How to Enhance Your Gut Microbiome for Brain & Overall Health
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Welcome to the huberman la podcast, where we discussed science and science space tools for everyday life. I'm Andrew huberman and i'm a professor of neurobiology and optometry gy at stanford school of medicine. Today we are going to discuss the gut and the brain, and we are going to discuss how your gut influences your brain and your brain influences your gut.

As many of you probably know, there is a phenomenon called your gut feeling, which tends to be something that you seem to know without really knowing how you know IT. That's one version of the gut feeling. The other is that you send something in your actual, got in your body, and that that somehow drives you to think or feel or act in a particular way, maybe to move towards something or to move away from something.

Now, today, we aren't going to focus so much on the psychology of gut feelings, but on the biology of gut feelings and how the gut and brain interact, because indeed, your gut is communicating to your brain both directly by way of neurons, nerve cells, and indirectly by changing the chemistry of your body, which permeates up to your brain and impacts various aspects of brain function. But IT works in the other direction to your brain, is influencing your entire gut. And when I say entire gut, I don't just mean you're stomach, I mean your entire digestive track.

Your brain is impacting things like how quickly your food is digesting the chemistry of your gut if you haven't be stressed or not stressed, whether or not you are under a particular social chAllenge or whether not you're particularly happy will, in fact, adjust the chemistry of your gut. And the chemistry you've got, in turn, will change the way that your brain works. I'll put all that together for you in the context of what we call the gut microbiome.

The gut microbial are the trillions of little bacteria that live all the way along your digestive tract and that strongly impact the way that your entire body works at the level of metabolic immune system and brain function. And of course, we will discuss tools, things that you can do in order to maintain or improve your gut health. Because, as you'll also soon see, god health is immensely important for all aspects of our well being, at the level of our brain, at the level of our body.

And there are simple, actionable things that we can all do in order to optimize our good health, in ways that optimize our overall nervous system functioning. So we will be sure to review those today. This episode also serves as bit of a primer for our guest episode that's coming up next week with doctor Justin sonn bird from the stanford university.

Doctor SONY berg is a world expert in the gut microbial, and so we will dive really deep into the gut in all its complexity. Will make IT all very simple for you. We will also talk about actual tools in that episode.

This episode is a stand alone episode, so you'll get a lot of information in tools. But if you have the opportunity, see this episode first. I think I will service a nice prime for the conversation with doctor sonnet's.

org. Before we begin, i'd like to emphasize that this podcast is separate from my teaching and research roles at stanford. IT is, however, part of my desire and effort to bring zero cost to consumer information about science and science related tools to the general public.

In keeping with that theme, i'd like to thank the sponsors of today's podcast. Our first sponsor is athletic Greens. Athletic Greens is in all in one of vitamin, mineral, probiotic drink. I've been taking athletic Greens since two thousand and twelve, so i'm delighted that their sponsor in the podcast, the reason I started taking athletic Greens on the reason I still take athletic Greens once or twice a day, is that IT helps me cover all of my basic nutritional need to make up for any deficiencies that I might have. In addition, IT has probiotics, which are vital for microbial on health.

I've done a couple of episodes now on the so called gut microbiome and the ways in which the microbiome interacts with your immune system, with your brain to regulate mood, and essentially with every biological system relevant to health throughout your brain and body. Letter Greens, I get the vitals I need, the minerals I need and the probiotic to support my microbial. If you'd like to try athletic Greens, you can go to athletic Greens dot com slash huberman and claim a special offer.

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Again, that's waking up dot com slash huberman to access a free thirty day trial. Okay, let's talk about the gut in the brain and how you're gut in your brain communicate in both directions. Because, as I mentioned before, your gut is communicating all the time with your brain, and your brain is communicating all the time with your gut.

And so the two are in this ongoing dance with one another that or nearly is below your conscious detection. Although you're probably familiar with the experience of everyone's in a while getting a stomach ache or of eating something that doesn't agree with you or conversely, eating something that you find particularly delicious and that sensation or that experience rather being a whole body experience, your mind is excited about what you're eating or just eight. Your god is excited about what you're eating or just eight.

And IT seems to be a kind of unified perception of both brain and body. Today we're gona talk about how that comes about in the negative sense, like you know, when you meet someone you really dislike or only have a stomach ache. And in the positive sense, when you act with somebody that you really, really like and you'd like to spend more time with them, for instance, or when you eat something that you really, really like and you would like to spend more time with that food, so to speak.

Now, the gut in the brain represent what we call a biological circuit, meaning they include different stations. So station a communicates with station b, which communicates with station c and so on. And as I mentioned earlier, IT is by directional, take two way street between gut and brain.

I want to make the important point at the outset that when I say the word gut, when I referred to the gut, i'm not just referring to the stomach. Most of us think that the gut equates to the stomach because we think of having a gut, or not having a gut, or having a gut feeling of some sort. But in the context of gut brain signaling and the related microbiome, the gut includes the entire digestive tract that's right from start to finish the entire digestive track.

So much so that today we're going to talk about, for instance, the presence of neurons, nerve cells that reside in your gut, that communicate specific locations in the brain and cause the release of specific neurochemicals, such as the neurochemical doping or serotonin, that can motivate you to seek more of a particular food or type of interaction or behavior, or to avoid particular foods, interactions and behaviors. And some of those neurons, many of those neurons, in fact, reside in your, in testers, not in your stomach. They can be in the small, in testing or the large and testing.

In fact, you actually have taste receptors and neurons located all along your digestive track. You have neurons that are located all along your digestive track. And they are communicating to your brain to impact what you think, what you feel and what you do.

Okay, so for the gut brain access, we need to deal with the brain part. And then we need to deal with the gut part. Let's just quickly talk about the brain part because there the word brain is also a bit of a misnomer in that when we say they got brain access, IT does include the brain but includes a lot of other things as well.

So as many of you probably know by now, you're listeners of this podcasting. If you don't, that's fine. Your nervous system includes your brain and your spinal cord.

And those together constitute was called the central nervous system, your neural retina, which are the lining the back of your eyes, and are the light sensing portion of your eyes, are also part of your central nervous system. So actually, your eyes are part of your brain. There are the only parts of your brain that are outside the crony involved. So your retina, your brain proper and your spinal court make up the central nervous system. The other parts of your nervous system constitute what's called the peripheral nervous system, which are the components of your nervous system that resides outside the retina, brain and spinal court.

Now this is very important because today we're going to talk a lot about how the gut communicates with the brain, and IT does that by way of peripheral nervous system components, meaning nerve cells that reside in the gut and elsewhere in the body, that communicate to the brain and cross into the central nervous system to influence what you think in what you feel. So, so that's the nervous system, part of what we call the gut, brain access. Brain, again, just being a short hand for including all the elements I just described.

Gut, as you now know, includes all the elements of the digestive tract. Let's talk about the architecture, the structure of the gut, of your digestive system. Now, not surprisingly, your digestive system, A K, your gut begins at your mouth and ends at your annis.

And all along its live, there are a series of swingers that cut off certain chAmbers of the digestive track from the other chAmbers. Now also along this tube that we call the digestive track, there is great variation in the degree of acidity, or P. H.

As IT sometimes called. That variation in acidity turns out to give rise to different little micro environments in which particular microbiota microban Terry can thrive or fail to thrive. And so the way i'd like you to think about the digestive tract, this got component of the gut rain access, is that it's not just one component.

It's not just your stomach with a particular actually and a bunch of microorganism that work particularly well to make you feel good and make your digestive pathways working well. It's a series of chAmbers, little micro environment in which particular microbiota thrive and other microbiota do not in certain behaviors that you undertake and certain experiences that you have will adjust those micro environments in ways that make particular microbiota certain bacteria more likely to thrive and others less likely to thrive. Will talk about how that was set up for you early in life.

Actually, from the moment that you came into the world, that microbiome was being established, IT was actually strongly impacted depending on whether not you were born by sea section or by vag inal birth. And IT was strongly impacted by who handled you when you came into the world, literally, the hands that we're on you, how much skin contact you had, whether not you're a premier baby or not, whether not you had pets at home, whether not you allowed to play in the dirt, whether not you allowed to eat snails, or whether or not you were kept in a very antiseptic environment. All of those experiences shaped these little microenvironment and shaped what constitutes best or worst for those micro environments.

Okay, so you have this long tube that we call the digestive tract, and it's very, very long. In fact, if we were to splay IT out where to take all the curves in, turns out of the in teston, we'd find that IT is very long. It's approximately nine meters long.

Now the structure of that digester track turns out to be very important in terms of gut brain signaling. Once again, it's a tube, and the hollow of that tube is called the loomin L U M E N. But the walls of the tube are not necessarily smooth, at least not for significant portions of the digestion of track.

For much of the digestive track, there are bumps and grooves that look very much like the folds in the brain. But these bombing grooves are made up of other tissues, are made up of what's called a new costal linings. So there's a lot of mucus there.

And if we were to look really closely, what we would find is that there are little Harry like cellular processes that we call microbial that are able to push things along the digestive track. The microbiota reside everywhere along the lumen of the digestive track, starting at the mouth and all the way to the other end. And they resided within those microbial, and they reside within the lemon.

And if we were to look really closely at the bombs and grooves along the digester track, what we would find is that there are little niches, little areas in which particular things can grow and reside best. I might some kind of gross, but IT actually is a good thing, especially what's growing and residing there, or micro bacteria, organisms that are good for your gut and that signal good things to your brain. And we will talk about what that signaling looks like and how that's done in accomplishing just a few moments.

But I want you to get a clear mental picture of your gut, something that we don't often see. And often when we think about the gut again, we just think about the hollow of the stomach, food going in there and getting digested. But it's far more complex and actually far more interesting than that.

Now i've been referring to the gut microbiome into the microbiota and these bacteria, I mean, define those terms a little bit more specifically, just to avoid any confusion. The microbial a, the actual bacteria, the microbial is used to referred to the bacteria, but also all the genes that those bacteria make, because IT turns out that they make some important genes that actually impact all of us. You have loads and loads of these little microbiota, these bacteria. In fact, right now you are Carrying with you about two to three kilograms, so that's more than six pounds of these microbiota, these bacteria.

