indietary fiber, these gut bacteria are starving is so they really are forced torely on the mucus...the carbohydrates that are found in the mucus layers that linethe our large intestine. so as we don't consume enough dietaryfiber, these microbes become closer to our mucus lining. they're eating that foodbecause that's all they have to eat, and they inching ever closer to our ownepithelial cells, and that creates a situation in which the human aspect of ourgi tract and the microbial aspect, that fence that keeps them separated startsthinning and setting up a scenario where
our immune system now can startoverreacting to these microbes encroaching and these microbes potentially get alittle more aggressive because they're lacking in the food that they require. - and then, one thing that i just wantedto add, there's a lot of focus on these short-chain fatty acids that are thesemajor product of fiber degradation by the microbiota in the distal gut, but there'sa variety of other interesting chemicals that these microbes are producing.bacterial metabolism is something that's really not studied well enough, andthere's...we can think of these...each bacteria in our got has a littleunsupervised drug factory that's
constantly making interesting smallmolecules and interesting chemicals. we don't known the identity of most of thesecompounds, we don't know how they effect our biology. they're circulating in all ofour blood right now, they're slightly different between me and you, and theychange in a single individual over the course of the day. so, understanding howthese chemicals are impacting different aspects for biology is one of the greatfrontiers of research. - yeah. so about 10 different things cameto my mind as both of you guy spoke so i'm going to try fire away, but as erica wassaying it's really interesting you're talking about how when you're starvingthese gut bacteria in the colon, how they
start to eat away the mucus and of coursethat's the gut barrier that is the mucus. most people know about the gut barrierwhen that breaks down, you start to have the immune cells which are usually not incontact with all these bacteria in you gut. so it starts to come in contact andthen they can start to have an immune response. it's an interesting way becausei usually think about it as when you're starving the bacteria of the fiber thatthey need to make this short-chain fatty acids as starving the gut epithelial cellswhich rely on these short-chain fatty acids for energy. i think i read somewherelike between 60% to 90% of the goblet cells which are the specialized cell inthe gut that produce mucin which is
actually the mucus. slimy stuff that makesup the gut barrier. they rely on that as energy. it's almost like maybe there's adouble whammy going on where it's like he bacteria are feeding on the mucin that'sbreaking it down but at the same time, the cells that make the mucin are beingstarved of the energy substrates they need to make that mucin. so you just got thislike double whammy compounded effect. - absolutely, yeah, that's a veryinteresting point and i don't there's been any systematic study to look at rate ofmucin production based on the fiber in the diet, but this would be veryinteresting 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 thatcame to mind was when justin mentioned the effects of some of the short-chain fattyacids and other compounds that we have yet to identify, possibly how they effect thet regulatory cells. t regulatory cells as you mentioned, they keep the immune systemin check, they make sure that you're not having an hyperactive immune responsewhich leads to autoimmune diseases, and i think i've read that type 1 diabetes,rheumatoid arthritis, and multiple sclerosis. all of which have an autoimmunecomponent to them have been linked to the disruptions in the gut microbiome, and ithink there's direct evidence as well like
looking at animal models.. so i mean, you nailed it, right? thesediseases of the western world, i mean, i'm not sure if there's a complex interactionbetween people that have gene polymorphism that already predisposed them to ahyperactive immune response, and then, on top of that, having this unhealthy gut andnot being able to make as many tregs is like the perfect storm to create ms ortype 1 diabetes or any kind of that, but at the very least, you can't control whatgenes that you're born with but you can control what you put in to your mouth andwhat 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 humangenome and the polymorphisms that predispose us to all different differentdiseases is actually very misguided. i think that's just overlaying normal humangenetic variation on something that's very amiss in our environment, and namely, ourmicrobiota. so and you named a few of the diseasesfor which excessive inflammation is thought to be driver, but it extends farbeyond that. i mean, many cancers are driven by inflammation and heart diseasesdriven by inflammation. all the metabolic disorders are thought to beinflammation-promoted now and certainly all the autoimmune disease. so when youlook at...you're talking about tons of
disease that we have on the western worldthat largely aren't present in these traditional societies that have a muchhigher fiber consumption and also have a much more diverse gut microbiota. so itreally... i think you know when you look at all these things together and then themechanisms of how fiber degradation attenuates inflammation. it really lookslike our lack of fiber in the western world and our diet is deteriorating themicrobiota, and this is predisposing us to this tens of different diseases. i think it's very unlikely that there tonsof different causes for these diseases. i think that inflammation is thecommon denominator in the microbiota and
