How Foods and Nutrients Control Our Moods

00:00:00.000 | - Welcome to the Huberman Lab Podcast,

00:00:02.280 | where we discuss science and science-based tools

00:00:04.900 | for everyday life.

00:00:05.920 | My name is Andrew Huberman,

00:00:10.880 | and I'm a professor of neurobiology and ophthalmology

00:00:13.920 | at Stanford School of Medicine.

00:00:15.920 | This podcast is separate from my teaching

00:00:17.680 | and research roles at Stanford.

00:00:19.480 | It is, however, part of my desire and effort

00:00:21.540 | to bring zero cost to consumer information

00:00:23.560 | about science and science-related tools

00:00:25.640 | to the general public.

00:00:27.400 | In keeping with that theme,

00:00:28.560 | I'd like to thank the sponsors of today's podcast.

00:00:31.480 | Our first sponsor today is Theragun.

00:00:34.120 | Theragun is a handheld percussive therapy device

00:00:36.800 | that releases deep muscle tension.

00:00:39.400 | I was first introduced to Theragun in 2017

00:00:42.040 | while on a laboratory expedition.

00:00:44.160 | We were in the middle of the Pacific Ocean

00:00:45.800 | filming great white sharks for my laboratory studies

00:00:48.000 | on fear using virtual reality.

00:00:50.720 | We were working very hard around the clock,

00:00:52.880 | and I and other people on the trip

00:00:54.360 | were picking up a lot of aches and pains

00:00:55.900 | and just kind of chronic soreness.

00:00:57.440 | A couple of people had injuries that were flaring up

00:00:59.680 | because of all the hard work and lack of sleep.

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00:01:17.720 | I use it on muscles that are sore.

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00:01:26.120 | The great thing about Theragun is it's really quiet,

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00:01:53.440 | whenever you want and even while enjoying other activities.

00:01:56.160 | So that's theragun.com/huberman.

00:01:59.040 | The second sponsor of today's podcast is Inside Tracker.

00:02:02.400 | Inside Tracker is a personalized nutrition platform

00:02:04.920 | that analyzes data from your blood and DNA

00:02:07.760 | to help you better understand your body

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00:02:22.680 | In order to understand what's going on

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00:03:38.720 | Athletic Greens is an all-in-one

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00:03:42.640 | I started using Athletic Greens in 2012.

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00:03:48.280 | The reason I started using Athletic Greens

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00:05:00.560 | Today, we're talking all about emotions.

00:05:03.480 | Emotions are central to our entire experience of life.

00:05:07.000 | Whether or not we're happy or sad or depressed or angry

00:05:11.040 | is our life experience.

00:05:13.240 | And yet, I think with all the importance

00:05:15.800 | that we've placed on emotions,

00:05:17.140 | very few people actually understand how emotions arise

00:05:19.960 | in our brain and body.

00:05:21.180 | And I mentioned brain and body because as you'll see today,

00:05:24.640 | emotions really capture the brain-body relationship.

00:05:28.280 | We cannot say that emotions arise

00:05:30.300 | just from what happens in our head.

00:05:31.720 | It also involves events, biological events,

00:05:34.840 | chemical events within our body.

00:05:37.120 | The other thing about emotions is that

00:05:40.440 | there's no real agreement as to what's a good emotion

00:05:43.060 | or a bad emotion.

00:05:44.880 | Today, we're going to talk about the biology

00:05:46.680 | of the chemicals and pathways that give rise to emotions.

00:05:49.880 | And I'm going to equip you with several, if not many tools

00:05:54.000 | that will allow you to regulate and change

00:05:56.120 | and steer your emotions should you want,

00:05:58.220 | but not using the typical advice.

00:06:00.440 | Everyone's probably heard of this thing,

00:06:01.660 | "Oh, if you're feeling depressed, just smile.

00:06:04.480 | It's impossible to be depressed while smiling."

00:06:07.180 | Look, if that were true,

00:06:08.280 | we wouldn't have any depressed people

00:06:09.820 | because depressed people don't want to be depressed.

00:06:12.440 | And it is not the case that simply smiling

00:06:15.280 | will reverse depression or sadness.

00:06:17.520 | And it's simply not the case

00:06:19.000 | that smiling can inhibit sadness.

00:06:22.640 | It just doesn't work that way.

00:06:24.380 | However, it is the case that certain things

00:06:26.540 | that are happening in our body

00:06:27.800 | influence how our brain functions

00:06:30.020 | and the chemicals that are released.

00:06:32.360 | And today we're going to talk a lot

00:06:34.420 | about how the brain and body interact

00:06:36.340 | to create these things called emotions

00:06:38.480 | in the context of food and nutrition.

00:06:41.880 | And the reason we're doing that

00:06:43.200 | is not because I'm beating the drum

00:06:45.600 | about particular diet regimens or anything.

00:06:47.640 | In fact, I'm not going to do any of that.

00:06:48.960 | What I'm going to do is I'm going to review

00:06:51.080 | some of the most important scientific data

00:06:53.040 | that point to how ingesting certain nutrients,

00:06:56.280 | both macronutrients like proteins, fats, and carbohydrates,

00:06:59.520 | as well as micronutrients can impact the chemicals

00:07:02.800 | in our brain that give rise to the feelings

00:07:05.240 | of being happy or sad or sleepy

00:07:08.520 | or alert when you want to be sleepy

00:07:10.880 | or sleepy when you want to be alert.

00:07:12.720 | So this is sure to be a broad discussion

00:07:15.480 | and yet we're going to get very specific

00:07:17.120 | about what emotions are, how they arise in the body,

00:07:20.280 | tools that one can use

00:07:21.600 | in order to better control their emotions,

00:07:24.620 | tools that people can use to, believe it or not,

00:07:27.340 | feel happier or feel calmer.

00:07:29.980 | And that's because in the last 20 years or so,

00:07:32.880 | there's been an explosion of scientific studies

00:07:35.540 | exploring how the brain and body interact

00:07:38.040 | to support certain neurochemicals

00:07:40.520 | that give us these feelings of being alert and happy

00:07:43.880 | or depressed or certain that our life is going to be terrible

00:07:47.580 | or certain that our life is going to be great.

00:07:49.760 | So as mysterious as all that might sound

00:07:51.620 | and confusing as all that might sound,

00:07:53.040 | we're going to make it very clear today.

00:07:54.820 | And you're going to come away from this conversation

00:07:56.820 | with a lot of tools that you can act on immediately.

00:08:01.500 | And those tools are grounded in scientific data.

00:08:03.880 | We are going to provide links to several of the studies.

00:08:06.000 | And I'm going to mention several of those studies

00:08:08.400 | as we go along.

00:08:10.020 | But overall, the goal today is for you to understand

00:08:12.880 | how moods and emotions arise

00:08:14.960 | and the different pathways in your brain and body

00:08:16.900 | that allow them to happen

00:08:18.180 | and how you can use those pathways to change those emotions

00:08:21.540 | and the tools that you can rely on in very specific ways

00:08:26.480 | to shift from being, say,

00:08:28.440 | slightly depressed to feeling happier.

00:08:30.240 | There actually are ways to do that,

00:08:32.340 | or from feeling too alert and anxious to feeling calmer.

00:08:35.480 | And these are tools that are distinct

00:08:36.700 | from the tools I've talked about in previous episodes.

00:08:39.660 | The discussion around emotions has a long and rich history

00:08:43.260 | going back to Darwin, and even long before Darwin.

00:08:46.580 | This is a conversation that philosophers and scientists

00:08:49.260 | have been having for hundreds, if not thousands of years.

00:08:52.740 | The idea that Darwin put forth

00:08:55.980 | and that was really attractive for about the last 100 years

00:08:59.060 | was that emotions are universal

00:09:01.640 | and that some of the facial expressions

00:09:03.140 | around emotion are universal.

00:09:04.840 | And other people have capitalized on that idea.

00:09:08.540 | And to some extent, it's true.

00:09:10.160 | I mean, I think that the two most robust examples of that

00:09:14.920 | would be when we see something or we smell something

00:09:19.380 | or we taste something that we like,

00:09:21.260 | there does tend to be a postural leaning in.

00:09:24.620 | We tend to inhale air at that time.

00:09:27.100 | We tend to bring in more

00:09:28.700 | of whatever chemical substance is there.

00:09:30.420 | So we tend to do these mmm and kind of lean in closer

00:09:33.740 | to things that are attractive to us.

00:09:35.780 | And when we see and experience things that we don't like,

00:09:40.280 | sometimes it's a mild aversion.

00:09:41.860 | We just kind of lean back or look away.

00:09:43.620 | Other times it's an intensive version of disgust

00:09:46.700 | and we tend to cringe our face.

00:09:48.340 | We tend to avoid inhaling any of the chemicals.

00:09:50.700 | This probably has roots in ancient biological mechanisms

00:09:54.860 | that are to prevent us from ingesting things

00:09:57.540 | that are bad for us,

00:09:58.580 | chemical compounds and tastes that might be poisonous.

00:10:01.460 | So much of the foundation of any discussion about emotion

00:10:05.740 | has to center around this kind of push-pull

00:10:07.920 | of attraction to things or aversion from things.

00:10:11.700 | Now that's a very basic way of thinking about emotions.

00:10:14.560 | But if you think about it,

00:10:15.740 | it works for a lot of different circumstances.

00:10:17.920 | And in the brain,

00:10:19.080 | everywhere from the deep circuits of the brain

00:10:21.260 | to the more kind of what we call higher order evolved

00:10:23.900 | centers of the brain, we have this push-pull thing.

00:10:27.260 | We're either, in a previous episode, I talked about GO,

00:10:29.860 | the circuits that allow you to emphasize action

00:10:33.440 | and then no-go circuits,

00:10:35.500 | the circuits in the basal ganglia

00:10:36.860 | that allow you to de-emphasize action and prevent action.

00:10:40.300 | We talked about how that's a push-pull.

00:10:42.080 | So aversion and attraction is a push-pull too.

00:10:44.860 | Delight or happiness or excitement are attractions

00:10:48.620 | to certain things and ideas, songs, people, places, foods.

00:10:53.500 | Aversion is a leaning out.

00:10:55.420 | It's a disgust, it's an avoidance.

00:10:58.180 | And so we can break down the discussion about emotions

00:11:01.540 | into these simpler versions of themselves.

00:11:04.500 | But at the core of that, of attraction or aversion,

00:11:08.540 | is an important theme that you might realize already

00:11:11.900 | but most people tend to overlook,

00:11:13.760 | which is that there's an action there.

00:11:16.180 | You're either moving forward

00:11:17.700 | or you're moving away from something.

00:11:19.860 | And anytime you're talking about action

00:11:21.660 | in the nervous system, you're talking about motor behaviors.

00:11:24.820 | You're talking about literally the contraction of muscles

00:11:27.660 | to move you toward or away from things.

00:11:29.620 | And anytime you're talking about nerve to muscle and action,

00:11:34.220 | you're talking about the brain and the body

00:11:36.740 | because the brain can't move itself.

00:11:39.260 | The brain has a body so that the organism can move.

00:11:43.580 | And the body has a brain so that the organism, you,

00:11:47.300 | can move toward or away from things

00:11:49.100 | that you deem to be good or bad for you.

00:11:51.380 | Now, some of these things that we're attracted to

00:11:53.340 | and some of them that we avoid

00:11:54.840 | are what we call innate or hardwired.

00:11:57.380 | You know, when we taste bitter compounds,

00:12:00.900 | I'm not saying about bitter,

00:12:01.780 | like you like a little bit of bitters in your drink

00:12:04.260 | or something like that, but really bitter compounds,

00:12:06.380 | we tend to avoid those

00:12:07.420 | because they're associated with poisons.

00:12:09.480 | When we taste things that are sweet or that are savory,

00:12:12.960 | we tend to pursue more of those.

00:12:15.700 | We tend to lean toward those, so to speak.

00:12:18.140 | And we tend to not avoid them.

00:12:20.100 | So there are circuits in the brain for aversion

00:12:22.720 | and for attraction toward things.

00:12:24.340 | And the body is governing a lot of that.

00:12:27.200 | And so immediately in this conversation,

00:12:29.160 | I want to raise an important point,

00:12:31.320 | which is about a nerve pathway

00:12:33.600 | that many, many people have heard of

00:12:35.720 | that gets discussed all the time.

00:12:37.200 | And that is one of the most kind of oversold

00:12:40.320 | for the wrong reasons and undersold, unfortunately,

00:12:43.440 | for its real power, which is the vagus nerve.

00:12:46.840 | So the vagus nerve is one, not the only,

00:12:50.540 | but one way in which our brain and body are connected

00:12:53.420 | and regulates our emotional states.

00:12:56.880 | Now, many of you have probably heard

00:12:58.220 | about polyvagal theory.

00:12:59.520 | I'm going to talk about this today.

00:13:01.000 | Polyvagal theory was popularized by Stephen Porges.

00:13:05.280 | And it's an interesting theory.

00:13:07.600 | Certain aspects of it, frankly, hold up to the science.

00:13:10.480 | Some of it doesn't.

00:13:11.800 | And I'm going to discuss all of that today.

00:13:14.780 | A lot of the vagus and the excitement about the vagus,

00:13:18.040 | V-A-G-U-S, is because it somehow got into the mind

00:13:23.220 | of the public that the vagus is involved in calming us down.

00:13:27.140 | So what is the vagus nerve?

00:13:28.540 | Okay, we're going to make this really simple.

00:13:31.680 | In particular, for those that are just listening,

00:13:33.240 | you can just imagine this.

00:13:34.260 | For those of you that are watching,

00:13:35.540 | I'll point to the various areas.

00:13:36.800 | But basically, vagus is the 10th cranial nerve,

00:13:40.840 | which basically means that the neurons,

00:13:43.060 | the kind of the control center of each of those neurons

00:13:46.160 | in the vagus lives just kind of near the neck, right?

00:13:50.100 | And a branch of the vagus goes into the brain.

00:13:52.560 | They send a little wire into the brain.

00:13:54.180 | The other branch goes into the periphery,

00:13:56.240 | but not just the gut.

00:13:57.920 | It goes into the stomach, the intestines, the heart,

00:14:00.700 | the lungs, and the immune system.

00:14:02.640 | So this vagus nerve is incredible

00:14:04.700 | because it's taking information from the body

00:14:07.060 | and it has two directions.

00:14:08.320 | The first is what we call sensory.

00:14:10.200 | So it's sensing things that are happening

00:14:12.400 | in the gut, in the lungs.

00:14:13.880 | Everything, for example,

00:14:15.120 | in the lungs when our lungs are distended,

00:14:17.640 | the vagus nerve senses that

00:14:20.160 | and sends that information up into the brain.

00:14:22.600 | It also can sense things in the gut,

00:14:24.540 | like how distended or empty your stomach happens to be.

00:14:27.900 | It can sense heart rate.

00:14:30.280 | It can sense your immune system,

00:14:31.920 | whether or not you have bacteria

00:14:33.320 | or things invading you in your body.

00:14:35.580 | So it sends that information up to the brain.

00:14:37.520 | So it's a two-way street

00:14:38.480 | and sensory information is going up to the brain.

00:14:40.740 | That's all vagus.

00:14:42.480 | So it's like a super highway.

00:14:43.400 | Sensory information going one way.

00:14:44.840 | And then the other direction is motor control.

00:14:48.120 | So the vagus is not just for sensing things,

00:14:50.160 | it's actually for controlling things.

00:14:51.520 | It's got a sensory pathway and a motor pathway.

00:14:54.000 | So that's the first thing I think everyone should know

00:14:57.120 | about the vagus.

00:14:58.000 | In fact, it's so important

00:15:00.560 | that I feel like this is as important as people knowing

00:15:03.160 | that walking involves flexors and extensors.

00:15:05.800 | And if you don't think that's important,

00:15:07.380 | it's as important as walking frankly,

00:15:09.280 | because the vagus is the way in which you can govern

00:15:11.840 | the brain-body connection

00:15:13.620 | and in which you can steer various aspects

00:15:16.600 | of your mood and wellbeing.

00:15:17.760 | But most people just don't understand how to use it.

00:15:20.200 | So first you got to understand what it is.

00:15:21.920 | So you've got sensory information coming

00:15:23.520 | from all these different organs of the body up to the brain.

00:15:26.080 | You got motor information going

00:15:27.460 | from the brain back to the body.

00:15:29.080 | And so you've got this super highway within you.

00:15:31.520 | Now what actually regulates the vagus?

00:15:34.080 | Oftentimes you'll hear things like,

00:15:36.080 | oh, this particular behavior,

00:15:39.200 | rubbing your face at a particular location

00:15:41.880 | or breathing in a particular way,

00:15:44.120 | or a warm bath or something stimulates the vagus.

00:15:48.560 | Well, right now I want everyone to know

00:15:50.180 | that "stimulating the vagus" broadly speaking

00:15:53.640 | is a terrible way to think about the vagus.