And if we were to look at them under a microscope, but we would see, as these are relatively simple little organisms, some remaining stationary, so they might pop down into the mucosal lining, or they might hang out on a particular microbial, or they might be in one of those little niches, and others can move about, but they basically feel the entire loomin they surround and kind of coat the surface of the micro villa, and they are tucked up into any of those little niches that are available to them to tuck into. If you were to take the head of a pin and look at IT under the microscope, you could fit many, many hundreds, if not thousands or more of these little microbes, turia. And the reason I say many, many thousands or more, and giving up a kind of broad range there, is that they do very in size.

And again, they're various to whether they can move or they don't move. Now they're constantly turning over in your gut, meaning they're being born, so to speak, and they're dying off. And some will stay there for a very long parts of time within your gut, and others will get extreem about sixty percent of your store. As unpleasant as that might be to think about is made up of live and dead microban turia.

So you're constantly making an extreem, these micro bacteria, and which microbes turia you make and how many stay inside your gut and how many leave, meaning how many are exceeded, depends a lot on the chemistry of your gut and depends very strongly on the foods that you eat and the foods that you do not eat. Now, just because what we eat strongly influences our microbiome, meaning of microbes, tera, does not mean that there are not other influences on what constitutes or microbes. Our microbial is also made up by microbes, turia, that access our digestive track through our mouth, through breathing, through kissing and through skin contact.

In fact, one of the major determinants of our microbiome is who we interact with and the environment that we happen to be in. And that actually includes whether not we interact with the animals in a little bit or talk about some data as to whether not you drop in the home that had animals, whether not you drop in the home, whether not there was a lot of social contact, skin contact, or whether not you group in a more animal sparse contact, sparse environment, and how that shape your microbial. But the simple point is that what you eat influences your microbiome, but also what you do, what you think and what you feel.

And many of the low microban turia that get into your digestive tract do so by way of social interactions. In fact, if you ask a neutral logic what the role of the microbiome, they'll tell you, almost certainly that is there to impact brain function. But if you have friends that are microbiologists such as um I do, they'll tell you, well, maybe the brain and nervous system are there to support the microbial.

It's the other way around. You have all these little microorganism that are taking residents in our body. They don't really know what they're doing.

As far as we know, we don't know that they have a consciousness or they don't. We can't rule that out, but IT seems pretty unlikely. none. There's they are taking advantage of the different environments all along your digestive track.

They are taking advantage of the sort of social interactions, for instance, the people you talk to and that breathe on you, the people that you shake hands with, the people that you kiss or don't kiss, the people that you happen to be romantically involved with or not your dog, your cat, your lizard, your rat, whatever pet you happen to own is impacting your microbial. There's absolutely no question about that. So hopefully now you have some sense of the architecture of the digestive pathway, and you have some sense of the trillions of little micro bacteria that are living all along the different components of that digestive pathway.

But what we haven't talked about yet, and what i'd like to talk about now, is what those little microbiota a are actually doing in your digestive tract. In addition, just living there for their own intense and purposes, they are contributing, for instance, to your digestion. Many of the genes that those microbiota ic are, genes are involved in fermentation, and genes are involved in digestion of particular types of nutrient.

And in a little bit we will talk about how what you eat can actually change the that those microbial components make ends, largely being things that are responsible for digestion. They city's other sorts of cellar events. But in the context of the digester pathway, we're talking about enzymes that helped digester food.

So those. Riot are indeed helping you in many ways. And if you like certain microbiota that can help you digest, IT stands to reason that you would have chAllenges digesting certain types of foods. The other amazing thing that these microbiota do is they change the way that your brain functions by way of meta lizer or facilitating the metabolism m of particular neurotransmitters.

So one of the ways that having certain microbiota present in your gut can improve your mood or degrade your mood, for instance, is by way of certain microbiota being converted into or facilitating the conversion of chemicals such as gaba. Gaba is in what we call an inhibitory nor transmitter, or is involved in suppressing the action of other neurons. And that might sound like a bad thing, but all types of sensitives, for instance, alcohol and a lot of neurons that naturally make ga, can help quite certain circuits in the brain.

For instance, ince circuits responsible for anxiety in people who have epilepsy. The gaba argia neons, as their called, can often be disrupted in their signals, meaning they are not cranking out as much gaba. And therefore the excitation irons, which typically released other molecules like glutamate, can engage in what's called runaway exit.

And that can give us rise diseases. So the simple message here is that the microbiota, by way of making neurochemicals, can influence the way that your brain functions. So you want to support those microbiota, and we will give you tools to support those microbiota.

But the takeaway at this point is that those microbiota are making things locally to help digest food. Other microbiota are helping to make certain neal transmitters like gaba. And we'll also talk about dopamine and serotonin.

And so the very specific microbiota that reside in your gut have a profound influence on many, many biological functions, especially immune system function, brain function and digestion. So that should give you a fairly complete picture of your gut microbiome. Now i'd like to talk about how your microbiome and your brain communicate, or more accurately, how your microbial in the rest of your nervous system communicate.

Neurons, which simply means nerve cells are the cells that do most of the heavy lifting in your nervous system. There are, of course, other cell types that are important glial cells for instant, very, very important cell types you have into theoria cells, which are responsible for blood flow, Perry sites and other types of cells. But the neurons are really doing most of the heavy lifting for most of the things we think about in terms of nervous system function.

You have neurons in your gut, and that should not surprise you. Neurons reside in your brain, your point to court your eyes, and in fact, all over your body. And you've got them on your heart and in your heart, and you've got them in your lungs, and you've got them in your spleen, and they connect to all the different organs and dishes of your body. So that's not surprising that you have neurons in your gut. What is surprising, however, is the presence of particular types of neurons that resided near or in the mucosal lining just next to that looming of the gut, and that are paying attention.

And I explain what I mean by paying attention to the components of the gut, both the nutrient and the microbiota, and thereby can send signals up to the brain by way of a long wire that we call an acts on, and can communicate what the chemistry and what the nutritional quality and what the other aspects of the environment are at the got, at a given location, up to the brain in ways that can influence the brain to, for instance, seek out more of a particular food. Let me give you a sort of action based picture of this. Let's say, like most people, you enjoy sweet foods I don't particularly enjoy swiftly.

Ds, but there are a few that I like. I'm a sucker for a really good dark chocolate, or really good ice cream, or I get this thing for donuts that seems to just not quit. Although I don't indulge very often, I do like them if I eat that particular food.

Obviously, digestion starts in the mouth. Their enzi there gets chewed up. The food goes down into the gut. These neons are activated, meaning that causes the neurons to be a electrically active when ticula components, certain nutrient in those foods are present.

And for the cell types where, I should say, the neuron types that matter here, the neutrons that really trigger their activation are sugar, fatty acid and a mino assets. Now these particular neons have the name international indecent cells, but more recently they've been defined as neurological ells. Neuropathic ells were discovered by a gago horses s lab at duke university.

This is a phenomenal set of discoveries made mostly in the last ten years. These neurology cells, as I mentioned, are activated by sugar fati assets or amino acids, but have a particularly strong activation to sugars. They do seem to be part of the sweet sensing system.

And even though i'm focusing on this particular example, they represent a really nice example of how a particular set of nerve cells in our gut is collecting information about what is there at a particular location in the gut and sending that information up to our brain. Now they do that by way of a nerve pathway called the veggies nerve. The vegas nerve is part of the proferred nervous system, and the veggies nerve is a little bit complex to describe.

If you're just listening to this, if you're watching this, i'll try to use my hands as a diagram. But really the best thing to do, if you want really want to learn neural atomy, is to just imagine IT in your mind as best you can. And if you can track down a picture of a terrific, but here's that works.

Neurons have a cell body that we call our soma. That's where all the DNA are contained. That's where a lot of the Operating machinery of the of the cells are contained and allow the instructions for that cell of what to be and how to Operate are contained.

The cell bodies of these neurons, or the relevant neurons, are actually up near the neck. So you can think of them as kind of A A clump of grapes to sell. Bodies tend to be round or over lish.

And then they send a process that we call an acts on in one direction out to the gut. And they'll send another process up into the brain. And that low, clustered near the neck that's relevant here is called the noodles gangling N O dos e.

The noodles gang is low cluster of neurons on either side of the neck. IT has a process that goes out to the gun, a process that goes up into the brain. Again, these are just one component of the so called vegas nerve.

The vague st. Nerve has many, many branches, not just to the gut there, also branches to the liver, branches to the longs, branches to the heart, branches to the array, and even to the spin and and other areas of the body that are important. But right now, we're just concentrating on the neuron sitter in the gut that signal up to the brain.

And what the bahrain's lab has shown is that these neuro pod cells are part of this network. They're sensing several different nutrients, but in particular, when they sent sugar, they send signals in the form of electrical firing up to the brain in ways that trigger activation of other brain stations that caused you to seek out more of that particular food. Now this brings us to some classic experiments that, at least to me, are incredible.

And these are highly reproduced, able findings showing, for instance, that even if you bypass taste by infusing sweet liquid or putting sweet foods into the gut, and people can never taste them with their mouth, people will seek out more of that particular food. And if you give them the option to have a sweet food infused into their gut, or a bitter food infused into their gut, or a sweet versus sour, or a more sweet versus less sweet food, people have a selective preference for sweet food, even if they can't taste them. Now, this is important.

Understand in the context of gut brain signalling, because we always think that we like sweet foods because of the way they taste. And indeed, that's still true. But much of what we consider the great taste of a sweet food also has to do with a gut sensation that is below our conscious detection.

How do we know that? Well, the bork s. Lab has performed experiments using modern methods and their classic experiments showing that animals and humans will actively seek out more of a particular sweet food, even if IT bypasses this taste system.

