This episode explains the brain-body connections that allow the
specific foods we eat to control our moods and motivation. I discuss
the vagus nerve and its role in dopamine and serotonin release in the
brain. I review Omega-3 fatty acids and the key role of the gut
microbiome in supporting (or hindering) our mental and emotional
states. Many actionable tools are reviewed and discussed related to
fasting, ketogenic and plant-based diets, probiotics, fermented foods,
fish oils, artificial sweeteners, specific supplements that promote
dopamine and serotonin, and some remarkable behavioral (and belief)
effects.
- Introduction
- Emotions: Aligning Mind & Body
- Nutrients, Neurochemicals and Mood
- Primitive Expressions and Actions
- The Vagus Nerve: Truth, Fiction, Function
- “Vagus Stimulation”: A Terrible Concept
- Polyvagal Theory
- Vagus Senses Many Things, & Moves Our Organs
- Sugar Sensing Without Perception of Sweetness
- Eating-Induced Anxiety
- We Eat Until Our Brain Perceives “Amino Acid Threshold”
- Reward Prediction Error: Buildup, Letdown and Wanting More
- L-Tyrosine, Dopamine, Motivation, Mood, & Movement
- Supplementing L-Tyrosine, Drugs of Abuse, Wellbutrin
- Serotonin: Gut, Brain, Satiety and Prozac
- Eating to Promote Dopamine (Daytime) & Serotonin (Night Time)
- Supplementing Serotonin: Sleep, & Caution About Sleep Disruptions
- Examine.com An Amazing Cost-Free Resource with Links to Science Papers
- Mucuna Pruriens: The Dopamine Bean with a Serotonin Outer Shell
- Emotional Context and Book Recommendation: “How Emotions Are Made”
- Exercise: Powerful Mood Enhancer, But Lacks Specificity
- Omega-3: Omega-6 Ratios, Fish Oil and Alleviating Depression
- Fish Oil as Antidepressant
- EPAs May Improve Mood via Heart Rate Variability: Gut-Heart-Brain
- Alternatives to Fish Oil to Obtain Sufficient Omega-3/EPAs
- L-Carnitine for Mood, Sperm and Ovary Quality, Autism, Fibromyalgia, Migraine
- Gut-Microbiome: Myths, Truths & the Tubes Within Us
- Probiotics, Brain Fog, Autism, Fermentation
- Artificial Sweeteners & the Gut Microbiome: NOT All Bad; It Depends!
- Ketogenic, Vegan, & Processed Food Effects, Individual Differences
- Fasting-Based Depletion of Our Microbiome
- How Mindset Effects Our Responses to Foods: Amazing (Ghrelin) Effects!
- How Mindset Controls Our Metabolism
- Closing Comments, Thanks, Support & Resources
- HubermanLab #Emotions #Neuroscience
-- Welcome to the Huberman Lab Podcast where we discuss science and
science-based tools for everyday life. [upbeat music] My name is
Andrew Huberman, and I'm a Professor of Neurobiology and Ophthalmology
at Stanford School of Medicine. This podcast is separate from my
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Today we're talking all about emotions, and emotions are central to
our entire experience of life. Whether or not we're happy or sad or
depressed or angry is our life experience. And yet I think with all
the importance we've placed on emotions. Very few people actually
understand how emotions arise in our brain and body. And I mentioned
brain and body because as you'll see today emotions really capture the
brain body relationship. We cannot say that emotions arise just from
what happens in our head. It also involves events, biological events
chemical events within our body. The other thing about emotions is
that there's no real agreement as to what's a good emotion or a bad
emotion. Today we're gonna talk about the biology of the chemicals and
pathways that give rise to emotions. And I'm going to equip you with
several, if not many tools that will allow you to regulate and change
and steer your emotions should you want, but not using the typical
advice. You know, everyone's probably heard of this thing. Oh if
you're feeling depressed, just smile, you know, it's impossible to be
depressed while smiling. Look, if that were true we wouldn't have any
depressed people because depressed people don't want to be depressed.
And it is not the case that simply smiling will reverse depression or
sadness. And it's simply not the case that smiling can inhibit
sadness. It just doesn't work that way. However, it is the case that
certain things that are happening in our body influence how our brain
functions and the chemicals that are released. And today we're gonna
talk a lot about how the brain and body interact to create these
things called emotions in the context of food and nutrition.
And the reason we're doing that is not because I am beating the drum
about particular diet regimens or anything. In fact, I'm not gonna do
any of that. What I'm gonna do is I'm gonna review some of the most
important scientific data that point to how ingesting certain
nutrients, both macro nutrients like proteins, fats, and
carbohydrates, as well as micronutrients can impact the chemicals in
our brain that give rise to the feelings of being happy or sad or
sleepy or alert when you want to be sleepy or sleepy when you want to
be alert. So this is sure to be a broad discussion and yet we're gonna
get very specific about what emotions are, how they arise in the body,
tools that one can use in order to better control their emotions,
tools that people can use to believe it or not feel happier or feel
calmer. And that's because in the last 20 years or so there's been an
explosion of scientific studies exploring how the brain and body
interact to support certain neurochemicals that give us these feelings
of being alert and happy or depressed or certain that our life is
gonna be terrible or certain that our life is going to be great. So as
mysterious as all that might sound and confusing as all that might
sound we're gonna make it very clear today. And you're gonna come away
from this conversation with a lot of tools that you can act on
immediately. And those tools are grounded in scientific data. We are
gonna provide links to several of the studies, and I'm gonna mention
several of those studies as we go along. But overall, the goal today
is for you to understand how moods and emotions arise and the
different pathways in your brain and body that allow them to happen
and how you can use those pathways to change those emotions and the
tools that you can rely on in very specific ways to shift from being,
say, slightly depressed, to feeling happier. There actually are ways
to do that, or from feeling too alert and anxious to feeling calmer.
And these are tools that are distinct from the tools I've talked about
in previous episodes.
The discussion around emotions has a long and rich history going back
to Darwin. And even long before Darwin, this is a conversation that
philosophers and scientists have been having for hundreds if not
thousands of years. The idea that Darwin put forth and that was really
attractive for about the last hundred years was that emotions are
universal and that some of the facial expressions around emotion are
universal and other people have capitalized on that idea. And to some
extent it's true. I mean, I think that the two most robust examples of
that would be when we see something or we smell something or we taste
something that we like, there does tend to be a postural leaning in.
We tend to inhale air at that time, we tend to bring in more of
whatever chemical substances there is. We tend to these mm's and kind
of lean in closer to things that are attractive to us. And when we see
and experience things that we don't like sometimes it's a mild
aversion. We just kind of lean back or look away. Other times it's an
intensive version of disgust and we tend to cringe our face. We tend
to avoid inhaling any of the chemicals. This probably has roots in
ancient biological mechanisms that are to prevent us from ingesting
things that are bad for us, chemical compounds and tastes that might
be poisonous. So much of the foundation of any discussion about
emotion has to center around this kind of push pull of attraction to
things or aversion from things. Now that's a very basic way of
thinking about emotions but if you think about it, it works for a lot
of different circumstances and in the brain everywhere from the deep
circuits of the brain to the more kind of what we call higher order
evolved centers of the brain. We have this push pull thing where
either a previous episode, I talked about go, the circuits that allow
you to emphasize action and then no go circuits, the circuits and the
basal ganglia that allow you to de-emphasize action and prevent
action. We talked about how that's a push pull. So aversion and
attraction is a push pull too. Delight or happiness or excitement are
attractions to certain things and ideas, songs, people, places, foods
aversion is a leaning out. It's a disgust, it's an avoidance. And so
we can break down the discussion about emotions into these simpler
versions of themselves, but at the core of that of attraction or
aversion is an important theme that you might realize already. But
most people tend to overlook which is that there's an action there
you're either moving forward or you're moving away from something. And
any time you're talking about action in the nervous system, you're
talking about motor behaviors. You're talking about literally the
contraction of muscles to move you toward or away from things. And any
time you're talking about nerve to muscle and action, you're talking
about the brain and the body, because the brain can't move itself that
the brain has a body so that the organism can move. And the body has a
brain so that the organism, you, can move toward or away from things
that you deem to be good or bad for you. Now, some of these things
that we're attracted to and some of them that we avoid are what we
call innate or hardwired. You know, when we taste bitter compounds,
I'm not saying about bitter like a little bit of a bitters in your
drink or something like that, but really bitter compounds. We tend to
avoid those because they're associated with poisons. When we taste
things that are sweet or that are savory we tend to pursue more of
those. We tend to lean toward those so to speak and we tend to not
avoid them. So there are circuits in the brain for aversion and for
attraction toward things. And the body is governing a lot of that. And
so immediately in this conversation I want to raise an important point
which is about a nerve pathway that many, many people have heard of
that gets discussed all the time.
And that is one of the most kind of oversold for the wrong reasons and
undersold, unfortunately, for its real power, which is the vagus
nerve. So the vagus nerve is one, not the only, but one way in which
our brain and body are connected and regulates our emotional states.
Now, many of you have probably heard about polyvagal theory. I'm gonna
talk about this today. Polyvagal theory was popularized by Stephen
Porges and it's an interesting theory, certain aspects of it, frankly,
hold up to the science, some of it doesn't. And I'm gonna discuss all
of that today. A lot of the vagus and the excitement about the vagus,
V-A-G-U-S, is because it's somehow got into the mind of the public
that the vagus is involved in calming us down. So what is the vagus
nerve? Okay, we're gonna make this really simple, in particular for
those that are just listening, you can just imagine this, for those
are watching I'll point to the various areas, but basically vagus is
the 10th cranial nerve which basically means that the neurons, the
control center of each of those neurons in the vagus lives just kind
of near the neck, right? And a branch of the vagus goes into the
brain. They send a little wire into the brain. The other branch goes
into the periphery but not just the gut. It goes into the stomach, the
intestines the heart, the lungs, and the immune system. So this vagus
nerve is incredible because it's taking information from the body and
it has two directions. The first is what we call sensory. So it's
sensing things that are happening in the gut in the lungs, everything,
for example, in the lungs when our lungs are distended, the vagus
nerve senses that and sends that information up into the brain. It
also consents things in the gut like how distended or empty your
stomach happens to be, it can sense heart rate. It can sense your
immune system, whether or not you have bacteria or things invading you
in your body. So it sends that information up to the brain. So it's a
two-way street and sensory information is going up to the brain.