00:15:55.920 | Because did you know what?

00:15:57.420 | If you have a contaminant inside your body,

00:16:00.260 | the vagus senses that

00:16:02.200 | and projects that information to your brain

00:16:04.320 | and you start to generate a fever.

00:16:06.600 | You start to try and kill that contaminant in your body.

00:16:09.980 | So I don't know that you want to stimulate the vagus

00:16:12.120 | just as like a general theme.

00:16:13.460 | Today we're going to get specific

00:16:14.920 | about how you can activate particular circuits,

00:16:18.200 | certain pathways from certain organs to the brain

00:16:21.180 | in order to feel better or relieve certain conditions.

00:16:24.680 | But you certainly don't want to just stimulate the vagus.

00:16:28.880 | Now, excitement about the vagus in part

00:16:31.340 | is because of what quite honestly

00:16:34.680 | was a fairly pioneering theory about the vagus,

00:16:37.760 | which is polyvagal theory.

00:16:39.320 | So polyvagal, the word poly means many,

00:16:42.120 | is cool because it acknowledges

00:16:45.280 | that the vagus has a lot of different branches.

00:16:48.160 | It's not just one thing.

00:16:49.760 | And so I really like that.

00:16:51.100 | I like the naming polyvagal.

00:16:53.100 | The idea that Portis put forward

00:16:54.660 | was that there's a dorsal vagus,

00:16:56.840 | which is kind of runs the back of the spinal cord,

00:16:59.200 | which is involved in alertness and activation

00:17:01.520 | and kind of fight or flight type stuff.

00:17:03.560 | And that there's a ventral pathway

00:17:06.600 | and that that's involved in more kind of empathic behaviors.

00:17:10.740 | That is not quite in agreement with the modern anatomy,

00:17:14.480 | but he was doing the best with what he had at the time.

00:17:16.700 | So, okay.

00:17:18.240 | The problem I have with the polyvagal theory

00:17:20.840 | is the way that it's discussed.

00:17:22.680 | People will often say,

00:17:23.600 | oh, if your dorsal vagus is too active,

00:17:27.620 | then you tend to be someone who's a little too keyed up.

00:17:29.520 | And people who are kind of in a state of freeze

00:17:32.420 | or kind of flaccid and kind of like just not really active

00:17:37.420 | and they're just lethargic,

00:17:39.960 | well, then that pathway is hypoactive.

00:17:42.000 | It should be more active.

00:17:43.240 | So there are a lot of theories

00:17:44.600 | about how psychology maps onto the vagus

00:17:46.680 | that as far as I know, don't map to any real physiology.

00:17:50.340 | Now, the other problem with this kind of the way

00:17:53.760 | that the polyvagal theory is discussed,

00:17:55.720 | probably not by the real experts, but by a lot of people,

00:17:58.160 | is that people start to diagnose different psychological

00:18:02.240 | and physical manifestations through the vagus.

00:18:05.740 | They would say things like,

00:18:06.700 | oh, this person is hyper-flexible at the joints

00:18:10.060 | and therefore their dorsal vagus isn't active enough

00:18:13.020 | or something like that.

00:18:14.120 | And it's really kind of gone way outside the lane lines.

00:18:17.080 | So today we're going to clean up a lot of that.

00:18:19.280 | Let's make it really simple

00:18:20.460 | about how the vagus actually works,

00:18:22.160 | at least as we understand it today in 2021.

00:18:26.040 | First of all, as I mentioned, you have sensory information,

00:18:29.360 | the same way that you detect light with your eyes

00:18:31.440 | or you hear sounds with your ears,

00:18:33.460 | you have sensors in your gut

00:18:35.560 | that sense how full or empty your gut is.

00:18:38.580 | It can also sense how acidic your gut is.

00:18:41.520 | It can sense various things within your gut.

00:18:44.620 | Your heart is doing the same.

00:18:45.740 | It's informing the brain how fast your heart is beating,

00:18:47.820 | how full your lungs are has been communicated,

00:18:50.040 | and then the status of your immune system.

00:18:52.060 | So the way to think about the vagus

00:18:54.740 | is the same way I would think about the eyes.

00:18:56.820 | The eyes are looking at colors, they're looking at motion,

00:18:59.780 | they're looking how bright it is.

00:19:01.120 | And each one of those things, those features,

00:19:03.980 | is telling the brain something different.

00:19:05.340 | So the brain can decide when to be awake or asleep,

00:19:07.680 | whether or not it's looking at somebody attractive

00:19:10.320 | or unattractive.

00:19:11.680 | The vagus nerve is also analyzing many features

00:19:14.840 | within the body and informing the brain

00:19:17.320 | of how to feel about that and what to do.

00:19:20.860 | So a really good example that I think is an exciting one

00:19:24.220 | is as it relates to sugar.

00:19:26.940 | So we all know that sweet things generally taste good.

00:19:30.340 | I'm not particularly a fan of very sweet things.

00:19:33.460 | I'd much rather have cheese or pizza or hamburger or steak.

00:19:38.440 | I like savory, fatty foods, but I do like sweet foods.

00:19:41.320 | And most people find sweet foods to be attractive.

00:19:44.980 | They want them.

00:19:45.820 | Or they might not be able to regulate their behavior

00:19:49.660 | around them, but they want them.

00:19:51.520 | And what's really interesting is that for hundreds of years,

00:19:54.940 | people have thought that that's because of the way

00:19:56.660 | that sweet foods taste.

00:19:59.720 | So that makes sense, right?

00:20:00.780 | You eat something, it tastes sweet, you want more of it.

00:20:03.440 | Well, it turns out that it's much more interesting

00:20:06.460 | than that.

00:20:07.300 | When you eat something sweet, within your stomach,

00:20:10.940 | you have cells, neurons that sense the presence

00:20:14.800 | of sugary foods independent of their taste

00:20:18.060 | and signal to the brain.

00:20:19.740 | So those sensors, those neurons send information

00:20:23.260 | up the vagus to your brain, goes through a series

00:20:25.900 | of stations, and then you release dopamine,

00:20:28.540 | this molecule that makes you want more of whatever it is

00:20:32.820 | that you just ingested.

00:20:34.380 | In fact, this pathway is so powerful

00:20:37.440 | that they've done experiments where they completely numb

00:20:40.620 | all the taste and feeling in somebody's mouth.

00:20:43.640 | They're blindfolded so they don't know what they're eating.

00:20:45.440 | And they're eating a food that's either sugary

00:20:47.820 | or not sugary.

00:20:48.980 | And what they find is that even though people can't taste

00:20:51.600 | the sugary food, they crave more of the food

00:20:55.220 | that contains sugar because of the sensors in the gut

00:20:59.020 | that sense sugar.

00:21:00.460 | So to put this differently, you actually have sensors

00:21:03.660 | within your body that make you crave sugar independent

00:21:08.100 | of the sweet taste of those things.

00:21:10.240 | Now that's incredible.

00:21:11.540 | And what it does and what it tells us is that we have

00:21:14.300 | circuits in our body that are driving us towards

00:21:17.260 | certain behaviors and making us feel good,

00:21:20.200 | even though we can't perceive them.

00:21:22.220 | Now, for those of you that are really interested

00:21:23.940 | in gut intuition and kind of gut feelings,

00:21:26.800 | this is a gut feeling,

00:21:28.180 | except this is a chemical gut feeling.

00:21:30.280 | This is a particular set of neurons detecting that something

00:21:34.620 | in your body has a particular feature, in this case,

00:21:37.620 | the presence of sugars and sending information to the brain

00:21:41.100 | to essentially to control your behavior.

00:21:44.020 | And I find this remarkable because what it means is that

00:21:47.140 | what we call attractive isn't always coming from our

00:21:50.980 | thoughts about that, or our feelings or even our perception.

00:21:54.580 | We are drawn to particular foods and we're drawn to perhaps

00:21:58.100 | also to particular people, places and other things

00:22:01.580 | because of information that's coming from our body.

00:22:04.900 | And we're gonna talk about what one can do

00:22:07.140 | with this information.

00:22:07.980 | I know many people are thoughtful or concerned about

00:22:10.860 | sugars these days thinking, you know,

00:22:12.220 | we all ingest too much sugar.

00:22:13.720 | There's sugar snuck into all the things we eat.

00:22:17.060 | And indeed that's true.

00:22:18.140 | I mean, this should completely reframe the way

00:22:20.160 | that we think about the sort of so-called hidden sugars

00:22:23.560 | in foods.

00:22:24.400 | What this means is that even if a food is very savory,

00:22:26.780 | like a piece of pizza or a piece of bread,

00:22:29.660 | or even like a salad dressing,

00:22:32.480 | if there's sugar snuck into that and you can't taste it,

00:22:36.140 | you will still crave more of that thing without knowing

00:22:40.460 | that you crave it because it has sugar.

00:22:42.560 | In other words, you might find yourself wanting

00:22:44.500 | certain foods and not knowing why you want those foods.

00:22:47.540 | So I find this to be a fascinating aspect of our biology.

00:22:50.420 | And yes, it relates to mood and emotion.

00:22:52.880 | And we'll talk about how that is in a moment.

00:22:55.220 | So let's just back up a bit and ask the question,

00:22:58.320 | why do we eat certain things?

00:23:00.640 | And why do certain foods make us feel good

00:23:03.440 | and other foods actually make us feel anxious?

00:23:06.040 | I think some people may be familiar with this,

00:23:07.680 | other people might not,

00:23:09.060 | but most people don't realize that as you approach eating,

00:23:13.700 | there's an anxiety associated with that.

00:23:16.240 | It's an alertness.

00:23:17.080 | Remember in the previous discussions,

00:23:19.380 | or even if you don't and you haven't seen those,

00:23:22.000 | all of your moods and feelings of wellbeing

00:23:24.180 | are anchored on this continuum of alertness versus calmness.

00:23:28.160 | And we hear so often about rest and digest,

00:23:31.120 | that, oh, after we eat, we feel really nice and full,

00:23:33.880 | hopefully comfortably full and not too full,

00:23:36.500 | and we're relaxing and we feel satiated.

00:23:40.240 | It's associated with serotonin, this molecule of satiation.

00:23:43.440 | That's all true.

00:23:45.080 | But what most people don't know is that

00:23:46.720 | there's an area of the hypothalamus,

00:23:48.200 | so deep in the brain, kind of in the middle,

00:23:50.160 | deep portion of the brain, called the lateral hypothalamus.

00:23:53.640 | And the lateral hypothalamus is really interesting

00:23:56.200 | because it controls feeding, but it inhibits feeding.

00:24:00.800 | It stops us from feeding.

00:24:02.940 | And there's another area in the brain,

00:24:05.120 | if you want names, I'll give them to you.

00:24:06.480 | If you don't want names, just ignore them,

00:24:08.120 | delete them from your memory and awareness,

00:24:10.740 | called the locus coeruleus.

00:24:12.120 | Now, the locus coeruleus sits back further

00:24:14.360 | in the brainstem and it releases norepinephrine,

00:24:16.640 | which is essentially adrenaline, and makes us feel alert.

00:24:20.240 | Now, locus coeruleus has a lot of different functions

00:24:22.480 | in the brain, but when we are going to eat,

00:24:24.660 | let's say we walk into a restaurant,

00:24:26.000 | we sit down or we're preparing a meal,

00:24:28.960 | locus coeruleus is known to release

00:24:31.440 | norepinephrine in the brain.

00:24:33.080 | It's creating a kind of alertness.

00:24:35.160 | This has ancient utility, but it's creating this alertness.

00:24:39.320 | And for many people, they experience that

00:24:42.100 | as they approach food as stress, as anxiety.

00:24:45.060 | But what's interesting is that as we approach food,

00:24:48.820 | locus coeruleus is releasing all these molecules

00:24:52.040 | that make us feel more anxious and alert.

00:24:54.460 | Sometimes it's felt as excitement,

00:24:56.100 | and that has probably to do

00:24:57.260 | with how we feel about food generally.

00:24:58.820 | Are we happy with our relationship to food?

00:25:00.820 | Are we trying to restrict our relationship to food?

00:25:02.840 | Are people coming over for dinner?

00:25:04.220 | All that will play in, of course,

00:25:06.060 | but there's a certain stress and anxiety

00:25:08.900 | on approach to food.

00:25:10.880 | And as we approach food and we feel that anxiety,

00:25:15.200 | locus coeruleus activates the lateral hypothalamus

00:25:19.160 | in a way that inhibits feeding,

00:25:21.640 | that makes us not want to eat.

00:25:23.180 | So a lot of people who have kind of pre-meal anxiety

00:25:26.040 | or anxiety around food,

00:25:28.040 | and they can't seem to just calm down and have a good meal

00:25:30.560 | to access that later rest and digest,

00:25:33.200 | a lot of that is because of this heightened stress

00:25:35.800 | upon approach to food.

00:25:37.160 | And a lot of the tools that are out there,

00:25:39.700 | both for eating disorders

00:25:40.860 | and for just kind of the general public

00:25:42.760 | who isn't suffering from eating disorders,

00:25:44.560 | things like mindfulness around meals.

00:25:48.180 | They always tell you,

00:25:49.020 | "You should never eat when stressed."

00:25:50.480 | I'm sorry, but my life is not organized

00:25:52.180 | in a way that I can't do that.

00:25:53.380 | I would never eat, right?

00:25:54.700 | Because I eat when I'm awake,

00:25:56.140 | and I don't know if I'm stressed,

00:25:58.060 | but I don't think I am,

00:25:59.840 | but I tend to run around a lot during the day.

00:26:02.260 | I don't generally take time

00:26:04.180 | to do two or three deep breaths before I eat.

00:26:06.320 | I generally will just keep, will eat.

00:26:09.580 | That can be healthy or unhealthy

00:26:10.840 | depending on the quality of your digestion.

00:26:13.140 | I think using digestion as a guide is good.

00:26:15.680 | But a lot of people aren't aware

00:26:17.300 | that this interaction between locus coeruleus

00:26:20.760 | and lateral hypothalamus is a basic mechanism

00:26:23.560 | where we are supposed to get a little bit alert

00:26:25.760 | and anxious around mealtime.

00:26:28.040 | And then as we eat,

00:26:29.880 | the mechanisms for calming and satiation

00:26:32.320 | are supposed to kick in.

00:26:33.760 | And those mechanisms involve,

00:26:35.560 | as I mentioned earlier, two things.

00:26:37.020 | One is how things taste.

00:26:38.400 | Digestion starts in the mouth, of course.

00:26:41.240 | We taste our food.

00:26:43.140 | Everyone tells us we should chew our food more.

00:26:45.080 | Yes, that can improve digestion.

00:26:46.440 | We're not supposed to drink too many fluids as we eat.

00:26:48.600 | That's true too.

00:26:49.920 | But a lot of how we feel while we eat

00:26:54.580 | and after we eat is because of this

00:26:57.960 | vagus sensing of what's in our gut.

00:27:00.440 | It's sending information all the time.

00:27:02.880 | Is there sugar?

00:27:04.640 | Are there fats?

00:27:06.180 | Are there contaminants?

00:27:08.200 | There are a lot of information,

00:27:09.600 | these so-called parallel pathways

00:27:10.940 | that are going up into our brain

00:27:12.180 | that regulate whether or not

00:27:13.300 | we want to eat more of something or not.

00:27:15.360 | And there are accelerators,

00:27:16.840 | things that make us want to eat more,

00:27:18.760 | like sugar and fats,

00:27:20.920 | because those are nutrient dense

00:27:22.400 | and they helps generally, at least in the short term,

00:27:24.620 | support the survival of animals,

00:27:27.120 | but also amino acids.

00:27:29.120 | And this is very important.

00:27:31.520 | There are a lot of data,

00:27:33.540 | but much of what comes from the data

00:27:37.200 | on what people eat and how much they eat

00:27:39.840 | is from a subconscious detection

00:27:42.500 | of how many amino acids and what the array,

00:27:47.140 | meaning the constellation of amino acids is in a given food.

00:27:50.640 | And it's fair to say that the sum total of these studies

00:27:54.600 | point in a direction where people will basically eat,

00:27:58.140 | not until their stomach is full,

00:28:00.780 | but until the brain perceives

00:28:04.500 | that they have adequate intake of amino acids.

00:28:07.840 | Now, this is a conversation that comes up

00:28:11.380 | in the context of the meat only, the keto,

00:28:14.740 | the kind of zone diet, the Mediterranean diet,

00:28:17.860 | the vegan diet.

00:28:18.700 | I'm largely going to ignore the kind of strict camps today.

00:28:23.600 | I will talk a little bit about it

00:28:25.100 | because I think each one of them

00:28:26.400 | actually taps into something important

00:28:28.220 | about this brain-body relationship

00:28:29.700 | that the other ones don't.

00:28:31.540 | But I don't want to get into a discussion

00:28:33.220 | about the ethics of different foods

00:28:35.420 | of animal-based or non-animal-based

00:28:36.860 | 'cause that's not the topic today.

