Today you’ll learn about how time flies as we age, how scientists are learning more and more about the microbiome within a human body, and the potential for a new phone app that can predict when you might die.
Today you’ll learn about how time flies as we age, how scientists are learning more and more about the microbiome within a human body, and the potential for a new phone app that can predict when you might die.
Time Flies
Human Microbiome
Smartphone Death Predictor
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Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/time-flies-human-microbiome-smartphone-death-predictor
SFX: INTRO MUSIC/WHOOSH]
NATE: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from Discovery. Time flies when you’re learnin’ super cool stuff. I’m Nate.
CALLI: And I’m Calli. If you’re dropping in for the first time, welcome to Curiosity, where we aim to blow your mind by helping you to grow your mind. If you’re a loyal listener, welcome back!
NATE: Today you’ll learn about how time flies as we age, how scientists are learning more and more about the microbiome within a human body, and the potential for a new phone app that can predict when you might die.
CALLI: Without further ado, let’s satisfy some curiosity!
[SFX: WHOOSH]
NATE: Calli, do you ever feel like your days are getting shorter and shorter as you get older?
CALLI: Uhh, I don’t know if you know this Nate but I’m not aging. My days feel like they last a billion years, because I’m immortal. So uh, sounds like a “you” problem. But tell me where this is going.
NATE: It all starts with the idea of time being relative - meaning, time clearly exists for everything, but our perception of time only exists to us. So for example, when you were ten years old and somebody told you about something that happened a year ago, that probably FELT like a million years. But if I were to ask you what you were doing one year ago today, Calli…
CALLI: Oh gosh, one year ago? That was… before COVID, right?
NATE: Calli, one year ago, we came onto this podcast. “Before” COVID was around three years ago.
CALLI: What?! Okay, I don’t actually know where my time has gone. So I get what you mean about time being relative.
NATE: But there is a deeper, more scientific reason for this phenomenon: it’s because our brains are getting older and processing images much more slowly.
CALLI: What do you mean by that?
NATE: Think about the best days of your life from when you were younger. Maybe you have a memory from when you were a teen of taking a night drive to the Santa Monica Pier and drinking coffee, making jokes, and just having a good time. And you remember every detail - from the flavor of the coffee to the smell of the ocean. To you, that day felt like it lasted forever in the best way possible.
CALLI: Sounds like a really good day. And if we did something like that today…?
NATE: Then in a few years, the new day might not be quite as vivid. And it’s because the older we get, the slower our memories develop. That’s because our nerves and neurons grow as we get older, meaning signals have to travel further through our brains. Plus, those pathways are degrading, much like a body does.
CALLI: Oh. And so that’s why my days, I mean… YOUR days, feel quicker?
NATE: Yeah. We can’t view the same amount of images from day to day as we did when we were younger. And if we can’t see the same amount of images, we can’t retain the memories either. You can see this in action with babies, who move their eyes around frequently. That’s because they’re collecting as much information about this brand new world as their brains can handle.
CALLI: So you’re saying that a baby is able to enjoy life more than me?
NATE: Hate to break it to you, but yeah. And there’s a bit of a philosophical sidenote to that thought - as we experience more and more in our lives, we measure the importance of events differently. Like when someone asks us “what’s new” and we say “nothing,” it’s because we’ve measured most of our experiences as not being interesting or new anymore. But for people who have kids, you get to witness, firsthand, that EVERY experience is new and exciting. And that’s the core of the idea here.
CALLI: Huh. I like this, because it seems like the science is there… but also, it’s more of an existential idea. We tend to think of life like a ticking clock… eventually, time runs out. To me, it almost sounds like you’re saying that the less time we have, we also GET less time to do things from day to day. Is that right?
NATE: Yep. And it all comes back to a piece of advice that a researcher named Christopher Dwyer shared on the subject. He says, “don’t wish your life away.” Basically: don’t wait for the next milestone, because you might wait awhile, and since every day gets shorter in a psychological sense, we begin wasting time FASTER. There is a way around it, though.
CALLI: Is it an anti-aging machine? Tell me it’s an anti-aging machine.
NATE: Nope! It’s “relentless positivity.” Be present in the now, and find enjoyment in everything you’re doing in life. Even if it seems things are bad, find the joy! Because once you get whatever you actually want, it might not be what you wanted. So you may as well enjoy the way you ended up there in the first place.