our diet is really at the heart of this. - well, yeah, inflammation is a driver ofaging. so you're talking about these diseases which many are age-related. soyou'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 theheart disease, that's the number one killer in the united states, and as ericamentioned, when you're starving your gut microbiome of this fiber, and the bacteriastarts to break down the mucin and gut cells possibly aren't making as this muchmucin, then when those immune cells become in contact with bacteria. they start tokill 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 killbacteria, this releases lipopolysaccharide endotoxin and what happens when yourelease endotoxin, it gets released in the bloodstream while your body has anadoptive response to it. it produces more cholesterol, the ldl, and the reason forthat is because there is binding sites the ldl receptors on the ldl and also on hdlcholesterol. bind endotoxin is the way stopping it up to protect your body. youdon't want to go into sepsis, and so you're producing more cholesterol that'swhy when you're in inflammed state you produce more cholesterol. that's really alink that i think between inflammation and
heart disease. it's also the reason whyyou should always get your cholesterol measured more than once because you maybesick or stress and you're inflamed and then your cholesterol is really high, andyour doctor might go, "whoa. let's get you on statins." so maybe that's not the bestscenario. but i want to get back to the fiberbecause you're talking about how important it is to get fiber and how we don't get asmuch fiber as our predecessors or whatever you want to call it. what kind of fiber? what kind of foodsources do you think are...do you think a broad spectrum approach where you try toget all types of fiber to because we don't
know what justin mentioned, we don't knowwhat all these gut bacteria are producing. so can you talk a little bit about thetypes of fiber. how much fiber? - yes, if you look at the average americanis eating around 10 to 15 grams of dietary fiber per day. the u.s. governmentrecommend 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 westudy in our lab. these hunter gatherers that lived in tanzania, they're eating onthe order of a 100 to a 150 grams of dietary fiber per day. so it's clear thatthe amount of fiber that we're consuming as americans is something that could be onthe order of 10 times less of what our
ancestors probably ate in the past. sothere's this issue of an amount of fiber that we just have to increase that toincrease the food that's getting to our gut bacteria, but then there's also thisissue 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 typesof complex carbohydrate that are found in dietary fiber are important. so you could imagine if you ate just onetype of complex carbohydrate, there would be, say, a handful of bacteria that arereally good at metabolizing of fermenting
that type of carbohydrate. those who getvery about maybe at the expense of other types of microbes, but if you're eatingmany different types of carbohydrates, complex carbohydrates, then you can fostera community kind of an ecosystem that's more rich and robust. so, if you areeating, say, 20 different types of dietary fibers then you're providing sustenancefrom many different types of microbes that might specialize in different types ofcarbohydrate consumption. and that appears to be important. thishaving a diverse community of bacteria in the gut, and so we think about itsometimes ;like as a rainforest. you want forest or this ecosystem tend to be morestable when there's a lot of complexity of
life on them. if you have, say, just alawn of only grass then one small things happens and that would harm that grass andthen everything dies or it's unstable. but if you have an ecosystem that has grassand trees and shrubs and all different things then it's less likely to collapseafter just one event. so that's how we like to think about it. you want a diversecommunity of microbes in your gut and the best way to foster that is to provide themdiverse amount of substrate. a diverse amount of complex carbohydrates. - so specifically, what foods would yousay would provide that diverse? - so we think that foods so fruits,vegetables, whole grains, and legumes are
all food that are high in dietary fiberand so we tried to consume many different types of each of those, and one sort ofeasy 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 fruitsand vegetables. i don't know if you have some other. - i mean, the other piece of advice that iwould give is just to avoid foods that comes in wrappers or packages. i mean, ijust think that processed food manufacturers have not caught on to theimportance of dietary fiber in health, and if you go to most of these processedfoods, if they do claim high fiber it
usually a single type of fiber thatthey're supplementing with. either inulin or celium husk or chickory or somethinglike that, and it doesn't provide the breadth of fiber that you would get if youwere to go to a produce section and pick ahandful of vegetables to cook. so i just think that until the processedfood people get on board with the importance of fiber, it's good just toavoid food that comes in packages. - so a couple things come to mind. one isthat maybe even prebiotics aren't the magic pill either, but the other thing isthe effect of processed food on the gut bacteria. have you guys looked in tospecifically any or do you anyone else in
terms of mechanisms, what happens, how iteffects the gut bacteria. i remember reading a paper, i believe it waspublished in nature not too long ago on the effect of artificial sweeteners likeaspartame. are you familiar with that? - yeah, absolutely, yeah. so there's avariety of compounds in processed foods now that seem to be problematic for themicrobiota. the artificial sweeteners is a good example, and although, the mechanismwasn't well delineated and how this is impacting the microbiota. it certainlyappeared that artificial sweeteners and they looked at three different classes ofartificial sweeteners. all affect the microbiota and go on and impact insulinresistance in the host. so a measure of
diabetes in metabolic syndrome. similarly, emulsifiers recently have beenlooked 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 tobacteria getting closer to a host tissue and induce inflammation, and that alsoleads to a metabolic problems. so i think there's a...the other thing that processedfoods do in addition to not providing dietary fiber is that they provide allthese other compounds that just haven't....in most cases, haven't beenwell studied. and in the cases where they have beenstudied, it appears that they're