And the reverse is also true. There have been experimented done in animals and in humans that have allowed animals or humans to select and eat sweet foods. Indeed, that's what they do if they're given the option, and yet to somehow eliminate the activation of these neurons within the gut that can sense sweet foods.

Now there are couple different ways that those experiments have been done in classic experiments that date back to the eighties. This was done by what's called sub diagram tic vegoil, amy. So this means cutting off the branch of the vegas that innovates the gut below the diagram so that the other organs can still function because the veg is very important, but basically cutting off the sweet sensing in the gut, still giving people the opportunity to taste sweet foods with their mouth.

And they don't actively seek out quite as much of the sweet food when they don't have. This got sensing mechanism that we now know to be dependent on these neurologic ells. More recent experiments involved selective silencing of these neurologic ells, and they're been a lot of different derivation of the sort of thing.

But the take away from IT is that our experience of in our desire for particular foods has everything to do with how those foods taste. IT also has to do, as you probably know, with their texture and the sensation of those foods in our mouth and even indeed how they go down our throat sometimes can be very pleasing or very unpleasant. And IT also has to do with the subconscious processing of taste that occurs in the gut itself.

And again, when I say that, I don't just mean in the stomach, they are actually neurons, neuro pod cells, further down your digestive of track, which are signaling to your brain about the presence of sweet foods, as well as friends such as a mino acid rich foods, or foods that are rich in particular types of fati assets, signals up to your brain and causing you to seek out more of those foods or to consume more of those foods. Now you're probably asking, what is the signal? How does that actually make me want more of those foods without me realizing IT? What does that by adJusting the release of particular neuromodulators? For those of you that are not familiar with neuromodulators, these are similar to neurotransmitters, ors.

But they tend to act more broadly. They tend to act, impact many more neurons all at once. And they go by names like dopamine, serotonin in a seto, Colin, epa, fran, so forth.

Sometimes people referred to those as our transmitters. Technically, they are newer modulators. I'll refer to them almost always as neutral modulators. The neurology cells signal by way of a particular branch of vegas through the noodles gangling that we talked about before and through a number different stations in the brain stem, eventually caused the release of the new modulator dopamine.

Dopamine is often associated with a sense of pleasure and reward, but IT is more appropriately thought of as a no modulator. The impacts, motivation, craving and pursuit. IT tends to put us into modes of action, not necessarily running and moving through space, although I can do that too.

But in the context of feeding, IT tends to make us look around more, chew more, reach for things more and seek out more of whatever. Is that giving us that sensation of delights satisfaction? And again, that sense of delighting satisfaction you might experience only consciously as the way that something tastes e on your mouth.

But IT actually is caused again by both the sensations in your mouth, but also by the activation of these neuropace cells. So this is an incredible system of got brain signaling, and IT is but one system of got brain signaling. IT, turns out, is the system that we know the most about at this point time. There are other components have got painted ling that will talk about in a moment, for instance, the serotonin system.

But in terms of examples of good brain signalling, for which we know a lot of the individual elements in how they work, I think this neuro pod neuron sensing of sweet foods, fatty acids and a mino assets in the gut in communicating that up to the brain by way of the vegas and causing us to seek out more of the foods that deliver those nutrients is an incredible pathway that really deliniates the beauty and the power of the scut rain access. Let me talk about time scales here. I'm talking about a particular type of neuron that is signaling up to the brain using electrical signals to cause us to want to seek out a particular category of foods that's happening relatively fast compared to the hormonal pathways of the gut, which also involved neurons.

So your gut is also communicating to your brain by way of neurons, nerve cells. But some of those in their cells also released hormones. And those hormones go by named like C C K glucagon like peptide one P Y Y eeta.

A good example of a hormone pathway, or what sometimes called a hormone peptic pathway that is similar to the pathway of, talked about before, but a little bit slower is the Green pathway glin ghor E I N increases with fasting. So the longer been since you ve eaten, or if you're just eating very little food compared to your chlorate needs, glen levels are going to go up in your bloodstream. And they go up because of processes that include processes within the gut and include the nervous system.

So it's a slow pathway driving you to seek out food. Generally, as far as we know, the gillin system is not partial to seeking out of sweet foods. Are, fatty foods are so on growing increases.

The longer has been sent, you ve eaten sufficient calories, and IT stimulate tes a feeling of you wanting to seek out food. Well, how does he do that? IT does that again by impacting neural circuits within the brain, neural circuits that include what we call the brain stem autonomic center.

So IT tends to make you feel alert. And quite a, we say, high levels of automation, ic, s. So if you have an eaten in a while, you might think that you just get really exhausted, right? Because we all hear that food is energy, and tolerate energies is what we need to burn.

But you actually have a lot of energy stored in your body that you would be able to use if you really needed energy. But typically we have an eaten a while. We started to get agitated, and we get agitated by way of release of the new modulator epiphone, which causes us to look around more, move around more and seek out food that all occurs in brain stem audino ic centres.

And in the hypothesis omas, we didn't entire episode on feeding behavior and metabolic as well. And you can find those episodes that huberman lab docs. So I don't want to go into a lot of detail about hypothermic and brain stem centers, but there's a particular area of the brain called the nucleus of the solitary tract.

The N S T is its called that's very strongly impacted by the circulating hormones intends to drive us told feeding behavior. So the important point here is that we have a fast system that is paying attention to the nutrients in our gut or the absence of nutrients in our gut, and stimulating us to seek out food or to stop in certain foods. And we have a slower hormone related system that also originates in the gut and impact the brain.

But all of those converge on neural circuits for feeding. The neural circuits for feeding include things like the argument, includes the hype atheists. They include a bunch of other neurochemicals.

But the point is that you ve got a fast route and a slow route to drive you to eat more or eat less, right? To seek out food and consuming, or to stop eating, to essentially kick start the satie mechanisms as they are called. And those are Operating in parallel.

It's not like one happens first, then stops in the other. They're always Operating in parallel. And I bring this up because there's a bigger theme here, which we see over and over again in biology, which is the concept of parallel pathways.

You've always got multiple accelerators and multiple breaks on a system. It's very, very rare to have just one accelerator and one break on the system. And this will become important later when we talk about tools for optimizing your got microbiome, for healthy eating and for healthy digestion, every healthy brain function.

I want to take a moment and talk about google like peptide one, which is also called G L P one. G L P one is made by neurons in the gut end. By neurons in the brain is a fairly recent discovery, but it's an important one.

Glp one tends to inhibit feeding and tends to reduce appetite. There are a number of drugs released on the market now. One, for instance, goes by the name summer blue tide, which is essentially in G, L, P.

One agonist IT causes the release of more G L P. One is being used to treat type two diabetes, which is insulin resistant diabetes. This is different than one diabetes where people don't actually make insulin, is also being used as a drug to reduce obesity.

And IT seems pretty effective, at least in certain populations. There are certain foods and substances that increase G, L, P. one.

I've talked about a few of these on the podcast, one that i'm a particular fan of for entirely other reasons, is year by mott can stimulate the release of top one in south america, is often used as an appetite of present, probably in large part because of its effects on top one release, but probably also because IT does contain caffeine, which is a bit of a stimulant, which also can be involved in light policies, which is the utilization of fat stores for energy and so forth. A brief mention about your b mote. There are some report out there that your romantic can increase certain types of of cancers.

The data that i've seen on this is that IT tends to relate to whether not those are smoked versions of the year, bom ta t, the amount of consumption. And the debate is still. So I invite you to look at those papers.

You can search for those online. Nonetheless, yb mota is one source of G, L, P one stimulation. Some a gu tide is another source.

IT also can be stimulated by various food ds nuts of aaos eggs and so forth. Certain high fiber complex grains will also stimulate. Gp one, I raise this as not necessarily I wrote that you want to take in order to reduce food intake.

I don't even know that that's your goal, but that G, L, P. One is another one of these got to brain signaling mechanisms that are just appetite that is dependent on diet, depends on what you eat or drink. And that the glp won pathway does seem particularly sensitive to the constitution of diet.

There is at least one quality study I was able to find, showing that the kidgin ic diet, for instance, which almost always involved in gestion of very low levels of carbon high drink, can increase G, L, P. One, although as I mentioned before, there are other foods that fall outside the the range of what we would consider key to genet. Canossa stimulate gloppy one.

And as I mentioned, their prescription drugs, like some a glue tide the other ones as well. Now to stimulate G L P one. So how does gp one reduce appetite? IT does that in part by changing the activity of neurons in the hyper athamas, this cluster of neurons just above the roof of our mouth that themselves to make G L P one. And that cause the activation of motoring circuits for reaching chewing, all the things that we associate with feeding behavior.

So I use G L, P one as an example of a pathway that you might choose to tap into by industry of your bermont, or by injecting the foods I mentioned. It's something that interest you, key to gene diet. But I also mention IT simply because it's another beautiful example of how our hormone pathway can impact the activity of brain circuits that are directly involved in a particular behavior.

So yet another example of how god is communicating to brain in order to change what we think we want, or to change what our actual behaviors are. So the next time you find yourself reaching for food, or you find yourself wanting a particular sweet thing or fatty thing, or something that contains a lot of a mino assets, a protein rich food, keep in mind that that's not just about the taste of the food, and it's not even necessarily about the nutrients that you need or don't need. You could be, but it's also about the subconscious signal that's coming from your body all the time, waves of hormones, waves of nerve cell signals, electrical signals that are changing the way that your brain works.

And this raises for me a memory of the episode that I did with doctor Robert supose key, who a world expert colleague, minet stanford, who um is expert on things like hormones and behavior. But we got into the topic of free will, which is a bit of a barbed wire topic as many, if you know, IT gets into the realm of philosophy. IT said a and we were kind of batting back and forth the idea I was saying, well, I think there's free will.

And can there certainly be free will? Or or certainly the idea that we can avoid certain choices. And Robert was saying no.

In fact, he said, now he doesn't believe that we have any free will. He thinks that events in our brain are determined by biological events that are below our conscious detection. And that occur seconds to milliseconds before we make decisions or assessments.

