SciShow Tangents - Hormones

Starting point is 00:00:00 Hello and welcome to SciShow Tangents, the lightly competitive science knowledge showcase. I'm your host, Hank Green, and joining me this week as always is science is science expert in Forbes 30 Under 30 Education Luminary, Sari Reilly. Hello. And today, instead of that ding-dong Sam Schultz, Sam wrote this, I think. I don't think anybody else would have called him a ding-dong. We have our other resident, usually behind the scenes, science expert. Oops, it's all science. It's Deboki Traugervardi.

Starting point is 00:00:42 I feel like if I say hi, I'm co-signing, calling Sam a ding-dong. But hello. Yeah. Sam's not a ding-dong. He's a ding-dong in all the best ways. Yeah. I've got a question for you. Since before we started the podcast, we were talking about Worcester, Massachusetts.

Starting point is 00:00:55 Yeah. What's the best sauce? Oh. I want to say like the green chutney sauce that you put on a samosa. I feel like when those two meet, that's a very, good sauce oh no i'm lying i'm wrong the best sauce the best sauce is the chili crisp oil the one that has like the like old auntie on it like the red cap that is the best sauce that goes on everything it belongs with everything you should eat it with everything it's good what. What is it? What's it called?

Starting point is 00:01:25 Lao Gan Ma. Oh, yeah. L-A-O-G-A-N-M-A. Actually, if you search Chili Crisp Oil Old Auntie, it comes up. They know. Everyone knows. She's the one. Yeah.

Starting point is 00:01:37 You know who that is. Yeah. I've never tried that. And I'm looking forward. I think Catherine will lose her shit over this. It seems right up her alley. Yeah, it's great. Because it's not just the taste. The flavor is great. The fact that it's oily is great. It seems right up her alley. Yeah, it's great. It's like, cause it's not just the taste.

Starting point is 00:01:47 The flavor's great. The fact that it's oily is great. It's also the texture. It's like the crisp is crisp. So like, it's always nice. Like if you put it on eggs or something, it's just always, it just really makes it good. All right, Sari. Come on with your Irish blood.

Starting point is 00:02:03 Yeah. My favorite sauce is brown gravy, which is up there, actually. I love gravy. I would stand by it. But I think my favorite sauce, my favorite deluxe sauce, is there is a diner-ish place,

Starting point is 00:02:19 also in the Boston area, that makes a strawberry habanero dipping sauce. And it is basically jam, but with a little spiciness. And I think it's great. I've had it with cheesy french fries. I've had it with tater tots. I've had it with like also potato products. So whatever you can dip a potato into to enhance the flavor is my favorite sauce. I'm a big fan of calling it the best thing just based on how much I use it. So it's got to be the best. Like otherwise I'd use the other sauces. So the answer

Starting point is 00:02:51 is honey mustard. Ketchup was in there in the running for me. Yeah. Ketchup has been overtaken by honey mustard in my house for sure. I'm not like usually a ketchup person. I have to like, I'm appreciating it more now that I'm older because it's like, oh yeah, sometimes I need like a little bit of a tomato flavor. I need a little bit of an acid in my food, but growing up, I hated ketchup. But you want that spicy chili crisp. Oh yeah. Yeah. I mean, those are two completely different food groups. Those are two. Like if ketchup was crispy, maybe I would like it, but. Spicy crispy ketchup coming soon from PokeCh great well i mean let's just mix them and see what happens yeah i think that's it i think more sauces should be crispy i feel like chili crisp has got

Starting point is 00:03:37 the dominant crisp in the market i'm sorry i whispered and i totally ruined sari's thought no that's okay you whispered but now it ruined Sari's thought. No, that's okay. You whispered, but now... I have a surprise package. I don't even know how they got my address, but it's from Nabisco, the creators of Oreo, and it was a package of Oreos. And I was like, well, you didn't tell me you were sending me these, so I don't feel any obligation to make content around them. So I just busted them open and had an Oreo. And then when I was finished with the Oreo, I was like, that was fine. And then my mouth started to bubble because there were pop rocks in the Oreo. And I did not read the introductory paragraph. I was like, why is this

Starting point is 00:04:15 so crunchy? What is happening to my mouth? Do you not tear your Oreos apart? Oh, no. I put it in my mouth as fast as I could. Okay. Okay. So like you had no way to prepare yourself other than by reading the letter. That's a very obvious way to prepare yourself. Yeah. Taking the tiniest amount of preparation. That doesn't sound like me. That is the purest Pop Rocks experience, though. Complete surprise.