CALLI: “It’s all about the journey, not the destination,” or however that quote goes, right?
NATE: You said you’re immortal, right? You’ll have time to figure it out.
[SFX: WHOOSH]
CALLI: So you might know this but it was a bit of a surprise to me to learn that the human body is actually a kind of ecosystem or microbiome.
NATE: Like a terrarium right?
CALLI: Kindof? But it’s a lot more impressive than what you might build to keep a frog as a pet. Our bodies are filled with either hundreds or thousands of species of microbes, which are microorganisms and usually bacteria. And there’s potentially as many as thirty TRILLION of these combined inside of us. But nobody knows for sure how many. That’s why, for the first time, scientists have created a synthetic human microbiome to figure out just how much life there is inside of us - and what, exactly, each of their purposes are.
NATE: Thousands of tiny little things inside of me, eh, Calli? Sounds like a horror show. But speaking of horror shows, how exactly do scientists create a synthetic microbiome?
CALLI: By combining 119 species of bacteria naturally found inside a human body to create this microbiome that, might I add, can withstand aggressive pathogens that can cause diseases, meaning that the specific combination they used is powerful enough to repel conditions like E Coli. Researchers started off the experiment by mixing this bacteria together from stool samples and giving it to mice via a kind of… broth. The mice were raised in a germ-free environment so they didn’t have a microbiome of their own. What they discovered is that various numbers and combinations of the bacteria can make themselves at home in the mice and can even boost their immune systems.
NATE: Wow. Just gonna blow past the stool broth because that sounds disgusting but this seems huge. What will it accomplish in the future?
CALLI: Don’t worry - the broth was just a way to introduce the bacteria to the mice. But in terms of future use, it might be a powerful way to fight the hell out of a LOT of diseases. It’s already being used to treat life-threatening stomach infections from the bacteria Clostridium difficile.
NATE: How do they do that?
CALLI: Stool transplants from a healthy donor.
NATE: Oh great, stool transplants again. That’s when you take poop from someone and put it inside another person, right?
CALLI: As gross as it sounds, the silver lining here is that the synthetic microbiome can help researchers learn about the role of every individual microbe in the human body. As common as this research seems, a lot of our knowledge of the human microbiome is very, very new.
NATE: New for science or new in general?
CALLI: Both, but mostly in general. Most of what we knew before the early 2000s came from growing a few species in a petri dish. It wasn’t until around 2001 or so that scientists managed to fish DNA out of human spit, stool, and skin to create a catalog of species in our bodies… not only was the list MASSIVE, but most of the species were previously unknown. To make things even more confusing, most species didn’t co-exist in multiple people. Meaning: there is no ONE human microbiome.
NATE: That almost seems like it would make researching the microbiome impossible. But as we’ve seen time and time again, very little is actually impossible. And I’m guessing that’s where the mice come in.
CALLI: Yep. Over time, the microbes introduced to the mice began replicating throughout the mice and taught us some pretty crazy things about how our microbes work.
NATE: Like what?
CALLI: Well, it not only affects their immune systems. In some experiments, the germ-free mice that received microbiomes from obese people put on more weight than mice who were given microbiomes from average-weighted people.
NATE: So how does that work exactly?
CALLI: Unfortunately, they have no idea. There’s no way to completely manipulate the microbiome in a stool sample, species by species, because again: each microbiome is completely different. And that’s where the synthetic microbiome comes in, because it created the most secure ecosystem to research microbes we’ve yet seen.
NATE: Great. So what’s next?
CALLI: Next, the researchers are running experiments in which they leave out certain microbes from the cocktail making up the synthetic, so they can better understand how it works. Specifically, they want to figure out how the microbiome influences obesity. They know part of the answer is that microbes help our intestines absorb fatty elements from our foods. They just don’t know which microbes are helping and which are getting in the way.
NATE: Awesome. I guess in the meantime those little mice will keep eating those lovely fecal cocktails and the researchers will continue to gather the data!
CALLI: Please never say fecal cocktail ever again.
NATE: Well, until the next story about it.
[SFX: WHOOSH]
NATE: I know it’s a bit of a cliche to say at this point, but there really is an app for everything on your smartphone these days. Whether you’re monitoring your steps, or your diet, or even how many Pokemon are around you in Pokemon Go, it seems like there’s a market for anything you can imagine. But even knowing that, I was surprised to find out that there might soon be an app that monitors you for only six minutes - and then predicts whether you’re going to die in the next five years.