That's all vagus. So it's like a super highway sensory information
going one way and in the other direction is motor control. So the
vagus is not just for sensing things. It's actually for controlling
things. It's got a sensory pathway and a motor pathway. So that's the
first thing I think everyone should know about the vagus. In fact,
it's so important that I feel like this is as important as people
knowing that walking involves flexors and extensors. And if you don't
think that's important, it's as important as walking, frankly, because
the vagus is the way in which you can govern the brain body
connection. And in which you can steer various aspects of your mood
and wellbeing, but most people just don't understand how to use it. So
first you got to understand what it is. So you've got sensory
information coming from all these different organs of the body up to
the brain. You've got motor information going from the brain back to
the body. And so you've got this super highway within you. Now what
actually regulates the vagus. Oftentimes you'll hear things like, oh
this particular behavior rubbing your face at a particular location or
breathing in a particular way, or a warm bath or something stimulates
the vagus.
Well, right now, I want everyone to know that, quote unquote,
stimulating the vagus broadly speaking is a terrible way to think
about the vagus because do you know what, if you have a contaminant
inside your body the vagus senses that and projects that information
to your brain, and you start to generate a fever you start to try and
kill that contaminant in your body. So I don't know that you want to
stimulate the vagus just as a general theme today, we're going to get
specific about how you can activate particular circuits, certain
pathways from certain organs to the brain in order to feel better or
relieve certain conditions. But you certainly don't want to just
stimulate the vagus. Now excitement about the vagus in part is because
of what quite honestly, was a fairly pioneering theory about the vagus
which is his polyvagal theory.
So polyvagal, the word poly means many, is cool because it
acknowledges that the vagus has a lot of different branches. It's not
just one thing. And so I really liked that. I liked the naming
polyvagal. The idea that Porges has put forward was that there's a
dorsal vagus, which is kind of runs in the back of the spinal cord,
which is involved in alertness and activation and kind of fight or
flight type stuff. And that there's a ventral pathway and that that's
involved in more kind of empathic behaviors. That is not quite in
agreement with the modern anatomy, but he was doing the best with what
he had at the time. So, okay. The problem I have with the polyvagal
theory is the way that it's discussed people often say, oh if your
dorsal vagus is too active then you tend to be someone who's a little
too keyed up and people who are kind of in a state of freeze or kind
of flacid and kind of like just not really active and they're just
lethargic. Well, then that pathway is hypoactive. It should be more
active. So there are a lot of theories about how psychology maps onto
the vagus. That as far as I know, don't map to any real physiology.
Now, the other problem with this kind of the way that the polyvagal
theory is discussed probably not by the real experts, but by a lot of
people is that people start to diagnose different psychological and
physical manifestations through the vagus. They would say things like,
Oh this person is hyper flexible at the joints and therefore their
dorsal vagus isn't active enough or something like that. And it's
really kind of gone way outside the lane lines. So today we're gonna
clean up a lot of that. Let's make it really simple about how the
vagus actually works. At least as we understand it today in 2021.
First of all, as I mentioned, you have sensory information the same
way that you detect light with your eyes or you hear sounds with your
ears, you have sensors in your gut that sense how full or empty your
gut is.
It can also sense how acidic your gut is. It can sense various things
within your gut. Your heart is doing the same. It's informing the
brain how fast your heart is beating, how full your lungs are has been
communicated and then the status of your immune system. So the way to
think about the vagus is the same way I would think about the eyes.
The eyes are looking at colors, they're looking at motion they're
looking how bright it is. And each one of those things, those features
is telling the brain something different. So the brain can decide when
to be awake or asleep whether or not it's looking at somebody's
attractive or unattractive. The vagus nerve is also analyzing many
features within the body and informing the brain of how to feel about
that and what to do. So a really good example that I think is an
exciting one is as it relates to sugar. So we all know that sweet
things generally tastes good. I'm not particularly a fan of very sweet
things. You know, I'd much rather have cheese or pizza or hamburger or
steak.
I like savory fatty foods, but I do like sweet foods. And most people
find sweet foods to be attractive. They want them, they might or they
might not be able to regulate their behavior around them, but they
want them. And what's really interesting is that for hundreds of years
people have thought that that's because of the way that sweet foods
taste. So that makes sense, right? You eat something that tastes
sweet. You want more of it. Well, it turns out that it's much more
interesting than that. When you eat something sweet within your
stomach, you have cells, neurons, that sense the presence of sugary
foods independent of their taste and signal to the brain. So those
sensors, those neurons send information up the vagus to your brain
goes through a series of stations. And then you release dopamine. This
molecule that makes you want more of whatever it is that you just
ingested. In fact, this pathway is so powerful that they've done
experiments where they completely numb all the taste and feeling in
somebody's mouth they're blindfolded. So they don't know what they're
eating and they're eating a food. That's either sugary or not sugary.
And what they find is that even though people can't taste the sugary
food they crave more of the food that contains sugar because of the
sensors in the gut, that sense sugar. So to put this differently, you
actually have sensors within your body that make you crave sugar
independent of the sweet taste of those things. Now that's incredible.
And what it does, and what it tells us is that we have circuits in our
body that are driving us towards certain behaviors and making us feel
good even though we can't perceive them. Now, for those of you that
are really interested in gut intuition and kind of gut feelings this
is a gut feeling except this is a chemical gut feeling. This is a
particular set of neurons detecting that something in your body has a
particular feature, in this case the presence of sugars, and sending
information to the brain essentially to control your behavior. And I
find this remarkable, because what it means is that what we call
attractive isn't always coming from our thoughts about that or our
feelings, or even our perception. We are drawn to particular foods and
we're drawn to perhaps also to particular people, places and other
things because of information that's coming from our body. And we're
gonna talk about what one can do with this information. I know many
people are thoughtful or concerned about sugars these days thinking we
all ingest too much sugar. There's sugar snuck into all the things we
eat. And indeed, that's true. I mean, this should completely reframe
the way that we think about the sort of so-called hidden sugars in
foods. What this means is that even if a food is very savory like a
piece of pizza or a piece of bread or even like a salad dressing if
there's sugar snuck into that and you can't taste it you will still
crave more of that thing without knowing that you crave it because it
has sugar. In other words, you might find yourself wanting certain
foods and not knowing why you want those foods. So I find this to be a
fascinating aspect of our biology and yes, it relates to mood and
emotion. And we'll talk about how that is in a moment. So let's just
back up a bit and ask the question why do we eat certain things?
And why do certain foods make us feel good? And other foods actually
make us feel anxious. I think some people may be familiar with this.
Other people might not, but most people don't realize that as you
approach eating there's an anxiety associated with that. It's an
alertness. Remember in the previous discussions, or even if you don't
and you haven't seen those, all of your moods and feelings of
wellbeing are anchored on this continuum of alertness versus calmness.
And we hear so often about rest and digest. You know that, oh, after
we eat, we feel really nice and full, hopefully comfortably full and
not too full. And we're relaxing. And we feel satiated, it's
associated with serotonin this molecule of satiation. That's all true.
But what most people don't know is that there's an area of the
hypothalamus. So deepen the brain kind of in the middle deep portion
of the brain called the lateral hypothalamus. And the lateral
hypothalamus is really interesting because it controls feeding, but it
inhibits feeding. It stops us from feeding. And there's another area
in the brain. If you want names, I'll give them to you. If you don't
want names, just ignore them, delete them from your memory and
awareness, called the locus coeruleus, now the locus coeruleus sits
back further in the brainstem and it releases norepinephrine which is
essentially adrenaline. It makes us feel alert. Now, locus coeruleus
has a lot of different functions in the brain, but when we are going
to eat let's say we walk into a restaurant, we sit down or we're
preparing a meal, locus coeruleus is known to release noradrenaline in
the brain. It's creating a kind of alertness. This has ancient
utility, but it's creating this alertness. And for many people, they
experience that as they approach food as stress as anxiety. But what's
interesting is that as we approach food locus coeruleus is releasing
all these molecules that make us feel more anxious and alert sometimes
it's felt as excitement. And that asks probably to do with how we feel
about food generally, are we happy with our relationship with food?
Are we trying to restrict our relationship to food, are people coming
over for dinner, all that will play in of course, but there's a
certain stress and anxiety upon approach to food. And as we approach
food and we feel that anxiety locus coeruleus activates the lateral
hypothalamus in a way that inhibits feeding that makes us not want to
eat. So a lot of people who have kind of pre-meal anxiety or anxiety
around food and they can't seem to just calm down and have a good meal
to access that later rest and digest. A lot of that is because of this
heightened stress upon approach to food and a lot of the tools that
are out there, both for eating disorders and for just kind of the
general public who isn't suffering from eating disorders, things like
mindfulness around meals. You know, they always tell you you should
never eat when stressed. I'm sorry, but my life is not organized in a
way that I can do that. I would never eat. Right because I eat when
I'm awake and I don't know if I'm stressed, but I don't think I am but
I tend to run around a lot during the day. I don't generally take time
to do two or three deep breaths before I eat. I generally will just
eat. That can be healthy or unhealthy depending on the quality of your
digestion. I think using digestion as a guide is good, but a lot of
people aren't aware that this interaction between locus coeruleus and
lateral hypothalamus is a basic mechanism where we are supposed to get
a little bit alert and anxious around mealtime. And then as we eat,
the mechanisms for calming and satiation are supposed to kick in and
those mechanisms involve as I mentioned earlier, two things. One is
how things taste, digestion starts in the mouth. Of course, we taste
our food. Everyone tells us we should chew our food more. Yes, that
can improve digestion. We're not supposed to drink too many fluids as
we eat. That's true too, but a lot of how we feel while we eat and
after we eat is because of this vagus sensing of what's in our gut.
It's sending information all the time. Is there sugar? Are there fats?
Are there contaminants? There are a lot of information. These so-
called parallel pathways that are going up into our brain that
regulate whether or not we want to eat more of something or not. And
there are accelerators, things that make us want to eat more, like
sugar and fats because those are nutrient dense. And they helps
generally, at least in the short term support the survival of animals,
but also amino acids. And this is very important.