Starting point is 00:04:40 Surprise Pop Rocks. Yeah. I can't wait to give one to Oren. This is our new sauce line where we just mix in pop rocks as a secret ingredient to every single sauce that is like the one thing to take the chili crisp oil to the next level is like surprise pop rocks i don't think you could put pop rocks in ketchup because ketchup has too much water and pop rocks reacts with water there's no water in chili oil yeah that's gonna be a win for me this is why we need the material scientists to create a little

Starting point is 00:05:06 like my cell kind of capsule encapsulate the pop rock so that dissolves in your tongue with your saliva enzymes but not in the ketchup we cracked it scientists go yeah we could do it i like the idea that this is our like uh hot ones so we're gonna do the weird chemistry experiment hot ones yeah my new hot ones show where we eat cookies that on the inside you don't know what there is i think i would eat those cookies actually i'd watch that show yeah and it's very you it's very on brand be like i'm gonna confuse you and teach you something yeah and you'll be like this is very gross and i don't know what it is and it only goes chocolate chip and mustard.

Starting point is 00:05:45 All right. Well, billion dollar ideas out here. Starting outside show tangents. This is a show where every week we get together to try to one up a maze and delight each other with science facts, while also trying and failing to stay on topic. Our panelists are playing for glory and for Hank Bucks, which I will be awarding as we play. And at the end of the episode, one of them will be crowned the winner. Now, as always, we're going to introduce this week's topic with a traditional science poem this week from Deboki. I wonder what it would be like to have a body that's hormone-free. Would I hear my thoughts more clearly or know even less of me? Would I still know how to love

Starting point is 00:06:19 without the oxytocin? And how would I spend my nights without some melatonin? And what does it mean when my mood swings and I do not feel like me, yet through the haze of hormones, I find some clarity? It's hard to know where I end and where the body begins, where the fear is mine and of my mind. Oh wait, maybe that belongs to adrenaline. Perhaps the answers cannot be found entirely in biology. I suppose these molecules help me live, but how is ultimately up to me. Hormones. The topic of the day is hormones, which I think we don't give them enough credit. They're doing a lot of stuff in there.

Starting point is 00:07:01 We're awful focused on the genome, I think, a lot of the time. I think the hormone's making a comeback, though. I think people are getting really into the hormones. We got to do the human hormone project. I guess we know all the hormones, right? Do we know all the hormones in the people anyway? I mean, how do we know if we know all the hormones? I don't think so.

Starting point is 00:07:20 I don't like that. I think we're missing a lot. Are we really? You think we're missing a lot. Are we really? You think we're missing a lot of the hormones? Or like missing our understanding of molecules that act as like 20 different things as opposed to just one different thing. The thing that you have to remember about your own goddamn body and all the animals and plants in life is that nobody was thinking, here, we'll use this to do this. It was just like, whatever worked is what you end up with. And so things are reused in a thousand different ways. It makes no sense. But Sari, what is a hormone?

Starting point is 00:07:57 Who really knows? Anyway, they're also a kind of recent thing. Like the understanding of them? The understanding of them, yes. So the word hormone, I'm going to start with the etymology this time. The first hormone and the word hormone was really, like the idea of it was crystallized in like 1902 to 1905-ish. So there is an English physician named Ernest Henry Starling and a physiologist named William Bayliss who were looking into like intestines and secretions and whatnot, like taking different organs that we thought would like control things in the body, like the thyroid and the spleen and whatnot, extracting stuff from them and trying to figure out how these things worked. So it was just like, let's pull chemicals out and put them somewhere else and be like, a thing occurred.

Starting point is 00:08:51 The chemical did it. Yep. The chemical did it. And now like, what are these chemicals? And at the time, at least the Pavlov school of thought thought that like a lot of neural nervous system reactions controlled the entire body so like neurons specifically you thought something or whether it was conscious or unconscious and then that controlled something so like for example what they were studying was the duodenal i think that's how you say duodenal duodenal acidification it's intestines getting your intestines all watery uh is what they were

Starting point is 00:09:25 studying and they extracted something from the pancreas which they called secretin that even if all nerves were removed from an intestine it induced an effect to or like all nerves were blocked that it induced that effect to have water flow in and out like change the water balance and so it was just this compound that induced that change in this body system and so then they called it a hormone from the ancient greek word hormone that means set in motion or to urge on so these compounds called hormones urge on another process within the body. And then from there, they kind of defined it as anything in a human or animal body that regulates another behavior. And specifically, like starting with the idea that it was produced by a gland,

