Curiosity Daily

The Amazon’s Future, Sugar Rush Retcon, A Study on Studies

Episode Summary

Today, you’ll learn about the state of the Amazon rainforest, the truth behind the mythical sugar rush, and how studies involving MRI scans may have been too small to produce significant results, but researchers may have found a solution.

Episode Notes

Today, you’ll learn about the state of the Amazon rainforest, the truth behind the mythical sugar rush, and how studies involving MRI scans may have been too small to produce significant results, but researchers may have found a solution.

The forest needs attention - not the company.

 

Maybe sugar isn’t the problem.

Data sets need to grow to bolster studies.

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Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/the-amazons-future-sugar-rush-retcon-a-study-on-studies

Episode Transcription

TITLE:

THE AMAZON’S FUTURE, SUGAR RUSH RETCON, A STUDY ON STUDIES

SCRIPT

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 the state of the Amazon rainforest, the truth behind the mythical sugar rush, and how studies involving MRI scans may have been too small to produce significant results, but researchers may have found a solution.

CALLI: Without further adieu, let’s satisfy some curiosity!

[SFX: Whoosh]

CALLI: Nate, what’s Earth’s favorite place?

NATE: I don’t think I understand the question.

CALLI: No, like, the Earth itself? If it had a favorite place on itself, what do you think it would be?

NATE: Disneyland?

CALLI: No ... the Amazon rainforest!

NATE: Oh, now I think I get it. It’s Earth’s favorite because, in many ways, it’s the most Earth! It is the most biologically rich region on the planet.

CALLI: Bingo. And, that’s one reason—as we’ve known since we were little—it’s so important to keep it alive and well. Unfortunately, right now it’s so damaged that researchers think it may soon cross the critical line into resilience loss.

NATE: Resilience loss?

CALLI: It could lose its resilience: the forest’s ability to bounce back from damaging events like wildfires and droughts.

NATE: So it’s kind of like its immune system becomes so weak, it’s even more open to getting sick. Oh, man, that means the earth could get really sick too.

CALLI: Exactly. Of course, we’ve seen the attacks on the forest’s well-being ... like the great wildfires that spread in 2019.

NATE: I heard there was a drought in Brazil just last year too.

CALLI: The worst they’ve had in over ninety years.

NATE: Is there a theory on what happens once the forest loses its resilience?

CALLI: Well, they think a lot of it would shift to a more savanna-like ecosystem.

NATE: So we’re getting zebras in the Amazon? What would you call a Brazilian zebra? A Brazebra?

CALLI: Like a zebra that speaks Portuguese and loves soccer? No, I don’t think we’d immediately see Savanna animals start popping up left and right. But, picture the Savanna ... a smattering of trees, as opposed to the Amazon now: a dense forest. One of the Amazon’s biggest functions is the ability of its trees to absorb carbon dioxide - one of the major heat-trapping gasses that’s a significant cause of global warming.

NATE: I want to make so many jokes about heat trapping gasses.

CALLI: Trust me, I’ve already heard them all.

NATE: How much absorption do the trees account for? 

CALLI: Nearly a hundred billion tons of carbon.

NATE: You said “a hundred billion”? With a “b”? Tons?! How do I wrap my head around that number.

CALLI: Well, the Great Wall of China weighs about fifty-eight million tons. So, about seventeen-hundred of those.

NATE: Seventeen hundred Great Walls of China?! That’s how much carbon is stored in the trees and plantlife of the rainforest?!

CALLI: Yes! And since, during photosynthesis, they absorb carbon dioxide, the trees also account for filtering about four hundred billion tons of that!

NATE: So, almost seven thousand Great Walls.

CALLI: That number looks like it’s shrinking. Some parts of the Amazon have been found to be emitting more carbon than they absorb now. Creating a terrible cycle within the rainforest that continues to damage it further. It’s terrible really. The Amazon and its wellbeing are crucial to the air regulation of the planet.

NATE: Well then we definitely can’t let it get any worse. When do they think it might cross the line?

CALLI: The Amazon is such a highly complex system - it’s difficult to pinpoint when a tipping point could be reached.

NATE: Wouldn’t we start noticing the physical changes in the forest?

CALLI: Some of them, yes. Like deforestation, you can see in satellite images of course. But it’s tough. The forest can look generally the same despite being on the path to resilience loss. Or, it can even look not-good and be fine. You know, like how forest fires occur naturally, and sometimes can be restorative and healthy for a forest? The thing they’re looking for is whether or not the forest can bounce back, or how vulnerable they are to another attack. They’re looking at canopy density, tree diameter, and other factors. Researchers have actually found signs of loss in more than seventy-five percent of the forest since the early 2000s.