problematic. this is... i guess somewhatintuitive when you consider that our body hasn't adapted to a lot of these chemicalsthat we're exposed to in process food. it doesn't know how to handle them, andtherefore, potentially problematic to our long term health. - so it's not just a lack of fiber, butit's also they're doing something actively bad in addition to that. again, one ofthose compound it affects. so the other thing that comes to mind iswhen 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 situationprescribing antibiotics. but, the problem
is that they are prescribed in many notlife or death situation. in fact, they're very over prescribed for just things thatare not necessary. sinus infection or cold, common cold. what effect does justeven 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 canrecover from that. - yes, i think we have to realize thatwhen antibiotics were developed there was no thought placed on gut microbes. theseare 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 awide variety of microbes so that they can
be used for many different types ofinfection. what we're finding is that these antibiotics do wreak havocin our guts. so many of the microbes that are beneficial that inhabitus are killed by these antibiotics, and what we're finding is that often themicrobiota....there is or it is able to rebound, but often it is not able torebound exactly as it was before. from studies done, others in stanford,not us, but a colleague of ours, david relman. they showed that with multiplerounds of antibiotics, with each additional round there is another sort ofhit that the microbiota takes that makes it less likely to recover. so with eachadditional round of antibiotics, they saw
like an increase deterioration of thebacterial community that was there in a way that it was not able to go back to thestate that it was before. we don't know exactly what that means but there's a lotof evidence that, for example, children that go on multiple rounds of antibioticare more likely to develop a lot of these autoimmune diseases like asthma andallergies, and so there's evidence that this lot of antibiotic use is detrimentalfor 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 animalthat those children are somewhat protected from the antibiotic effects just throughincreased environmental
microbial exposure. so there is kind of this too we're killingmicrobes with the antibiotics, but if we can reintroduce more microbes so in caseswhere you really do need antibiotics, we need to think about ways of repopulatingthat community in a beneficial way to kind of mitigate the effects that antibioticshave on our gut. - i think it's important to recognize thatantibiotics are wonderful drugs if they are used appropriately, and i think theproblem is that for many years they were used without recognition that there's acost associated. i think the first cost that was recognized was the idea ofantibiotic resistance, and if antibiotics
are overused you can actually getpathogens that are resistant to these drugs that then are very difficult toeradicate. i think there's a second wave recognitionfor reasons to limit antibiotic use which is that there is acost associated with harming our resident microbes. i think, from a very practicalsense, just talking people that worked in our lab and other people that are in fieldof microbiota research. if you have a conversation with yourphysician, and let them know that you don't expect antibiotics every time youget sick. if the wait-and-see approach is appropriate, that you're comfortable withthat. a lot of times, physicians will not
prescribed antibiotics when they otherwisewould. we've heard of physicians that would say thing like, "i thought youwanted antibiotics. i'm fine with not giving you any." so i think it's justimportant for people to understand that every time they take antibiotics, they'reharming this really important part of their biology, and if they can avoid itthat's certainly a better course of action. - yeah, so if it is necessary for like letsay in the case of a surgery or something, after the antibiotic course then...justeating the fiber, if you've deplete those...if you've killed off thosebeneficial bacteria often called commensal
bacteria that are producing all thesecompounds, short-chain fatty acids, if you kill it off and eating dietaryfiber only can do so much, right so. what about repopulating it with the bacteriaitself. probiotics, food that contain probiotics. are they ways that you thinkare better than others? - yeah. this is something that reallyhasn't been explored experimentally in great detail. the best way to recoverafter some major perturbation whether it's antibiotics or preparation for acolonoscopy or food poisoning, diarrhea or something like that. if you look at trialsthat have been performed, probiotics certainly have a place in recovery fromthis major perturbation. it's clear that
probiotics, either in supplement form orin fermented foods. things like yogurt can actually shortenduration of antibiotic associated diarrhea or make it less common in people takingprobiotics. so this really suggest that probiotics are doing something beneficial. now, that mechanism isn't well understoodbut it's fairly well recognized that these organisms that you can buy as supplementsor you find in fermented foods don't take up permanent residence in the guttypically but they do something as they're passing through this community. it's knownthat they can be viable, they're alive, and they can actually have interactionseither with the microbiota or the host's
immune system. so i think, a nice way tothink of it is just using probiotics as place holders while your microbiota isrecovering using those organisms that are present in fermented foods for instancecan actually help to prevent pathogens, bad bacteria from taking up residenceduring that time. - i've read a few studies with a probioticcalled vsl 3 which i use myself. i definitely use it if i have to take ourkids over a round of antibiotics but it's got like 450 billion bacteria which islike 10 times more than anything else in the market. if you think about, you take aprobiotic not to mention comes shipped cold, a lot of these probioticsin the market i think also are dead.