Starting point is 00:10:19 and then travels through the bloodstream and then has a targeted effect somewhere else. And it has to be like a chemical that's separate from the cell because cells do that. Yeah. And I think that's where it gets. Yeah. Is that why the gland is like kind of an important part of that definition where it's like made somewhere, sent somewhere else. Sent somewhere else has that effect. But now our understanding of hormones has expanded and gotten so, so blurry where it's just like any biological compound that is used to like

Starting point is 00:10:51 organize or control or coordinate functions of any cells or tissues. And they can be created from lots of different places. Like we have the adrenal gland and we have the pituitary gland, but also fat cells create hormones that travel throughout the body. Plants have phytohormones. So like ethylene gas is a hormone. Like a banana. Yeah. Can ripen because of a hormone sent through the air by a different banana. But because it still falls under that umbrella for like a compound that causes a long-term change biologically are pheromones hormones then yeah it feels like that's probably why they have the own

Starting point is 00:11:30 yeah it's a it's it's a combination of the greek uh convey fear and with hormone it's a conveying moan and like an external maybe as opposed to an internal and i then ethylene is external so maybe i don't know depending on who who you are and what you're studying i guess if you study humans then hormones are internal pheromones are external but if you're studying plants then all bets are off this feels like one of those definitions that when we first came up with it it seemed really clear that we should have it and then we learned more and now it is confusing yeah well even like the first hormone being named secretin is like they thought that was genius they were like oh this one this one causes another the duodenum to secrete you know what no no my favorite is relaxin which is

Starting point is 00:12:18 like one of the early pregnancy hormones that literally just makes your like limbs just like weird and relaxed yeah they called it relaxin and like somehow that feels like an understatement as a name yeah you got you guys ever get sort of upset that you're just a bunch of chemicals researching this episode absolutely there's so much yeah some people sometimes people like are like the universe is so big and it's so upsetting to me and i'm like that's nope, that doesn't bug me anymore. Nope. What bugs me though, is I am like a bag of water. Yeah.

Starting point is 00:12:50 I don't even have time to think about the universe. I'm having a crisis about myself. Yeah. I'm just a bunch of, I'm just a bunch of chemicals that, that can think about themselves. And somehow keep working together to doing the right thing. Like we don't even know what the right order of things is. Yeah. And it works. It works so

Starting point is 00:13:05 well for so long and and then we die and people are like what went wrong and i'm like i don't know how did it go right i got like disease is just like the most complicated thing on the earth not working quite right yeah how did my cells divide correctly at every other point in my life yeah i mean it makes total sense that if a cell line is able to make more of itself in my body, there would be more of it until I die. So hopefully the doctor's got it. Anyway. All right.

Starting point is 00:13:35 Well, I feel like I don't know what a hormone is, but I also feel like I'm not supposed to, and nobody does. So we're going to be playing today, A Truth or Fails, written by Sam Schultz. So just so everybody knows, he's still with us in one way. It is currently in the vicinity of Valentine's Day when you are hearing this,

Starting point is 00:13:52 which means love either will be or is or was on your mind, possibly. Maybe not. And I wanted to celebrate that beautiful day of romance that either has happened or will happen imminently by presenting you with a Valentine's Day truth or fail featuring all of the hormones that make hearts and other stuff swell. Horrible, Sam. Horrible. These are three facts and one of them is true. You guys know how truth or fail works.

Starting point is 00:14:25 So our first fact. Tradition demands that at the beginning of a Valentine's Day date, flowers are gifted. A recent study has found that subjects exposed to the smell of certain flowers experienced an increase in the hunger hormone ghrelin. Scientists aren't totally sure why this response happens, but it does make that steak dinner you're about to have go down even easier. That might be a lie, though. It could be this one. Fact number two. So you're at dinner and your date slides a velvet box across the table to you

Starting point is 00:14:55 and you open it to find a diamond necklace. How do you respond? The answer to that seems to depend on your age. In a 2017 study, scientists found that most baby boomer age participants experienced a release of dopamine in response to the idea of receiving diamonds as a gift. Gen X and millennial participants, on the other hand, were far more likely to experience the release of the stress hormone cortisol in amounts that increased as the participants' age decreased. Kids, turns out, hate diamonds.