There are a lot of data, but much of what comes from the data on what
people eat and how much they eat is from a subconscious detection of
how many amino acids and what the array, meaning the constellation of
amino acids is in a given food. And it's fair to say that the sum
total of these studies pointing in a direction where people will
basically eat, not until their stomach is full but until the brain
perceives that they have adequate intake of amino acids. Now, this is
a conversation that comes up in the context of you know, the meat,
only the keto, the kind of zone diet, the Mediterranean diet, the
vegan diet. I'm largely going to ignore the kind of strict camps
today. I will talk a little bit about it, because I think each one of
them actually taps into something important about this brain body
relationship that the other ones don't. But I don't want to get into a
discussion about the ethics of different foods of animal based or non
animal based. 'Cause that's not the topic today. It's really about
nutrient sensing and amino acid sensing. So we generally will eat
until our gut tells our brain that we have adequate amounts of these
amino acids. Amino acids of course are important because they are the
building blocks of sure, muscle, and the other things in our body that
need repair. But what most people don't realize is that amino acids
are what the neurochemicals in the brain are made from. Now, this is
vitally important. Okay, so we've heard dopamine is this molecule that
makes you feel good. Actually dopamine is a molecule that makes you
feel good. It's released within the brain. And it does feel very good
when you have dopamine release, dopamine releases caused by surprise,
excitement, events that you're looking forward to and they turnout
well, it is inhibited by events you're looking forward to that don't
work out when someone says they're going to call that you're really
really excited to talk to, and then they don't, or you thought a movie
was gonna be really great and it's not, or you expect a meal to be
really delicious. And it's kind of, eh, and we actually there's a name
for that. It's called reward prediction error. And you can actually
use this in the context of meals and plans in a way that's very useful
with yourself and people you know, essentially if you expect something
to be really terrific it really does place a higher expectation at the
chemical level.
So if you don't get as much dopamine as you're expecting from
something, so you you hear about a really great restaurant or a place
that has a really, in my case, I have, I wouldn't call it an
addiction. I would call it more of an affliction for croissants. The
best vegetable of course, is the croissant. And I get really excited
about the fact that someone will tell me, oh there's this place and
they have incredible croissants. You gotta go there. So I get really
excited, and I'll go. And just them telling me that it's gonna be
really terrific raises an expectation, a dopamine expectation. And
unless those croissants are amazing chances are I'm going to
experience them as less good, less satisfying. I will truly release
less dopamine than I would had they just said, oh yeah, I think that
there are croissants down the street. Or if I just tried one at
random, and that's because of this reward prediction error your
expectation of something releases dopamine and the actual event
releases dopamine. And if the event related dopamine does not exceed
the expectation or at least match it, there's a much higher tendency
that you won't pursue that thing again. So dopamine is really powerful
and it's not just the molecule of reward. It is the molecule of
desire. It's the molecule of wanting not just the molecule of having.
And a book, since people often ask for book recommendations. I don't
know the author personally, but I love the book. It's called "The
Molecule Of More". It's a terrific book. I wish I had written it,
frankly, but if you want to learn more about dopamine reward
prediction error and how dopamine regulates various aspects of your
emotional and motivational life, it's a terrific read. Dopamine is
what's going to lead us to want to eat more of something or to not
want more of something, because dopamine really is about craving. It's
about motivation and it's about desire. And as I mentioned, these
amino acid sensors in our gut are detecting how many amino acids but
they're also detecting which amino acids. And there's a particular
amino acid called L-tyrosine which comes from food.
You can look up online, which foods contain L-tyrosine. It is in
meats. It is in nuts. It is also in some plant-based foods. L-tyrosine
is the precursor to a couple other molecules like L-DOPA, et cetera,
that make dopamine. And so there's a misconception out there that most
of the serotonin is in our gut. And most of the dopamine is in our
gut. And therefore our mood is in our gut. That's not quite the way it
works. Okay. we'll talk about serotonin in a moment but dopamine is
synthesized from the amino acids that you eat. However, the dopamine
neurons that give rise to these feelings of good or wanting more or
desire and motivation, those reside in the brain. So we don't want to
get too confused. We want to respect and honor the power of the gut
and this vagal pathway, but it's really neurons within your brain that
drive the pursuit and decision-making, so what does this mean? Well,
some people make too little dopamine. Some people make so little
dopamine that they need prescription dopamine. They need L-DOPA,
people with Parkinson's take L-DOPA and other compounds to increase
dopamine because Parkinson's is associated with deficits in movement,
starts as a tremor, actually starts with some other things that are
interesting. We'll talk about in a moment, but Parkinson's is a
depression. It's a blunting of motivation and mood and effect, and
it's a tremor. And then eventually in severe conditions it's
challenges in speaking and walking so that some famous examples would
be Muhammad Ali, Michael J. Fox, the great boxing trainer, Freddie
Roach, like these people have Parkinson's and they at least later in
their life had challenges speaking. Now it's not just fighters that
develop Parkinson's as far as I know, Michael J. Fox wasn't a fighter.
People can develop Parkinson's and Parkinson's is a depletion of
dopamine neurons in the brain. And it's not just movement challenges.
It's challenges with mood. Now, hopefully most of you all of you don't
have Parkinson's, but it's clear that dietary L-tyrosine supports the
healthy production of things like dopamine and as well as other
factors within the brain.
Now, some people immediately ask, well should I supplement L-tyrosine?
So let's just talk about that because that's gonna come up. Full
disclosure, I sometimes take L-tyrosine. I'm not taking it right now,
but I take it only occasionally, you can buy this in capsule form. It
does increase kind of a mood and elevation and alertness. It is over
the counter. You have to check with your doctor. I'm not responsible
for your healthcare and I'm not a doctor, whether or not it's safe for
you, people with preexisting hyper dopaminergic conditions like mania
should probably not take L-tyrosine. The other thing about taking
L-tyrosine is there is a crash, okay? It's not a massive crash if you
take it at appropriate doses and it's right for you but it can produce
a crash and a lethargy and a kind of brain fog after the next day or
so. And so L-tyrosine however can be ingested through foods or through
supplementation to increase dopamine levels. That's well-known, taken
chronically however, it can disrupt those dopamine pathways. Now there
are other drugs that will increase L-tyrosine and dopamine as well.
But those are severe enough that they generally tend to have addictive
properties. So things like methamphetamine, things like cocaine are
terrible because they really ramp up the dopamine system so much that
people really can't achieve dopamine release through any other
mechanisms. But food and the ingestion of L-tyrosine has a profound
effect on our levels of dopamine. It takes a little while but that
really will impact level of mood. Certain antidepressants fall into
the category of dopaminergic antidepressants. One of the most famous
ones of course is Wellbutrin. Wellbutrin with developed because a lot
of the other antidepressants tend to make people feel kind of
lethargic or they had side effect profiles that people didn't like. So
they developed this thing that, the generic name is different, but
it's generally called Wellbutrin. Wellbutrin activates dopamine and
epinephrin, which is a substrate of dopamine. And both of those are
involved in motivation and alertness and effort. So you might say,
wow, this sounds like a great drug. However, this drug, the side
effect profile tends to be the things that are associated with
elevated mood and alertness. So this isn't like taking some
L-tyrosine. This isn't like eating some tyrosine rich foods. This is
really a much greater release of dopamine and epinephrin, and it
increases things like anxiety, sweating, the pupils dilate. It has
certain effects on, in particular people with epilepsy, it's been used
somewhat successfully for smoking cessation, but again, it's not for
everybody and I'm not here to encourage the use of these things. I'm
just describing the biology and the rationale for why these drugs were
developed. So let's back up a second. Let's just kind of take stock of
where we're at. We have a brain body connection. There are many of
them, but one of the main ones is the vagus nerve. The vagus collects
information about a lot of things, breathing, heart rate stuff that's
happening in the gut, et cetera, and gut by the way, includes the
stomach and the intestines, sends that information up to the brain.
The brain is using that information to decide one of two things, move
toward something or move away. It can also pause, but essentially
pausing is not moving toward. So that's the dopamine pathway and foods
rich in L-tyrosine generally give us an elevated mood and make us want
to do more of whatever it is that we happen to be doing as well as
other things, motivation, generalizes to other things it's not unique
to just ingesting foods but foods that give us a big pulse of dopamine
will make us crave more of that food. It will make us crave more of
the activity that led to the ingestion of that food. And as I
mentioned earlier, a lot of that is happening at a subconscious level
that you're not even aware of. And this is why I think the concern
about hidden sugars and over ingestion of sugars is serious because
it's not just that the sugars are impacting our blood glucose in
negative ways. Although often it is, it's not just the obesity crisis
that's happening. It's also the fact that it's disrupting our dopamine
systems. Now that doesn't mean all sugar is bad. Some people have a
quite healthy relationship to sugar but I think most people are just
not aware that sugar isn't just operating at the level of taste it's
operating at the level of neurochemicals and it's doing it
subconsciously. So I'd like to talk about some of the other pathways
between brain and body that regulate our moods and emotions but also
are actionable.
So the other neuromodulator that's really interesting in the context
of the vagus is serotonin. Serotonin, just to remind you is a
neuromodulator therefore it creates a bias in which neural circuits
which neurons in the brain and body are going to be active and it
makes it less likely the other ones are going to be active. I think
it's fair to say without ever having measured it that my bulldog
Costello, just his brain and body must be swimming in serotonin,
because he's very calm and he eats a lot but he generally feels pretty
sated. He's kind of an animal that's obsessed with comforts. He's a
bit of a hedonist, and serotonin when it's elevated tends to make us
feel really comfortable and kind of blissed out wherever we are. And
that contrast with dopamine and epinephrin which mainly put us in
pursuit of things. Motivation is pursuit. Serotonin is more about
feeling really comfy where we are. The conversation around the brain
body relationship and mood and serotonin for many years was, well, you
eat a big meal. The gut is distended. You've got all the nutrients you
need you rest and digest and serotonin is released. That's sorta true,
but there's a lot more going on and a lot more that's interesting and
actionable that's going on. First of all, some of you, but perhaps not
all have heard that more than 90% of the serotonin that we make is in
our gut. And indeed we have a lot of serotonin in our gut. We have
neurons in our gut that makes serotonin. We have neurons in our brain
that make serotonin, but here's the deal. Most of the serotonin that
impacts our mood and our mental state is not in our gut. Most of it is
in the neurons of the brain in an area called the raphae nucleus of
the brain, there are a few other locations too, and those are the
neurons that control whether or not we feel satiated or not. Whether
or not we feel happy and calm. You can't have a discussion about
serotonin without having discussion about antidepressants. Because
during the late eighties and early nineties there was this explosion
in the number of prescription drugs that were released. Things like
first one and most famous one is Prozac, Zoloft and Paxil, a number of
other ones that are so-called SSRI selective serotonin re-uptake
inhibitors. That's a long acronym, but basically those drugs work by
preventing the gobbling up of serotonin or re-uptake of serotonin into
neurons after it's been released which leads to more serotonin overall
which means to elevate serotonin. And indeed those drugs were and can
be very useful for certain people to feel better in cases of
depression and some other clinical disorders as well. So I really
don't want to dismiss them as useless or dangerous for everybody. They
can be quite useful for many people. Not everyone responds well to
them as I'm sure you've all heard. And their side effect profile has
affects like blunting affect. It can make people feel kind of flat,
kinda meh, it can reduce appetite for food. It can reduce appetite for
sex. It can do all sorts of things, or it can work really well.