00:28:38.260 | It's really about nutrient sensing and amino acid sensing.

00:28:41.740 | So we generally will eat until our gut tells our brain

00:28:45.820 | that we have adequate amounts of these amino acids.

00:28:48.460 | Amino acids, of course, are important

00:28:50.300 | because they are the building blocks of sure,

00:28:52.780 | muscle and the other things in our body that need repair.

00:28:56.500 | But what most people don't realize

00:28:58.380 | is that amino acids are what the neurochemicals

00:29:02.600 | in the brain are made from.

00:29:04.800 | Now, this is vitally important, okay?

00:29:07.260 | So we've heard dopamine is this molecule

00:29:10.060 | that makes you feel good.

00:29:11.180 | Actually, dopamine is a molecule that makes you feel good.

00:29:13.760 | It's released within the brain

00:29:15.740 | and it does feel very good when you have dopamine release.

00:29:19.460 | Dopamine release is caused by surprise, excitement,

00:29:22.720 | events that you're looking forward to and that turn out well.

00:29:25.860 | It is inhibited by events you're looking forward to

00:29:28.380 | that don't work out.

00:29:29.840 | When someone says they're going to call

00:29:31.020 | that you're really, really excited to talk to

00:29:32.560 | and then they don't.

00:29:33.560 | Or you thought a movie was going to be really great

00:29:35.740 | and it's not.

00:29:36.580 | Or you expect a meal to be really delicious

00:29:38.400 | and it's kind of eh.

00:29:40.060 | And we actually, there's a name for that.

00:29:42.000 | It's called reward prediction error.

00:29:44.260 | So if, and you can actually use this

00:29:46.460 | in the context of meals and plans

00:29:48.140 | in a way that's very useful with yourself

00:29:50.180 | and people you know.

00:29:51.820 | Essentially, if you expect something to be really terrific,

00:29:56.340 | it really does place a higher expectation

00:29:59.660 | at the chemical level.

00:30:01.080 | So if you don't get as much dopamine

00:30:03.600 | as you're expecting from something.

00:30:04.980 | So you hear about a really great restaurant

00:30:07.860 | or a place that has a really, in my case,

00:30:09.400 | I wouldn't call it an addiction.

00:30:11.300 | I would call it more of an affliction for croissants.

00:30:14.020 | The best vegetable of course is the croissant.

00:30:16.260 | And I get really excited about the fact

00:30:18.180 | that someone will tell me, oh, there's this place

00:30:20.300 | and they have incredible croissants.

00:30:21.820 | You got to go there.

00:30:22.780 | So I get really excited and I'll go

00:30:24.340 | and just them telling me that it's going to be

00:30:26.540 | really terrific raises an expectation,

00:30:29.020 | a dopamine expectation.

00:30:30.780 | And unless those croissants are amazing,

00:30:34.980 | chances are I'm going to experience them

00:30:37.420 | as less good, less satisfying.

00:30:40.300 | I will truly release less dopamine

00:30:43.440 | than I would had they just said,

00:30:45.000 | oh yeah, I think that there are croissants down the street

00:30:47.100 | or if I just tried one at random.

00:30:48.720 | And that's because of this reward prediction error.

00:30:51.260 | Your expectation of something releases dopamine

00:30:54.660 | and the actual event releases dopamine.

00:30:58.040 | And if the event related dopamine

00:31:01.520 | does not exceed the expectation or at least match it,

00:31:04.740 | there's a much higher tendency

00:31:06.240 | that you won't pursue that thing again.

00:31:08.500 | So dopamine is really powerful

00:31:10.120 | and it's not just the molecule of reward.

00:31:12.320 | It is the molecule of desire.

00:31:13.960 | It's the molecule of wanting,

00:31:16.100 | not just the molecule of having.

00:31:18.420 | And a book, since people often ask for book recommendations,

00:31:21.580 | I don't know the author personally, but I love the book.

00:31:23.760 | It's called "The Molecule of More."

00:31:25.340 | It's a terrific book.

00:31:26.720 | I wish I had written it frankly,

00:31:28.760 | but if you want to learn more about dopamine,

00:31:30.580 | reward prediction error and how dopamine regulates

00:31:33.100 | various aspects of your emotional and motivational life,

00:31:35.820 | it's a terrific read.

00:31:37.000 | Dopamine is what's going to lead us

00:31:41.700 | to want to eat more of something

00:31:43.500 | or to not want more of something

00:31:45.140 | because dopamine really is about craving.

00:31:48.140 | It's about motivation and it's about desire.

00:31:51.120 | And as I mentioned, these amino acid sensors in our gut

00:31:54.440 | are detecting how many amino acids,

00:31:56.780 | but they're also detecting which amino acids.

00:31:59.300 | And there's a particular amino acid called L-tyrosine,

00:32:02.600 | which comes from food.

00:32:03.920 | You can look up online which foods contain L-tyrosine.

00:32:06.860 | It is in meats, it is in nuts.

00:32:08.660 | It is also in some plant-based foods.

00:32:11.200 | L-tyrosine is the precursor to a couple other molecules

00:32:16.200 | like L-DOPA, et cetera, that make dopamine.

00:32:19.580 | And so there's a misconception out there

00:32:22.260 | that most of the serotonin is in our gut

00:32:25.400 | and most of the dopamine is in our gut

00:32:27.540 | and therefore our mood is in our gut.

00:32:29.880 | That's not quite the way it works, okay?

00:32:32.060 | We'll talk about serotonin in a moment,

00:32:33.500 | but dopamine is synthesized

00:32:36.160 | from the amino acids that you eat.

00:32:38.900 | However, the dopamine neurons that give rise

00:32:42.200 | to these feelings of good or wanting more

00:32:45.380 | or desire and motivation, those reside in the brain.

00:32:48.640 | So we don't want to get too confused.

00:32:49.900 | We want to respect and honor the power of the gut

00:32:52.700 | and this vagal pathway,

00:32:54.140 | but it's really neurons within your brain

00:32:55.740 | that drive the pursuit and decision-making.

00:32:58.660 | So what does this mean?

00:32:59.620 | Well, some people make too little dopamine.

00:33:03.460 | Some people make so little dopamine

00:33:04.940 | that they need prescription dopamine.

00:33:07.300 | They need L-DOPA.

00:33:08.260 | People with Parkinson's take L-DOPA

00:33:10.380 | and other compounds to increase dopamine

00:33:12.420 | because Parkinson's is associated

00:33:14.900 | with deficits in movement.

00:33:16.900 | It starts as a tremor,

00:33:18.660 | actually starts as some other things that are interesting

00:33:20.460 | we'll talk about in a moment,

00:33:21.440 | but Parkinson's is a depression.

00:33:25.540 | It's a blunting of motivation and mood and affect,

00:33:28.640 | and it's a tremor.

00:33:29.540 | And then eventually in severe conditions,

00:33:31.220 | it's challenges in speaking and walking.

00:33:33.340 | So some famous examples would be Muhammad Ali,

00:33:36.420 | Michael J. Fox, the great boxing trainer, Freddie Roach.

00:33:41.280 | Like these people have Parkinson's

00:33:43.240 | and they at least later in their life

00:33:45.160 | had challenges speaking.

00:33:46.780 | Now it's not just fighters that develop Parkinson's.

00:33:49.380 | As far as I know, Michael J. Fox wasn't a fighter.

00:33:54.640 | People can develop Parkinson's

00:33:55.980 | and Parkinson's is a depletion

00:33:57.660 | of dopamine neurons in the brain.

00:33:59.160 | And it's not just movement challenges,

00:34:01.100 | it's challenges with mood.

00:34:02.620 | Now, hopefully most of you,

00:34:03.900 | all of you don't have Parkinson's,

00:34:06.400 | but it's clear that dietary L-tyrosine

00:34:09.380 | supports the healthy production of things like dopamine

00:34:14.380 | and as well as other factors within the brain.

00:34:17.340 | Now, some people immediately ask,

00:34:19.000 | well, should I supplement L-tyrosine?

00:34:20.820 | So let's just talk about that

00:34:22.000 | because that's going to come up.

00:34:24.160 | Full disclosure, I sometimes take L-tyrosine.

00:34:26.600 | I'm not taking it right now,

00:34:27.640 | but I take it only occasionally.

00:34:29.500 | You can buy this in capsule form.

00:34:31.540 | It does increase kind of mood and elevation and alertness.

00:34:35.560 | It is over the counter.

00:34:36.680 | You have to check with your doctor.

00:34:37.940 | I'm not responsible for your healthcare

00:34:39.420 | and I'm not a doctor.

00:34:40.940 | Whether or not it's safe for you.

00:34:41.980 | People with preexisting hyper dopaminergic conditions

00:34:44.920 | like mania should probably not take L-tyrosine.

00:34:48.840 | The other thing about taking L-tyrosine

00:34:50.340 | is there is a crash, okay?

00:34:52.060 | It's not a massive crash

00:34:53.300 | if you take it at appropriate doses and it's right for you,

00:34:56.220 | but it can produce a crash and a lethargy

00:34:59.020 | and a kind of brain fog after the next day or so.

00:35:02.540 | And so L-tyrosine, however,

00:35:06.100 | can be ingested through foods or through supplementation

00:35:08.700 | to increase dopamine levels.

00:35:09.880 | That's well known.

00:35:11.020 | Taken chronically, however,

00:35:12.660 | it can disrupt those dopamine pathways.

00:35:14.900 | Now there are other drugs that will increase L-tyrosine

00:35:18.060 | and dopamine as well,

00:35:19.540 | but those are severe enough

00:35:20.620 | that they generally tend to have addictive properties.

00:35:22.680 | So things like methamphetamine, things like cocaine

00:35:25.600 | are terrible because they really ramp up

00:35:27.760 | the dopamine system so much

00:35:29.460 | that people really can't achieve dopamine release

00:35:32.060 | through any other mechanisms.

00:35:33.660 | But food and the ingestion of L-tyrosine

00:35:35.900 | has a profound effect on our levels of dopamine.

00:35:38.880 | It takes a little while,

00:35:40.160 | but that really will impact level of mood.

00:35:43.400 | Certain antidepressants fall into the category

00:35:46.060 | of dopaminergic antidepressants.

00:35:48.020 | One of the most famous ones, of course, is Wellbutrin.

00:35:51.020 | Wellbutrin was developed

00:35:52.560 | because a lot of the other antidepressants

00:35:54.960 | tend to make people feel kind of lethargic

00:35:57.060 | or they had side effect profiles that people didn't like.

00:35:59.860 | So they developed this thing

00:36:01.580 | that the generic name is different,

00:36:04.060 | but it's generally called Wellbutrin.

00:36:05.760 | Wellbutrin activates dopamine and epinephrine,

00:36:08.840 | which is a substrate of dopamine,

00:36:10.700 | and both of those are involved in motivation

00:36:12.820 | and alertness and effort.

00:36:14.380 | So you might say, wow, this sounds like a great drug.

00:36:16.240 | However, this drug, the side effect profile

00:36:19.640 | tends to be the things that are associated

00:36:21.320 | with elevated mood and alertness.

00:36:22.980 | So this isn't like taking some L-tyrosine,

00:36:25.100 | this isn't like eating some tyrosine rich foods,

00:36:27.180 | this is really a much greater release

00:36:29.740 | of dopamine and epinephrine,

00:36:31.380 | and it increases things like anxiety, sweating,

00:36:34.900 | the pupils dilate.

00:36:36.380 | It has certain effects on, in particular,

00:36:38.820 | people with epilepsy.

00:36:40.260 | It's been used somewhat successfully for smoking cessation,

00:36:43.760 | but again, it's not for everybody,

00:36:45.380 | and I'm not here to encourage the use of these things,

00:36:48.100 | I'm just describing the biology

00:36:49.460 | and the rationale for why these drugs were developed.

00:36:52.680 | So let's back up a second.

00:36:55.400 | Let's just kind of take stock of where we're at.

00:36:57.040 | We have a brain-body connection.

00:36:58.560 | There are many of them,

00:36:59.600 | but one of the main ones is the vagus nerve.

00:37:01.560 | The vagus collects information about a lot of things,

00:37:04.020 | breathing, heart rate, stuff that's happening in the gut,

00:37:07.380 | et cetera, and gut, by the way,

00:37:08.600 | includes the stomach and the intestines,

00:37:10.420 | sends that information up to the brain.

00:37:12.700 | The brain is using that information

00:37:14.420 | to decide one of two things,

00:37:16.140 | move towards something or move away.

00:37:18.620 | It can also pause,

00:37:19.640 | but essentially pausing is not moving toward.

00:37:22.460 | So that's the dopamine pathway,

00:37:24.860 | and foods rich in L-tyrosine generally give us

00:37:27.480 | an elevated mood and make us want to do more

00:37:29.900 | of whatever it is that we happen to be doing,

00:37:32.100 | as well as other things, motivation generalizes

00:37:34.220 | to other things.

00:37:35.060 | It's not unique to just ingesting foods,

00:37:37.260 | but foods that give us a big pulse of dopamine

00:37:40.040 | will make us crave more of that food.

00:37:42.940 | It will make us crave more of the activity

00:37:45.220 | that led to the ingestion of that food.

00:37:47.900 | And as I mentioned earlier,

00:37:48.980 | a lot of that is happening at a subconscious level

00:37:51.860 | that you're not even aware of.

00:37:53.140 | And this is why I think the concern about hidden sugars

00:37:56.220 | and over-ingestion of sugars is serious

00:37:58.740 | because it's not just that the sugars are impacting

00:38:02.180 | our blood glucose in negative ways,

00:38:04.180 | although often it is,

00:38:05.380 | it's not just the obesity crisis that's happening,

00:38:08.260 | it's also the fact that it's disrupting

00:38:10.700 | our dopamine systems.

00:38:12.220 | Now that doesn't mean all sugar is bad.

00:38:14.340 | Some people have a quite healthy relationship to sugar,

00:38:17.420 | but I think most people are just not aware

00:38:19.060 | that sugar isn't just operating at the level of taste,

00:38:21.700 | it's operating at the level of neurochemicals

00:38:23.580 | and it's doing it subconsciously.

00:38:25.940 | So I'd like to talk about some of the other pathways

00:38:28.120 | between brain and body that regulate our moods and emotions,

00:38:31.700 | but also are actionable.

00:38:33.820 | So the other neuromodulator that's really interesting

00:38:36.200 | in the context of the vagus is serotonin.

00:38:39.280 | Serotonin, just to remind you, is a neuromodulator,

00:38:42.660 | therefore it creates a bias in which neural circuits,

00:38:46.160 | which neurons in the brain and body are going to be active

00:38:49.140 | and it makes it less likely

00:38:50.440 | that other ones are going to be active.

00:38:53.000 | I think it's fair to say without ever having measured it

00:38:55.660 | that my bulldog Costello, just his brain and body

00:38:59.480 | must be swimming in serotonin because he's very calm

00:39:04.140 | and he eats a lot, but he generally feels pretty sated.

00:39:07.300 | He's kind of an animal that's obsessed with comforts.

00:39:10.700 | He's a bit of a hedonist.

00:39:12.180 | And serotonin, when it's elevated,

00:39:13.800 | tends to make us feel really comfortable

00:39:16.100 | and kind of blissed out wherever we are.

00:39:18.980 | And that contrast with dopamine and epinephrine,

00:39:22.480 | which mainly put us in pursuit of things,

00:39:25.180 | motivation is pursuit.

00:39:27.260 | Serotonin is more about feeling really comfy where we are.

00:39:30.500 | The conversation around the brain-body relationship

00:39:34.500 | and mood in serotonin for many years was,

00:39:36.420 | well, you eat a big meal, the gut is distended,

00:39:39.000 | you've got all the nutrients you need, you rest and digest,

00:39:41.980 | and serotonin is released.

00:39:43.820 | That's sorta true, but there's a lot more going on

00:39:47.880 | and a lot more that's interesting

00:39:49.240 | and actionable that's going on.

00:39:51.060 | First of all, some of you, but perhaps not all have heard

00:39:54.100 | that more than 90% of the serotonin that we make

00:39:57.800 | is in our gut.

00:39:59.020 | And indeed, we have a lot of serotonin in our gut.

00:40:01.860 | We have neurons in our gut that make serotonin.

00:40:04.180 | We have neurons in our brain that make serotonin.

00:40:06.940 | But here's the deal.

00:40:07.940 | Most of the serotonin that impacts our mood

00:40:11.540 | and our mental state is not in our gut.

00:40:14.600 | Most of it is in the neurons of the brain

00:40:16.720 | in an area called the raphe nucleus of the brain.

00:40:19.060 | There are a few other locations too.

00:40:20.860 | And those are the neurons that control

00:40:22.340 | whether or not we feel satiated or not,

00:40:24.700 | whether or not we feel happy and calm.