Starting point is 00:15:25 But that one might be a lie. It could be fact number three. Finally, after the flowers, the gift, maybe a romantic dinner, maybe Valentine's Day dates, move on to the next phase, cuddling. Cuddling is a nice activity for a lot of reasons. But per a 2014 study,

Starting point is 00:15:42 one lesser known benefit of holding your sweetie in your arms is that the so-called love hormone oxytocin is released while cuddling and that can reduce swelling improving bone health and even help heal damaged muscle in your body maybe wolverine from the x-men healed so fast because he was in love all the time but probably he wasn't able to heal when he was dating rogue because they couldn't physically touch. Sorry, that got too deep for the proud I'm in right now. That was just for Tuna. It would have been for Sam too, unfortunately. So which is the true fact? Is it that flowers make you hungry and we aren't sure why?

Starting point is 00:16:23 The youth are stressed out by diamonds or cuddling increases your healing factor. I mean, the cuddling feels like the cat's purring thing, which I do feel like is a form of cuddling, but I just don't feel like that's what he's describing. Because that is the thing. Cats purring makes like help each other heal. Yeah, supposedly. I read that in a science fiction book. I wasn't sure if it was real. Yeah, I'm not sure either, but I just tell myself it's true book. I wasn't sure if it was real. Yeah, I'm not sure either.

Starting point is 00:16:45 But I just tell myself it's true when my cat sits on me and it feels real. Like I'm definitely healing. Yeah, nature is healing now. And it feels the most like ooey gooey Valentine's Day-y also. Like, wouldn't that be nice if this is the true fact? The diamond study is weird. I feel like it is totally a scientific study that people would do because everyone like very clickbaity very easy to talk about very probably easy to get

Starting point is 00:17:12 like relatively speaking like funding for from like the diamond industry who's funding these studies just the university yeah they use people five thousand dollars for that yeah it feels like a behavioral economist was like i found it behavioral economists i don't know how they fund their stuff but i feel like it's selling books afterward yeah yeah i think that's a great way to do mostly what they do yeah but i do feel like i haven't seen any gen z's killing diamond industry headlines yet i have totally seen those oh okay there was like a millennials are killing the diamond oh yeah i assume we're killing everything but i don't know like if gen z has gotten to that point yet where they get to kill everything yeah they're all

Starting point is 00:17:54 they're right on the cusp yeah yeah flowers inducing hunger hormones very funny to me and i wonder if it has something to do with like spreading seeds or some like some sort of I don't know residual thing of being omnivorous is like oh I just want to eat that flower for some it also does seem like the kind of thing that would randomly be tested and randomly like be an effect that you would notice like I feel like I could just like imagine someone being like I wonder what this flower would do to people I don't know that I would imagine someone being like, I wonder what this flower would do to people. I don't know that I would imagine them being like, let's look at the hunger hormone. Yeah, let's just look at a hormone panel, see what happens. If you look at enough of them, then you'll just p-hack it and end up with a study, like a result, even if there isn't one. I guess I'm going to go with flowers because I want that one to be true.

Starting point is 00:18:41 If it is the oxytocin one, I'm going to be a little bit mad at Sam because it's so... Yeah, I was going to go with flowers, but I guess to spread it out, I will go with the cuddling one because I feel like that feels more likely than the diamonds. So oxytocin is the hormone that generally increases social bonds,

Starting point is 00:18:58 kind of makes you fall in love with someone. It's released in response to friendly physical touch, sex, after childbirth, in the birthing parent, and even when people see cute baby animals. And as we age, oxytocin production starts to drop off a bit. The same is also true in mice. And in a 2014 study from UC Berkeley, researchers injected oxytocin under the skin of older mice with muscle injuries. And after being injected, their damaged muscles healed at rates comparable to the speed at which muscle damage heals any younger mice.

Starting point is 00:19:27 So, Deboki, congratulations on your win. Sari, I'm sorry about doing the very thing you said was going to make you angry. You know, one of us, at least one of us won. I talked myself out of the right answer, which is pretty far for the And it's fine because you saved me from doing it. I was going to do it about five seconds before you. So I must continue to read what Sam wrote here. He says, when oxytocin production is blocked in young mice, they suffer premature aging, loss of muscle mass, and decreased bone health. So basically, this study found that oxytocin is

Starting point is 00:20:03 vital for all kinds of tissue repair and plays a part in the aging process that doesn't seem to have been something that people knew about before the study. Thus, cuddling may help you heal, and that's something you can actually put in, say, a pop science headline. Unfortunately, adding extra oxytocin to a younger mouse did not make them super healers, but this is still good news for all of us old people. The researchers suggested that anti-aging therapies using oxytocin could not just help people keep healthy for longer into their lives, but also treat diseases in which age seems to be a factor, like Parkinson's. Wolverine, however, doesn't heal fast because he's always in love, but because of his X gene mutation, which in his case gives him the ability to heal several

Starting point is 00:20:43 thousand times faster than non-mutant humans,, as well as a really good sense of smell for some reason. The other two facts were just totally made up by Sam from the the hormones mentioned and their general functions, because when it came to this topic, I was definitely over my head. I apologize if either of them were accidentally real. Love, Sam. over my head i apologize if either of them were accidentally real love sam yeah well sam didn't explain see back to the genes i'm sure wolverine has at least one hormone in there just one yeah gotta be some hormones yeah absolutely all right we're headed to the break with the bokeh in the. We'll be back with the Fact Off. Welcome back, everybody. Now get ready for the fact-off.