Sometimes it's a dose-related issue, et cetera. Serotonin is
fascinating however, because how well those neurons in the raphe work
is impacted by some events within the gut. Although you might be
surprised to find out what those events are. So let's go a little bit
deeper into the gut. And again, the gut includes the stomach and then
the small intestine in the large intestine and ask like, what is going
on with serotonin in the gut? How is it impacting serotonin in the
brain? And let's think about this in the context of how some of us
might want to increase or decrease our serotonin levels. So as far as
I know, there aren't any really good at home blood tests for things
like serotonin and dopamine. There's some commercial products out
there. But to me, just to me, I'm not particularly impressed. You
know, it's not the same as getting your hormones levels measured or
your metabolic factors measured, that's can be daunting. It can be
done rigorously. There are tests out there. There are even some,
believe it or not. There's some questionnaires that, and I think
actually last year it made some of the bigger newspapers, are you more
of a dopamine or a serotonin? Are you a this or that? I find that
stuff to be a little silly although I do appreciate, and like the fact
that people are thinking about and talking about neuromodulators there
aren't really great ways to measure these things outside the clinic.
There's some great clinical tools that you can get inside of a
hospital or from a proper endocrinologist or neurologist, but no great
at-home tool. So maybe that's a call to arms for some of you
entrepreneurial folks out there to create these tests, accurate tests
please, that could be done at home. But some people feel like they're
too anxious or they're always in a motivated state and they're trying
to adjust their serotonin. Many people adjust their serotonin by just
eating more food and carbohydrate rich foods will increase serotonin.
I've talked about this on a previous podcast but I personally am a big
fan at least for me is I usually fast and exercise in the early part
of the day I eat a relatively high protein and moderate fat zero carb
or low carb meal at lunch in the afternoon to stay alert because those
foods tend to favor dopamine production acetylcholine production,
epinephrin production and alertness.
My mood is generally pretty good most of the time. And then as evening
comes around and I'm concerned about sleep and a good night's sleep,
not concerned in an anxious way, but I want to get a good night's
sleep. I will ingest foods that promote serotonin release because they
contain a lot of tryptophan. So if I do eat meat, it would be like a
white meat, turkey meat. I don't tend to, I've never liked turkey. I
don't mind the animal but I don't like ingesting the meat, but starchy
carbohydrates will increase serotonin. Some people also will take
serotonin.
You can now buy 5-HTP supplements. This is a little bit tricky. 5-HTP
supplements can of course increase 5-HTP. It is 5-HTP or serotonin but
that sometimes can create problems in endogenous or self-made
production of serotonin. So I'm never a fan of taking things very
close to the chemical you're trying to increase for very long periods
of time. Maybe for occasional use. I have the problem that if I take
serotonin supplements, 5-HTP, I fall asleep. The sleep I have is very
intense and I wake up three or four hours later. And we know based on
sleep studies with good measurements in the lab that serotonin release
tends to be in the later part of the night. And so by taking it early
in the night it really can disrupt the pattern of sleep in the depth
of sleep. Nonetheless, some people are interested in taking serotonin
to get some of the more blissed out effects. You can achieve that with
foods. As I mentioned, that are carbohydrate rich. So as you're seeing
this isn't really a discussion about nutrition per se. This is
discussion about food which contains amino acids, amino acids being
the precursors to neuromodulators and neuromodulators having a
profound effect on your overall state of alertness or calmness,
happiness, sadness, and wellbeing. So there are a number of things
that one can take. As I mentioned, one of them being 5-HTP itself. Now
I'm not recommending people take anything, but if you're interested in
what this does and you want to explore this of course you'd want
permission from your doctor. You can go to this free website. I love
this resource. They don't pay me to say that, but I just love this
resource. I've followed it for a long time called examine.com. Thank
you folks at examine.com for putting this free resource out on the web
that has links through what they call the human effect matrix. So it's
links to all the PubMed studies for particular effects of particular
compounds that one combined and just incredible as well as important
health warnings. So I'm not gonna read through everything but if you
were to go to examine.com as I have now and you put in 5-HTP they're
only looking at things that have strong evidence. PubMed articles,
articles that are in the PubMed archive. So for instance, I didn't
know this, but 5-HTP produces a notable decrease in appetite, three
studies.
And this appetite suppression makes sense, of course, because we
ingest foods to get serotonin. And if we have enough serotonin then
there's no reason to ingest more foods. It tends to have a blunting of
appetite. It probably does that also through other mechanisms. So I'm
not saying you should do this but if someone's trying to blunt their
appetite could be a interesting route, although I don't recommend
chronic use, not surprisingly there's a decrease in body weight as a
consequence, an increase in cortisol. So that's kind of important to
note that when you typically in biology, if you pull on one string
really hard and other one moves it's a little bit like a puppet in
there. It's more than one string on the puppet. So it does seem to
increase cortisol though they report as a minor effect. Again, links
to all those are there which is why I'm not listing them out in our
caption notes. You can go and get them at examine.com, put in
serotonin and you'll find that. So I find it fascinating that nowadays
there are things that are somewhere between doing nothing, getting
serotonin from tryptophan and foods and prescription drugs. There's
this other category of supplements that are really interesting for
modulating these chemicals in the body. And I should mention before I
move on, because I mentioned L-tyrosine I neglected to mention earlier
in our discussion about dopamine, if you're interested in the dopamine
pathway, go to examine.com, put in Mucuna pruriens, it's M-U-C-U-N-A,
separate word, P-R-U-R-I-E-N S.
It is a velvet bean that grows from vines and is very itchy to touch
due to serotonin on its surface. Amazing, this bean has serotonin on
its surface and indeed serotonin at if you were to put it on your skin
would cause some irritation of the skin, amazing. Inside the bean is
L-DOPA, Mucuna pruriens is not just something that promotes dopamine
release because of some weird mystical ancient thing or whatever, or
sorcery. It is chemically L-DOPA the precursor to dopamine. It
contains some other molecules as well and low levels of other
psychoactives. This stuff is available over the counter. Incredible. I
personally find it incredible. Its effects are really interesting. I'm
not gonna read them all off but I mentioned these effects not because
I'm encouraging you to take it but because you get a window into what
dopamine, acute dopamine increase does in the non-Parkinsonian
context. And you can start to think about foods that are rich in
L-tyrosine as biasing certain effects or not others. So when you hear
food is medicine, food isn't really medicine. Food is food, but food
has these chemical effects as well. So first one listed is three
studies with very high rigor that overall have a minor effect on of
all things, sperm quality. So it appears that sperm motility itself,
I'm assuming when they say sperm quality I don't know what features of
sperm of quality they looked at with sperm, that's not discussion I
want to have, but I'm assuming it's motility because I know enough
about reproductive biology to know that sperm ability to swim depends
on some proteins that are present in the front of the sperm, et cetera
things like contractions and sperm motility is generally associated
with sperm quality. Sperm that don't move are generally not very
useful sperm. Symptoms of Parkinson disease are are notably degraded
with Mucuna pruriens. So fascinating. That's not surprising. And there
are a lot of other effects here. Feelings of subjective wellbeing,
testosterone, reductions in prolactin, not surprising. Prolactin is a
hormone that's involved in milk letdown, it's in lactating mothers.
It's involved in feelings of peace and generally is antagonistic to
sexual desire in both men and female. So it's really interesting that
things like Mucuna pruriens which are L-DOPA reduce prolactin,
increased sperm motility, increased testosterone, subjective
wellbeing. So you're starting to see a theme, right? Dopamine really
makes us motivated. Feel in pursuit, makes us feel good. Serotonin
makes us feel more relaxed and calm. Now this whole month is about
emotion. So you might be thinking, well, wait where are we going with
all this as it relates to emotions. But in the last episode I said
something I'm gonna repeat it now briefly, which is that much of what
we talk about is good emotions or bad emotions.
There's a context to that. There's a social context. We can't really
say an emotion is good or bad. Grieving at a funeral is healthy. Being
happy at a funeral, assuming you loved the person that died is most
people probably wouldn't think that was healthy. So we can't really
say that certain emotions like sadness or happiness are healthy. It's
context is important. Cultural context is important. Many of you have
asked for book recommendations. This is an opportunity to raise a
mention of another book. Again, I don't have any financial affiliation
or anything but if you want to read more about emotions and how the
context and cultural things impact our emotions I'm a huge fan of Lisa
Feldman Barrett. I learned about her from the Lex Fridman Podcast.
I've had discussions with her on my Instagram Live, she's at
Northeastern University, a world expert in emotions. Her first book is
"How Emotions Are Made" This is not a book she sent me. I paid for
this with my own money years ago, bought it, read it, loved it long
before I met Lisa, I'm just delighted that we've got to known each
other a little bit. It's a really interesting read into the psychology
of emotions and some of the subjectivity of emotions. So, whereas I'm
talking about mainly the biology of emotions this gets a little bit
more into the psychology and the biology as well. And Lisa's just
terrific. She's also putting a lot of information out into the world
about emotion. So if you want to learn more about that check out her
work, again, it's Lisa Feldman Barrett. And that book is "How Emotions
Are Made" Hopefully she'll continue to write many more books. So now
you understand the relationship I hope between foods and dopamine,
foods and serotonin and that they're both being communicated to the
brain via the vagus, right? We ingest these foods, these supplements
are things people take, they don't put them directly into the brain.
They put them in our gut. So yes, there's a gut brain connection but
it's not about the serotonin in the gut that makes you feel calm and
placid. It's not about the dopamine in the gut. It's just been
oversold that way because I think there's something really attractive.