NATE: So, staying with the sick analogy - it’s almost like having a virus but not showing symptoms?

CALLI: Right. But the biggest factors affecting the Amazon are external - deforestation and climate change. Trees are being cut down for industrial purposes, and sometimes fire is used to clear the trees. This is the cause of most of the wildfires that have taken over the Amazon.

NATE: Wow. I didn’t realize how much damage had already been done to the area.

CALLI: There is some good news...

NATE: Thank goodness! Please, hit me with it!

CALLI: The rainforest is essential to life on Earth. Crucial! And being so important, there are a ton of people, organizations and companies who get that, and are dedicated to keeping it healthy, and even actively restoring it. Groups like Amazon Watch and the Amazon Conservation Association fight for restoration efforts and work with local groups who live in the Amazon to ensure its protection and wellbeing.

NATE: Is there anything we can do to help from afar?

CALLI: Your best bet is going to be advocacy. We’ll put a link to some good organizations in the show notes, places like Amazon Now and the Amazon Conservation Team. These are places you can donate to, or maybe try to work with if you wanna get your hands dirty.

NATE: Sounds like the Amazon needs all the help she can get. Maybe a little chicken soup would help.

CALLI: I doubt it, but it’s worth a try.

[SFX: Whoosh]

NATE: Calli, were you allowed to eat candy as a kid? 

CALLI: Of course, but really only on special occasions, my parents were always worried I'd go all kooky-Calli, bouncing off the walls. 

NATE: Kooky-Calli? 

CALLI: Yeah, like if I had too much sugar sometimes I’d go a bit nutty as a kid.

NATE: Ah, I think that had a lot less to do with candy and a lot more to do with you.

CALLI: Hey!

NATE: Research is showing that the much-maligned sugar rush—feared by parents of young children the world over—is a myth. Correlation is not causation, even if it is delicious. 

CALLI: If it's not a real thing, then why is every parent I’ve ever met concerned with it? 

NATE: It goes back to the 70s when some dieticians started positing that diet could affect behavior. Then, researchers published a study in Food and Cosmetics that proposed sugar causes hyperactivity in children. Though it was later debunked, there was no putting the myth back in its chocolate box. 

CALLI: But I feel like I’ve seen sugar rushes before, kids zipping around at a million miles an hour after a piece of birthday cake or a soda.

NATE: There are a lot of these observational studies that seem to link sugar and hyperactivity. But scientists have tested it over and over again. One such test involved giving some children sugar, and others a non-sugary snack. Parents would then watch the children play and guess if their child was in the group that got the sugar. The majority incorrectly assumed their children had had sugar, when in fact they had not. 

CALLI: I don’t want to sound like I am acting against the science here, but I still can’t get the image out of my mind of every kid, from toddlers to fifth graders, buzzing around a birthday party at a million miles an hour after a piece of cake.

NATE: Totally, but that's classic correlation not causation. Researchers think something much simpler is going on there. Often we witness this supposed post-sugar hyperactivity in social situations. Think birthday parties, holiday events, events that often also happen to come with the rare sweet treat. But researchers think that this hyperactivity isn’t from the sugar, it's from the excitement of a party! There is so much going on, new faces, fun to be had ... kids are prone to hyperactivity and sensory overload in these types of situations. 

CALLI: So it's not kids on candy, it's kids on fun?

NATE: Right. And, it’ll settle with age. It's why adults don’t go bonkers after a slice of birthday cake, sugar doesn't make us hyperactive. Kids just don’t yet have good emotional or cognitive self control. It takes time, maturity...

CALLI: ... the feeling like maybe you want less parties and more sitting and reading by a nice window on a cloudy day.

NATE: Sure! And before they mature out of it—when the kids do go to parties—they get hyperactive as they try to process all the new people and other unusual sensory inputs.

CALLI: There just happens to be sugar nearby.

NATE: You got it.

CALLI: So I guess what would be really…sweet… is if parents let this old thought go.

NATE: Absolutely! In fact, some studies have shown that this expectation that their kids will get worse after sugar, actually causes parents to see their children as acting more unruly, even if the kids’ actions don’t change. Parents start to hover, become more critical of the kids and their choices. Even though there is no real sugar rush, they see one, and end up being worse parents in anticipation of these phantom behavioral issues. 

CALLI: So, do you hear that, kids? Dive into that bag of candy! Your parents can’t blame the sugar! You can’t help it if you’re unruly! It's just your developing brain!