Starting point is 00:21:51 Our panelists have brought in science facts to present in an attempt to blow my mind, and after they have presented their facts, I will judge them and award them any way I see fit. But to decide who goes first, I have a trivia question. In 1997, the Galapagos island of Pinta had a big problem. In 1959, three goats had been released onto the island, and in their intervening years, their population had exploded to the point where they were eating the native species out of house and home and threatening to destroy the island's ecosystem. So scientists and conservationists decided to do something about these goats once and for all,

Starting point is 00:22:20 launching Project Isabella, a huge ecological restoration effort that, simply put, involved loads of people scouring the island, shooting any goat they found. And to draw the goats out, they used so-called Judas goats, female goats who were sterilized and injected with hormones that made them be permanently in heat and irresistible to male goats. By 2006, with the combined efforts of bullets and hormones, the goat scourge

Starting point is 00:22:48 of Pinta had been completely eliminated. The question is approximately how many goats were killed by Project Isabella? Sad, horny goat slaughter. Yeah, this is opposite of cuddling. Sam really had a lot of whiplash here being like oh it's so cute

Starting point is 00:23:07 and then now murder goats these poor goats the the female goats i feel almost worse for just like going from place to place drawing men out and then being like ah jeremy i'm just gonna go with 700 i feel like that's just 100 goats that's the number oh i think it's like 50 000 there's got to be a lot of goats on the island this is this is uh this is interesting this is interesting i think 700 they probably could have put away pretty quick but 140 000 goats might take a decade yeah that that tracks they killed 140 000 goats how many how many sterilized females did they need for that that seems like a lot i i don't know how big this island is but how do you fit that many goats on an island i mean i guess they're like still making more goats as you're killing

Starting point is 00:23:54 them yeah it's not like a one-way thing and they killed them to like completion like the population was gone completely they have extincted the goats on the island wow yeah which is not easy to do but when it's an island it's easier sometimes people will say this about like why don't we just kill all the wild boars in america and i'm like ha because that because no like it's not ever going to happen yeah or like mosquitoes or something like that it's like we can try our best but they can fly and like hide in little things. Hide in cargo. Yeah, like a goat not going to be able to get very far without a human seeing it.

Starting point is 00:24:32 All right. So that means that Sarah gets to go first. So our nervous system is basically in a tug of war between the parasympathetic or the rest and digest system and then the sympathetic fight or flight system and hormones can sway our bodies one way or another when it comes to stress the big name players are usually the adrenal gland and a group of hormones called glucocorticoids which in humans includes adrenaline aka epinephrine and cortisol that amp up our heart rates and increase energy availability and all those things but in a a September 2019 paper, a team of researchers published some results that point to another key player in how we experience stress, our bones. So it can be kind of easy to

Starting point is 00:25:18 forget that bones are living tissue full of blood vessels and living cells and nerves, in addition to being these hard calcium-based minerals. But they are. Some of the cells in bones are called osteoblasts, which secrete lots of different proteins involved in bone growth and calcification and whatnot, including what some scientists think is a bone-derived hormone called osteocalcin, which is very weird because bone is not a gland. It's one of these other things in our bodies that might secrete hormones. So I note that as I was digging into this fact, I found papers from the last few years with scientists arguing about whether osteocalcin is in fact a hormone that has effects on other non-bone systems like glucose metabolism or

Starting point is 00:25:59 muscles or brains. And honestly, my takeaway is that the endocrine system is complicated and hard to study. This like really informed my definition section at the endocrine system is complicated and hard to study this like really informed my definition section at the beginning where i was like no one knows what a hormone is the hormone scientists are arguing with each other yeah they're being kind of rude about it too like these are some spicy papers back and forth of people being like wild some have accused me of saying that this is as soon as the some have accused me it comes out i'm like all right take it down a notch yeah maybe we're just maybe it's okay it's also funny to me because i feel like often scientists use some as like a very hedging thing but this is very pointed like

Starting point is 00:26:35 some have accused me so i stepped into a can of worms with osteocalcin, but this is still a fun study, so I'm going to talk about it. So in this 2019 paper, scientists tested a variety of stress conditions in a couple different animals. Mice or rats who had been restrained by putting them into small tubes with air holes. Mice who received electric shocks to their little feets. Mice who smelled a compound in fox urine that is known to cause a fear response, and humans who were either cross-examined or had to do public speaking, which I think is very funny to like compare mice being shocked on their feet to like humans who had to give a speech. Sounds right though.