And I understand about the idea that because certain things about our
experience of life and our emotions is happening in our body. That
maybe we have a little more control, right? Because this thing is a
hard container. We can't just stuff some dopamine in there. I could
probably take a Mucuna pruriens bean and stuff it in my ear, please
don't do that. It'd make my ear itchy because of the serotonin on the
outside. But you can't get stuff in there. What you have to do is
ingest things that are metabolized in certain ways that communicate to
the brain or so maybe they pass into the brain themselves across
what's called the blood brain barrier. I'll talk about the blood brain
barrier in a minute. It's actually called the BBB. So it ends up
sounding like baby, BBB. I guess that's like BB, anyway, BBB, but
they're also nerves in the gut that are sensing the nutrient contents
of food and then saying, oh, you should feel better and want more. Oh,
that's got a lot of bitterness and acid taste to it. You should want
less of that. So as I transitioned out of the discussion about
dopamine and serotonin in the gut hopefully you've got some actionable
items there under your belt, pun intended, where you can understand
how certain foods and certain nutrients and you can look these up,
might impact your mood. If you're somebody who's really anxious and
really wired. Well, then the dopamine adrenaline pathway epinephrine
pathway is probably not one that you want to lean on any harder. If
you tend to be someone who's pretty passive and you're having trouble
with motivation. Well then think about ramping up the dopamine pathway
through, I always think behaviors and proper food choices is the best
way to start. And behaviors include things like exercise, et cetera.
But one of the problems with the discussion around mood and exercise
or mood and meditation is that it's so subjective.
It's like, I love certain forms of exercise and not others. Certain
ones are aversive to me. Certain ones are attractive to me, and it's
never really clear. No one's ever told me. Okay, you have to do 10
minutes on the bike at X number of RPM at so-and-so or on the skier in
order to get your dopamine up. But we can actually say, if you ingest
more L-tyrosine there's a high probability that you're going to make
more dopamine. And I'm talking about ingesting it through food or
through supplementation if you like. Mucuna pruriens, I've tried. I
should just mention it was too dopaminergic for me. I got really,
really jazzed up and then a severe crash for me the next day. But
that's, I think because I tend to ride pretty high on the kind of
alertness and motivation scale. I'm always being told by Costello and
other people in the podcast studio to slow my speech down. This is me
uncaffeinated, and I could probably afford a little more serotonin in
my life. So, whereas Costello, he can afford to wake up every couple
of days and just say hello to us. This dog sleeps more than any other
creature. It's remarkable. So there are things that we can do and
they're actionable. And they are in some ways they're quantitative
because you can regulate dosages and you can regulate amounts and you
can regulate timing. And everyone has to play with these things and
figure out what's right for them in terms of feeding. And everyone has
to explore and understand what's safe and right for them. But, and of
course, exercise is still very important. I talked about social
connection in the last episode super important for activation of
serotonin but when it comes to this gut brain, body brain
relationship, what we eat really matters in terms of the
neurochemicals that we make. So let's talk a little bit more about
things that we ingest in our body and then allow our body to inform
our brain to shift our mood.
And this is something I've been doing for years. And I just want to
say I've found to be a complete game changer. There's excellent
science to support it. And I think most people are familiar with it in
a different context but I don't think most people know this simple
fact which is that the omega-3 to omega-6 fatty acid ratio has a
profound effect on depression. It has a profound effect on mood so
much so that in a double-blind placebo controlled study that I will
provide the link too, this was a study first published in 2008 but
there've been many others as well. First of all, an experiment done in
animals. They found there's a model of learned helplessness in
animals. It's not very kind to the animals, but they put rats or mice
in a jar. They let them swim and they'll swim, swim, swim to try and
save their life. And eventually they give up, it's a learned
helplessness. They don't let them drown, they take them out. Adjusting
the omega-3 omega-6 ratio so that the omega-3's are higher led to less
learned helplessness, meaning these animals would swim longer. Now
that's an animal. That's a rat, not a particularly kind study, but
that same study was essentially done in humans although they didn't
have them swim to the point of near drowning. What they did is they
took people who were clinically depressed, major depression. Major
depression is severe maladaptive state meaning it inhibits job,
relationships, appetite, all sorts of negative health effects. And
they did a comparison of a thousand milligrams a day of EPA. So EPA is
one of the elements that contains high levels of omega-3's that's in
things like fish oil, I'll talk about other sources in a little bit
but it wasn't a thousand milligrams of fish oil. It was a thousand
milligrams of EPA. Compared that to 20 milligrams of Fluoxetine which
is Prozac, okay. Really increases serotonin. And in this study of 60
individuals, again, I'll provide the links to the study. They found
that they were equally effective in reducing depressive symptoms. So
imagine that, a food-based compound that you can't make without,
right, this is not a situation where you can make your own omega-3s.
You have to get them from food sources or from supplementation, was as
effective as 20 milligrams of fluoxetine over the course of eight
weeks. And what was really interesting in addition to that is that the
combination of a thousand milligrams of EPA and Fluoxetine had a
synergistic effect in lowering depressive symptoms. I find this
remarkable. I heard about this when it first came out and I wasn't
sure what to make of it. 'Cause there are a lot of studies that come
out and I generally like to focus my changes in behavior around things
where there's a large center of mass. There's a lot of information. A
couple years later, I did in fact start taking a thousand milligrams
per day of EPA in fish oil. Now there are a few side effects of fish
oil. People who have blood, who are bleeders who have Factor V Leiden
mutations or in women who are taking birth control, which can affect
blood clotting and things of that sort really should talk to your
doctor make sure it's okay for you. Fish oil also can give people
fishy breath which is pretty gross, frankly, but there are now fish
oils that either because of the Encapsulations or because they put
some lemon flavoring in there doesn't have that effect. In any event,
a thousand milligrams per day of EPA. I started ingesting that
regularly. I just felt better. I wasn't clinically depressed, but I
generally, I did feel at least for me, an increase in mood and affect.
And a number of other things it's supposed to reduce inflammation. The
cardiovascular effects are controversial for a long time everyone
thought the effects on platelets were really terrific. Then there were
articles that came out in major newspapers saying maybe not so much
but the effects on mood are really profound. And now there are lots of
studies. If you go into PubMed and you were to put EPA or fish oil and
depression you would find that there were a number of really
impressive results showing that it's at least as effective as certain
SSRI antidepressants at these dosages and it can amplify or improve
the effect of low dosages of some of these SSRIs.
So I feel like more people should know about this. This is nutrition,
but it's profoundly affecting mood and depression is terrible, right?
Depression can have a component of anxiety in some cases where people
are they feel lousy and very uncertain. That's kind of how I talk
about depression with anxiety is you talk to someone who is anxious
and you can tell them everything's gonna be okay. And they're always
concerned about what they might not know. You don't really know the
plane isn't gonna crash. You don't really know that life is gonna go
okay. And in some sense, they're right, no one has a crystal ball or
can predict the future, but they tend to perseverate or fixate on the
uncertainty. And then of course there are the versions of depression
that involve certainty. People are lethargic and they're certain they
say, yeah, I'm certain, I'm never gonna get another job. I'm certain,
I'm never gonna meet anyone new. I'm certain I'm gonna fail. So
there's this kind of a divide in the sphere of depression around
certainty and uncertainty. But what's interesting is this thousand
milligrams per day or more of EPA has been shown to relieve both forms
of depression. Now, does that mean it's gonna work for everybody? No,
I'm not here to try and play psychiatrist. I want to point you in the
direction of these manuscripts so that you can make informed choices
for yourself. You can discuss it with your doctor and family and make
the choices that are right for you. But here's what's especially
interesting about the heart effects, because we've heard that these
omega-3s, which of course you can get from other sources too, you can
get from fatty fish, they're in flax seeds, hemp seeds.
There are a number of chia seeds, these kinds of things but the levels
of EPA that are required are quite high. So this thousand milligrams
per day is that's pretty hard to get from food although it can be done
depending on what you're eating. What's interesting is that the heart
effects that are solid that really stand up in the literature have a
lot more to do with something we talked about in a previous episode.
And I'll mention again, which is heart rate variability. So we know
that having a heart rate that's really high or heart rate, that's
really low. Neither of those are good. A lot of people think, oh you
just want a low heart rate, big stroke volume. You know, if you're
running a lot you may have 30 or 40 beats per minute. That's great to
be in shape but you still want heart rate variability. It has a lot to
do with the tone of the autonomic nervous system talked about last
time. How, when you inhale, it speeds up heart rate. When you exhale,
it decreases heart rate. That's called respiratory sinus arrhythmia.
That's the basis of heart rate variability. We'll maybe do a short
post about this. So you can get all the mechanism and the behaviors
that spill out of that that might be useful for you. But the point is
heart rate variability. HRV is good. And what's interesting is that
there was a study in 2009 that showed that people who eat a diet where
they fail to supplement in a way that there's a high omega-6 to three
ratio, so not enough omega-3s, not only are there markers of an
inflammatory cytokines, elevated things like IL-6 and TNF-alpha, but
they tend to be non-responders to antidepressants. Shifting that
omega-3 omega-6 ratio did a couple things. First of all, increasing
the amount of EPA shifted the ratio. So it was higher omega-3 to
omega-6 ratio, which was good, lowered the inflammation markers, and
then allowed antidepressants to have their effect, even at low doses.