they're dehydrated dead bugs. so, there'sbeen like 25 published studies, clinical trials and also animal studies where i'veseen, it's actually effective, it does increase certain amounts of commensalbacteria, it does lower inflammation. in fact, it also increases brain driveneurotrophic factors in the brain. so it's having an effect in the brain. but i did apersonal trial myself where i took vsl 3 for 30 days, and i measured... well, i i didn't specifically measure it, i usedubiome, a company allows you to send in a little sample of your poop and they'lltell you what sort of bacteria are in it.
so i did this before and after 30 days ofvsl 3. i was very interested to see that i was expecting just to have an increase insome of this commensal bacteria that were in the probiotic, but what i found to mysurprise was that i have new strains of bacteria that weren't identifiedpreviously cropping up. i am not sure if that's because the commensal bacteria aremaking more of these compounds which were feeding other types of bacteria thatcouldn't be detected. now they are flourishing or what, but that was sort ofsurprising to me to see, but i think that in terms of recovering from something likeantibiotic use or even people that have inflammatory bowel disease or colitis,eating these fermented foods, eating the
fiber, broad spectrum fiber, and possiblydoing a round of the vsl 3 maybe a good thing to do after any sort of procedure. - yeah. i think your story is reallyinteresting in a couple of respect. so, the first is that i think it reallyreinforce 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 highnumbers 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 thatwould crop up over a certain period of time. so it's not hard to believe that youwould new species flourishing in the
presence of this new community membersadded at high numbers. i think the other to be aware of is, and i think you'reinsinuating this with talking specifically about vsl 3 that the supplement market isa mess. it's not regulated. there are a lot ofreally poor products out there. many of which don't have the viable organisms thatthey suggest they have in their label. many of them don't have the actual speciesthat they say that they do on their label or they have contaminants that arepresent. so i think it's really important if people want to go the route ofprobiotic supplements to make sure that you go with a company that you trust.there are independent organizations that
can verify the contents of probioticssupplements. so usp is a symbol that you can look for in probiotic supplements asan independent verificatoin of the contents. not efficacy but of thecontents. i think fermented foods are really great way to go just because youget this diversity of microorganisms, and we really don't know which ones are bestfor different individuals. so, it really requires that each person take apersonalized approach to this becomes systematic in testing what appears to workwell. be compatible with your system and isn't causing problematic side effects. sothat's just kind of a personal journey that each person to go on.
- now, that's really a good insight andadvice. another thing i wanted to just touch on briefly because i know that youguys 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 aboutthe development of it in uterus at all or if it's known at all how that works interms of what the mom's eating or doing etc. so starting from conception in uterodevelopment to giving birth. can you talk a little bit about that and thedevelopment of the microbiome. - yeah. so i think for many years, it waslargely thought that the, while the baby was in the womb that that was alargely...an environment that was largely
devoid of bacteria. and now there's starting to be some newstudies that looks like maybe there are some bacteria in the amniotic fluid butit's clear that even if that pans out to be true that these are not majorcontributors to the initial colony that forms in the new born infant. so whenyou're, you are born with gut largely sterile and what happens at that point isthat there is this land rush by microbes to colonize this new habitat. what we'veseen is that children depending if they're born by c-section or vaginally will havevery different initial microbial communities.