00:40:27.000 | You can't have a discussion about serotonin

00:40:30.280 | without having a discussion about antidepressants

00:40:32.400 | because during the late '80s and early '90s,

00:40:35.420 | there was this explosion in the number of prescription drugs

00:40:38.700 | that were released, things like first one

00:40:40.640 | and most famous one is Prozac, Zoloft, and Paxil,

00:40:43.500 | a number of other ones that are so-called SSRI,

00:40:46.260 | selective serotonin reuptake inhibitors.

00:40:50.320 | That's a long acronym, but basically those drugs work

00:40:53.720 | by preventing the gobbling up of serotonin

00:40:58.240 | or reuptake of serotonin into neurons

00:41:02.400 | after it's been released,

00:41:03.380 | which leads to more serotonin overall,

00:41:05.560 | which means to elevate serotonin.

00:41:07.120 | And indeed those drugs were and can be very useful

00:41:11.200 | for certain people to feel better in cases of depression

00:41:14.680 | and some other clinical disorders as well.

00:41:17.080 | So I really don't want to dismiss them as useless

00:41:20.900 | or dangerous for everybody.

00:41:22.660 | They can be quite useful for many people.

00:41:25.620 | Not everyone responds well to them

00:41:27.480 | as I'm sure you've all heard.

00:41:29.140 | And their side effect profile

00:41:31.880 | has effects like blunting affect.

00:41:34.760 | It can make people feel kind of flat, kind of meh.

00:41:37.180 | It can reduce appetite for food.

00:41:39.800 | It can reduce appetite for sex.

00:41:41.320 | It can do all sorts of things or it can work really well.

00:41:44.400 | Sometimes it's a dose related issue, et cetera.

00:41:47.720 | Serotonin is fascinating, however,

00:41:50.000 | because how well those neurons in the raphe work

00:41:53.480 | is impacted by some events within the gut.

00:41:55.880 | Although you might be surprised

00:41:57.800 | to find out what those events are.

00:42:00.280 | So let's go a little bit deeper into the gut.

00:42:03.100 | And again, the gut includes the stomach

00:42:05.740 | and then the small intestine and the large intestine

00:42:07.840 | and ask like, what is going on with serotonin in the gut?

00:42:10.400 | How is it impacting serotonin in the brain?

00:42:13.440 | And let's think about this in the context

00:42:15.960 | of how some of us might want to increase

00:42:18.480 | or decrease our serotonin levels.

00:42:20.280 | So as far as I know,

00:42:23.340 | there aren't any really good at home blood tests

00:42:26.980 | for things like serotonin and dopamine.

00:42:29.240 | There are some commercial products out there,

00:42:30.880 | but to me, just to me, I'm not particularly impressed.

00:42:35.120 | It's not the same as getting your hormones levels measured

00:42:37.960 | or your metabolic factors measured.

00:42:39.700 | That can be done and can be done rigorously.

00:42:43.320 | There are tests out there.

00:42:44.440 | There are even some, believe it or not,

00:42:45.960 | there's some questionnaires.

00:42:47.680 | And I think actually last year

00:42:49.040 | it made some of the bigger newspapers.

00:42:50.560 | Are you more of a dopamine or a serotonin?

00:42:52.760 | Are you a this or a that?

00:42:54.280 | I find that stuff to be a little silly,

00:42:55.820 | although I do appreciate and like the fact

00:42:58.160 | that people are thinking about

00:42:59.220 | and talking about neuromodulators.

00:43:01.460 | There aren't really great ways to measure these things

00:43:04.760 | outside the clinic.

00:43:05.680 | There's some great clinical tools

00:43:06.980 | that you can get inside of a hospital

00:43:08.480 | or from a proper endocrinologist or neurologist,

00:43:10.720 | but no great at-home tool.

00:43:12.400 | So maybe that's a call to arms

00:43:13.600 | for some of you entrepreneurial folks out there

00:43:16.320 | to create these tests, accurate tests, please.

00:43:19.120 | They could be done at home.

00:43:20.680 | But some people feel like they're too anxious

00:43:23.640 | or they're always in a motivated state

00:43:25.920 | and they're trying to adjust their serotonin.

00:43:27.680 | Many people adjust their serotonin by just eating more food

00:43:31.320 | and carbohydrate-rich foods will increase serotonin.

00:43:35.160 | I've talked about this on a previous podcast,

00:43:36.920 | but I personally am a big fan, at least for me,

00:43:39.700 | as I usually fast and exercise in the early part of the day,

00:43:43.780 | I eat a relatively high protein and moderate fat,

00:43:48.420 | zero carb or low carb meal at lunch

00:43:51.700 | and in the afternoon to stay alert

00:43:53.460 | because those foods tend to favor dopamine production,

00:43:56.760 | acetylcholine production, epinephrine production

00:43:58.820 | and alertness.

00:43:59.940 | My mood is generally pretty good most of the time.

00:44:03.480 | And then as evening comes around

00:44:05.240 | and I'm concerned about sleep and a good night's sleep,

00:44:08.720 | not concerned in an anxious way,

00:44:09.980 | but I want to get a good night's sleep,

00:44:11.620 | I will ingest foods that promote serotonin release

00:44:14.600 | because they contain a lot of tryptophan.

00:44:16.500 | So if I do eat meat,

00:44:17.500 | it would be like a white meat, turkey meat.

00:44:19.100 | I don't tend to, I've never liked turkey.

00:44:21.500 | I don't mind the animal, but I don't like ingesting the meat.

00:44:25.160 | But starchy carbohydrates will increase serotonin.

00:44:28.840 | Some people also will take serotonin.

00:44:32.220 | You can now buy 5-HTP supplements.

00:44:35.280 | This is a little bit tricky.

00:44:36.700 | 5-HTP supplements can of course increase 5-HTP.

00:44:40.720 | It is 5-HTP or serotonin,

00:44:43.480 | but that sometimes can create problems

00:44:46.360 | in endogenous or self-made production of serotonin.

00:44:49.660 | So I'm never a fan of taking things

00:44:52.160 | very close to the chemical you're trying to increase

00:44:54.420 | for very long periods of time, maybe for occasional use.

00:44:57.820 | I have the problem that if I take serotonin supplements,

00:45:00.700 | 5-HTP, I fall asleep, the sleep I have is very intense

00:45:04.120 | and I wake up three or four hours later.

00:45:05.620 | And we know based on sleep studies

00:45:08.180 | with good measurements in the lab

00:45:09.660 | that serotonin release tends to be

00:45:12.040 | in the later part of the night.

00:45:13.520 | And so by taking it early in the night,

00:45:15.200 | it really can disrupt the pattern of sleep

00:45:17.240 | and the depth of sleep.

00:45:18.440 | Nonetheless, some people are interested in taking serotonin

00:45:21.420 | to get some of the more blissed out effects.

00:45:23.980 | You can achieve that with foods, as I mentioned,

00:45:25.760 | that are carbohydrate rich.

00:45:27.420 | So as you're seeing,

00:45:28.260 | this isn't really a discussion about nutrition per se.

00:45:30.400 | This is a discussion about food, which contains amino acids.

00:45:33.760 | Amino acids being the precursors to neuromodulators

00:45:36.440 | and neuromodulators having a profound effect

00:45:39.320 | on your overall state of alertness or calmness,

00:45:42.360 | happiness, sadness, and wellbeing.

00:45:44.420 | So there are a number of things that one can take.

00:45:47.600 | As I mentioned, one of them being 5-HTP itself.

00:45:50.160 | Now I'm not recommending people take anything,

00:45:52.520 | but if you're interested in what this does

00:45:55.360 | and you want to explore this,

00:45:56.640 | of course you'd want permission from your doctor.

00:45:58.760 | You can go to this free website.

00:46:00.680 | I love this resource.

00:46:02.280 | They don't pay me to say that, but I just love this resource.

00:46:04.660 | I followed it for a long time, called examine.com.

00:46:07.540 | Thank you folks at examine.com

00:46:10.640 | for putting this free resource out on the web

00:46:12.420 | that has links through what they call

00:46:14.120 | the human effect matrix.

00:46:16.040 | So it's links to all the PubMed studies

00:46:18.040 | for particular effects of particular compounds

00:46:20.280 | that one can buy and ingest.

00:46:21.360 | Incredible, as well as important health warnings.

00:46:23.920 | So I'm not going to read through everything,

00:46:25.160 | but if you were to go to examine.com, as I have now,

00:46:27.760 | and you'd put in 5-HTP,

00:46:30.280 | they're only looking at things that have strong evidence.

00:46:32.540 | PubMed articles, articles are in the PubMed archives.

00:46:37.540 | So for instance, I didn't know this,

00:46:39.520 | but 5-HTP produces a notable decrease in appetite.

00:46:44.000 | Three studies.

00:46:45.360 | And this appetite suppression makes sense of course,

00:46:48.000 | because we ingest foods to get serotonin.

00:46:51.440 | And if we have enough serotonin,

00:46:53.420 | then there's no reason to ingest more foods.

00:46:55.700 | It tends to have a blunting of appetite.

00:46:57.560 | It probably does that also through other mechanisms.

00:46:59.640 | So I'm not saying you should do this,

00:47:01.160 | but if someone's trying to blunt their appetite,

00:47:03.380 | could be a interesting route.

00:47:05.740 | Although I don't recommend chronic use.

00:47:07.800 | Not surprisingly, there's a decrease in body weight

00:47:11.960 | as a consequence, an increase in cortisol.

00:47:14.120 | So that's kind of important to note that when you,

00:47:17.040 | typically in biology,

00:47:18.320 | if you pull on one string really hard, another one moves.

00:47:20.580 | It's a little bit like a puppet

00:47:21.880 | and there's more than one string on the puppet.

00:47:24.040 | So it does seem to increase cortisol,

00:47:26.400 | though they report as a minor effect.

00:47:27.880 | Again, links to all those studies are there,

00:47:30.160 | which is why I'm not listing them out in our caption notes.

00:47:32.480 | You can go and get them at examine.com,

00:47:34.280 | put in serotonin and you'll find that.

00:47:36.700 | So I find it fascinating that nowadays,

00:47:40.880 | there are things that are somewhere between doing nothing,

00:47:44.980 | getting serotonin from tryptophan in foods

00:47:47.440 | and prescription drugs.

00:47:48.560 | There's this other category of supplements

00:47:51.080 | that are really interesting for modulating

00:47:53.840 | these chemicals in the body.

00:47:55.200 | And I should mention before I move on,

00:47:57.180 | because I mentioned L-tyrosine,

00:47:58.460 | I neglected to mention earlier

00:48:00.480 | in our discussion about dopamine.

00:48:02.060 | If you're interested in the dopamine pathway,

00:48:04.140 | go to examine.com, put in mucuna pruriens,

00:48:08.260 | it's M-U-C-U-N-A, P separate word, P-R-U-R-I-E-N-S.

00:48:13.260 | It is a velvet bean that grows from vines

00:48:20.060 | and is very itchy to touch due to serotonin on its surface.

00:48:23.460 | Amazing, this bean has serotonin on its surface.

00:48:25.900 | And indeed serotonin, if you were to put it on your skin,

00:48:29.060 | would cause some irritation of the skin, amazing.

00:48:31.620 | Inside the bean is L-DOPA.

00:48:35.260 | Mucuna pruriens is not just something

00:48:37.780 | that promotes dopamine release

00:48:39.620 | because of some weird mystical ancient thing

00:48:42.740 | or whatever, or sorcery, it is chemically L-DOPA,

00:48:46.980 | the precursor to dopamine.

00:48:49.340 | It contains some other molecules as well

00:48:51.480 | and low levels of other psychoactives.

00:48:53.820 | This stuff is available over the counter,

00:48:55.580 | incredible, I personally find it incredible.

00:48:58.240 | Its effects are really interesting,

00:49:00.580 | I'm not going to read them all off,

00:49:01.940 | but I mentioned these effects

00:49:03.460 | not because I'm encouraging you to take it,

00:49:05.220 | but because you get a window into what dopamine,

00:49:08.100 | acute dopamine increase does

00:49:10.340 | in the non-Parkinsonian context.

00:49:12.840 | And you can start to think about foods

00:49:14.600 | that are rich in L-tyrosine

00:49:16.580 | as biasing certain effects or not others.

00:49:20.100 | So when you hear food is medicine,

00:49:21.420 | food isn't really medicine, food is food,

00:49:23.420 | but food has these chemical effects as well.

00:49:25.900 | So first one listed is three studies with very high rigor

00:49:30.900 | that overall have a minor effect on,

00:49:35.780 | of all things, sperm quality.

00:49:37.300 | So it appears that sperm motility itself,

00:49:39.820 | I'm assuming when they say sperm quality,

00:49:41.300 | I don't know what features of sperm of quality

00:49:43.260 | they looked at with sperm,

00:49:44.100 | that's not a discussion I want to have,

00:49:45.740 | but I'm assuming it's motility

00:49:47.240 | because I know enough about reproductive biology

00:49:49.940 | to know that sperm ability to swim

00:49:52.860 | depends on some proteins

00:49:54.220 | that are present in the front of the sperm, et cetera,

00:49:56.580 | things like pentraxins,

00:49:58.000 | and sperm motility is generally associated

00:50:00.940 | with sperm quality.

00:50:02.100 | Sperm that don't move are generally not very useful sperm.

00:50:05.620 | Symptoms of Parkinson disease

00:50:07.260 | are notably degraded with macuna prurin.

00:50:10.100 | So fascinating, that's not surprising.

00:50:12.100 | And there are a lot of other effects here,

00:50:13.840 | feelings of subjective wellbeing,

00:50:15.420 | testosterone, reductions in prolactin, not surprising.

00:50:18.860 | Prolactin is a hormone that's involved in milk letdown.

00:50:22.240 | It's in lactating mothers.

00:50:24.500 | It's involved in feelings of peace

00:50:26.940 | and generally is antagonistic to sexual desire

00:50:30.900 | in both men and female.

00:50:33.260 | So it's really interesting that things like macuna prurin,

00:50:37.180 | which are L-DOPA, reduced prolactin, increased motility,

00:50:40.260 | increased testosterone, subjective wellbeing.

00:50:42.180 | So you're starting to see a theme, right?

00:50:44.020 | Dopamine really makes us motivated, feel in pursuit,

00:50:47.180 | makes us feel good.

00:50:48.220 | Serotonin makes us feel more relaxed and calm.

00:50:51.760 | Now, this whole month is about emotions.

00:50:53.540 | So you might be thinking, well, wait,

00:50:54.940 | where are we going with all this as it relates to emotions?

00:50:57.240 | But in the last episode,

00:50:59.540 | I said something I'm gonna repeat it now briefly,

00:51:01.860 | which is that much of what we talk about

00:51:04.120 | as good emotions or bad emotions,

00:51:06.060 | there's a context to that, there's a social context.

00:51:08.620 | You can't really say an emotion is good or bad.

00:51:11.380 | Grieving at a funeral is healthy, okay?

00:51:14.500 | Being happy at a funeral,

00:51:16.500 | assuming you loved the person that died,

00:51:18.580 | is most people probably wouldn't think that was healthy.

00:51:21.580 | So we can't really say that certain, you know,

00:51:24.700 | emotions like sadness or happiness are healthy,

00:51:26.840 | it's context is important, cultural context is important.

00:51:29.920 | Many of you have asked for book recommendations.

00:51:31.920 | This is an opportunity to raise a mention of another book.

00:51:35.100 | Again, I don't have any financial affiliation or anything,

00:51:38.260 | but if you wanna read more about emotions

00:51:40.280 | and how the context and cultural things impact our emotions,

00:51:44.360 | I'm a huge fan of Lisa Feldman Barrett.

00:51:47.000 | I learned about her from the Lex Fridman podcast.

00:51:50.700 | I've had discussions with her on my Instagram Live.

00:51:52.720 | She's at Northeastern University, a world expert in emotions.

00:51:56.060 | Her first book is "How Emotions Are Made."

00:51:58.420 | This is not a book she sent me.

00:51:59.580 | I paid for this with my own money years ago,

00:52:02.640 | bought it, read it, loved it long before I met Lisa.

00:52:05.740 | I'm just delighted that we've got

00:52:06.760 | to known each other a little bit.

00:52:08.060 | It's a really interesting read

00:52:09.400 | into the psychology of emotions

00:52:10.940 | and some of the subjectivity of emotions.

00:52:13.740 | So whereas I'm talking about mainly the biology of emotions,

00:52:16.820 | this gets a little bit more into the psychology

00:52:18.880 | although the biology as well.

00:52:21.160 | And Lisa's just terrific.

00:52:23.200 | She's also putting a lot of information

00:52:24.560 | out into the world about emotions.

00:52:25.920 | So if you wanna learn more about that, check out her work.

00:52:29.920 | Again, it's Lisa Feldman Barrett

00:52:32.040 | and that book is "How Emotions Are Made."

00:52:34.120 | Hopefully she'll continue to write many more books.