And here's the really interesting thing. It worked by increasing heart
rate variability, and you think, well, how in the world would this
happen? But you know how I mean, that's a ton of effects but the way
it works is because of the way that these things are impacting the gut
and the autonomic nervous system. Remember earlier, I said, the vagus
includes connections from the heart signaling about sensory
information about how fast the heart is beating to the brain not just
stuff on the lungs, but information from the heart and the brain then
adjusts heart rate by heart rate variability. So it's incredible that
there's a way that one can use the gut, the ingestion of more of these
EPA's, either through food or supplementation to increase rate
variability and thereby to improve symptoms, meaning reduce symptoms
of depression, and to even make low levels of antidepressants that
wouldn't otherwise work work. And I think I like this study so much
because a, it's super cool. It bridges the brain body access. It
incorporates nutrition and micronutrients in the brain but also
because it really points to something that we hear all the time, which
is our body is a whole system. It's working as a whole system and the
brain isn't working in isolation up there in the skull. It's reacting
to things that are happening in the body in the gut and in the heart
rate and heart rate variability. And that the things we ingest can
have a profound effect on them. Now, of course, I really want to
emphasize something which is that no one compound or nutrient or
supplement or drug or behavior for that matter is going to be the be
all end all of shifting out of depression or improving one's mood or
improving sleep. It's a constellation of things. And this is
especially true when people start to get excited about supplements and
drugs of all kinds and their potential for various things. Right now,
there's a lot of excitement about psychedelics and their therapeutic
uses. And I think great, but as a good friend of mine who's a
physician clinician says better living through chemistry still
requires better living. You cannot expect to take a compound
regardless of source or potency and have it completely shift your
experience of life without having to continue to engage in the proper
behaviors, all the things we know proper sleep, exercise, social
connection, food, et cetera. There are many others as well. So I still
find that this collection of studies about omega-3 to omega-6 ratios
to be profoundly important so much so that it's completely changed the
way that I think about food, the foods I eat, I do supplement. I don't
necessarily that think that's for everybody but I really think it's
incredible that there are these compounds that have these robust
effects on our feelings of wellbeing. And there are others too. So
that thousand milligram per day threshold of fish oil that's
beneficial requires that one take a reasonable amount of these things,
either through food or through supplementation.
I acknowledge that not everyone wants to take fish oil. There are a
couple of reasons why one might want to avoid that. One would be for
ethical reasons. You have an emotional relationship or a relationship
to the environment that makes you not want to ingest fish related
products. There's krill oil. Krill is still an organism. It's a little
tiny thing that whales eat a lot of and people generally eat very
little of. So krill is out there, I personally, just me, I don't know
why, I didn't react well to krill. It didn't make me feel very good. I
had some like kind of skin itches and things like that. And they
stopped when I stopped taking it but I don't want to bias you against
it. If that's your preference. Some people really like krill oil as a
source of omega-3s. I did mention some of the other sources like chia
seeds and flax seeds, but as you'll notice these are not things that
we tend to ingest a lot of on a regular basis. It is possible to get
omega-3s from meats. If the animals have grazed on grasses that
contain a lot of omega-3s. So for those of you that ingest meat you're
the source of those meat is gonna be very important as it relates to
omega-3s. Even within the category of fish oil there's a concern
sometimes about mercury and other contaminants. You want to go with a
brand that emphasizes that they've gone to really good sources and
that they decontaminate regardless. And so you have to search out
those brands. There is a test that you can do as to whether or not the
fish oil is a rancid or not. Some people take it in liquid form.
Some people take in capsule form. The liquid form is gonna be more
affordable. The capsule form is more is a little easier and a little
more portable. You can actually just chew one of the gel tablets. And
if it tastes really fishy kind of rancid, you'll know it's disgusting.
You want to spit it out. And if it doesn't and it's tolerable then
you'll know that that it's okay. Unfortunately you have to buy it
first in order to do that. Although, I don't know, maybe you can get
them to open up the bottle for you in the store and tell them you want
to try it. Someday perhaps fish oil and omega-3, it'll be like tasting
wine at a restaurant where you can send it back for now. I think you
have to purchase it first, but find a brand you trust in like, and
then work with them. If you decide to go that route of course. There
are other compounds that are also interesting for mood elevation that
are essentially like foods or are supplement based that now,
fortunately, there are really good data from peer reviewed studies.
And the next one I want to mention because I think it's really
interesting is L-carnitine. Now, L-carnitine has been around a long
time and it's been discussed in the context of heart health and a
number of other things. It was actually being touted as a bit of a
weight loss agent in the early nineties, but L-carnitine actually has
some really impressive effects on depression. And again, we will look
to PubMed because looking at examine.com is essentially for me anyway
looking at PubMed, what is L-carnitine okay. L-carnitine is most
prevalent in meat and in beef in particular. Now for the vegans,
please know that L-carnitine is available through non-meat sources as
well. Although it's not as enriched in non-meat sources. It's a really
interesting molecule because acetylcarnitine is essentially what's
made from L-carnitine but it's acetylated. If you're interested in the
biochemistry, you can look that up, it's acetylated into a form that
can cross the blood-brain barrier. The blood-brain barrier or BBB is a
barrier. It's a wall around the brain and you have this barrier
because the brain is so important. And it has this feature that the
neurons there don't recreate themselves after injury, like other
organs of the body. There's not a lot of turnover of cells despite
what you might've heard. And so nature has created this BBB, this
blood brain barrier to make sure that certain molecules in particular,
large molecules don't get across the blood-brain barrier. 'Cause it
can be damaging to those tissues. Incidentally, you also have a very
rigid or stringent barrier around other organs, which are the gonads.
So the ovaries and the testes and the brain are the organs of the body
that nature has gone out of its way to protect, give this additional
layer of the blood-brain barrier or as you might imagine for the
testes and the ovaries, it's going to be the blood gonadal barrier. So
these barriers exist to make it such that just because you eat
something, just because you ingest it doesn't mean it's going to cross
the blood-brain barrier, but L-carnitine when taken is acetylated and
converted into this form that gets across the blood-brain barrier. And
it has a lot of effects, it's involved in mitochondrial activation of
long chain fatty acids which that's a big mouthful, that we'll get
into some time when we're talking about metabolic, but it has some
interesting effects on the neuro side. So if you decide to check it
out on examine.com you'll see some really interesting things, lots of
effects on ammonia, C-reactive proteins, things of that sort, blood
glucose is lowered, et cetera. That's all stuff that's the level of
blood and periphery, slight effects in lowering cholesterol. Here's
some interesting ones. Rates of pregnancy go way up when people are
taking L-carnitine both the father and the mother but the source of
sperm and the source of egg are affected in ways that favors
pregnancy. It does increase, here we go again with sperm quality sperm
motility in males and it seems to have positive effects on females
that have polycystic ovary syndrome. So check that out. You know, the
effects are very strong. There are three studies listed there. Again,
I'm not promoting this, but that that people take L-carnitine,
especially if you're trying to get pregnant but check it out because
the effects there and the studies that are mentioned are published in
peer reviewed rigorous journals. In terms of the neural effects. Those
are quite interesting. The effects on depression are still emerging
but they do seem to exist that people feel a notable decrease in
depressive symptoms. There are seven studies listed on examine.com
that it has a notable benefit in a variety of circumstances where
participants have heightened depression already. They start taking
L-carnitine and they start feeling better. And they talk about dosages
in those various studies. It also has been shown to have a notable
decrease in the symptoms of autism, which I find fascinating. Also
again, the things we ingest impact the chemicals in our brain and how
they impact the rest of our body. There's other things that's been
used to treat certain forms of alcohol dependence. I think this is
going to be a very exciting emerging area. We're gonna do a whole
month about addiction. I've got a great guest lined up for that month,
but there's now an emerging field about what people can take and
supplement to help ease the cravings and the withdrawal when trying to
quit drugs of abuse, like cocaine, alcohol, heroin, and smoking and
things of that sort. So really interesting area. This is, I like to
think is the early days and we're gonna discover a lot more. There's a
huge list of things here. Since we talked about pain on a previous
episode and I know a lot of people have written to me about
fibromyalgia. It does L carnitine has been shown to reduce symptoms of
fibromyalgia. Again, all the links to studies are on examine.com,
totally free site. And that was my bulldog being a battering ram.
There's nothing graceful about this bulldog. He's decided he wanted to
leave to go get a drink of water. And so please forgive the noise.
Okay. So now let's turn to another aspect of the gut-brain
relationship that will surprise you, in some cases might shock you.
And that has some really cool and actionable biology. And that's the
gut microbiome, probiotics and prebiotics. I know today we're talking
about emotions and not pain but I'd be remiss if I didn't mention
another effect of acetylcarnitine that's been reported and that you
can find listed with link to study on examine.com which is its effect
in reducing the symptoms of migraine. This was a randomized controlled
trial with 133 participants who had frequent migraines. They were
taking 500 milligrams of L-carnitine or nothing for 12 weeks. So the
control is a little bit, the control experiment there is a little bit
tricky but it had a significant effect on reducing the number of
migraine attacks per month. So I find that really interesting and
there's a lot more listed there about the study. And I think these
compounds are powerful. They carry risks for certain people, not for
others. So again, you have to find out what's right for you but I do
think they are super interesting as potential therapeutics for various
people.
So what's the deal with the gut microbiome and the gut brain axis.
Today we've actually been talking a lot already about the gut brain
axis that has nothing to do with microbiomes. We've been talking about
this vagus nerve that connects providing sensory information from the
body to the brain. And then the brain also sends in the same nerve
motor information to control the motility that got the heart rate how
fast we breathe and deployment of immune stuff killer cells and things
of that sort. But oftentimes when we hear about the gut brain axis
these days, it's a discussion about the gut microbiome. And once
again, we're in a situation where there's incredible biology, I'm very
happy there's so much discussion about the gut microbiome. I am
somewhat dismayed and concerned that most of what I hear out there is
either false or partially false. So we're gonna clear up some of the
misconceptions, first by understanding the biology. And then we're
going to talk about some of the actionable items. It is true that we
have a lot of these little microorganisms living in our gut. They're
not there because they want to help us. They don't have brains, they
are adaptive however, they try and find and create environments that
make it easier for them to proliferate. So they don't care about you
and me but they are perfectly willing to exploit you and me in order
to make more of themselves the same way viruses are, viruses don't
have a mind, they infect cells, they hijack the genome, and they use
that genome to make more of themselves. The microbiota that live in us
vary along the length of our digestive tract. But let's just take a
step back and think about how our body plan is made. We are actually a
series of tubes. Our brain is actually a tube. You see, it's all
squishy on the outside. And then it's got that long thing. The spinal
cord that goes down to the base of the spine. That's the central
nervous system that all started out as a tube. It just looks like a
cauliflower on the other end up in the brain because the tube is so
big and it has to be crammed into the skull. So it gets all wrinkled
up. But if we were to splay it out you'd find that it's just one big
tube. Similarly, our digestive tract and our airways are essentially
one big tube. It starts with our mouth, also our nose. And then we
have all these other tubes. They go down through our throat and then
into our stomach and then into our various intestines. And then the
tube ends out the other end. So we are one long tube for digestion.