Starting point is 00:27:17 Yeah. I mean, if they could make mice give a speech, they would have done that. Sweaty palms and then a little shock. But across all these experiments, there was a release of osteocalcin in addition to stress reactions like increased heart rate and blood pressure. And that osteocalcin was biologically active, basically meaning it was in a form that is known to do things and bind to cell receptors in the body. They compared genetically altered mice, who are some that can make osteocalcin, to others that couldn't. And their stress response is to try and figure out what exactly it was doing in the body. And basically, they think it inhibits the parasympathetic nerves and their signals to slow down breathing and heart rate and whatnot. So it's not like powering up the fight or flight response like cortisol does. But if you imagine that like tug of war between the sympathetic and parasympathetic nervous system, it's making the parasympathetic

Starting point is 00:28:09 response weaker. So the sympathetic response that fight or flight is winning a little bit better. And at its most extreme conclusion, if you're writing a pop science, like extreme article about it, you can say our bones make us stress and panic and avoid danger. And like your skeleton gets scared. Doing so much stuff. Yeah. My bones are scared. Why are you so worried when you're about to do public speaking?

Starting point is 00:28:31 My bones. Literally, my bones are scared of this. Yes. My bones are scared. Why bones? Why use bones? Why not? They're there.

Starting point is 00:28:40 And if they can do it, I guess. I think that it's just around. But yeah, our bodies are more interconnected than we thought because it's weird. And our bones are just also playing a role. They secreted this compound. And I think it does like help maybe with bone growth too. But then it also, we just evolved receptors. How do my bones know when my little feetsies are being shocked?

Starting point is 00:29:00 Other hormones, I think, probably. I think it's like in conjunction with other hormonal responses like it's not the only thing that goes on is so there's also like adrenaline and cortisol going on i wish that we knew more yeah i want to know about my stressed out bones because i feel it i feel stressed out in every pore of my body yeah Yeah. Now that you say it, it does feel like my bones are worried. Yeah. Sometimes I get kind of caught up on the fact that like the body of science is limited by the number of people doing science. And I'm like, more people need to be doing science.

Starting point is 00:29:37 The amount of funding we have for people to do science. Yeah. I was going to say, I think there are a lot of people who want to do the science. Yeah. Who aren't able to. Yeah. Bullshit do you got the bogey i have another mystery hormone situation okay so babies are notoriously bad at telling the time in general they don't care i honestly that you say it's notorious but that's the first I've heard of that. Never been reported before. When they're born, they don't usually care about morning or night. They just want food when they want food.

Starting point is 00:30:18 Over time, they do develop a circadian rhythm. So they learn about things like light cues and the timing of when they're fed. And so that's great for everyone involved. But there's still a lot that's mysterious about how they figure out a circadian rhythm, but hormones in breast milk might be a part of it. So over the course of the day, breast milk actually changes. There are nutritional changes like iron levels usually apparently peak around noon, but also there are hormone changes. In the morning, breast milk tends to contain more cortisol, which I think we've talked about. It's a hormone tied to alertness. And in the evening, breast milk tends to have more melatonin, which is a hormone that helps with sleep and digestion. So the idea

Starting point is 00:30:56 is that for babies that are breastfed, that breast milk might actually be kind of teaching them the difference between morning and night by like teaching them when they should be more alert versus when they should be asleep, which is a form of something that scientists call chrononutrition, which is generally interested in this idea of how to coordinate food with a person's internal clock. And it's something that's studied in a variety of contexts and usually in adults, but this is the interesting baby context. And it's also particularly interesting in a modern context because we're living in an age where you can pump breast milk and refrigerate it and store it for later. Whereas generally for most of the existence of humans, babies that were

Starting point is 00:31:37 being breastfed were being breastfed the milk as it was being produced. So they were basically getting breast milk with that specific time's hormone signatures. So there's this potential idea that scientists have become interested in that maybe one way that babies now are having their circadian rhythm get kind of maybe thrown off is they're being fed breast milk that was pumped in the morning, but they're being fed it in the evening or vice versa. And so that could be causing their circadian rhythm to get mixed up. So there's this idea that maybe one way to like help prevent that is to like kind of just store morning milk for morning and evening milk for like evening milk feeds, though it's still like not very well understood or well studied. And