And therefore, we just can't control what we do, what we think in what we feel. And at the time, I sort of didn't buy IT, I thought, I don't know. I just I guess I really wanted to believe in free will. And so I stand, I still do.

But as we talk about how these neurons in our gut, and these hormones and our gut are influencing our brain and the decisions that we are making at the level of circuits like the hypothalamic, the nucleus of the solitary track, these are areas the brain way below our frontal cortex and our conscious perception. Think these are examples that really fall in the favor of what doctors oppose, he was arguing, which is that events that are happening within our body are actually changing the way our brain works. We might think that we want the cupcake.

We might think that we don't need to eat something or do need to eat something, and that that is entirely on the basis of prior knowledge and decision making that we're making with our head. But in fact, it's very clear to me, based on the work from the bok's lab classic work over the years, dating back to the eighties and indeed back to the fifties, that will talk about a moment that our body is shaping the decisions that our brain is making, and we're not aware of IT at all. Now the good news is that whether not you believe in freezer or not, the simple knowledge that this whole process is happening can perhaps be a benefit to you.

You can perhaps leverage yet to get some insight and understanding and perps, even a wedge into your own behavior. You might think, I think I want that particular food, or I think I want to avoid that particular food, but actually that's not a decision that are making on a purely rational basis. IT has a lot to do with what my gut is telling my brain.

So we've largely been talking about chemical communication between the gut and the brain chemical, because even though these europol cells are communicating with the brain by way of electrical activity, what we call action potentials. And in neural language, we call those Spikes, Spikes of action potentials. Spikes of action potentials, meaning those neural signals caused the release of chemicals in the brain like doping.

So it's chemical transmission. Similarly, hormones, even though they act more slowly, hormones like neuropace tide y, like C, C, K, like Green, they are signaling chemically, they're moving through the body. They're going, in their effect, the chemical output of different cells.

And they're changing the chemistry of those cells and the chemistry of the cells those cells talk to. So that gives us one particular category of signaling from gut to brain, which is chemical signals. But of course, there are other forms of signals, and those fall under the category of mechanical signalling.

You're probably familiar with this. If you've ever eaten a very large meal or consumed a lot of fluid, you experience that as the tension of the gut. And that doesn't just have to be the tension of the stomach, but detention of your in tests as well. That extension is registered by neurons that reside in your gut. The signals go up to your brain and communicate with areas of the brain that are responsible for suppressing further consumption of food and or fluid, and under certain circumstances, can also be associated with the activation of neural circuits that caused vomiting or the desire to vomit in.

So whatever you've eaten too much or you eaten something that doesn't agree with you, that information is communicated by way of mechanical sensors that sense the mechanics of your gut, possibly also the chemistry of your gut, but mostly the mechanics of your gut signal up to the brain and activate brain centers that are involved in stopping the eating behaviour and activation of an area of the brain stem that is effectively referred to as the vomit t center among neuron demise. This is a area that, more appropriately, is called the key interceptor trigger zone, the C, T, Z, or area post rama in neons in this area actually will trigger the vomiting reflects. So the way that the gotten in the brain communicate is both chemical and mechanical, and IT can be both for sake of increasing certain types of behavior.

Today we're talking mainly about feeding behavior up until now anyway, but also seizing to eat, closing your mouth, moving away from food, turning away from food, all behaviors that were familiar with any time we feel kind of sick on the basis of activation of mechanical sensor for gastro distress. So we've got chemical signals and mechanical signals. And I also want to emphasize that we have direct and indirect signal from the gut to the brain.

Direct signaling is the kind of signal of the sort i've been talking about mainly up until now, which is neurons in the gut communicating with neurons in the brain stem that communicate with neurons in the hypothetical mas. And of course, those are also going to interact with neurons of the preferences cortex, which is the area of the brain involved in decision making. The, you know, I think I was the shrimp that made me sick.

I I just don't want any more of that or i'm never going back to that restaurant again because after I ate there about an hour later, I started a feeling really not well. I felt feverish, but my god didn't feel well. My digestion was really off.

All of that kind of information is handled in the press onto cortex at a conscious level. But the immediate decision to stop eating or to eat more of something, to move toward something away from that made by neural circuits that reside at the, we would say, the subconsciously o level. But what we really mean is below the level of the neo cortex, below the cortex, is essentially below our level of conscious awareness.

So we talked about two types of information within the gut that are communicated to the brain, chemical information, meaning information about the nutrient that happen to be there, and mechanical information, detention of the gutter, lack of detention and so forth. And we talked about how these europol cells can signal the released of dopamine and circuits within the brain to cause you to seek out more of something. Now, in a very logically consistent way.

Dopamine is also involved in the whole business of bombing. You might think, well, that does not make any sense. I thought dope was always a good thing.

It's involved in moderation, in reward, IT said. But turns out the area post rama, this vomit center and the brain stem is chock a block full of dopamine receptors. And if dobin levels go too high, I can actually trigger vomiting. And this we see in the context of various drugs that are used to treat things like parkinsons. Parkinsons is a deficiency in depine or a lack of dopamine neurons, typically that causes arresting tremor, difficulty in movement, because dopamine is also associated with a lot of the neural circuits for movement.

Many drugs that are used to treat parkinson, like l dopa, increased levels of dopamine so much, or at least activate doping receptors to such a great degree in certain ways of the brain that they can cause activation of things like the trigger to form IT. Now this should also make sense in the natural context of, if you gorge yourself with food, gorge yourself with food, gore yourself with food, the news in your gut that respond to that are simply detecting the presence of nutrients. But they don't really make decisions themselves.

They don't know to stop eating, your brain knows to stop eating or to object that food. And so it's a wonderful thing that those neurons are communicating with areas of the brain, not just that stimulate consuming more food, but that are communicating with areas of the brain for area post ma, that when dobbin levels get too high, cause us to either stop in in that food, or, in the case of ominous, to object that food. So I raise this and not to give you a kind of disgusting counter example to what we call competitive behaviors, things that we like to do more of, but simply to give you a sense of just how strongly even these reflexes that we think of as feeling sick, vomiting or the desire to seek out more food are really being controlled by a kind of push pull system by parallel pathways that are arriving from our gut.

And the same neurochemicals, in this case depine, are being used to create two opposite type behaviors, one behavior, or to consume more. One behavior, to get rid of everything you've already consumed. So our brain is actually sensitive to the amount of signaling coming from our gut, not just the path by which that signal arrives.

Our brain is very carefully paying attention to whether or not the levels of dopamine that are being triggered with an a Normal range for typical eating behavior, or whether that we've gorged ourselves to the point where enough already. Now, of course, mechanical signals will also play into erap drama and into the bombing reflects. If we have a very distended gut, we feel loud and just IT actually can hurt very badly, and we will have the desire of moment, or we will just simply vomit.

Mechanical and chemical signals are always arriving in parallel. They never work in unison on. And so now we have chemical signals, mechanical signals, and are now i'd like to talk about direct and indirect signals, because almost everything I ve talked about up until now are direct signals, a neural pathway that converses in the brain to create a particular feeling, thought or behavior.

But there are also indirect pathways, and that's what takes us back to the gut microbiome into these little microbiota. And to just give you the take away message at the front here. And then i'll give you a little more detail as to how IT comes about.

You have neurotransmitters ors in your brain and in your spinal cord and in your eyes and in your preferable nervous system, they cause the activation or the suppression of nerve activity, meaning they other electrically activate other nerve cells, or they cause other nerve cells to be less electrically active. And they do that by way of neurotransmitters ors. But as IT turns out, the got microbiota are capable of influencing metaphoric events, and in some cases, are capable of synthesizing their transmitters themselves.

So what that means is that these little bugs, these little microbiota that are cargo, and you're got the six pounds of cargo, they actually can make neurochemicals that can pass into the bloodstream and into your brain, and actually impact the other cells of your body and brain indirectly. So without involving these very intricate nerve pathways that we've been talking about, in other words, the food do you eat, the environment of your got microbial can actually create the chemical substrates that allow your brain to feel one way or the other, to feel great, or to feel ali, to seek out more of a particular type of behavior, or to avoid that behavior. And that would constitute indirect signal.

So i've been talking a lot about the structure and function of the gut to brain pathway, focusing mainly on feeding behaviours. And in some cases, avoiding feeding or even ejecting food from the digestive track. I'd like to drill a little bit deeper into this indirect signal pathway from the gut to the brain, because IT bridge us nicely from onal signals in the gut to the brain, or mono signals from the gut to the brain, to what also includes the microbiome, which is what we started talking about at the beginning of the episode I mentioned a couple of minutes ago.

Certain cut microbiota can actually synthesize a certain neural transmittals that can go impact the brain. And we actually have some knowledge about which microbiota can synthesize particular neurotransmitters. Ors, for instance, the neuromodulator doping can be synthesized by or from billis.

And Sarah tia, now these are just names of microbiota. Don't expect that any of you would necessarily recognize them. These aren't the sorts of things you necessarily would run out and buy to get more doping. But the point is that particular got microbiome can create dopamine in our gut that can get into our bloodstream and can generally change our baseline levels of doped within the brain and other areas of the body. I mention baseline levels of dopamine because, as I talk about on an episode, all about dopamine, but I just repeat the basics here.

Now we have baseline levels of transmittals or neuromodulators, the act to sort of the level of the tide, the overall level, and then we can have peaks of dopamine e that are created by behaviors or by industry of particular foods or drugs at sea. So basilican sarita tend to increase our baseline levels of doping. So if IT turns out that we are creating the right gut microbiome environment that these particular got microbiota can thrive in, well then our baseline levels of dopamine will be elevated.

And in general, that leads to enhancement of mood. Similarly, there are other good microbiota. For instance, kenda stripped a caucus, various international ucs. These always have these kind of strange and um not so attractive names at least to me is another biology.

None there's those particular microbiota support the production of or can even be metabolize into serotonin, which is a new modulator associated with mood, with social interactions, with a huge number of different types of events and behaviors. Again, these gut microbiota, when present and allowed to thrive in our gut, will increase our overall levels of serotonin. And riding on top of that level of serotonin will be the serotonin that specifically in response to certain behaviors.