00:52:37.520 | So now you understand the relationship, I hope,

00:52:41.680 | between foods and dopamine, foods and serotonin,

00:52:46.200 | and that they're both being communicated

00:52:47.920 | to the brain via the vagus, right?

00:52:49.640 | We ingest these foods.

00:52:51.100 | These supplements are things people take.

00:52:53.680 | They don't put them directly into the brain.

00:52:55.520 | They put them in our gut.

00:52:56.420 | So yes, there's a gut-brain connection,

00:52:58.660 | but it's not about the serotonin in the gut

00:53:01.760 | that makes you feel calm and placid.

00:53:04.160 | It's not about the dopamine in the gut.

00:53:06.480 | It's just been oversold that way

00:53:09.760 | because I think there's something really attractive.

00:53:11.720 | And I understand about the idea

00:53:14.160 | that because certain things about our experience of life

00:53:18.060 | and our emotions is happening in our body,

00:53:19.620 | that maybe we have a little more control, right?

00:53:21.720 | Because this thing is a hard container.

00:53:23.400 | We can't just stuff some dopamine in there.

00:53:25.100 | I can't just let, you know,

00:53:26.340 | I could probably take a macuna purines bean

00:53:28.760 | and stuff it in my ear.

00:53:29.760 | Please don't do that.

00:53:30.600 | It'd make my ear itchy

00:53:31.520 | 'cause of the serotonin on the outside,

00:53:32.960 | but you can't get stuff in there.

00:53:34.480 | What you have to do is ingest things

00:53:36.280 | that are metabolized in certain ways

00:53:38.360 | that communicate to the brain,

00:53:40.440 | or so maybe they pass into the brain themselves

00:53:43.300 | across what's called the blood-brain barrier.

00:53:45.680 | I'll talk about the blood-brain barrier in a minute.

00:53:48.280 | It's actually called the BBB.

00:53:49.800 | So it ends up sounding like baby, BBB.

00:53:51.800 | I guess that's like BB.

00:53:54.900 | Anyway, BBB.

00:53:57.720 | But there are also nerves in the gut

00:53:59.980 | that are sensing the nutrient contents of food

00:54:02.680 | and then saying, oh, you should feel better and want more.

00:54:05.160 | Oh, that's got a lot of bitterness and acid taste to it.

00:54:09.880 | You should want less of that, okay?

00:54:12.080 | So as I transition out of the discussion

00:54:14.080 | about dopamine and serotonin and the gut,

00:54:16.880 | hopefully you've got some actionable items there

00:54:19.160 | under your belt, pun intended,

00:54:21.380 | where you can understand how certain foods

00:54:23.960 | and certain nutrients, and you can look these up,

00:54:26.040 | might impact your mood.

00:54:27.840 | If you're somebody who's really anxious and really wired,

00:54:30.620 | well then the dopamine adrenaline pathway,

00:54:32.900 | epinephrine pathway is probably not one

00:54:34.440 | that you want to lean on any harder.

00:54:36.880 | If you tend to be someone who's pretty passive

00:54:39.320 | and you're having trouble with motivation,

00:54:40.740 | well then, think about ramping up the dopamine pathway.

00:54:44.320 | I always think behaviors and proper food choices

00:54:46.920 | is the best way to start,

00:54:48.200 | and behaviors include things like exercise, et cetera.

00:54:51.340 | But one of the problems with the discussion

00:54:53.280 | around mood and exercise or mood and meditation

00:54:57.200 | is that it's so subjective.

00:54:59.480 | It's like I love certain forms of exercise and not others.

00:55:01.920 | Certain ones are aversive to me.

00:55:03.320 | Certain ones are attractive to me.

00:55:05.000 | And it's never really clear.

00:55:06.000 | No one's ever told me, okay,

00:55:07.200 | you have to do 10 minutes on the bike

00:55:09.760 | at X number of RPM at so-and-so or on the skier

00:55:12.940 | in order to get your dopamine up.

00:55:14.460 | But we can actually say if you ingest more L-tyrosine,

00:55:18.680 | there's a high probability

00:55:19.920 | that you're going to make more dopamine.

00:55:22.240 | And I'm talking about ingesting it through food

00:55:23.600 | or through supplementation, if you like.

00:55:25.460 | Macuna purines I've tried, I should just mention,

00:55:28.520 | it was too dopaminergic for me.

00:55:30.540 | I really, really jazzed up

00:55:33.280 | and then severe crash for me the next day.

00:55:36.560 | But that's, I think, because I tend to ride pretty high

00:55:39.320 | on the kind of alertness and motivation scale.

00:55:41.320 | I'm always being told by Costello

00:55:43.640 | and other people in the podcast studio

00:55:44.960 | to slow my speech down.

00:55:46.640 | This is me uncaffeinated and I could probably afford

00:55:49.860 | a little more serotonin in my life.

00:55:51.760 | So whereas Costello, he could afford,

00:55:54.520 | well, he could afford to wake up every couple of days

00:55:57.440 | and just say hello to us.

00:55:58.680 | This dog sleeps more than any other creature.

00:56:01.560 | It's remarkable.

00:56:02.660 | So there are things that we can do and they're actionable

00:56:06.960 | and they are, in some ways they're quantitative

00:56:09.520 | because you can regulate dosages

00:56:11.120 | and you can regulate amounts and you can regulate timing.

00:56:13.500 | And everyone has to play with these things

00:56:14.760 | and figure out what's right for them in terms of feeding.

00:56:17.400 | And everyone has to explore

00:56:19.680 | and understand what's safe and right for them.

00:56:21.760 | But, and of course, exercise is still very important.

00:56:25.000 | I talked about social connection in the last episode,

00:56:27.320 | super important for activation of serotonin.

00:56:30.800 | But when it comes to this gut brain,

00:56:33.040 | body brain relationship, what we eat really matters

00:56:36.440 | in terms of the neurochemicals that we make.

00:56:38.960 | So let's talk a little bit more about things

00:56:41.120 | that we ingest in our body and then allow our body

00:56:43.680 | to inform our brain to shift our mood.

00:56:46.280 | And this is something I've been doing for years

00:56:48.800 | and I just want to say,

00:56:50.080 | I've found to be a complete game changer.

00:56:52.560 | There's excellent science to support it.

00:56:55.120 | And I think most people are familiar with it

00:56:58.960 | in a different context,

00:57:00.100 | but I don't think most people know this simple fact,

00:57:03.460 | which is that the omega-3 to omega-6 fatty acid ratio

00:57:08.460 | has a profound effect on depression.

00:57:12.600 | It has a profound effect on mood.

00:57:15.160 | So much so that in a double blind placebo controlled study

00:57:20.040 | that I will provide the link to,

00:57:21.220 | this was a study first published in 2008,

00:57:23.300 | but there've been many others as well.

00:57:25.200 | First of all, in an experiment done in animals,

00:57:29.740 | they found there's a model of learned helplessness

00:57:31.940 | in animals.

00:57:32.780 | Not very kind to the animals,

00:57:33.840 | but they put rats or mice in a jar.

00:57:35.680 | They let them swim and they'll swim, swim, swim

00:57:38.440 | to try and save their life.

00:57:39.440 | And eventually they give up.

00:57:40.560 | It's a learned helplessness.

00:57:41.460 | They don't let them drown, they take them out.

00:57:43.680 | Adjusting the omega-3 omega-6 ratio

00:57:47.140 | so that the omega-3s are higher

00:57:49.620 | led to less learned helplessness,

00:57:51.900 | meaning these animals would swim longer.

00:57:54.080 | Now that's an animal that's a rat,

00:57:55.660 | not a particularly kind study,

00:57:57.940 | but that same study was essentially done in humans,

00:58:01.440 | although they didn't have them swim

00:58:02.680 | to the point of near drowning.

00:58:04.500 | What they did is they took people

00:58:07.700 | who were clinically depressed, major depression, okay?

00:58:10.580 | Major depression is severe maladaptive state,

00:58:14.540 | meaning it inhibits job, relationships, appetite,

00:58:17.900 | all sorts of negative health effects.

00:58:20.620 | And they did a comparison

00:58:21.940 | of 1,000 milligrams a day of EPA.

00:58:26.300 | So EPA is one of the elements

00:58:29.300 | that contains high levels of omega-3s

00:58:31.300 | that's in things like fish oil.

00:58:32.820 | Talk about other sources in a little bit,

00:58:35.060 | but it wasn't 1,000 milligrams of fish oil.

00:58:38.520 | It was 1,000 milligrams of EPA.

00:58:41.760 | Compare that to 20 milligrams of fluoxetine,

00:58:45.220 | which is Prozac, okay?

00:58:47.480 | Really increases serotonin.

00:58:49.440 | And in this study of 60 individuals,

00:58:52.280 | again, I'll provide the links to the study,

00:58:54.980 | they found that they were equally effective

00:58:59.540 | in reducing depressive symptoms.

00:59:01.260 | So imagine that.

00:59:03.060 | A food-based compound that you can't make without, right?

00:59:07.820 | This is not a situation

00:59:09.300 | where you can make your own omega-3s.

00:59:10.980 | You have to get them from food sources

00:59:12.360 | or from supplementation was as effective

00:59:15.020 | as 20 milligrams of fluoxetine

00:59:17.440 | over the course of eight weeks.

00:59:19.380 | And what was really interesting in addition to that

00:59:22.560 | is that the combination of 1,000 milligrams of EPA

00:59:26.320 | and fluoxetine had a synergistic effect

00:59:28.500 | in lowering depressive symptoms.

00:59:30.300 | I find this remarkable.

00:59:31.540 | I heard about this when it first came out

00:59:35.380 | and I wasn't sure what to make of it

00:59:37.020 | 'cause there are a lot of studies that come out

00:59:38.380 | and I generally like to focus my changes in behavior

00:59:41.740 | around things where there's a large center of mass.

00:59:43.700 | There's a lot of information.

00:59:45.180 | A couple of years later,

00:59:47.100 | I did in fact start taking 1,000 milligrams per day of EPA

00:59:52.100 | in fish oil.

00:59:53.300 | Now, there are a few side effects of fish oil.

00:59:57.020 | People who have blood, who are bleeders,

00:59:59.820 | who have factor V Leiden mutations,

01:00:02.280 | or women who are taking birth control,

01:00:05.620 | which can affect blood clotting and things of that sort

01:00:08.260 | really should talk to your doctor,

01:00:10.340 | make sure it's okay for you.

01:00:12.080 | Fish oil also can give people fishy breath,

01:00:14.900 | which is pretty gross, frankly.

01:00:17.060 | But there are now fish oils

01:00:18.180 | that either because of the encapsulations

01:00:20.340 | or because they put some lemon flavoring in there

01:00:24.960 | doesn't have that effect.

01:00:26.620 | In any event, 1,000 milligrams per day of EPA,

01:00:29.020 | I started ingesting that regularly.

01:00:30.720 | I just felt better.

01:00:31.620 | I wasn't clinically depressed,

01:00:32.840 | but I generally, I did feel, at least for me,

01:00:35.700 | an increase in mood and affect

01:00:37.780 | and a number of other things.

01:00:39.060 | It's supposed to reduce inflammation.

01:00:40.340 | The cardiovascular effects are controversial.

01:00:42.340 | For a long time, everyone thought

01:00:44.180 | the effects on platelets were really terrific.

01:00:47.060 | Then there were articles that came out in major newspapers

01:00:49.080 | saying maybe not so much,

01:00:50.660 | but the effects on mood are really profound.

01:00:53.800 | And now there are lots of studies.

01:00:56.140 | If you go into PubMed and you were to put EPA

01:00:59.520 | or fish oil and depression,

01:01:01.280 | you would find that there were a number

01:01:03.040 | of really impressive results

01:01:04.660 | showing that it's at least as effective

01:01:06.700 | as certain SSRIs antidepressants at these dosages.

01:01:11.620 | And it can amplify or improve the effect of low dosages

01:01:14.860 | of some of these SSRIs.

01:01:16.300 | So I feel like more people should know about this.

01:01:18.220 | This is nutrition, but it's profoundly affecting mood.

01:01:21.220 | And depression is terrible, right?

01:01:23.140 | Depression can have a component of anxiety in some cases

01:01:27.100 | where people are, they feel lousy and very uncertain.

01:01:30.660 | That's kind of how I talk about depression with anxiety

01:01:32.700 | is you talk to someone who's anxious

01:01:34.500 | and you can tell them everything's going to be okay, okay.

01:01:36.300 | And they're always concerned

01:01:37.420 | about what they might not know.

01:01:39.380 | You don't really know the plane isn't going to crash.

01:01:41.300 | You don't really know that life is going to go okay.

01:01:43.860 | And in some sense, they're right.

01:01:44.920 | No one has a crystal ball or can predict the future,

01:01:47.700 | but they tend to perseverate or fixate on the uncertainty.

01:01:50.940 | And then of course, there are the versions of depression

01:01:53.420 | that involve certainty.

01:01:55.080 | People are lethargic and they're certain.

01:01:56.540 | They say, yeah, I'm certain

01:01:57.860 | I'm never going to get another job.

01:01:58.960 | I'm certain I'm never going to meet anyone new.

01:02:00.580 | I'm certain I'm going to fail.

01:02:01.740 | So there's this kind of a divide in the sphere of depression

01:02:05.480 | around certainty and uncertainty.

01:02:06.820 | But what's interesting is this thousand milligrams per day

01:02:10.680 | or more of EPA has been shown to relieve

01:02:13.420 | both forms of depression.

01:02:16.280 | Now, does that mean it's going to work for everybody?

01:02:18.500 | No, I'm not here to try and play psychiatrist.

01:02:20.660 | I want to point you in the direction of these manuscripts

01:02:23.520 | so that you can make informed choices for yourself.

01:02:26.140 | You can discuss it with your doctor and family

01:02:28.140 | and make the choices that are right for you.

01:02:30.420 | But here's what's especially interesting

01:02:32.540 | about the heart effects,

01:02:33.480 | because we've heard that these omega-3s,

01:02:36.860 | which of course you can get from other sources too.

01:02:38.860 | You can get from fatty fish, there are flax seeds,

01:02:41.700 | hemp seeds, there are a number of chia seeds,

01:02:45.840 | these kinds of things.

01:02:47.980 | But the levels of EPA that are required are quite high.

01:02:51.340 | So this thousand milligrams per day,

01:02:53.580 | that's pretty hard to get from food,

01:02:55.140 | although it can be done depending on what you're eating.

01:02:58.480 | What's interesting is that the heart effects that are solid,

01:03:03.480 | that really stand up in the literature,

01:03:05.700 | have a lot more to do with something we talked about

01:03:07.860 | in a previous episode and I'll mention again,

01:03:09.620 | which is heart rate variability.

01:03:11.620 | So we know that having a heart rate that's really high

01:03:13.980 | or a heart rate that's really low,

01:03:15.580 | neither of those are good.

01:03:17.020 | A lot of people think, "Oh, you just want a low heart rate,

01:03:18.720 | "big stroke volume."

01:03:20.660 | You know, if you're running a lot,

01:03:22.060 | you may have 30 or 40 beats per minute.

01:03:24.180 | That's great to be in shape,

01:03:25.460 | but you still want heart rate variability.

01:03:27.720 | It has a lot to do with the tone

01:03:29.340 | of the autonomic nervous system.

01:03:31.220 | I talked about last time how when you inhale,

01:03:33.140 | it speeds up heart rate.

01:03:34.260 | When you exhale, it decreases heart rate.

01:03:35.840 | That's called respiratory sinus arrhythmia.

01:03:38.580 | It's the basis of heart rate variability.

01:03:40.980 | We'll maybe do a short post about this

01:03:42.500 | so you can get all the mechanism

01:03:44.340 | and the behaviors that spill out of that

01:03:46.900 | that might be useful for you.

01:03:48.180 | But the point is heart rate variability, HRV, is good.

01:03:51.760 | And what's interesting is that there was a study in 2009

01:03:54.860 | that showed that people who eat a diet

01:03:58.580 | and fail to supplement in a way

01:04:00.500 | that there's a high omega-6 to 3 ratio,

01:04:03.240 | so not enough omega-3s,

01:04:05.260 | not only are there markers

01:04:06.620 | of inflammatory cytokines elevated,

01:04:08.980 | things like IL-6 and TNF-alpha,

01:04:11.500 | but they tend to be non-responders to antidepressants.

01:04:16.460 | Shifting that omega-3 omega-6 ratio did a couple things.

01:04:19.900 | First of all, increasing the amount of EPA,

01:04:22.660 | shifted the ratio so it was higher omega-3 to omega-6 ratio,

01:04:26.580 | which was good, lowered the inflammation markers,

01:04:29.380 | and then allowed antidepressants

01:04:31.500 | to have their effect even at low doses.

01:04:34.000 | And here's the really interesting thing.

01:04:36.060 | It worked by increasing heart rate variability.

01:04:40.060 | And you think, well, how in the world would this happen?

01:04:42.700 | But I mean, that's a ton of effects.