Starting point is 00:32:20 there are a lot of questions about how breast milk even develops this pattern and whether it's based on like the internal clock of the person doing the breastfeeding or if it's like other behaviors like when they're sleeping or eating food. So there's a lot that's still mysterious about it. So is that does that mean that there's like to go follow the theme of the episode and also of all of our lives? Is that like the pop science article version of this is like you have to give your baby the breast milk from the night at night? Well, definitely the scare tactic version to make people feel terrible about how they're like, because I think most of the Internet like that's geared towards parenting is really geared towards guilting parents as being like you are feeding your baby the wrong breast milk. Like you could be doing breast milk wrong, too. But that's not the case. People just whatever works, works.

Starting point is 00:33:04 Whatever works whatever works works this is like the main takeaway of everything to do with parenting yeah um sweet cool weird so either i have to pick between um breast milk helping to establish the circadian rhythms of babies or my bones are scared losing out fear this is tricky they seem very equal to me but deboki came out on top in the first one so i'm gonna we're gonna give deboki the win for the episode yay teaching us the word chrononutrition yeah which is my new favorite term of like it really is i will never be able to use it but i will just whip it out as like science communication jargon of like, oh, I'm eating an Oreo right now, a Pop Rock Oreo right now for chrononutrition. Yeah.

Starting point is 00:33:50 Yeah. I feel like breakfast is chrononutrition. Absolutely. It's the most important meal of the day for chrononutritional reasons. I did see a YouTube video that was like, you're taking your supplements wrong. You should be taking them based on the time of day. And I was like, wow, wow your supplements wrong. You should be taking them based on the time of day. And I was like, wow. Wow.

Starting point is 00:34:07 Here we are. I'm like, I'm trying to not eat Oreos for lunch. We're not at you taking your supplements at the wrong time of day. We are at go outside sometimes. Yeah. I'm at take a break for lunch. Remember to take your meds at some point during the 24-hour

Starting point is 00:34:30 period. Yeah. Drink water. Not a particular amount. Any amount. Any amount, yeah. Reduce the headache. Well, congratulations to Boki on the win, and now it is time to ask the science couch where we ask a listener question to our extra finely honed couch of scientific minds.

Starting point is 00:34:50 At Crystal R99 on Twitter asked, why does an influx of hormones affect mood so much? Are emotions just a specific elixir of hormones? We really need all three science brains on this because this feels like a philosophy question. I think that the problem is, is the illusion that our self exists. Cause we observe it. Like we're connected to it.

Starting point is 00:35:24 I, I observed myself. I have like a pretty strong understanding of what it is uh but it's but i don't think i but i but uh if i look too hard i will notice that like myself is different based on what i what i've whether i've eaten recently so i'm i'm affected by the what my body is. And my mind is part of that. Like throughout the month or throughout various different circumstances. Like I'm going to be different based on the cocktail, the blood cocktail in my body. Yeah.

Starting point is 00:36:00 You're more like a. Yeah, I guess you are. You are a cocktail, but also like a cauldron, like a bubbling cauldron of mystery. Uh huh. Yeah. Yeah. You're more like a, yeah, I guess you are a cocktail, but also like a cauldron, like a bubbling cauldron of mystery goo. Uh-huh. Yeah. Yeah, because a cocktail, you know what's in it. Cauldron, you have no idea what's in it. Always a mystery.

Starting point is 00:36:14 Yeah. A witch says what's in her cauldron, she's lying. You never know. Always lies. Yeah. So I feel like that's it like yeah because one of the trippiest experiences for me is like an adult was like finding out like i had to like take thyroid medication and like then taking the medication and being like oh right so i was really just angry and tired

Starting point is 00:36:39 because of this like hormone issue and it was like huh so like i felt completely different for reasons that were like not like they were me but they weren't me like they were also the hormone and like it was very weird to have that experience and then just be like oh all it took was just like a little bit of hormone and now now it's all good like what was that about is that okay yeah yeah yeah yeah and i mean that's that is it i thought thyroid is one of the ones on my list i just like grabbed random ones i googled like a hormone that i can think of and mood and dug in so if you want to dig more into this topic yourself uh the source list for this ask the science couch very robust um but the but like we don't know why it happens just that it happens