And I really want to drive home this point of basic lines and peaks the baseline levels serotonin might set our overall mood, whether not we wake up feeling pretty good or really lousy, of our certain levels happen to be very, very low. Whether or not we tend to be in kind of a calm space or whether not we tend to be somewhat vital. But then, of course, individual events as we go about our day, maybe a compliment that we get, or maybe somebody says something irritating to us, whatever IT may be, will also influences levels of serotonin.

But those serret an events are going to be related to events, at particular neural circuits in the brain. And this is an important topic because I think that a lot of people here, quite accurate, oh, ninety and ninety five percent of our serotonin is manufactured in the gut. And indeed, that's true. It's manufactured from the sort of microbiota that I just described.

And there are many, many experiments now mostly in animal models, but as also sum in humans that show that if they got microbiome is deficient in some way to these particular um bacteria that certa and levels drop in people's mood suffers maybe the immune system functions, maybe even the exacerbate tes certain psychiatry illnesses. However, a lot of people take that to mean that the serotonin of the brain all comes from the gut or mostly comes from the gut. That's not the case, is still the case that you have neons in the brain that are responsible for releasing seaton directly in response to certain things like social touch or through other types of positive social experiences.

So we've got got microbiota that can literally be turned into dopamine and raise our baseline levels of dopamine. We've got got microbiota that can literally raise our baseline levels of serotonin. And indeed, there are other got microbial, a like lack of a illis, or before the before, do bacterium, excuse me, hard, complex names to pronounce, but do bacterium that can give rise to increases in gabble levels, this in three neuro transmitter, or that can act, is a little bit of a mild sensitive, can reduce your ability at seta.

But that's just the baseline, the kind of tired of those neuromodulators. Again, I want to emphasize that we still have neural circuits within the brain and body that are specifically releasing, in a very poor way, mean sea and gaba. So the two things act in concert, even though the gut and the brain are acting both in parallel and directly influencing one another.

IT is a powerful synthetic c effect. And there are now hundreds of studies, maybe even been thousands by this point, mostly performed an animal models, typically mice, but also some studies in humans that show that creating the correct environment for these cut microbiota to thrive really does enhance mood and well being. And that when our got microbiome is not healthy, that IT really can deplete our mood and sense of well being.

Now there are two major phases to creating a healthy gut microbes, one you can control, and the other one is less under your control. I get into this in a lot of detail in the episode with doctor sonne g, which is coming out immediately after this one, the following monday, that is. But for now, I wanted just capture a few of the main points about the early establishment of the gut microbial IT.

Turns out that the environment that we are exposed to, the things that come in to contact with our skin and digestive tract and any other mucosal lining, even that you re throw the nasal passages, any opening to the outside world that brings in certain, excuse me, certain microbiota in the first three years of life is going to have a profound impact on the overall menu of microbiota that we will be able to Carry within our body. And IT really does seem that getting exposure to and building a first microbial in those first three years as critical. There is a lot of speculation and some data as to syrian delivered babies having less diverse microbiome compared to baggini delivered babies.

There been attempts, although not conclusive attempts, to link that to the presence of autism spectrum disorders, which at least by some statistics, seem to be of higher probability in the sarian deliveries. Although there are other studies that refute that, I want to make that clear. However, it's clear that babies do not get much, if any, exposure to microbiota inside of the wm.

Maybe a little bit, but not much, but is during the birth process and in the days and weeks immediately after they arrive in the world that their gut microbiome is established, that those gut microbial to take a residence within the gut. So IT will depend on whether not they were breast feather bottle fed. IT depend on whether not they were exposed to a household pet or not, whether they were LED by multiple caregivers or just by one, whether not they were a premier baby and were containing in A A particularly restrictive environment in order to encourage their further development before they could be brought home or not.

I don't want to give the picture that if you were isolated or you were delivered by sea section, that you are somehow doomed to have A A poor microban that simply not the case. However, IT is the case that the more diversity of microbiota that one can create early in life is really helpful for long term outcomes in terms of brain to get signaling, got to brain signaling. And for sake of the immune system, there are some decent studies showing that if children are exposed to a lot of anti biotic treatment early in life, that can be very detrimental to establishment of a healthy gut microbiome.

And fortunately, that reestablishing a healthy, that microbial, can help rescue some of those deficits. So doctors in nowaday are much more cautious about the prescription of antibiotic drugs to children in their early years, not just up to three years, but extending out to, you know, five and seven and ten years. And even in adults, they're very, very careful about that or they ought to be.

One reason is the existence, or I say, the proliferation of annoying oic resistance bacteria that are becoming more common in hospitals and elsewhere, and that can cause serious problems. But in addition to that, because of this understanding that the gut microbiome is influencing and actually creating newer transmittals that can impact mood and mental health, impact immune health and so on. As I mentioned earlier, there are hundreds, if not thousands, of studies emphasizing the key role of the microbial on brain health, psychiatric health, etcetera.

I wanted just highlight a few of those studies, and in particularly some recent studies that come from labs that have been working on this sort of thing for a very long time. One of the more exciting studies comes from the work of a marrow costa mattioli lab, which is bailer college of medicine. Morrow's lab has has been working on mouse models of autism spector disorder for a long time and looking at social behavior using a mouse model for a long time.

And they've been able to identify particular types of microbiota that when they take residents in the gut, can help offset some of the symptoms of autism, at least the symptoms of autism that exists in these mouse models. Okay, so again, this is not human work. This is work being done, a mouse models for the simple reason that you can do these kind of manipulations, where basically they took mice that were in germ free environments or non germ free environments, or they exposed mice to particular microbiota and not other microbiota.

And they discovered that a particular microbiota called l rut ery its l period R E U T E R I treatment with rutter's correct the social deficits present in these artisan models. And IT does so by way of activating our old friend, the vegas nerve, but not simply because the vegas nerve triggers the release of dopamine. But IT turns out that this particular cut microbiota l rutley, can correct the social deficits in this autism spector disorder model.

IT does that by way of a vegal nerve pathway that stimulates both document release and oxytocin release. And they establish this really mechanistically by showing, for instance, if you get rid of the oxytocin recept, you don't see this rescue. Now those are mouse models, so we have to take those with the appropriate grain assault.

But they're really exciting. And they come to us in parallel with other studies that are being done, taking the microbiome of people who have one condition, or lack of condition, and putting IT into people who have one condition or another condition. Let me explain what I mean by that.

The early discovery of the got microbiome and its potential to impact health was not in the context of the gut to brain pathway, but rather was in the context of coitus. States back to studies in the fifties, whereby people with very severe, intractable collides, for which no other treatment was going to work, received fecal transplants. So yes, that's exactly as that sounds, taking the steel of healthy people who do not have collides, transplant ting those schools into the lower digestive of track of people who do have collide s and they saw significant improvement, if not rescue of the collider.

That was one of the first indications that something within stool of all things could actually rescue another individual from disease, which sounds kind of wild and crazy and may even sound disgusting to some of you. But as I mentioned at the beginning, the episode almost sixty percent of school is live or dead bacteria, microbiota and IT really opened up this entire field of expLoring how different microbiota might might have therapeutic fax. And indeed, that has been shown to be the case also in fecal transplants for and psychiatric illnesses.

These are still ongoing studies. The very inequality um is these are hard studies to do for all sorts of reasons, getting the appropriate parent population, getting agreement at a um making sure that everything's handled properly. But what this involves is fecal transplants from individuals that lack a particular psychiatric condition or met a ballet condition into people who have a particular metabolize tion.

And there has been tremendous success in some cases one of the more powerful and sAiling examples is for obesity. There are some people for which, even if they are just very low numbers of calories, even if they go on a liquid protein diet, simply can't lose weight, somewhat rare disorders. But these are people that would either do get gastric bypass surgery.

Some people are now getting these fecal transplants from people that have healthy, healthy weight, and they take the, the, the stool from them they put in into lower digestive track. And they can see substantial improvement in weight loss in people that were otherwise unable to do that. In some cases, actually, they can start eating relatively Normal levels of food and still lose way.

So pretty remarkable. And that tells us there's something in this microbiota that's really power. Now how those effects are generated isn't clear.

One idea is that it's impacting the meta one component to the metabolic. Almost certainly that's going to be the case. Another idea is that is impacting their transmittals, which change behavior and food choices within the brain.

Although as I mentioned, some of these people are already eating very little food to begin with. So that's a little bit harder of an argument to create. There are also some somewhat famous examples now of how fecal transplants can lead to negative outcomes, but those negative outcomes further underscore the power of the microbiome in impacting bodily health.

One key example of this, for instance, is transfer of final matter into another person in order to treat something like code us. And IT effectively does that. But if the donor of the of the stool of the final matter happen to be obese or have some other metals lic syndrome, it's been observed that the recipient can also develop that metaphoric syndrome simply by way of receiving that donors particular microbiota.

So these microbiota can create positive outcomes, or they can create negative outcomes. Now most of us, of course, are not interested in or pursuing fecal transplants. Most people are interested in just creating a healthy gut microbiome environment for sake of immunity, stem and brain function.

And we'll talk about how to do that in just a few minutes. But I just want to further underscore the power of the microbiota in shaping brain chemistry and in shaping things like mood or other aspects of mental health that typically we don't associate with our gut. There are several studies published in recent years, one that all just highlight. Now, first author is tony an win N G U Y E N.

The title of the paper is association of loneliness and wisdom with gut microbial diversity and composition and exploratory ory study so interesting study looked at one hundred and eighty four community dwelling of adults, excuse me, ranging from twenty eight to ninety seven years old, they explored whether not having enhanced microbial diversity somehow related to these variables that they refer to as loneliness and wisdom. They used the number of different um tests to evaluate those. Those are common test in the psychology literary and not so much in the biology but nonetheless there are our ways of measuring things like loneliness and wisdom wisdom in this case being the the opposite of lonely ess uh at least in the context of this study.