01:04:45.720 | But the way it works is because of the way

01:04:48.620 | that these things are impacting the gut

01:04:50.540 | and the autonomic nervous system.

01:04:51.980 | Remember, earlier I said the vagus

01:04:54.020 | includes connections from the heart

01:04:56.080 | signaling about sensory information

01:04:57.780 | about how fast the heart is beating to the brain,

01:05:00.340 | not just stuff from the lungs,

01:05:01.560 | but information from the heart.

01:05:03.580 | And the brain then adjusts heart rate

01:05:05.400 | by heart rate variability.

01:05:07.140 | So it's incredible that there's a way

01:05:09.280 | that one can use the gut,

01:05:12.080 | the ingestion of more of these EPAs,

01:05:14.260 | either through food or supplementation,

01:05:16.280 | to increase heart rate variability

01:05:18.980 | and thereby to improve symptoms,

01:05:22.800 | meaning reduce symptoms of depression,

01:05:25.060 | and to even make low levels of antidepressants

01:05:28.540 | that wouldn't otherwise work work.

01:05:30.480 | And I think I like this study so much

01:05:32.640 | because A, it's super cool.

01:05:34.400 | It bridges the brain-body axis.

01:05:36.140 | It incorporates nutrition and micronutrients in the brain,

01:05:39.420 | but also because it really points to something

01:05:42.080 | that we hear all the time,

01:05:43.460 | which is that our body is a whole system.

01:05:45.140 | It's working as a whole system,

01:05:46.180 | and the brain isn't working in isolation

01:05:47.980 | up there in the skull.

01:05:49.400 | It's reacting to things that are happening in the body,

01:05:51.800 | in the gut, and in the heart rate,

01:05:53.180 | and heart rate variability,

01:05:54.380 | and that the things we ingest

01:05:55.660 | can have a profound effect on them.

01:05:57.500 | Now, of course, I really want to emphasize something,

01:06:00.260 | which is that no one compound,

01:06:03.780 | or nutrient, or supplement, or drug,

01:06:06.700 | or behavior for that matter,

01:06:08.580 | is going to be the be-all, end-all

01:06:11.380 | of shifting out of depression,

01:06:13.820 | or improving one's mood, or improving sleep.

01:06:16.760 | It's a constellation of things.

01:06:18.540 | And this is especially true

01:06:20.140 | when people start to get excited

01:06:21.460 | about supplements and drugs of all kinds,

01:06:23.680 | and their potential for various things.

01:06:25.300 | Right now, there's a lot of excitement

01:06:26.700 | about psychedelics and their therapeutic uses,

01:06:28.500 | and I think, great.

01:06:29.400 | But as a good friend of mine,

01:06:30.820 | who's a physician clinician, says,

01:06:33.560 | "Better living through chemistry

01:06:36.220 | still requires better living."

01:06:38.380 | You cannot expect to take a compound

01:06:41.260 | regardless of source or potency,

01:06:43.640 | and have it completely shift your experience of life

01:06:46.760 | without having to continue to engage

01:06:48.660 | in the proper behaviors, all the things we know,

01:06:50.860 | proper sleep, exercise, social connection, food, et cetera.

01:06:54.440 | There are many others as well.

01:06:56.380 | So I still find that this collection of studies

01:07:00.820 | about omega-3 to omega-6 ratios to be profoundly important,

01:07:04.180 | so much so that it's completely changed

01:07:05.740 | the way that I think about food, the foods I eat,

01:07:08.420 | I do supplement,

01:07:09.260 | I don't necessarily think that's for everybody,

01:07:11.780 | but I really think it's incredible

01:07:14.740 | that there are these compounds

01:07:15.700 | that have these robust effects

01:07:17.140 | on our feelings of wellbeing, and there are others too.

01:07:20.640 | So that 1,000 milligram per day threshold

01:07:23.340 | of fish oil that's beneficial

01:07:25.580 | requires that one take a reasonable amount of these things,

01:07:28.740 | either through food or through supplementation.

01:07:31.840 | I acknowledge that not everyone wants to take fish oil.

01:07:34.980 | There are a couple reasons why one might want to avoid that.

01:07:37.780 | One would be for ethical reasons.

01:07:40.060 | You have an emotional relationship

01:07:42.060 | or a relationship to the environment

01:07:44.020 | that makes you not want to ingest fish-related products.

01:07:47.660 | There's krill oil, krill is still an organism.

01:07:49.940 | It's a little tiny thing that whales eat a lot of

01:07:52.380 | and people generally eat very little of.

01:07:54.080 | So krill is out there.

01:07:56.100 | I personally, just me, I don't know why,

01:07:58.500 | I didn't react well to krill.

01:08:00.660 | It didn't make me feel very good.

01:08:02.060 | I had some like kind of skin itchies and things like that.

01:08:05.580 | And they stopped when I stopped taking it,

01:08:06.940 | but I don't want to bias you against it

01:08:08.980 | if that's your preference.

01:08:09.920 | Some people really like krill oil as a source of omega-3s.

01:08:13.260 | I did mention some of the other sources

01:08:15.340 | like chia seeds and flax seeds.

01:08:18.180 | But as you'll notice, these are not things

01:08:19.720 | that we tend to ingest a lot of on a regular basis.

01:08:22.600 | It is possible to get omega-3s from meats

01:08:25.640 | if the animals have grazed on grasses

01:08:27.540 | that contain a lot of omega-3s.

01:08:30.040 | So for those of you that ingest meat,

01:08:34.540 | the source of those meats is going to be very important

01:08:37.220 | as it relates to omega-3s.

01:08:39.160 | Even within the category of fish oil,

01:08:41.500 | there's a concern sometimes about mercury

01:08:45.360 | and other contaminants.

01:08:47.020 | You want to go with a brand that emphasizes

01:08:49.700 | that they've gone to really good sources

01:08:52.820 | and that they decontaminate regardless.

01:08:56.500 | And so you have to search out those brands.

01:08:58.680 | There is a test that you can do as to whether or not

01:09:00.600 | the fish oil is rancid or not.

01:09:03.300 | Some people take in liquid form.

01:09:04.980 | Some people take in capsule form.

01:09:06.380 | The liquid form is going to be more affordable.

01:09:08.780 | The capsule form is a little easier and a little more

01:09:12.820 | portable.

01:09:13.640 | You can actually just chew one of the gel tablets.

01:09:18.700 | And if it tastes really fishy and kind of rancid,

01:09:20.800 | you'll know it's disgusting.

01:09:22.060 | You'll want to spit it out.

01:09:23.420 | And if it doesn't and it's tolerable,

01:09:25.340 | then you'll know that it's okay.

01:09:26.860 | Unfortunately, you have to buy it first

01:09:28.240 | in order to do that.

01:09:29.080 | Although, I don't know, maybe you can get them

01:09:30.940 | to open up the bottle for you in the store

01:09:33.140 | and tell them that you don't want to try it.

01:09:34.660 | Someday, perhaps, fish oil and omega-3s,

01:09:37.420 | it'll be like tasting wine at a restaurant

01:09:39.040 | where you can send it back.

01:09:39.960 | For now, I think you have to purchase it first,

01:09:42.260 | but find a brand you trust and like

01:09:44.460 | and then work with them

01:09:46.260 | if you decide to go that route, of course.

01:09:48.500 | There are other compounds that are also interesting

01:09:51.220 | for mood elevation that are essentially like foods

01:09:56.220 | or are supplement-based that now, fortunately,

01:10:00.500 | there are really good data from peer-reviewed studies.

01:10:03.160 | And the next one I want to mention,

01:10:04.700 | 'cause I think it's really interesting, is L-carnitine.

01:10:08.340 | Now, L-carnitine has been around a long time

01:10:11.300 | and it's been discussed in the context of heart health

01:10:13.720 | and a number of other things.

01:10:14.560 | It was actually touted as a bit of a weight loss agent

01:10:17.460 | in the early '90s, but L-carnitine

01:10:21.460 | actually has some really impressive effects on depression.

01:10:25.660 | And again, we will look to PubMed

01:10:29.020 | because looking at examine.com is essentially,

01:10:31.260 | for me anyway, looking at PubMed, what is L-carnitine?

01:10:34.780 | L-carnitine is most prevalent in meat

01:10:37.020 | and in beef in particular.

01:10:38.660 | Now, for the vegans, please know that L-carnitine

01:10:41.460 | is available through non-meat sources as well,

01:10:44.140 | although it's not as enriched in non-meat sources.

01:10:46.940 | It's a really interesting molecule

01:10:48.700 | because L-cetyl L-carnitine

01:10:50.900 | is essentially what's made from L-carnitine,

01:10:53.540 | but it's acetylated.

01:10:55.420 | If you're interested in the biochemistry,

01:10:56.940 | you can look that up.

01:10:57.760 | It's acetylated into a form

01:10:59.840 | that can cross the blood-brain barrier.

01:11:01.380 | The blood-brain barrier or BBB is a barrier.

01:11:04.260 | It's a wall around the brain.

01:11:06.820 | And you have this barrier because the brain is so important

01:11:11.280 | and it has this feature that the neurons there

01:11:13.300 | don't recreate themselves after injury.

01:11:15.500 | Like other organs of the body,

01:11:16.980 | there's not a lot of turnover of cells

01:11:18.980 | despite what you might've heard.

01:11:20.500 | And so nature has created this BBB,

01:11:23.180 | this blood-brain barrier to make sure

01:11:24.860 | that certain molecules, in particular large molecules,

01:11:27.660 | don't get across the blood-brain barrier

01:11:29.900 | 'cause it can be damaging to those tissues.

01:11:32.020 | Incidentally, you also have a very rigid

01:11:35.960 | or stringent barrier around other organs,

01:11:38.240 | which are the gonads.

01:11:39.120 | So the ovaries and the testes and the brain

01:11:41.920 | are the organs of the body

01:11:43.680 | that nature has gone out of its way to protect,

01:11:47.780 | give this additional layer of the blood-brain barrier,

01:11:50.900 | or as you might imagine for the testes and the ovaries,

01:11:54.820 | it's going to be the blood gonadal barrier.

01:11:57.520 | So these barriers exist and make it such

01:12:00.820 | that just because you eat something,

01:12:02.620 | just because you ingest it,

01:12:03.580 | doesn't mean it's going to cross the blood-brain barrier.

01:12:05.900 | But L-carnitine, when taken,

01:12:07.420 | is acetylated and converted into this form

01:12:10.520 | that gets across the blood-brain barrier.

01:12:12.700 | And it has a lot of effects.

01:12:14.200 | It's involved in mitochondrial activation

01:12:15.940 | of long-chain fatty acids,

01:12:17.300 | which that's a big mouthful that we can get into sometime

01:12:20.060 | when we're talking about metabolic.

01:12:21.660 | But it has some interesting effects on the neuro side.

01:12:24.780 | So if you decide to check it out on examine.com,

01:12:28.600 | you'll see some really interesting things.

01:12:29.760 | Lots of effects on ammonia, C-reactive proteins,

01:12:32.960 | things of that sort, blood glucose is lowered, et cetera.

01:12:35.980 | That's all stuff that's the level of blood in periphery,

01:12:39.620 | slight effects in lowering cholesterol.

01:12:41.720 | Here's some interesting ones.

01:12:44.120 | Rates of pregnancy go way up

01:12:48.200 | when people are taking L-carnitine,

01:12:51.140 | both the father and the mother,

01:12:52.840 | both the source of sperm and the source of egg

01:12:55.260 | are affected in ways that favor pregnancy.

01:12:59.660 | It does increase, here we go again with sperm quality,

01:13:02.260 | sperm motility in males,

01:13:04.640 | and it seems to have positive effects on females

01:13:08.340 | that have polycystic ovary syndrome.

01:13:11.080 | So check that out.

01:13:13.100 | The effects are very strong.

01:13:14.780 | There are three studies listed there.

01:13:16.300 | Again, I'm not promoting this,

01:13:18.060 | but that people take L-carnitine,

01:13:20.340 | especially if you're trying to get pregnant.

01:13:22.180 | But check it out because the effects there

01:13:25.040 | and the studies that are mentioned

01:13:26.320 | are published in peer-reviewed rigorous journals.

01:13:30.220 | In terms of the neural effects, those are quite interesting.

01:13:34.240 | The effects on depression are still emerging,

01:13:37.180 | but they do seem to exist,

01:13:38.780 | that people feel a notable decrease in depressive symptoms.

01:13:42.940 | There are seven studies listed on examine.com

01:13:45.500 | that it has a notable benefit in a variety of circumstances

01:13:48.960 | where participants have heightened depression already.

01:13:51.740 | They start taking L-carnitine and they start feeling better.

01:13:55.420 | And they talk about dosages in those various studies.

01:13:57.780 | It also has been shown to have a notable decrease

01:14:00.980 | in the symptoms of autism, which I find fascinating also.

01:14:04.400 | Again, the things we ingest impact the chemicals

01:14:08.600 | in our brain and how they impact the rest of our body.

01:14:11.540 | There's other things that's been used

01:14:12.920 | to treat certain forms of alcohol dependence.

01:14:15.480 | I think this is going to be

01:14:16.740 | a very exciting emerging area.

01:14:19.300 | We're going to do a whole month about addiction.

01:14:20.940 | I've got a great guest lined up for that month,

01:14:23.260 | but there's now an emerging field

01:14:27.060 | about what people can take and supplement

01:14:29.400 | to help ease the cravings and the withdrawal

01:14:32.860 | when trying to quit drugs of abuse, like cocaine, alcohol,

01:14:36.660 | heroin, and smoking, and things of that sort.

01:14:39.100 | So really interesting area.

01:14:41.700 | This is, I like to think is early days,

01:14:43.740 | and then we're going to discover a lot more.

01:14:44.900 | There's a huge list of things here.

01:14:47.300 | Since we talked about pain in a previous episode,

01:14:49.180 | and I know a lot of people have written to me

01:14:52.140 | about fibromyalgia, it does,

01:14:54.300 | carnitine has been shown to reduce symptoms of fibromyalgia.

01:14:57.660 | Again, all the links to studies are on examine.com,

01:15:01.340 | totally free site.

01:15:02.740 | And that was my bulldog being a battering ram.

01:15:05.660 | There's nothing graceful about this bulldog.

01:15:07.620 | He's decided he wanted to leave to go get a drink of water,

01:15:09.840 | and so please forgive the noise.

01:15:11.500 | Okay, so now let's turn to another aspect

01:15:15.220 | of the gut-brain relationship that will surprise you,

01:15:20.140 | in some cases might shock you,

01:15:22.100 | and that has some really cool and actionable biology.

01:15:25.780 | And that's the gut microbiome, probiotics, and prebiotics.

01:15:30.780 | I know today we're talking about emotions and not pain,

01:15:34.220 | but I'd be remiss if I didn't mention another effect

01:15:36.580 | of acetyl-L-carnitine that's been reported,

01:15:39.020 | and that you can find listed with link to study

01:15:41.500 | on examine.com, which is its effect in reducing

01:15:45.300 | the symptoms of migraine.

01:15:47.160 | This was a randomized controlled trial

01:15:49.740 | with 133 participants who had frequent migraines.

01:15:53.300 | They were taking 500 milligrams of L-carnitine

01:15:57.500 | or nothing for 12 weeks.

01:16:00.420 | So the control is a little bit,

01:16:02.220 | the control experiment there is a little bit tricky,

01:16:04.120 | but it had a significant effect on reducing the number

01:16:06.920 | of migraine attacks per month.

01:16:08.340 | So I find that really interesting.

01:16:10.460 | And there's a lot more listed there about the study.

01:16:13.740 | And I think these compounds are powerful.

01:16:17.260 | They carry risks for certain people, not for others.

01:16:19.680 | So again, you have to find out what's right for you.

01:16:22.960 | But I do think they are super interesting

01:16:25.760 | as potential therapeutics for various people.

01:16:28.800 | So what's the deal with the gut microbiome

01:16:32.260 | and the gut-brain axis?

01:16:34.300 | Today we've actually been talking a lot already

01:16:36.700 | about the gut-brain axis

01:16:38.740 | that has nothing to do with microbiomes.

01:16:40.860 | We've been talking about this vagus nerve

01:16:43.180 | that connects providing sensory information

01:16:47.380 | from the body to the brain.

01:16:48.820 | And then the brain also sends in the same nerve

01:16:52.560 | motor information to control the motility,

01:16:55.220 | the gut, the heart rate, how fast we breathe,

01:16:57.880 | and deployment of immune stuff, killer cells,

01:17:02.100 | and things of that sort.

01:17:03.300 | But oftentimes when we hear about the gut-brain axis,

01:17:08.500 | these days, it's a discussion about the gut microbiome.

01:17:13.100 | And once again, we're in a situation

01:17:15.220 | where there's incredible biology.

01:17:18.140 | I'm very happy there's so much discussion

01:17:20.100 | about the gut microbiome.