so children born vaginally got microbiotathat looks more like that of their mother's colon or vagina. whereas childrenthat are born by c-section actually have microbes in their gut that are more...thetype 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 themethod of birth, but there's all these other things that happen initially in achild's life that really dictate how the community goes. so whether a child isbreast fed or formula fed has a huge impact on the microbes. so this is the baby's diet and diet weknow is the basically, one of the major
levers to control this community. sobabies that are fed formula, their mircrobiota looks very different thanbreast mil. actually, what we see is breast milk has a component of it, one ofthe major component of breast milk is this type of carbohydrate called human milkoligosaccharides or hmos. for a long time it was really a mystery why thosemolecules where there because we knew that humans can digest human milkolisaccharides. so why would a mother put so much effort into creating thesecompounds and putting them in our milk if her baby can't even digest it. well come to find out it's actually thegut microbes that are digesting these
hmos. so in breast milk there's just notfood for the baby in form of lactose and fat, but these hmos that are food for thebaby's growing microbiota so the mother's feeding the baby and also her baby'sgrowing microbiota. these hmos are very specific for human milk and so far havenot been able replicated in formula. so that, we think is a large reason why thecommunities are so different. then of course, antibiotics the averageamerican child is on a round of antibitiotics every year, and we know thatthat's a huge makes a huge impact on that growing community. so all these thingsthat happen early in life could really set a child on a trajectory potentially forhaving potetially very good, healthy,
robust microbiota or potentially one thatisn't as good. so i think as parents especially of new children, we need to bemindful of the choices that we make early in a child's life because many of thesemicrobes that we have by the time, say, the age of five, many of these microbeswould be with us throughout our entire lives so we really want get that communitystarted in the best possible way. - so very interesting in terms of thegiving a vaginal delivery then do you think that having...the motherhaving...making sure that her bacteria in the vagina is populated with the right orgood types bacterias, something she can do during pregnancy or before that may helpwith that? are there certain...
- yeah. i don't think that that's beenstudied extensively. i mean, i think just common sense wise, you would imaging thatfoods that are healthy for the mother's microbiota so...which would be coming froma diet that's high in dietary fiber, fermented foods that that would be a goodcommunity to pass on to a child but that hasn't been looked at very carefully. - yeah, yeah, i mean, that would makesense logically, and the breast milk, obviously very important. do you know whycertain mother choose to use formula? is there a reason for that? - i think there are probably many reasonsi mean, i personally breast fed to of my
two children, and i can say as a workingmother, it was a challenge. i mean, a lot of work environment don't make it so easyto pump milk and provide breast milk for your child. it's a huge choleric load so ithink a lot of mother don't realize that you require more calories for generatingbreast milk that you did during pregnancy. so that's a huge work load for the motherat a time when her infant is young and isn't sleeping well. i mean, there's a lotof reasons why women choose not to breast fed, and unfortunately, this is a wholesociety issue that i think we need to address just on making that easier formothers especially for working mothers because we know it appears to be soimportant for the health of our child.
- perhaps, now knowing the effect onmicrobiome and setting them up for life is probably a good motivating factor to doextra work if you can. but this has been a very interesting conversation. there is somuch more i wanted to talk about in terms of obesity, transplanting gut bacteriafrom lean mice into obese, making them lean and vice versa, and the brain, but ithink 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 theyfind those things. - yeah. so we do research at stanford, andour lab website is sonnenburglab.stanford.edu and this givesan overview of all the various things
we're studying in the lab. i think ourbackground is researches. there is a really interesting intersection between aresearch impacting our own personal life. - we realize we were racing our kidsdifferently, we were eating a different diet because of this research that we aredoing on the gut microbiota and then we started talking to the other scientist inour field and realizing that they were making the same changes to their lifestylethat we were making. then we talked to other scientist, to other friends thatdidn't know about the gut microbiota, and they weren't doing these things. it reallystruck us that shouldn't be just the scientist studying this field that had theaccess to the information to make changes
to lifestyle and diet and so that reallyprompted us to try to get this message out there and our first step in doing this hasbeen 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 thescience very broadly but it also attaches that science to practical advice. how wechanged our lifestyle and how we think provides insight into how you can changewhat 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 wouldadd is that we have a facebook page
facebook, com/thegoodgut where post thingslike interesting studies that have come recently that are a broad appeal to lotspeople so we post in there couple times a week. - great. awesome guys. well, checkout the sonneburgs.
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