And what they found was the more microbial diversity, the more diverse one's microbiome was, the lower incidents of loneliness. And they did this by taking fecal samples, profiling them for R. N.

A. So essentially doing gene sequencing of the of these individuals, getting ratings of how lonely are not lonely they felt and correlation those. And that's just about one study I pointed out because it's particularly recent and like IT was particularly well done.

There is another study that I just refer you to. This was steady publishing twenty twenty and scientific reports. The title of the study is emotional well being and gut microbiome profiles by interOperable.

But I particularly like about this study is that they were able to corporate the presence of certain microbial to with feelings of subjective well being and lack of or presence of depressive symptoms. They did height to put gene sequences of the microbiome of individuals. So that meant measuring the microbiota gure out which microbiota were present.

How diversa microbiome, in general, got microbiome diversity is a good thing. And then to correlates that with what's called the P A N A S score, P A N A S tenants for positive affect, negative affect schedule. This is a test that my lab is used, pensively, that other labs used to evaluate mood and well being. And they defined what what we're called, three interior types, three different categories of people that ate very different diets that tended to fall into categories of having more or fewer emotional symptoms that were negative or more if you are emotional like symptoms that were positive in whether not they tend to be more depressed, anxious or have more stress related behaviours at sara.

And what they were able to derive from this study was some strong indications about what types of things we should ingest in our diet, maybe even certain things that we should avoid, but certainly of the types of things that we should ingest that can enhance mood and well being and content to shift people away from more depressive, like anxiety and stress related symptoms. Before we get into what the particular food items were that lend themselves to a healthy microbial, I want to raise a bigger and perhaps more important issue, which is, what is a healthy microbial? I think if you asked any number of world experts, and I certainly asses of doctor sonnier, what is a healthy microbial? They're all gona tell you it's a microbiome that has a lot of diversity, that includes a lot of different types of bacteria.

That makes sense IT. Because IT logically would include the um bacteria that produced gaba and dopamine and serotonin and that support the immune system and do a number of different things. But is IT simply the case that adding microbiota diversity is always a good thing? Well that doesn't seem to be the case.

Probiotics and probiotics, both of which can enhance macrobiotic diversity, can improve mood, digesting immune system and so on. That's been established, but it's mainly been established the context of post in a biotic treatment or people that are recovering from illness or people that have been um very stressed or have been dealing with all sorts of chAllenges, mental or physical, and they are an attempt to replenish the got microbes. However, it's also clear that excessive microbial a brought about by excessive intake of probiotics can lead to things like brain fog.

There's actually some good studies that point to the fact that certain meta lights of the microbiome, certain chemicals produced in the gut and in the body, can actually lead to brain fog states. This is thought to come about through the latest pathways of the gut that can then impact the brain. If you want to look more into this issue of whether or not probiotics taken in access perhaps can lead to brain fog, and engage you to look at a particular paper, this, a paper published in clinical and translational gater interros gy.

And the title of the paper is brain fog, ss gas and bloating. A link between sea boo, probiotics and metabolic adoo IT was published in twenty eighteen. We can provide a link to the study, and there are several other studies in the references that point to the fact that in some cases excessive and take a probiotics and excessive proliferation of got microbiota can actually be problematic.

I mention this not to confuse you, but because IT is confusing out there, we all would think that just increasing microbial to diversity is always a good thing. But there are threshold beyond which excessive microbial tal diversity might be problematic. I think everyone agrees that having to feel my corbie species living in us is not a good idea.

Now, none of that answers the questions that I think everyone really wants answers to, which are, what should we do? What should we not do to improve our got microbes? I mean clearly we can time travel back to when we were zero to three years old and get a dog if we didn't have a dog um get breast fed if we weren't breast fed, be delivered vaginally as opposed by c section.

If we didn't have that opportunity, we just can't time travel and do that. All of us, however, should be seeking to improve the conditions of our got microbes because of the critical ways in which IT impacts the rest of our brain and bodily health. So what we do? What shouldn't we do? Clearly, we know that stress can negatively impact to a microbial.

However, some forms have stressed that can, quote, quote, negatively impact the microbial include fasting, long periods of fast, which makes sense because a lot of microbiota need food in order to thrive. In fact, many of not all of them do. At some point, there are other questions, such as, should we eat particular foods and how often should we at those foods?

We've all been told that fiber is incredibly important because of the presence of prebiotic fiber, which can essentially feed the microbial. But is fiber really necessary? And how necessary is IT to encourage a healthy microbes? Clearly, there are a number of people following relatively low fiber diets, such as eocene, and those can have, in some cases, anti inflammatory effects, and can sometimes also improve certain microbiota species.

So IT can all be rather confusing. And for that matter, I asked our resident expert, doctor justice Sonia berg, at stanford, all of these questions, and he answers them very systematically in the episode that comes out after this one. But I don't want to withhold anything from you, so i'll just give a very top corn to a version of those answers and then you'll get more in depth answers.

During that episode, I asked about fasting. And the reason I asked about fasting is that years ago, I was at a meeting as part of the pew bio biomedical scholars meeting. And one of the other two bio medical scholars was an expert in got microby, and I said, are probiotics good for the microbiome? And if so, which one should I take? And his answer was very interesting.

He said, you know, in certain cases, they can be, especially if you're traveling or your stressed. But IT turns out that the particular bacteria that they put in most probiotics don't actually replenish the microbiota that you need most. And I thought, oh, well, why don't they make ones that replenish the microbial to that you need most? And his answer was, well, they don't replenish those, but they replaced other ones that then in turn, encourage the development of the microbiota that you do want once you start eating the appropriate food.

So they changed the environment, which makes the environment Better, which indirectly supports the proliferation of cotton. Good, good. microbiota.

Okay, so that was a somewhat convoluted answer, but I did appreciate his answer. Then I asked him about fasting. I said, well, lot of people are getting interest in intermet fasting now.

People are spending a significant importance of each twenty for our cycle, avoiding food for sake of time. Search of eating. What does that do to the gut microbiome? Does that make a healthier? Doesn't make IT unhealthier.

Well, my colleague from yale and doctor sonne g. Both confirmed that during periods of fasting, especially prolly periods of fasting, we actually started digest away much of our digestive track. Now the whole thing doesn't started as a peer, but there's thinning of the mucosal, lying at least disruption.

The a lot of the microbial to species can start to die off. And so IT was surprising to me, but none's interesting that fasting may actually cause a disruption to certain healthy elements of the gut microbes. But again, there's a kova.

The caveat is that when people eat after a period of fast, there may be a compensate prolifically, meaning an increase in healthy gut microbiota. So you start to get the picture that fasting is neither good nor bad. You start to get the picture that particular diets, meaning certain restriction diets or macor neutral rich diet, may not be good or bad for the microbiome. And yet there are some answers that arrived to us from doctor sonne g, but from other experts in the field, that there are certain foods and certain things that we can ingest, which you definitely enhance the microbiome and make IT healthier than IT would be where we do, not in just those foods. So next, i'd like to talk about what I think is a really pioneering, an important study in this area.

This is a study that was Carried out by the song in berg lab in collaboration with Chris gardeners lab, also at stanford, where they compared two general types of diets in humans, diets that were fibre rich, which has been proposed time and time again to enhance biotic diversity, to enhance got brain signaling even, and to enhance the immune system perhaps, and diet that were enriched in so called low sugar for mental foods. Before I dive into that study and what the conclusions were, because they are very interesting and very actionable for all of us, I do want to touch on probiotics because I want to avoid confusion. IT is not the case that in gestion of the bilos will always lead to brain fog.

I want to make that clear. IT is the case that in gestion of probiotics, even if those probiotic don't directly contain the microbial to species that one is trying to proferred can be useful for improving microbial to diversity. In general, IT seems that maintaining a healthy gut microbiome involves ingesting certain types of foods. We will talk about those in the moment, but perhaps also augmenting the microbial system through probiotics or probiotics at a fairly low level on a consistent basis. So these are not hyde's probiotics except under conditions of this BIOS is where, for instance, if somebody has done around of antibiotics and they need to replenish their gut microbiome, they are friends, and their pill form and powder form, probiotics and probiotics that can be very useful.

Or in cases where people have been very stressed or are going excessive travel or have shifted their diet radially, maybe that's to travel may be illness, may be distress, but when there are a number of different converging events that are stressing or depleting microbiology versy, that's when, at least I believe I can be useful to support. They got microbiome through the injections of quality probiotics or probiotics. So IT would be under conditions where people are stressed or their system is generally stressed for environmental or illness related reasons, that IT might be useful to lean towards higher doses of probiotics or probiotics than one might Normally use.

But that under Normal conditions, that one would focus on quality nutrient through diet and focus on in gestion of probiotics at a fairly low to moderate level and or probiotics at a fairly low to moderate level, that just seems like a logical approach based on the experts that i've spoken to. But certainly, if your doctor proscribes or suggest that you take high levels of probiotics for any reason, you should definite pay attention to your physician, and you should obviously pay attention to your physician. In any case, you should never add a room, move anything from your nutritional plan or supplementation plan without consulting a physician.

So what should we do in order to maximize the health of our gut brain access, as it's called? How should we support the diversity of the good microbiota that help us create all these newer transmittals that we want, improve our immune system function and so on and so forth? Well, some of that is going to be through the basics.

When I say the basics, I mean the foundational things that really set us up for overall health, this is going to be getting deep sleep of sufficient duration, eighty plus percent of the time. I mean, you can get one hundred percent of the time that would be great, but very few people accomplish that. It's going to be proper hda tion.

It's going to be proper social interactions. It's going to proper nutrition and will talk more about nutrition at the moment. It's going to be limiting excessive prolonged stresses or stress. And indeed, we've done episode about just about all of those things, but certainly about stress.