CALLI: Okay, listen I was really ready for a story about Pokemon Go and I was about to go ranting on valor and how great it is BUT now I’m worried about my own mortality, Nate. It’s a little grim. How would an app even make that prediction?
NATE: Okay, you might remember how we’ve talked about the Biobank in the UK before? If anyone doesn’t remember, they’ve been collecting information on the health of middle-aged and senior adults living in the UK for about a decade and a half. So, researchers from the University of Illinois Urbana-Champaign looked at a study the Biobank did where participants wore motion sensors on their wrists for one week. Within five years of the study, two percent of the participants had died. Now, that might not seem like a lot, but it gave the researchers the idea to monitor their own participants similarly, so they could try to develop an algorithm to determine whether they’d die in the next five years.
CALLI: But… how would an algorithm even figure that out from a smartphone? Like, I know that we’ve got Fitbits and we’ve got smart watches and all of that but not everybody carries their phone at ALL TIMES.
NATE: Well, that’s a good point which is why the algorithm was developed to be used, at least initially, on a wrist sensor. This sensor was able to predict a time of death after the user wore it just six minutes during walking. All that the participants had to do was keep their sensor on them for that amount of time, and the model would compare itself to data from other participants by determining the user’s c-index score.
CALLI: Ah yes… the famous c-index score. I definitely remember what that is.
NATE: No need to feel bad if you don’t know because it’s not super common knowledge but, a c-index score is a metric commonly used in biostatistics to assess just how accurate someone’s heart rate, breathing, et cetera are. So, a lower score equals a healthier person. So if the average c-index score for a person is 0.72, this is a low enough score for someone to have because it means the person is comfortable with daily physical activity. However, if the c-index score increases to 0.73, that means that the person is at risk of passing away in the next five years, and it carries on to the point where a score of 0.76 is signifying a potential one year risk.
CALLI: Those are not big number differences. That’s a little nerve-wracking, I’m gonna say.
NATE: It’s definitely a little weird, but rest assured that this isn’t an app just yet: just a theory that such an app COULD happen in the near future. And researchers believe that smartphones might actually be more effective than a wrist sensor, because you could theoretically do a daily test against a registry that evolves DAILY.
CALLI: Okay, that’s awesome but there still is just one problem with that. Not everybody has a smartphone! We’re really lucky with where we live but that’s not gonna be the case all over the world.
NATE: That’s true. And, like I was saying before, this was a study that took place in the UK, and they have about 92% of the population carrying smartphones. But the researchers believe that for the app to work on a global level, it should be pre-installed on cheap flip phones with motion sensors. That way they can be made available for free in territories with low cell phone availability, like parts of sub-saharan Africa, where less than 30% of people have a cell phone. Unfortunately, this is just a suggestion and not part of their experiment, but even if an app like this became available only to people with smartphones currently, it could have a monumental impact on global health.
CALLI: Yeah, global health is gonna go down because the app is gonna give us all heart attacks when we see a 0.76 score.
NATE: Hopefully that’s not the direction it goes and ideally, it could have the opposite effect! Depending on what a person is sick with, seeing a higher score could actually be the wake-up call people with treatable illnesses need to see a doctor and work on bettering themselves. Obviously it won’t apply to everybody, but imagine how many people there are out there who think they’re healthy, but could actually really benefit from being told that they need to get some help by an app saying that they might be in danger.
[SFX: WHOOSH]
NATE: Let’s recap what we learned today to wrap up. As we get older, the days feel shorter, and science unfortunately has confirmed - this is in fact the case. Our neurons and nerves continue to grow rapidly over the course of our lives, disabling our abilities to see new images and retain memories. So even though life does get shorter as it goes along, it gives us a good excuse to cherish every moment as they come!
CALLI: There are trillions of microorganisms inside of the human body, but scientists truly have no idea how many - or what each of them even do. But now, that might change with the creation of a synthetic human microbiome, which allows researchers to discover the purposes of as many as 119 different types of bacteria inside of us!
NATE: Fitbit. Pokemon Go. And an app that can tell you when you’re going to die? It’s not a new episode of Black Mirror - it’s a proposed app from the good people at the University of Illinois, who believe that an app could accurately predict whether you are going to die in the next five years based on your lifestyle. The app is still just a theory for now, but we might soon live in a world where we’ll know for sure if death is just around the corner!