01:17:21.780 | I am somewhat dismayed and concerned

01:17:24.260 | that most of what I hear out there

01:17:26.140 | is either false or partially false.

01:17:29.440 | So we're going to clear up some of the misconceptions,

01:17:32.580 | first by understanding the biology,

01:17:34.100 | and then we're going to talk about

01:17:34.940 | some of the actionable items.

01:17:36.420 | It is true that we have a lot of these little microorganisms

01:17:41.420 | living in our gut.

01:17:46.200 | They're not there because they want to help us.

01:17:49.380 | They don't have brains.

01:17:50.660 | They are adaptive, however.

01:17:52.440 | They try and find and create environments

01:17:56.540 | that make it easier for them to proliferate.

01:17:59.140 | So they don't care about you and me,

01:18:01.340 | but they are perfectly willing to exploit you and me

01:18:04.640 | in order to make more of themselves,

01:18:07.180 | the same way viruses are.

01:18:08.320 | Viruses don't have a mind.

01:18:09.620 | They infect cells, they hijack the genome,

01:18:11.660 | and they use that genome to make more of themselves.

01:18:14.260 | The microbiota that live in us

01:18:19.620 | vary along the length of our digestive tract,

01:18:22.720 | but let's just take a step back

01:18:23.760 | and think about how our body plan is made.

01:18:26.740 | We are actually a series of tubes.

01:18:28.660 | Our brain is actually a tube.

01:18:29.860 | You see it's all squishy on the outside,

01:18:31.740 | and then it's got that long thing,

01:18:32.980 | the spinal cord that goes down to the base of the spine.

01:18:34.980 | That's the central nervous system.

01:18:36.420 | That all started out as a tube.

01:18:37.920 | It just looks like a cauliflower on the other end

01:18:40.960 | up in the brain because the tube is so big

01:18:45.200 | and it has to be crammed into the skull

01:18:46.660 | so it gets all wrinkled up.

01:18:48.200 | But if we were to splay it out,

01:18:49.720 | you'd find that it's just one big tube.

01:18:52.280 | Similarly, our digestive tract and our airways

01:18:55.200 | are essentially one big tube.

01:18:57.660 | It starts with our mouth, also our nose,

01:19:00.220 | and then we have all these other tubes

01:19:01.640 | that go down through our throat and then into our stomach

01:19:05.040 | and then into our various intestines,

01:19:07.300 | and then the tube ends out the other end.

01:19:10.480 | So we are one long tube for digestion.

01:19:12.760 | And inside of that tube is a mucosal lining.

01:19:16.480 | It's these little microvilli, tiny, tiny, tiny little,

01:19:19.320 | like velvety ends of cells that are able to move

01:19:24.000 | and move things along, and mucus, mucosa.

01:19:29.320 | And the conditions of that mucosal lining

01:19:32.640 | set a number of different things.

01:19:34.660 | It sets the rate of our digestion

01:19:36.840 | and the quality of our digestion.

01:19:38.920 | It sets, for instance, our immune system.

01:19:41.360 | Most people probably don't realize this,

01:19:42.800 | but most infections in the environment,

01:19:45.080 | well, they have to get into our body somehow.

01:19:47.080 | Some of them are inhaled.

01:19:49.400 | A lot of them go into our mouth

01:19:51.160 | and lodge in the mucosal lining of the mouth,

01:19:53.760 | and then infections start there.

01:19:56.000 | You probably had the experience, unfortunately,

01:19:58.040 | of feeling like you have a tick in your throat,

01:20:00.060 | like something's irritating your throat,

01:20:01.360 | and then it kind of migrates up into a head cold

01:20:04.160 | or a runny nose.

01:20:06.120 | Sometimes it'll start as a headache.

01:20:07.520 | Sometimes it won't.

01:20:08.800 | But things that can migrate down into the gut.

01:20:12.680 | So we're ingesting things all the time.

01:20:14.720 | Think about air, bacteria, viruses.

01:20:17.540 | They're making their way into our gut.

01:20:19.440 | And some of those bacteria live in the gut,

01:20:21.920 | and some of those bacteria bias the mucosal lining

01:20:26.440 | in the gut, stomach and intestines,

01:20:29.800 | to be more acidic or more basic

01:20:33.920 | so that they can make more of themselves,

01:20:36.140 | so they can replicate.

01:20:36.980 | They like a particular comfort.

01:20:38.400 | It's like they like a particular kind of bedding

01:20:41.840 | to lie down in and create more of themselves.

01:20:44.680 | Now, some of those mucosal linings that they promote

01:20:48.960 | make us feel better.

01:20:50.200 | They make us feel more alert.

01:20:51.400 | They bolster our immune system,

01:20:52.760 | and others make us feel worse.

01:20:54.520 | So first rule, the microbiome isn't good or bad.

01:20:59.520 | Some of these little bugs that live in us

01:21:02.440 | do bad things to us.

01:21:03.600 | They make us feel worse.

01:21:05.120 | They lower our immunity.

01:21:06.520 | They affect us in negative ways.

01:21:08.840 | Some of them make us feel better.

01:21:10.400 | And they do that mainly by changing the conditions

01:21:13.960 | of our gut environment.

01:21:16.680 | In addition to that, they do impact the neurotransmitters

01:21:22.720 | and the neurons that live in the gut

01:21:25.360 | and that signal up to the brain

01:21:26.960 | to impact things like dopamine and serotonin

01:21:28.960 | that we've been talking about previously.

01:21:31.280 | So there's a vast world now

01:21:35.200 | devoted to trying to understand what sources of food,

01:21:38.520 | what kinds of foods are good or not good

01:21:41.280 | for the gut microbiome.

01:21:42.460 | So let's just talk about some general rules of thumb

01:21:44.800 | related to the research,

01:21:46.040 | quality research that's peer reviewed.

01:21:48.000 | And then in a future episode,

01:21:49.560 | we will go far deeper into the gut microbiome

01:21:52.540 | and gut brain access.

01:21:54.040 | But here's a few things

01:21:56.140 | that I think you might find surprising.

01:21:59.200 | First of all, supporting a healthy gut microbiome

01:22:02.740 | is good for mood, great for digestion

01:22:05.760 | and great for immune system function.

01:22:08.560 | However, that does not mean maxing out

01:22:13.240 | or taking the most probiotic and prebiotic

01:22:16.280 | that you can possibly manage.

01:22:18.200 | As I mentioned many times before,

01:22:19.740 | I do believe in probiotics.

01:22:21.400 | I take probiotics.

01:22:22.780 | But there are studies that show

01:22:23.920 | that if you take lots and lots of certain probiotics

01:22:27.320 | like lactobacillus and you really ramp up the levels more,

01:22:30.740 | it is not a case of more is better.

01:22:33.040 | There are things like brain fog that can come from that.

01:22:37.120 | Brain fog is just this inability to focus.

01:22:39.400 | People feel really not well generally.

01:22:41.920 | Some of those studies are a little bit controversial

01:22:43.560 | but I think it's fair to say that if people

01:22:46.100 | really increase the amount of probiotic

01:22:48.880 | that they're taking beyond a certain amount,

01:22:52.480 | then they start feeling foggy in the mind.

01:22:55.440 | Now, what's too much?

01:22:57.160 | Well, I get probiotics from,

01:23:00.240 | I've mentioned before, from athletic greens.

01:23:01.760 | You can get them from fermented foods

01:23:03.380 | like sauerkraut, pickles, kimchi, natto.

01:23:07.840 | These are different sources from around the world.

01:23:09.920 | Actually, I'd love to hear some of the other sources

01:23:11.860 | that people know, other foods from around the world.

01:23:13.740 | I'm fascinated by the way in which different cultures

01:23:17.080 | have all arrived at these foods that provide

01:23:22.080 | and support healthy microbiomes because they're fermented.

01:23:25.600 | I have a colleague at Stanford, Justin Sonnenberg.

01:23:28.760 | He and I have talked about this.

01:23:29.760 | I don't want to quote him inappropriately

01:23:33.880 | but we've had discussions about it and they've published

01:23:36.060 | that the ingestion of fermented foods

01:23:38.840 | is one of the best ways to support healthy levels

01:23:41.280 | of gut microbiota without exceeding the threshold

01:23:45.480 | that would cause things like brain fog.

01:23:47.940 | So foods and fermented foods are going to be the best source

01:23:51.240 | and there are a number of different ways

01:23:54.060 | that one could do that.

01:23:54.900 | Some people don't like fermented foods,

01:23:55.920 | however, some people supplement it.

01:23:57.920 | So it isn't a case of more is better.

01:24:00.760 | Okay, so we know that.

01:24:02.220 | The other is that it is true that healthy gut microbiota

01:24:06.920 | have been shown to improve symptoms

01:24:08.860 | of certain psychiatric illnesses

01:24:11.160 | as well as certain conditions like particular features

01:24:15.600 | along the autism spectrum, which is interesting.

01:24:17.920 | And those effects are probably due to not just improvement

01:24:21.880 | of immune system function but to the conditions

01:24:25.480 | in which the neurons that sense nutrients

01:24:29.140 | convey information to the brain

01:24:30.720 | and increase levels of serotonin and or dopamine.

01:24:34.280 | So gut microbiome provides kind of a foundation

01:24:37.400 | for healthy gut and healthy gut brain access.

01:24:41.160 | So much so that some people report

01:24:42.860 | that when they start eating small bits,

01:24:45.440 | 'cause it doesn't require a lot of fermented foods,

01:24:47.640 | that their overall mood is better.

01:24:49.080 | Not unlike the effects of EPA,

01:24:50.560 | although I don't think it's been looked at

01:24:52.600 | directly in the context of clinical depression yet.

01:24:55.760 | And if someone knows of a study,

01:24:57.440 | please mention it in the comments.

01:24:58.720 | That would be terrific.

01:24:59.880 | There are some things that you can do

01:25:02.200 | to really damage your gut microbiome.

01:25:04.540 | And this is where there's a huge misconception

01:25:06.860 | that I want to clear up.

01:25:08.480 | There was a study that was published in Nature,

01:25:10.580 | which is among the three top journals

01:25:13.260 | that we have in Science.

01:25:14.700 | Nature, Science, and Cell are considered the top tops,

01:25:17.460 | but excellent journal that showed

01:25:20.260 | that artificial sweeteners,

01:25:21.880 | but a particular artificial sweetener, which was saccharin,

01:25:25.440 | can disrupt the gut microbiome

01:25:28.660 | in ways that is detrimental

01:25:30.060 | to a number of different health markers,

01:25:32.120 | increasing inflammatory cytokines

01:25:34.500 | and all the other bad things that happen

01:25:36.720 | when the gut microbiome is thrown off kilter.

01:25:41.420 | That study was widely discussed,

01:25:43.740 | but there were a few things that were not mentioned there

01:25:46.300 | that are really important.

01:25:47.700 | That study was about saccharin in particular.

01:25:50.860 | Saccharin is not the most typical

01:25:54.620 | artificial sweetener that's used.

01:25:56.980 | The most typical artificial sweeteners that are used

01:25:59.640 | are things like aspartame, so-called NutraSweet,

01:26:03.180 | or sucralose, or these days, stevia.

01:26:05.640 | There's monk fruits, to my knowledge,

01:26:07.860 | and please correct me if anyone knows of any studies,

01:26:09.900 | to my knowledge, the negative effects

01:26:13.420 | of these artificial sweeteners on the gut microbiome

01:26:17.540 | were restricted to saccharin.

01:26:20.100 | Now, there is enough chemical similarity

01:26:22.580 | between saccharin and some of the other ones

01:26:24.540 | that I mentioned, but not all of them.

01:26:25.900 | For instance, stevia, monk fruit are distinct

01:26:29.660 | in their chemical makeup so that they probably don't have,

01:26:35.020 | if they have any, have lower effects,

01:26:37.100 | negative effects on the gut microbiome,

01:26:38.780 | but it should still be tested.

01:26:40.560 | So saccharin is really, it was shown in this study

01:26:43.780 | and several other studies,

01:26:45.000 | can really negatively impact, excuse me,

01:26:48.480 | the quality of the gut microbiome.

01:26:50.680 | Interestingly, the narrative around artificial sweeteners

01:26:54.380 | and gut microbiome is incorrect.

01:26:58.920 | Most people thought, oh, saccharin is bad for the microbiome.

01:27:02.900 | It must kill the microbiome.

01:27:04.840 | And so you hear people saying, oh, you know,

01:27:06.480 | artificial sweeteners kill the microbiome.

01:27:08.300 | That's not true at all.

01:27:09.140 | In fact, in that very same study published in Nature,

01:27:11.740 | they showed that the negative effects of saccharin

01:27:14.380 | on the microbiome could be blocked or eliminated

01:27:17.500 | by giving antibiotics.

01:27:19.620 | So what happens is certain artificial sweeteners,

01:27:22.260 | in particular saccharin, disrupt the microbiome

01:27:26.260 | and make the environment within the gut,

01:27:29.120 | that mucosal lining, more favorable

01:27:32.220 | to bacteria microbiota that are not good for the organism.

01:27:37.220 | Okay, this is an important distinction.

01:27:40.260 | It's not just that a language thing where people say,

01:27:42.800 | oh, you know, it kills the microbiome.

01:27:44.860 | It doesn't kill the microbiome, it shifts the microbiome.

01:27:48.280 | And shifts in the microbiome can be good

01:27:50.420 | or they can be bad.

01:27:51.340 | And that takes us to another topic.

01:27:53.460 | That's a bit of a hot button topic,

01:27:54.880 | but I'm willing to go there

01:27:55.780 | 'cause I think it deserves conversation,

01:27:58.080 | which is nowadays there are many examples out there

01:28:01.620 | where people have switched from a kind of standard diet

01:28:04.640 | or even a vegetarian diet or vegan diet to a keto diet.

01:28:09.640 | Now, keto doesn't necessarily have to mean

01:28:11.380 | the ingestion of meats, but it can.

01:28:14.380 | And they experience positive effects for themselves,

01:28:17.040 | not everybody.

01:28:17.880 | And I've talked previously about some of the

01:28:19.980 | kind of the incorrect,

01:28:23.500 | what I believe is incorrect marketing of keto

01:28:25.760 | as it relates to the cosmetic effects

01:28:28.020 | and some of the challenges with sleep that some people have.

01:28:30.060 | But some people love keto and it works great for them.

01:28:32.340 | But the ketogenic diet is interesting

01:28:35.340 | because when one shifts to the ketogenic diet,

01:28:37.860 | there is a shift in the gut microbiome

01:28:39.720 | and some people end up feeling better.

01:28:41.580 | Some people end up feeling worse.

01:28:43.800 | Likewise, some people go from ingesting animal products,

01:28:49.280 | including meat or they're vegetarian and they go to vegan,

01:28:52.860 | and they experience positive shifts in mood and affect.

01:28:57.140 | And we know that the transition to a more plant-based diet

01:29:01.940 | and especially the enrichment of fiber

01:29:04.420 | that's present in those diets

01:29:06.660 | also creates dramatic shifts in the gut microbiome.

01:29:09.940 | Some people feel better doing that, some people feel worse.

01:29:12.740 | And of course, it's going to depend on whether or not

01:29:14.540 | you're ingesting a lot of processed foods or not.

01:29:16.300 | There was a paper published in Cell,

01:29:18.940 | a Cell Press Journal, obviously, excellent journal,

01:29:21.140 | showing that ingestion of processed foods,

01:29:23.540 | regardless of whether or not they come from animal sources

01:29:26.360 | or non-animal sources,

01:29:28.000 | the processed foods themselves

01:29:29.420 | tend to create activity within the body.

01:29:33.100 | And this surely has roots in the nervous system

01:29:34.960 | that lead to over-consumption of calories and weight gain,

01:29:38.860 | even some weight gain that couldn't be explained

01:29:40.940 | by increased calories.

01:29:41.820 | In other words, processed foods are bad

01:29:43.380 | regardless of whether or not

01:29:44.640 | you're talking about animal products or non-animal products.

01:29:47.580 | Probably not surprising now,

01:29:48.700 | given what you know about these sugar sensing

01:29:50.700 | and other amino acid sensing cells in the gut

01:29:53.300 | that we talked about earlier.

01:29:54.820 | So the point of all this is that when I say

01:29:57.680 | you have to find what's right for you,

01:29:59.240 | that's not a throwaway statement.

01:30:01.180 | Some people's microbiome and the lining of their mucosa,

01:30:06.180 | excuse me, the mucosa lining of their throat,

01:30:10.800 | of their gut, of their nose, everything is improved

01:30:14.400 | by diets that are heavily meat-based

01:30:16.380 | and don't have many plants.

01:30:17.480 | Other people do much better on a plant-based diet

01:30:20.300 | without many meat products or animal products.

01:30:22.480 | It's highly individual.

01:30:23.900 | And this probably has roots in genetic makeup.

01:30:26.660 | This probably has roots in what people were raised on.