We have an episode of the human in lab podcast that you can find human lambda com, all about mastering stress, how to avoid long periods of intense stress, what to do to offset those, given that stress can disrupt the microbiome, whether not you're fasting or not, those tools ought to be useful. Now, in what I consider to be a landmark study expLoring the relationship between the gut microbiome, food intake and overall health, is this paper from justice on nberg lab and chis gardeners lab, both of which are at stanford. And the paper entitled cut microbiota targeted diets, modulate human immune status, was publishing the journal cell, which is among the three top journals, perhaps in the world, nature science and cell really being the apex journals for overall science, and especially for biomedical sciences.

Now this is very interesting study. IT was done on humans. There were two major groups. One group of humans was instructed to increase the amount of fiber in their diet, and in fact, eight, a high fiber diet. The other group was instructed to eat a hyphen minted food diet.

Now both groups started off not having eaten a lot of fiber or a lot of experimented foods, and were told to increase the amount of either fiber or fermented foods that they were interesting over a four week ramp up period. And that was to avoid any major gesture distress. IT turns out that if you're not already accustomed eating a lot of fiber, increasing in the amount of fiber dramatically can cause them gater distress.

But if you ease into IT over time as well, see, there's a mechanism behind this was unveiled in this study. But if easy into IT overtime, then the system can tolerate IT. Likewise, hyperrational ted foods can be readily tolerated if there's a ramp up phase of ingesting, maybe one serving a day, then maybe two surfings in rapping up, in this case, as highest six savings per day.

However, after this ramp up period, the group assigned to the high fiber condition maintained high fiber intake for six weeks, and the hy fermented food group maintained high fermented food intake for six weeks, after which they went off either the hype ber or the hydro mental food diet in there was a four week follow up period during which they gradually return to baseline. Throughout the study, they're got microban was evaluated for the diversity of got microbiota, and there were also a number of measures of immune system function, in particular measures of the so called in flamm ome. The immunity stem has a lot of different molecules involved.

I did a whole episode about the immune system. If you're interested in learning what some of those molecules are very sidelines and signaling molecules that reflect either high inflation tion states are reduced inflation tion states in the brain and body, you welcome to check out that episode. It's also at cuba and lab docs regardless.

In this study, they explored the sorts of immune markers that were expressed in either of the two groups and compared those. The basic takeaway of this paper was that, contrary to what they predicted, the high fiber diet did not lead to increase microbiota diversity, at least not in all cases. And that was somewhat surprising.

The idea is that prebiotic fiber and a lot of the material in fruits and vegetables and grains and so forth are supposed to support microbiology, versace and the proliferation of existing microbiota. And that is not what they observed, although I want to be very clear pointing out that the results do not indicate that fiber is not useful for health overall. But IT does point to the fact that increasing fibre take did not increase microbiota a diversity, which in general, as I mentioned before, is associated with improvements in microbiota function, health and overall well being.

Now the hydro mental food diet condition was very interesting. IT resulted in increased microbiome diversity and decrease in flamm tory signals and activity. So there was a tougher basically by ingesting hydro mental foods.

Fair abundance, right? You know, four to six savings or more per days is a lot of a mental food intake. We will talk about what some of those foods were, but the outcome was very positive.

There was a clear increase in microbiome diversity and decreased in flamm tory signals. So things like interludes six, a number of other interludes and sidecars that are associated with increased inflation tion in the brain and body will reduce significantly. Now let's talk a little bit about this notion of number of services ings at sea.

One somewhat minor point of the study, but I think is useful in terms of an act taking an actionable stance with this, is that the number of savings of from mental foods was not as strong. A predict of improvements in the inflamed to meaning reduced inflation tion and improvements in microbiology versy, as was the duration of time that the individuals were ingesting, commented food. In other words, the longer that one is consistently ingesting promoted foods on a daily basis.

The Better the outcomes in terms of the gut microbial and for reducing inflation tion. So I think that's an important point. And I make that point especially because for a lot of people, even if you do this ramp up, the six servings per day of formative foods can seem like quite a lot.

So what are these for mental foods, right? I think many of us are um familiar with certain cheese and being prevented and beer being prevented and kamboh. As in this study, they focus specifically on low sugar fermented foods. So this will be plain yogurt ah in some cases, kim chi or sour crowd.

An important consideration, however, is that IT needs to contain what I called live active cultures, which means they actually have to be a microbiota that are alive inside the circle at one way you know, whether or not that happening is, if you purchase power crowd or pickles or kim cha from a jar or a container that's on the non refrigerated shelf of the non refrigerated section of your grocery store, IT is not going to contain live active cultures of microbiota. And likewise, if you'd consume yogurt t that has a lot of sugar or other components, add IT to IT, it's not going to have the same positive effect on the microbiome. At least that's the prediction given some of the relationship between the sorts of microbiology live in sugar versus plain type yogurt, they gave people the option of consuming any number of different low sugar for mental foods.

Again, there could be soccer, wt. Kim, things like key for nato a in japan. And they consume nato, which is affirmative food.

Beer, not one of the fermented foods that was including the fermented food, delist. And when we say six servings per day, that is indeed six, six out savings or six, four to six out savings. IT was not six servings of what's listed on the package. So again, that turns out to be a fair amount of a mental food.

How should you gage whether not you're getting enough for this? Well, if you decide to a take on this protocol of ingesting more experimented foods, which at least by my read of this study and some of the following work that's being done, sounds like a terrific idea. If you want to improve your gut microbes for all the great reasons that one would want to brain body health, reduce information and on and on, well then you definitely want to focus on fermented foods that you enjoy consuming.

So for you, if that's key for for you that's playing yoga for you, that sour crowd which happens with my personal favorite ite, then you want to make sure that it's going to be something that you are going to enjoy interesting quite a lot of and that you're going to be OK with interesting probably throughout the day. Now people follow different meal schedules, of course, but this does require not just eating all the fermented foods just before bedtime or one meal. I suppose you could do that.

But in general, it's gonna best in terms of limiting gasters distress by spreading IT out throughout today. I also want to mention brain, brain is the liquid that surrounds our crowd. Um it's that very salty um fluid and that contains a lot of active live cultures.

And they did include um where they allowed people to include brian in this in this study and in discussions with doctor song and berg, which we will go into in more detail on the episode that comes out next week. We talk a lot about the particular value that brian might hold ms of bringing about microbiota diversity because of the richness of live cultures that IT contains. I do want to focus for a moment on the high fiber condition because there were some interesting observations about the people that were placed into that condition.

First of all, increasing the amount of fiber definitely increased the number of enzyme mes that can be used to digest fiber. This is in keeping with this idea of this ramp up phase, where accumulation of more viBrant take can, over time, lead to legg's distress, but also to more utilization of fiber, which overall should be a good thing. So while they didn't observe an increase in immune system function or an increase in in microbiology versy, there wasn't increase in these fibre digesting enzymes.

They also observed what they called personalized immune responses. These were some sub groups within the high fiber group that had interesting changes in terms of their reactions to A, I should say, their inflam'd, meaning the inflammatory markers they expressed, as well as their microbiota diversity. So there are essentially three groups.

One group actually shows an increase in inflammatory markers. That was quite surprising and probably not a wonderful for the message that fiber is always good for us, but that was a small cohorts within the fiber intake group. Another group and still another group both showed reductions in baseline microbiota university, although to varying degrees. So I don't want to paint the picture that fiber is bad, but fiber certainly did not have the positive effects on microbiota diversity that the hydrometer food diet did.

So my read of this study, and I think the stance that many others have taken as a consequent of these data, is that we should be increasing our formated food intake that that simply a good thing to do in order to support our good microbes ome and to reduce inflaming signals in our brain and body. And there are number of different ways to do that. I mentioned some of the particular foods.

However, any time you're talking about ingesting from mental foods, especially the high quality ones that come from the refrigerated section of the grocery store or that end that have low sugar content at sea, we do have to be considerate of cost because certain things like computers, as for instance, can be quite costly. Um I should also mention some computers actually contain alcohol. Some do not or contain very little amounts of alcohol.

One way to avoid the high cost of experimented foods while still being able to accumulate a lot of fermented food intake, is to simply make those experimented foods yourself. This is something that we started to expLoring and experimenting with in our home. One simple way to do this is to just make your own sour crowd that involves very few ingredients, basically involves cabbage, water and salt.

But there's a specific process that you need to follow in order to create these large volumes of shower crowd at home using that low costs method. The best resource that I know of in order to follow a great recipe to make homecare crd would be the recipe for homemade d hour crowd that contained in temporis book, the four hour chef. There's an excEllent protocol there.

IT involves chopping up the cabbage, putting into a ball, mashing up um with your hands, which can be fun and putting water in there, some salt covering IT and then keeping IT in a particular environment and then routinely scraping off some of the material from the surface. You have to do that in order to make sure that you're not getting a micro microbes and things growing IT that are bad for you. So you definitely to pay careful attention to the protocol, but that's a very, very low cost way of generating lots and lots of fermented food.

So you don't go broke trying to improve your microbiome. The other thing that you can do, if you're really a obsessed with compute r or something like that to avoid the high cost of computers, there always that you can get the scope, which basically allows you to make your own combo. Ch at home.

I've never tried this but when I was a postcard there was undergraduate in the lab I think um well, I won't out him but he's now gone on to medical school and I think he's passes recency and and is a practicing doctor but nonetheless he was always making combo ch at home he told me he was exceedingly easy but then again, he had a number of other skills and attributes that um maybe think that he could do pretty much anything with his or as I tend to struck with even basic cooking. So maybe if you are feeling a little more adventures, you could explore making your own computer, but there are a number of different protocols and recipes out there for making your own low sugar fermented foods. So you needn't run out and buy fresh shower crowd all the time.

I should also mention, for those of you that are interested in getting your fermented intake from pickles jard. Pickles rarely, if ever, contain ferment. Mostly they're just soaked in in vinegar water and with some spices, but there are some that contain for mid.

You actually have to look for that on the container. And I don't know, maybe someone else there knows how to make not to and knows how to make kim chi well and things to that sort. It's certainly is the case based on the data from the study that ingesting more servers of fermented food per day ought to be beneficial for a got microbial.