And inside of that tube is a mucosal lining. It's these little
microvilli, tiny, tiny, tiny little like velvety ends of cells that
are able to move and move things along and mucus mucosa. And the
conditions of that mucosal lining set a number of different things. It
sets the rate of our digestion and the quality of our digestion. It
sets for instance, our immune system. Most people probably don't
realize this, but most infections in the environment have to get into
our body somehow. Some of them are inhaled. A lot of them go into our
mouth and lodge in the mucosal lining of the mouth. And then infection
start there. You probably had the experience, unfortunately, of you
know, feeling like you have a tick in your throat, like something's
irritating your throat. And then it kind of migrates up into a head
cold or runny nose. Sometimes it'll start as headache. Sometimes it
won't, but things that are inert can migrate down into the gut. So
we're ingesting things all the time. Think about air, bacteria,
viruses, they're making their way into our gut. And some of those
bacteria live in the gut. And some of those bacteria bias the mucosal
lining in the gut, stomach and intestines to be more acidic or more
basic so that they can make more of themselves so they can replicate.
They like a particular comfort. It's like they like a particular kind
of bedding to lie down in and create more of themselves. Now, some of
those those mucosal linings that they promote make us feel better.
They make us feel more alert. They bolster our immune system and
others make us feel worse. So first rule, the microbiome isn't good or
bad. Some of these little bugs that live in us do bad things to us.
They make us feel worse. They lower our immunity. They affect us in
negative ways. Some of them make us feel better and they do that
mainly by changing the conditions of our gut environment. In addition
to that, they do impact the neurotransmitters and the neurons that
live in the gut. And that signal up to the brain to impact things like
dopamine and serotonin that we've been talking about previously. So
there's a vast world now devoted to try and understand what sources of
food what kinds of foods are good or not good for the gut microbiome?
So let's just talk about some general rules of thumb related to the
research quality research that's peer reviewed. And then in a future
episode we will go far deeper into the gut microbiome and gut brain
axis. But here's a few things that I think you might find surprising.
First of all, supporting a healthy gut microbiome is good for mood,
great for digestion and great for immune system function. However,
that does not mean maxing out or taking the most probiotic and
prebiotic that you can possibly manage. As I mentioned many times
before I do believe in probiotics, I take probiotics but there are
studies that show that if you take lots and lots of certain probiotics
like lactobacillus and you really ramp up the levels more it is not a
case of more is better. There are things like brain fog that can come
from that, brain fog is just this inability to focus. People feel
really not well generally. Some of those studies are a little bit
controversial but I think it's fair to say that if people really
increase the amount of probiotic that they're taking beyond a certain
amount then they start feeling foggy in the mind. Now what's too much?
Well I get probiotics I mentioned before from Athletic Greens, you can
get them from fermented foods like sauerkraut, pickles, kimchi natto,
these are different sources from around the world. Actually, I'd love
to hear some of the other sources that people know other foods from
around the world. I'm fascinated by the way in which different
cultures have all arrived at these foods that provide and support
healthy microbiomes because they're fermented. I have a colleague at
Stanford, Justin Sonnenberg, and he and I have talked about this. I
don't want to quote him inappropriately, but we've had discussions
about it, and they've published that the ingestion of fermented foods
is one of the best ways to support healthy levels of gut microbiota
without exceeding the threshold that would cause things like brain
fog. So foods and fermented foods are going to be the best source. And
there are a number of different ways that one could do that. Some
people don't like fermented foods, however some people supplement it.
So it isn't a case of more is better. So we know that. The other is
that it is true that healthy gut microbiota have been shown to improve
symptoms of certain psychiatric illnesses as well as certain
conditions like particular features along the autism spectrum, which
is interesting. And those effects are probably due to not just
improvement of immune system function, but to the the conditions in
which the neurons that sense nutrients convey information to the brain
and increase levels of serotonin and or dopamine. So gut microbiome
provides kind of a foundation for healthy gut and healthy gut brain
access so much so that some people report that when they start eating
small bits 'cause it doesn't require a lot of fermented foods, that
their overall mood is better, not unlike the effects of EPA. Although
I don't think it's been looked at directly in the context of clinical
depression yet. And if someone knows of a study please mention it in
the comments. That would be terrific. There are some things that you
can do to really damage your gut microbiome. And this is where there's
a huge misconception that I want to clear up. There was a study that
was published in "Nature", which is among the three top journals that
we have in science. You know, "Nature", "Science" and "Cell" are
considered the top tops, but excellent journal that showed that
artificial sweeteners but a particular artificial sweetener which was
saccharin can disrupt the gut microbiome in ways that is detrimental
to a number of different health markers, increasing inflammatory
cytokines and all the other bad things that happen when the gut
microbiome is thrown off kilter.
That study was widely discussed but there were a few things that were
not mentioned there that are really important. That study was about
saccharin in particular. Saccharin is not the most typical artificial
sweetener that's used, the most typical artificial sweeteners that are
used are things like aspartame, so-called NutraSweet or Sucralose, or
these days Stevia, there's monk fruits, to my knowledge and please
correct me if anyone knows of any studies, to my knowledge, the
negative effects of these artificial sweeteners on the gut microbiome
were restricted to saccharin. Now there is enough chemical similarity
between saccharin and some of the other ones that I mentioned, but not
all of them. For instance, Stevia, monk fruit are distinct in their
chemical makeup so that they probably don't have if they have any,
have lower effects, negative effects on the gut microbiome, but it
should still be tested. So saccharin is really, it was shown in this
study and several other studies can really negatively impact the
quality of the gut microbiome. Interestingly, the narrative around
artificial sweeteners and gut microbiome is incorrect. Most people
thought, oh, saccharin is bad for the microbiome. It must kill the
microbiome. And so you hear people saying, oh, artificial sweeteners
kill the microbiome. That's not true at all. In fact, in that very
same study published in nature they showed that the negative affects
of saccharin on the microbiome could be blocked or eliminated by
giving antibiotics. So what happens is certain artificial sweeteners
in particular saccharin disrupt the microbiome and make the
environment within the gut that mucosal lining more favorable to
bacteria microbiota that are not good for the organism. This is an
important distinction. It's not just a language thing where people
say, oh, you know, it kills the microbiome. It doesn't kill the
microbiome. It shifts the microbiome and shifts in the microbiome can
be good or they can be bad. And that takes us to another topic that's
a bit of a hot button topic but I'm willing to go there. 'Cause I
think it deserves conversation, which is nowadays there are many
examples out there where people have switched from a kind of standard
diet or even a vegetarian diet to a vegan diet, to a keto diet.
Now keto doesn't necessarily have to mean the ingestion of meats, but
it can. And they experience positive effects for themselves. Not
everybody. And I've talked previously about some of the kind of the
incorrect, what I believe is incorrect marketing of keto as it relates
to the cosmetic effects and some of the challenges with sleep that
some people have but some people love keto and it works great for
them. But the ketogenic diet is interesting because when one shifts to
the ketogenic diet there is a shift in the gut microbiome. And some
people end up feeling better. Some people end up feeling worse.
Likewise, some people go from ingesting animal products including meat
or they're vegetarian and they go to vegan and they experience
positive shifts in mood and affect. And we know that the transition to
a more plant-based diet and especially the enrichment of fiber that's
present in those diets also creates dramatic shifts in the gut
microbiome. Some people feel better doing that. Some people feel
worse. And of course, it's gonna depend on whether or not you're
ingesting a lot of processed foods or not. There was a paper published
in "Cell", "Cell Press" journal obviously, excellent journal, showing
that ingestion of processed foods, regardless of whether or not they
come from animal sources or non-animal sources the processed foods
themselves tend to create activity within the body and this surely has
roots in the nervous system that lead to over-consumption of calories
and weight gain. Even some weight gain that couldn't be explained by
increased calories. In other words, processed foods are bad,
regardless of whether or not you're talking about animal products or
non animal products, probably not surprising given what you know about
these sugar sensing and other amino acid sensing cells in the gut that
we talked about earlier. So the point of all this is that when I say
you have to find what's right for you, that's not a throwaway
statement. Some people's microbiome and the lining of their mucosa,
excuse me, their mucosa lining of their throat, of their gut, of their
nose, everything is improved by diets that are heavily meat based and
don't have many plants. Other people do much better on a plant-based
diet without many meat products or animal products. It's highly
individual. And this probably has roots in genetic makeup. This
probably has roots in what people were raised on because remember the
nervous system of course is set up by your genetic, your genes, your
genetic program but your nervous system adapts early in life to your
conditions. That's what it's for, the reason you have a nervous system
is to move your body appropriately towards things that are good for
you and away from things that are not. But also it was designed to
adapt. The early life period has this incredible thing about
plasticity that we spent a whole month on so that it can change so
that yes indeed some people may like certain foods and react to
certain foods better than others because of the way that their nervous
system was wired. This enteric as it's called nervous system that
lines the gut and the communicates with the brain. So most of what
I've talked about today is kind of black and white. These are things
that are present in all of us, the sugar sensing neurons of the gut,
the way the vagus is wired. The fact that omega-3 omega-6 is tend to
improve. The ratios tend to impact mood with high omega-3. omega-6
ratios improving mood. We talked about all sorts of things in the gut
brain and body brain axis, but when it comes to the microbiome the key
thing is that we all have a microbiome. You want a microbiome, but you
want to promote the microbiome that is right for you. And that can be
shifted and steered by ingesting certain categories of foods and not
others. And one thing that really frustrates me is when the people
show up with an agenda, like all meat agenda or a vegan agenda or a
keto agenda, and they talk about these positive effects on the gut
microbiome. And it's all true, frankly. And so it's highly individual.
Now this doesn't get to any of the ethical issues around animals or
the planet, and you hear rabid debates about that on both sides. And I
am not qualified or equipped to talk about whether or not regenerative
agriculture, animal products, or farming or any of these things, how
those actually impact the environment, that is not my expertise, but
when it comes to your health and your microbiome you want to support
the microbiome. It's very clear that these fermented foods support the
microbiome that we should be ingesting at least two servings per day.
Which is quite a lot that supplementation at low levels can be good.
Supplementation at high levels can create this brain fog even though
some people say that result is controversial. I've experienced this
myself and the data looked to me pretty darn solid. So that's one
thing to think about as well. And the other thing about the gut
microbiome is that it's highly contextual based on other things that
you're doing. So even things like exercise and social well-being and
connection, those things are also impacting the gut microbiome. So
find the diet that's right for you. And that works for you in the
context of the other ethical and lifestyle choices that are important
to you. That's my advice. A note about fasting. I have a colleague at
Yale, who's an expert in the gut microbiome. And he told me something
really interesting, which is when we fast, we actually digest certain
components within our dietary tract.