Starting point is 00:37:27 like that this is one of those things in science that we really it's two things that we really don't have a good grasp of which is like the biochemistry of communication in our body which is hormones but also neurotransmitters and like kind of the blurry line between them where we generally categorize like nervous system is really rapid transmission like fractions of the blurry line between them, where we generally categorize like nervous system is really rapid transmission, like fractions of a second of information. Neurotransmitters are the compounds that help transmit information from neuron to neuron or those like short distance very quick. Whereas the endocrine system and hormones are more like long distance, stick around a little bit longer in the blood or other body regions, maybe have a more widespread

Starting point is 00:38:13 effect on the body. But then you look at molecules like serotonin, which have both these like neurotransmitter effects, high like short bursts, doses, like effects on the neuro, your brain. And you have it working in the gut to activate gut metabolism or your eyes and activate muscle fibers in your eyes. Or it affects insulin secretion. And insulin is another hormone in your body. And so it's all these interconnected things. And the brain is an organ in addition to being part of the nervous system. So it all just kind of overlaps. And when you dig into any sort of like serotonin, testosterone, estrogen, thyroid hormones,

Starting point is 00:38:57 any of these things, you can find review papers of studies where they like take people and they measure their hormone content and they say they average it out and they go okay well this seems to be like quote-unquote normal range of testosterone or estrogen for at this time for this this subset of people um constrained by age and gender and weight and uh race and all these other co-factors and the people who have slightly more report on their self-administered mood surveys that they feel more angry or happy or sad and the people who have less report feeling more angry or happy or sad and here's our result and what do we do with that so it's hard to draw like patterns with that where there are some studies

Starting point is 00:39:54 that are like well it seems like in menopause when people whose bodies like normally produce estrogen on a cycle all of a sudden are missing that estrogen then replacing that can help stabilize mood but like there are so many confounding factors yeah emotions are weirdly robust i guess too like the the things that the hormones do are like often not down like kind of like you're saying like to one hormone it's like the their effects are like often built on like a really complex system. And so it's complicated. It's complicated. It's very weird.

Starting point is 00:40:28 And we killed 140,000 goats. We sure did. We sure did. If you want to ask the Science Scout your question, sorry we weren't super great at that one. Terms without hormones, not easy. You can follow us on Twitter and threads at SciShow Tangents, where we will send out topics for upcoming episodes every week. Or you can join the SciShow Tangents Patreon and ask us on our Discord. Thank you to at Charlie Crossing on Discord,

Starting point is 00:40:52 at CJGallagher55 on Twitter, and everybody else who asked us your questions. If you like this show and you want to help us out, it's really easy to do that. Go to patreon.com slash SciShow Tangents to become a patron, access to our Discord and our bonus episodes and also our minions commentary which is a real thing that i i think exists by now we've definitely recorded it i think it's out shout out to patron

Starting point is 00:41:16 les acre also for their support second you can leave us a review wherever you listen that's super helpful and helps us know what you like about the show. And finally, show your love for SciShow Tangents. Just tell people about us. Thank you for joining us. I've been Hank Green. I've been Sari Riley. And I'm Deboki Chakravarti. SciShow Tangents is created by us and produced by Jess Stempert. Our associate producer is Eve Schmidt.

Starting point is 00:41:37 Our editor is Seth Litzman. Our social media organizer is Julia Buzz-Bazio. Our editorial assistant is sometimes Deboki Chakravarti. Sometimes Sam Schultz occasionally. Our sound design is by Joseph Tuna Mettish. Our executive producers are Nicole Sweeney and me, Hank Green. And of course, we couldn't make any of this without our patrons on Patreon.

Starting point is 00:41:59 Thank you. And remember, the mind is not a vessel to be filled, but a fire to be lighted. But one more thing. Lots of rodents are nocturnal, including spiny mice that live in hot, rocky deserts in Egypt and nearby countries. Except when two different spiny mouse species are fighting for the same territory. When that happens, the golden spiny mouse reluctantly forages in the daytime instead. And I say reluctantly because even when they're foraging in the bright sun every day, their natural hormone cycles are still synced to the moon. in the bright sun every day, their natural hormone cycles are still synced to the moon. In a 2011 study, researchers found that all golden spiny mice have higher levels of cortisol metabolites in their poop during the full moon because that stress hormone can help them stay extra wary of nocturnal predators like owls during a bright moonlit night.

Starting point is 00:43:00 Stress is in your bones and your poop. Definitely in your poop. your poop definitely in your poop everything's in the poop all hormones are in your poop and piss definitely 100% we're a cauldron

SciShow Tangents - Hormones

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