And since this is an episode not just about got microbial, but got brain health, I should mention that one former signal betwen, the got microbiome and the brain, which we did not discuss, and i'll just touch on briefly, is that when the inflamed ome or the the genes and markers of inflammation are kept in a healthy range, there's an active signaling of that immune system status to the brain. There's an intermediate cell type that communicates immune status to the brain. And that sell type is the microgrid cells type of glee.

As the name suggests, when there's a lot of implementation in the body, these microgrid actually get activated and can start eating away at various components of the brain and nervous system. And I don't mean massive eating away. Then I going to digest the whole brain.

But these microgrid are sort of the resident macrophages of the brain. Macrolane are in the proferred, and they gobble up debris. And things that sort the microgrid on a regular basis are eating up debris that accumulates across waking cycles and in response to microgram ge of the brain, that occurs on a daily basis.

So they have a lot of important basic everyday, what we call housekeeping functions. But when there's a lot of inflation tion in the body, when there's a massive immune response, the microgrid can be hyper activated. And that's thought to lead to any number of different cognitive defects or chAllenges thinking or maybe in some forms of neurotic generation over time. Although that last point is more of a hypothesis, a well tempt down fact at this point, there's still a lot of investigation to be done in humans.

The animal data, however, are very, very strong, that when the immune system is activated or chronically activated or hyper activated, that neural tissue annotation in tissue, another central nervous system tissue can suffer, so there are a lot of reasons to want to not just improve microbial diversity, but to also improve immune system function, to limit the number of inflaming markers that are present in the body, because of the way those inflaming can signal diller's ous events in the brain. And while eating from mental foods and making your own experimented foods. In buying high quality for mental foods might seem like an inconvenience.

I would say that from the perspective of cost benefit or effort benefit, it's actually quite a good situation where if you can just ramp up the number of experimented foods that serving of for mental foods that reading per day over a period of a few weeks so that you're tolerating that. Well, that ought to have a very positive effect on your microbial diversity and indeed on gut brain function. And i'll be the last to suggest that people completely forget on fiber.

I think there's some debate out there as to how much fiber we need and whether not certain forms of fiber Better than others. I'm not going to get into that debate. It's barbed wires enough without me injecting my own views into that debate, but I think there's ample evidence to support the fact that for most people, ingesting a fair amount of fiber is going to be a good idea.

I would just say that make sure that you're also ingesting a fair amount of experimented foods and along the lines of fiber in an an accompanying ticket publishing cell, which was sort of what we call a news views peace about the song and burgan gardener paper. They make a quite good point, which is that the increase in fibre intake that LED to this increase in carbon hydrate active enzymes, C A Z simes, as they are called. These are enzymes s that helped fiber quote, indicating an enhance capacity for the microbes ome to degrade complex cover hydrates present in fibrous foods.

So in other words, eating more fiber in fibrous foods allowed for increase in these enzymes that allow you to eat still more fibrous foods or to Better digest fibers, foods that are coming in through other sources. So there is at least one utility for increasing fiber, even though IT separate from the gut microbial al diversity and reducing inflation tion. And i'd be remiss if I didn't touch on some of the data in controversy about artificial sweeteners and the got microbial.

I want to be very clear that what i'm about to tell you has only been established in animal models, in a mouths model, at least to my knowledge, what the studies have shown in. And there were several, but one published in the journal nature a few years back, as the one that got the most amount of attention is that animals that consume large amount of of artificial sweeteners, particular things like sacring or sucrose, show disruptions in their got microbes. I'm not aware of any studies in humans that show the equivalent effect, and i'm not aware have any studies in humans that show the equivalent effect for things like plant based low calory sweeteners, things like stevia on fruit and things of that sort.

And at least by my exploration, I couldn't find any data specifically related to the sweetener asper time. So right now, it's somewhat controversial. And actually this is kind of a third rail topic out there.

When one group will come out saying the artificial sweeteners ers are bad because they disrupt that got microbiome, the response generally from a number of people as well that only have been shown in animal models. And indeed, that's true. So right now, I don't think that there's a strong case one way or the other.

I think that people should basically ask themselves whether not they like artificial al sweeteners or not, whether not they're willing to risk or not. And obviously, that's an individual choice. I also want to point out a recent study from the go bork s lab, which actually shows, however, that neurons in the gut, those neurologic ells, are actually capable of distinguishing between real sugars and artificial sweet nes.

This is a really interesting body of work. IT was published just just recently, I should say, february ary, twenty twenty two. The title of the paper is the preference for sugar over sweetener depends on a gut sensor cell.

And to make a long story short, what they showed was there's a category of neurology cells that recognize sugar in the gut and signal that information about the presence of sugar in the gut to the brain via the pathways we talked about before. The noos, gangly of the vague st. Dopa at sea.

Interesting ly, the very same category of neurons can respond to artificial sweeteners and signal that information to the brain. But the pattern of signaling, and indeed the signature pattern that is conveyed to the brain and received by the brain, is actually quite a bit different when these same neurons are responding to artificial sweeteners versus actual sugar. This is very interesting, because what that means is, first of all, that neurons have incredible specificity in terms of what they are signaling from the got to the brain.

And IT also means that there may be a particular signal that the brain receives that says i'm receiving some intake a food or drink that tay sweet, but doesn't actually offer much nutrients in the direction of sweetness, meaning that he doesn't have calories despite being sweet. Now again, this is also conscious processing. And like with the previous studies we were just discussing about artificial sweeteners generally, and they got microban oe generally.

It's unclear how this relates to humans at this point in time. But given the similarity of cellular processes in molecular processes at the level of gut brain in mice, I think IT stands to reason that these neuroprotective ls very likely are capable of signaling sweet presence of real sweet nervous as artificial sweetener in humans as well, although that still remains to be determined empirically. So i'd like to just briefly recap what i've covered today.

I started off by talking about the structure and function of the good brain access. I described the basic structure function of the digestive pathway, and how that is just a pathway harbors microbiology es, meaning many, many little bacteria that can signal all sorts of things to the rest of the brain and body. And indeed, we talked about the various ways that they do that.

We talked about direct pathways, literally nerve networks, that extend from the gut up to the brain and from the brain back to the gut. And we talk about indirect pathways, how some of the gut microbiota can actually synthesize no transmittals that get out into the bloodstream, can impact the body, can act the immune system, and can get into the brain and act as nor transmittals in the brain, just as would nore. Transmittals that originate from within the brain also talked about what constitutes a healthy versus unhealthy microbiome.

And it's very clear that having a diverse microbiome is healthier than having a non diverse microbiome. But as I pointed out, there's still a lot of questions as to exactly what microbial species you want to enhance, in which ones you want to suppress in the gut in order to achieve the best gut brain access function. We talked about how things like fasting might impact the microbiome and how some of that might be a little bit counterintuitive based on some of the other positive effects of fasting.

Or we're not just discussing fasting, some other types of somewhat restrictive diets, either restrictive in time or restrictive in terms of micrometres ine intake, how those may or may not improve the health of got microbes. And the basic takeaway was that because we don't know exactly how specific died to impact that got microbial, and we don't know how fasting either promotes or degrades the microbial, we really can't say whether not they are improving or degrading the microbiome at this time. However, IT is clear that stress, in particular chronic stress, can disrupt the microbial.

It's also clear, of course, that anti biotics can disrupt that got microbiome. And that brings us to the topic of prebiotics and pro biotics. And I emphasize the fact that for most people, ingesting high quality, non profess foods that includes some prebiotic fiber, but also that includes some probiotics, will probably be healthy but not excessive levels of probiotic ics, high levels of supplemented probiotics of the sort that would come in a probiotics pillar.

Even prescription probiotics would probably lend themselves best to when people under severe chronic stress or had just come off a serious round or an ongoing or repeated rounds of anti bio dcs. That does not mean that ingesting probiotics in any form, any kind is not good IT just means that the very hyde's probiotic ics, again, typically found a prescription form or or capsule pill form, probably your best reserve. Two cases where of course your doctor prescribed es them, you should always follow your doctor's advice.

But in cases where perhaps you are jet lag, you're traveling excessively uh, for any reason or working excessively, you're not getting an sleep or your diet is radically changed from Normal. And we talked about how increasing the amount of fiber in your diet might be useful for increasing fibre digesting enzymes in the assistance lation of fibrous foods. But that is really the injections of fermented foods.

And in fact, getting anywhere from four, even up to six servings a day of fermented foods can be immensely beneficial for reducing inflammatory ory markers in the body and for improving microbiota diversity all along the gut, and thereby improving signaling and outcomes along the gut brain access. So we went all the way from structure to function to the four kinds of signal, mechanical, chemical, indirect, direct, probiotics, fiber and formatted foods. And I tossing a little bit at the end there also about ways that you can make your own experimented foods at home in order to try and offset some of the cost.

Also, it's just kind of fun to do, and some of those actually taste quite good. I've actually found that, uh the fermented h swr crowd they were making at home um actually rivals the care cwd that you can buy out of the refrigerated section at the grocery store when I am by no means a skilled cook or chef or in basically have no colony skilled whatsoever. So if I can do IT, you can do IT.

I hope you found this information useful, perhaps also actionable. One of my motivations for doing this episode was, again, as a primer for the episode with doctor Justin sonne. G, where we go really deep into the gut, microbes ome less so into the gut brain access, but really deep into got microbiome, what IT is, what IT does, what IT doesn't do.

And some of the emerging findings from his lab that are yet to be published. And I also was excited to do this episode because I think many of us, i've heard about the got microbiome, we hear about these bacteria that live in our gut, we hear about the gut brain access, or that ninety percent or more of the serotonin that we make is made in our gut. We heard about the gut as a second brain.

And so fourth, but I think for many people, they don't really have a clear picture of what they got. Microbiome is and the pathways of mechanisms by which IT can signal to the brain into the other parts of the body. So I hope that today's information at least improved the clarity around that topic and leaves you with a more vivid picture of this incredible system that is our gut brain access.

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