It actually depletes a good amount of the gut microbiome. And this is
interesting. I've had good results from I guess you would call it
intermittent or kind of circadian type fasting where I've never done
long fast, but where I push out my first meal by a few hours my first
meal is generally around lunchtime or so but the longer periods of
fasting that go for a day or two or three days are known to deplete
the gut microbiome in major ways. But that's not always necessarily a
bad thing because when it's replenished, it often is replenished at
levels that exceeded its previous level. But I think that some of the
GI tract and even some of the mental effects of returning to eating
after feeding sometimes people don't feel so good when they start
eating. They really want food, but then they start eating again. They
don't feel as good as they did on the fast. Some of that may be
related to the depletion of the microbiome that occurs during long
fast. So again, this is something to think about and talk about with
your doctor, but the idea that fasting across the board is good. There
may be some merits to that, and certainly in some cases, but it does
deplete the microbiome and that depletion of the microbiome is
significant because it means when you return to eating, you're
actually not in the same position to digest and assimilate those
foods. And those foods are not in the same position to impact your
brain and body the same way they were prior to the fast. And this is,
I think why people suggest a kind of gradual transition back to
consuming nutrients after a fast. So as we round up, I want to share
some results with you That without question will impact the way that
you respond to food mentally and even physically. And I know that
because that's the central theme of the studies I'm about to tell you
about. I have a colleague at Stanford, Alia Crum, who's done some
remarkable experiments on mindset.
And some people could think about these as placebo effects or belief
effects, but they actually go way beyond those terms. And there are a
number of different examples of this that Aaliyah's lab and her
coworkers have demonstrated. But two that are particularly interesting
to me I Want to share with you now because they really emphasize how
our beliefs can really impact the way that our brain and body work
together. I think the most famous of these is an experiment they did
where they had two groups of individuals. They were each given a
milkshake and they had some factors measured from their blood by an IV
while they ingested the milkshake. And then afterwards as well. And
one of the factors that they were looking at was something called
grehlin, G-H-R-E-L-I-N. Grehlin is a peptide that increases with
hunger. So the longer you haven't eaten that grehlin goes up. And I
know some of you say, well, I fast, I fast, I fast and I eventually
lose my appetite. Well, grehlin still goes up and then it drops. So if
you were one of these people that eats every three hours regularly,
grehlin kind of gets a little pulse as you get to that two hour and 50
minute mark. So it's a little bit of a timer as well. It's really
interesting peptide. In any event, what they did is they gave people
milkshakes, two groups, one group got a shake that they were told it
was a low calorie, healthy shake. The other got a milkshake that they
were told it was the very decadent high calorie shake. I think it was
something like two or maybe even two and a half times as many calories
as the other. Perhaps even more, I don't recall the details, but you
got a high calorie and a low calorie condition. And then they drank
the shake and then they measured grehlin in these subjects' blood. And
what they found was that the high calorie shake had a much more robust
effect on blunting grehlin and reducing grehlin. But the interesting
thing you probably guessed already is that it was the exact same shake
given to both groups. So people's belief about the content of
something impacted their physiology. And this speaks to the so-called
top down mechanisms or modulation of our physiology. In a previous
episode about pain we talked about the effects of obsessive believe it
or not, it was an obsessive infatuation and love on pain responses and
pain thresholds. This is yet another example where beliefs or
subjective feelings can impact physiology at the level of the
periphery, because grehlin is released in the periphery in the body.
Now, these beliefs affects extend beyond examples like this, another
good example that I'd like to share is Alia, Dr. Crum, and her
colleagues did an experiment where they took housekeepers, they were
essentially hotel workers, divide them into two groups. They had them
watch a short film. In one case, the film was about how their work was
important to help people feel comfortable in the hotel, et cetera, et
cetera. The other group heard that the activity that they were doing
cleaning and taking care of the hotel was good for them. It was good
for their health, et cetera, et cetera.
They controlled very nicely in the study for health parameters, for
individual differences. And for the behaviors of these people in the
period that followed this short tutorial. And what they found was
eight weeks later, the group that had been told that the activity was
good for them showed lower blood pressure. They had lost a significant
amount of body fat and they reported enjoying their work far more than
the other group. The same work, simply biased mentally by the
information that they were given, but their physiology followed that
information. And so this is not just the placebo effect. This is an
incredible set of findings that illustrate the extent to which whether
or not we believe a food is gonna be good for us or not good for us.
Well, we can't escape the reality. You can't tell yourself that a
poison is gonna be good for you and ingest that poison and expect it
to not kill you, nor can you tell yourself that eating 12 croissants,
I confess I've done it, it was after a very long run, a long time ago
but you can't tell yourself that that's necessarily going to be good
for you or that it's gonna make you lose weight. These belief effects
are not about lying to yourself in these cases, in these experiments
as you'll notice that subjects didn't have prior knowledge about
grehlin or about the effects of their daily routine on weight loss and
blood pressure. So in order for them to work you have to be naive to
the information, right? You can't simply lie to yourself and tell
yourself what you want to believe and that's important, but also
important is that the mind and the body are in this fascinating
interplay. And today we've talked mainly about how the body and things
that we put inside this tube, that runs from our mouth to the other
end to our rectum, basically is impacting all these cells, these
neurons, microbiota in their mucosal lining, heart, lungs and how all
that information is feeding up to the brain to impact how we feel up
here. But also how we feel up here is impacting how our body reacts at
levels of very core physiology that you couldn't just tell yourself
that this was gonna work, but what you believe about certain
substances, certain foods, certain nutrients does have a profound
effect on the magnitude of their impact and sometimes even the quality
and direction of that impact. Well, first of all, I want to thank
everybody for their support of this podcast.
The response that we've received since releasing at the beginning of
the new year has been tremendous. And we're so grateful for it. I know
some of you and people I've said, well, it's a lot of information.
It's like a college lecture. Indeed, there's a lot of information, but
I believe very strongly that if you learn mechanism and maybe even if
you hear it several times over eventually those mechanisms become
embedded into the way that you view an entire topic. As well, I always
try and put tools as I go along that you can look to immediately. Some
of them might be right for you. Others might not, try them if you like
and don't if you don't want to, and if they don't work for you, then
discard them. If however, you are finding benefits from the
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check out our sponsors that we've mentioned at the beginning of the
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mentioned supplements and I talk about supplements throughout the
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So it's thorne.com/u/huberman to get 20% off any supplements that
Thorne makes. So in today's episode, we took a full journey into the
brain body relationship and discussed a lot of the mechanisms and the
actionable items that you can approach if you want to explore this
aspect of your biology and psychology further. Last, but certainly not
least, I want to thank everybody for your time and attention today,
and as always, thank you for your interest in science. [upbeat music]
HubermanLab #Emotions #Neuroscience
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Artificial Sweeteners and Gut Microbiome:
* https://pubmed.ncbi.nlm.nih.gov/25231862/
* https://pubmed.ncbi.nlm.nih.gov/25231865/
Anti-Depressive Effects of EPAs
https://pubmed.ncbi.nlm.nih.gov/18247193/
Free Resource: Links to Studies on Supplements Discussed
https://examine.com
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Timestamps below:
* 00:00:00 Introduction
* 00:05:00 Emotions: Aligning Mind & Body
* 00:06:41 Nutrients, Neurochemicals and Mood
* 00:08:39 Primitive Expressions and Actions
* 00:12:30 The Vagus Nerve: Truth, Fiction, Function
* 00:15:45 “Vagus Stimulation”: A Terrible Concept
* 00:16:35 Polyvagal Theory
* 00:18:27 Vagus Senses Many Things, & Moves Our Organs
* 00:19:35 Sugar Sensing Without Perception of Sweetness
* 00:23:00 Eating-Induced Anxiety
* 00:27:30 We Eat Until Our Brain Perceives “Amino Acid Threshold”
* 00:29:45 Reward Prediction Error: Buildup, Letdown and Wanting More
* 00:32:01 L-Tyrosine, Dopamine, Motivation, Mood, & Movement
* 00:34:04 Supplementing L-Tyrosine, Drugs of Abuse, Wellbutrin
* 00:38:29 Serotonin: Gut, Brain, Satiety and Prozac
* 00:43:38 Eating to Promote Dopamine (Daytime) & Serotonin (Night Time)
* 00:44:30 Supplementing Serotonin: Sleep, & Caution About Sleep Disruptions
* 00:46:40 Examine.com An Amazing Cost-Free Resource with Links to Science Papers
* 00:48:05 Mucuna Pruriens: The Dopamine Bean with a Serotonin Outer Shell
* 00:51:00 Emotional Context and Book Recommendation: “How Emotions Are Made”
* 00:54:55 Exercise: Powerful Mood Enhancer, But Lacks Specificity
* 00:56:45 Omega-3: Omega-6 Ratios, Fish Oil and Alleviating Depression
* 01:01:00 Fish Oil as Antidepressant
* 01:02:40 EPAs May Improve Mood via Heart Rate Variability: Gut-Heart-Brain
* 01:07:24 Alternatives to Fish Oil to Obtain Sufficient Omega-3/EPAs
* 01:09:05 L-Carnitine for Mood, Sperm and Ovary Quality, Autism, Fibromyalgia, Migraine
* 01:16:29 Gut-Microbiome: Myths, Truths & the Tubes Within Us
* 01:21:55 Probiotics, Brain Fog, Autism, Fermentation
* 01:25:20 Artificial Sweeteners & the Gut Microbiome: NOT All Bad; It Depends!
* 01:28:00 Ketogenic, Vegan, & Processed Food Effects, Individual Differences
* 01:33:20 Fasting-Based Depletion of Our Microbiome
* 01:35:20 How Mindset Effects Our Responses to Foods: Amazing (Ghrelin) Effects!
* 01:38:30 How Mindset Controls Our Metabolism
* 01:41:03 Closing Comments, Thanks, Support & Resources
Please note that The Huberman Lab Podcast is distinct from Dr.
Huberman's teaching and research roles at Stanford University School
of Medicine. The information provided in this show is not medical
advice, nor should it be taken or applied as a replacement for medical
advice. The Huberman Lab Podcast, its employees, guests and affiliates
assume no liability for the application of the information discussed.
[Title Card Photo Credit: Mike Blabac https://www.blabacphoto.com/]