01:30:30.460 | Because remember, the nervous system, of course,

01:30:32.900 | is set up by your genes, your genetic program,

01:30:35.580 | but your nervous system,

01:30:36.740 | it adapts early in life to your conditions.

01:30:40.300 | That's what it's for.

01:30:41.140 | The reason you have a nervous system

01:30:42.420 | is to move your body appropriately

01:30:44.620 | towards things that are good for you

01:30:45.820 | and away from things that are not.

01:30:47.080 | But also, it was designed to adapt.

01:30:50.160 | The early life period has this incredible thing

01:30:52.280 | about plasticity that we spent a whole month on

01:30:54.260 | so that it can change so that, yes, indeed,

01:30:56.520 | some people may like certain foods

01:30:57.920 | and react to certain foods better than others

01:31:00.140 | because of the way that their nervous system was wired,

01:31:03.280 | this enteric, as it's called, nervous system

01:31:05.460 | that lines the gut and that communicates with the brain.

01:31:08.320 | So most of what I've talked about today

01:31:10.060 | is black and white.

01:31:12.560 | These are things that are present in all of us,

01:31:14.160 | the sugar-sensing neurons of the gut,

01:31:15.560 | the way the vagus is wired,

01:31:17.240 | the fact that omega-3, omega-6s tend to improve,

01:31:20.040 | that the ratios tend to impact mood with high omega-3,

01:31:22.920 | omega-6 ratios improving mood.

01:31:25.240 | We talked about all sorts of things

01:31:27.580 | in the gut-brain and body-brain axis.

01:31:30.080 | But when it comes to the microbiome,

01:31:32.320 | the key thing is that we all have a microbiome.

01:31:34.740 | You want a microbiome,

01:31:36.200 | but you want to promote the microbiome

01:31:38.680 | that is right for you.

01:31:40.300 | And that can be shifted and steered

01:31:43.080 | by ingesting certain categories of foods and not others.

01:31:47.320 | And one thing that really frustrates me

01:31:49.120 | is when the people show up with an agenda,

01:31:51.360 | like an all-meat agenda or a vegan agenda or a keto agenda,

01:31:55.680 | and they talk about these positive effects

01:31:57.320 | on the gut microbiome, and it's all true, frankly.

01:32:00.240 | And so it's highly individual.

01:32:01.440 | Now, this doesn't get to any of the ethical issues

01:32:03.600 | around animals or the planet,

01:32:05.160 | and you hear rabid debates about that on both sides.

01:32:10.600 | And I am not qualified or equipped to talk about

01:32:13.980 | whether or not regenerative agriculture

01:32:16.480 | or animal products or farming or any of these things,

01:32:18.400 | how those actually impact the environment.

01:32:20.540 | That is not my expertise.

01:32:22.220 | But when it comes to your health and your microbiome,

01:32:24.520 | you want to support the microbiome.

01:32:26.040 | It's very clear that these fermented foods

01:32:28.460 | support the microbiome,

01:32:30.040 | that we should be ingesting at least two servings per day,

01:32:33.640 | which is quite a lot.

01:32:35.280 | That supplementation at low levels can be good.

01:32:38.760 | Supplementation at high levels can create this brain fog.

01:32:41.280 | Even though some people say that result is controversial,

01:32:44.240 | I've experienced this myself,

01:32:45.520 | and the data looked to me pretty darn solid.

01:32:49.080 | So that's one thing to think about as well.

01:32:52.560 | And the other thing about the gut microbiome

01:32:55.500 | is that it's highly contextual

01:32:57.160 | based on other things that you're doing.

01:32:58.700 | So even things like exercise and social wellbeing

01:33:01.440 | and connection,

01:33:02.280 | those things are also impacting the gut microbiome.

01:33:04.280 | So find the diet that's right for you

01:33:06.280 | and that works for you in the context of the other ethical

01:33:10.360 | and lifestyle choices that are important to you.

01:33:12.380 | That's my advice.

01:33:13.440 | A note about fasting.

01:33:14.980 | I have a colleague at Yale

01:33:16.160 | who's an expert in the gut microbiome,

01:33:18.040 | and he told me something really interesting,

01:33:20.560 | which is when we fast,

01:33:23.000 | we actually digest certain components

01:33:27.880 | within our dietary tract.

01:33:29.980 | It actually depletes a good amount of the gut microbiome.

01:33:33.320 | And this is interesting.

01:33:34.240 | I've had good results from,

01:33:36.700 | I guess you would call it intermittent

01:33:38.120 | or kind of circadian type fasting

01:33:40.040 | where I've never done long fast,

01:33:41.400 | but where I push out my first meal by a few hours.

01:33:43.840 | My first meal is generally around lunchtime or so.

01:33:46.640 | But the longer periods of fasting

01:33:49.280 | that go for a day or two or three days

01:33:51.240 | are known to deplete the gut microbiome in major ways.

01:33:55.720 | And, but that's not always necessarily a bad thing

01:33:58.120 | because when it's replenished,

01:34:01.100 | it often is replenished at levels

01:34:03.440 | that exceeded its previous level.

01:34:05.600 | But I think that some of the GI tract

01:34:09.200 | and even some of the mental effects

01:34:10.920 | of returning to eating after feeding,

01:34:12.580 | sometimes people don't feel so good when they start eating.

01:34:14.620 | They really want food, but then they start eating again,

01:34:16.360 | they don't feel as good as they did on the fast.

01:34:18.240 | Some of that may be related to the depletion

01:34:20.800 | of the microbiome that occurs during long fast.

01:34:23.120 | So again, this is something to think about

01:34:24.800 | and talk about with your doctor.

01:34:26.440 | But the idea that fasting across the board is good,

01:34:31.000 | there may be some merits to that,

01:34:32.320 | and certainly in some cases,

01:34:33.700 | but it does deplete the microbiome.

01:34:36.640 | And that depletion of the microbiome is significant

01:34:38.960 | because it means when you return to eating,

01:34:41.160 | you're actually not in the same position

01:34:43.180 | to digest and assimilate those foods.

01:34:45.200 | And those foods are not in the same position

01:34:47.060 | to impact your brain and body

01:34:48.300 | the same way they were prior to the fast.

01:34:50.920 | And this is, I think, why people suggest

01:34:52.480 | a kind of gradual transition back

01:34:54.800 | to consuming nutrients after a fast.

01:34:58.280 | So as we round up, I want to share some results with you

01:35:01.500 | that without question will impact the way

01:35:04.680 | that you respond to food mentally and even physically.

01:35:08.780 | And I know that because that's the central theme

01:35:11.500 | of the studies I'm about to tell you about.

01:35:13.860 | I have a colleague at Stanford, Aaliyah Crum,

01:35:16.660 | who's done some remarkable experiments on mindset.

01:35:20.880 | And some people could think about these

01:35:23.320 | as placebo effects or belief effects,

01:35:26.120 | but they actually go way beyond those terms.

01:35:29.460 | And there are a number of different examples of this

01:35:32.300 | that Aaliyah's lab and her coworkers have demonstrated,

01:35:35.440 | but two that are particularly interesting to me,

01:35:39.640 | I want to share with you now,

01:35:40.700 | because they really emphasize how our beliefs

01:35:44.100 | can really impact the way

01:35:45.340 | that our brain and body work together.

01:35:47.560 | I think the most famous of these is an experiment they did

01:35:50.080 | where they had two groups of individuals.

01:35:52.100 | They were each given a milkshake,

01:35:55.760 | and they had some factors measured from their blood

01:35:59.840 | by an IV while they ingested the milkshake

01:36:02.280 | and then afterwards as well.

01:36:04.360 | And one of the factors that they were looking at

01:36:06.760 | was something called ghrelin, G-H-R-E-L-I-N.

01:36:10.720 | Ghrelin is a peptide that increases with hunger.

01:36:13.820 | So the longer you haven't eaten, the ghrelin goes up.

01:36:16.300 | And I know some of you say, well, I fast, I fast, I fast,

01:36:18.740 | and I eventually lose my appetite.

01:36:19.980 | Well, ghrelin still goes up and then it drops.

01:36:22.140 | So if you were one of these people

01:36:24.020 | that eats every three hours regularly,

01:36:26.180 | ghrelin kind of gets a little pulse

01:36:28.000 | as you get to that two hour and 50 minute mark.

01:36:30.540 | So it's a little bit of a timer as well.

01:36:32.340 | It's really interesting peptide.

01:36:34.760 | In any event, what they did is they gave people milkshakes,

01:36:39.020 | two groups, one group got a shake that they were told

01:36:42.580 | was a low calorie healthy shake.

01:36:44.700 | The other group got a milkshake that they were told

01:36:48.300 | was the very decadent high calorie shake.

01:36:52.180 | I think it was something like two or maybe even

01:36:54.360 | two and a half times as many calories as the other,

01:36:57.380 | perhaps even more.

01:36:58.760 | I don't recall the details,

01:36:59.700 | but you had a high calorie and a low calorie condition.

01:37:02.220 | And then they drank the shake,

01:37:04.580 | and then they measured ghrelin in these subjects blood.

01:37:08.440 | And what they found was that the high calorie shake

01:37:12.060 | had a much more robust effect on blunting ghrelin

01:37:15.980 | and reducing ghrelin.

01:37:17.800 | But the interesting thing you probably guessed already

01:37:20.900 | is that it was the exact same shake given to both groups.

01:37:24.580 | So people's belief about the content of something

01:37:28.740 | impacted their physiology.

01:37:31.260 | And this speaks to these so-called top-down mechanisms

01:37:35.260 | or modulation of our physiology.

01:37:37.500 | In the previous episode about pain,

01:37:38.740 | we talked about the effects of obsessive,

01:37:42.100 | believe it or not, it was kind of obsessive infatuation

01:37:44.700 | and love on pain responses and pain thresholds.

01:37:47.660 | This is yet another example where beliefs

01:37:50.040 | or subjective feelings can impact physiology

01:37:52.940 | at the level of the periphery,

01:37:54.080 | because ghrelin is released in the periphery in the body.

01:37:57.660 | Now, these belief effects extend beyond examples like this.

01:38:01.680 | Another good example that I'd like to share

01:38:03.440 | is Ali Dr. Crum and her colleagues did an experiment

01:38:08.440 | where they took housekeepers,

01:38:12.620 | they were essentially hotel workers,

01:38:14.180 | divide them into two groups.

01:38:15.400 | They had them watch a short film.

01:38:17.140 | In one case, the film was about how

01:38:19.460 | their work was important,

01:38:20.620 | it helped people feel comfortable in the hotel,

01:38:22.400 | et cetera, et cetera.

01:38:23.740 | The other group heard that the activity

01:38:25.680 | that they were doing,

01:38:26.620 | cleaning and taking care of the hotel was good for them,

01:38:29.200 | it was good for their health, et cetera, et cetera.

01:38:32.620 | They controlled very nicely in the study

01:38:34.940 | for health parameters, for individual differences,

01:38:38.960 | and for the behaviors of these people

01:38:40.820 | in the period that followed this short tutorial.

01:38:43.820 | And what they found was eight weeks later,

01:38:47.700 | the group that had been told

01:38:49.620 | that the activity was good for them

01:38:51.860 | showed lower blood pressure,

01:38:53.500 | they had lost a significant amount of body fat,

01:38:56.060 | and they reported enjoying their work

01:38:58.620 | far more than the other group.

01:39:00.040 | The same work, simply biased mentally

01:39:04.740 | by the information that they were given,

01:39:06.500 | but their physiology followed that information.

01:39:10.740 | And so this is not just the placebo effect,

01:39:14.140 | this is an incredible set of findings

01:39:16.560 | that illustrate the extent to which

01:39:18.140 | whether or not we believe a food is gonna be good for us

01:39:21.000 | or not good for us,

01:39:22.860 | well, we can't escape the reality.

01:39:24.620 | You can't tell yourself that a poison

01:39:26.180 | is gonna be good for you and ingest that poison

01:39:27.980 | and expect it to not kill you,

01:39:29.980 | nor can you tell yourself that eating 12 croissants,

01:39:34.980 | confess I've done it,

01:39:36.500 | it was after a very long run, a long time ago,

01:39:39.100 | but you can't tell yourself

01:39:40.080 | that that's necessarily going to be good for you

01:39:42.960 | or that it's gonna make you lose weight.

01:39:44.940 | These belief effects are not about lying to yourself.

01:39:48.040 | In these cases, in these experiments, as you'll notice,

01:39:50.780 | the subjects didn't have prior knowledge

01:39:53.740 | about ghrelin or about the effects of their daily routine

01:39:56.920 | on weight loss and blood pressure.

01:39:58.940 | So in order for them to work,

01:40:00.080 | you have to be naive to the information, right?

01:40:03.700 | You can't simply lie to yourself

01:40:05.300 | and tell yourself what you want to believe.

01:40:07.740 | And that's important, but also important is that the mind

01:40:12.300 | and the body are in this fascinating interplay.

01:40:14.780 | And today we've talked mainly about

01:40:16.780 | how the body and things that we put inside this tube,

01:40:20.580 | this that runs from our mouth to the other end,

01:40:24.220 | to our rectum basically is impacting all these cells,

01:40:28.040 | these neurons, microbiota in there,

01:40:31.180 | mucosal lining, heart, lungs,

01:40:34.080 | and how all that information is feeding up to the brain

01:40:36.160 | to impact how we feel up here.

01:40:38.080 | But also how we feel up here

01:40:39.700 | is impacting how our body reacts

01:40:42.380 | at levels of very core physiology

01:40:44.860 | that you couldn't just tell yourself

01:40:46.820 | that this was gonna work,

01:40:47.860 | but what you believe about certain substances,

01:40:51.100 | certain foods, certain nutrients

01:40:52.980 | does have a profound effect

01:40:54.500 | on the magnitude of their impact

01:40:57.260 | and sometimes even the quality and direction of that impact.

01:41:01.320 | Well, first of all,

01:41:02.160 | I wanna thank everybody for their support of this podcast.

01:41:05.240 | The response that we've received since releasing

01:41:07.740 | at the beginning of the new year has been tremendous

01:41:10.260 | and we're so grateful for it.

01:41:12.340 | I know some of you and people you know have said,

01:41:15.060 | well, it's a lot of information.

01:41:16.420 | It's like a college lecture.

01:41:18.260 | Indeed, there's a lot of information,

01:41:19.980 | but I believe very strongly that if you learn mechanism

01:41:24.020 | and maybe even if you hear it several times over,

01:41:26.620 | eventually those mechanisms become embedded

01:41:28.620 | into the way that you view an entire topic.

01:41:31.460 | As well, I always try and put tools

01:41:33.820 | as I go along that you can look to immediately.

01:41:36.460 | Some of them might be right for you,

01:41:37.880 | others might not.

01:41:39.140 | Try them if you like and don't if you don't want to,

01:41:41.900 | and if they don't work for you, then discard them.

01:41:44.400 | If, however, you are finding benefits from the information

01:41:47.520 | and from the tools and you know others

01:41:49.580 | that you think could benefit from it,

01:41:51.480 | please pass along information about the podcast.

01:41:55.040 | Please subscribe to the YouTube channel

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01:42:09.680 | In addition, if you'd like to support the podcast further,

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01:42:14.240 | It's patreon.com/andrewhuberman.

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01:42:20.940 | We have the 5HTP, serotonin for $5 a month,

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01:42:35.600 | That's one of the best ways to help support us.

01:42:37.880 | And we do believe in all the products that we support

01:42:41.480 | and our sponsors very much.

01:42:43.080 | Otherwise we wouldn't be working with them.

01:42:45.760 | So much so that when I mentioned supplements

01:42:48.880 | and I talk about supplements

01:42:50.360 | throughout the course of the episodes,

01:42:52.360 | I don't mention specific brands,

01:42:53.800 | but I would be remiss if I didn't mention the fact

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01:43:01.440 | And we've done that because we know

01:43:04.200 | that Thorne uses the highest levels of stringency

01:43:06.640 | in terms of the products they produce,

01:43:09.360 | what they say is in each capsule and tablet actually is,

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01:43:14.320 | by all the major sports teams

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01:43:18.480 | If you want to know which supplements I take,

01:43:20.600 | you can go to thorne.com/u/huberman

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01:43:33.160 | So it's thorne.com/u/huberman

01:43:37.960 | to get 20% off any supplements that Thorne makes.

01:43:41.880 | So today's episode, we took a full journey

01:43:44.320 | into the brain-body relationship

01:43:45.960 | and discussed a lot of the mechanisms

01:43:47.800 | and the actionable items that you can approach

01:43:50.760 | if you want to explore this aspect

01:43:52.480 | of your biology and psychology further.

01:43:54.720 | Last, but certainly not least,

01:43:56.920 | I want to thank everybody for your time and attention today.

01:43:59.560 | And as always, thank you for your interest in science.

01:44:02.600 | [upbeat music]

01:44:05.180 | (upbeat music)

How Foods and Nutrients Control Our Moods

Chapters