NATE: (laughs) Calli no! We should all still avoid processed sugar. Just because it's not responsible for hyperactivity, it's still responsible for a lot of non-behavioral ills. A sugar-high diet increases rates of chronic diseases like heart disease and type-two diabetes. And research is showing it increases your likelihood of developing dementia later in life. 

CALLI: Is this where you tell kids to eat carrots instead of candy bars? 

NATE: Well a nutrient-rich diet will give you energy and a healthy lifestyle.

CALLI: I bet you give out toothbrushes on Halloween!

NATE: Ha no, Almond Joys. Everything in moderation Calli.

[SFX: Whoosh]

CALLI: Nate, have you ever had an MRI?

NATE: I am very fortunate in that I’ve never needed one! They are very cool, though, using super powered magnets to get images of the workings of our brain? I love it.

CALLI: That's right, MRIs allow doctors to image the brain, and see its structure, activity, and patterns of connection. And new research is showing that—so long as we follow good repeatable standards of science—they can actually help us see the links between brain structure, activity, and even some cognitive ability or mental health conditions. 

NATE: Oh that’s incredible. If we could identify patterns or neurological features that were maybe cues for things like autism or Alzheimer’s, what a great thing that would be.

CALLI: Totally. It could help a lot of people. And some studies, called Brain-Wide Association studies, have tried to prove these sorts of connections, in hopes to see those benefits. To potentially prevent certain conditions, or help treat them.

NATE: A noble cause!

CALLI: For sure. Though, there’s a pretty big hurdle in these situations.

NATE: Well the brain is complex, so that makes sense. But, what kind of problems are we talking about?

CALLI: Basically, sample size. MRIs are expensive, to the tune of about a thousand dollars per hour, and many of these studies have limited funding. That means that a lot of studies claiming to have found an association between brain structure and a personality trait or condition ... well ... they’re often in groups that are too small to be repeatable. So, the results are statistically underpowered. 

NATE: How big would a group need to be?

CALLI: Researchers recently analyzed many of these past studies and found that the average number of participants was just 12. These small groups leave a big opportunity for the results to be association by chance. Results could be random, and potentially unrepeatable. 

NATE: Right, and we don’t want that.

CALLI: Totally. A big positive is that they reliably collected data. But when it comes to the analysis, it’s tough to be sure it’s sound. So, researchers dug in. They basically did a study about studies. They found that for studies of this kind to be scientifically sound, they would need sample sizes in the thousands. 

NATE: That’s a lot. At a thousand an hour just for the scans. So, wait, how did they track down past results and determine they are just chance?

CALLI: I’ll give you an example. Researchers looked at previous studies that found intelligence can be linked to the thickness of the brain's outermost layer. This study had a small sample size. Researchers tried to repeat the findings by looking at a new federal study that scanned thousands of adolescent brains. After analyzing more than one thousand scans, they couldn't replicate the connection between thickness and intelligence. Bigger sample size, different results.

NATE: Wow, must’ve been a shock to those initial researchers.

CALLI: Yeah, it’s unfortunate, but there’s some good news in there.

NATE: Right, yeah! It sounds like you can take scans from previous studies and kinda re-study them?

CALLI: Yes! If you have other associated data, for example intelligence data in the instance above, you can make a new, larger, more reliable study, by combining MRIs from different smaller studies and looking for different things.

NATE: So, a small sample size is typical because of how limiting the price of scans are, but scans can be used again and again.

CALLI: Absolutely. And, we know that when you do have a big enough study, you can make scientifically reliable connections between brain structure, activity, and health conditions. Researchers recently looked at hundreds of MRIs of people with different types of depression, and were able to use the data to build a model of what depression looks like in the brain.

NATE: Oh wow. A picture of depression.

CALLI: So, going forward, we need human behavior studies that use thousands of scans. It can be done by using one of the largest neuroimaging datasets currently available that has scans from 50,000 patients. In fact, it's already been used to identify some brain differences associated with schizophrenia.

NATE: This really illuminates one of my favorite things about science. Not only is it powerful, but it's made more powerful as humanity gains more knowledge, better technology, and adds new methods of research.

CALLI: Absolutely. And when we do that, we can learn just about anything, even how our own brains work. 

NATE: Too cool.

[SFX: Whoosh]

NATE: Let’s recap what we learned today to wrap up. Researchers believe the Amazon may be nearing a dangerous ecological tipping point. With some areas now emitting more carbon than they absorb, the rainforest’s hope lies in the valiant efforts of Amazon conservation and restoration groups.

CALLI: Parents have long been maligning sugar for children’s behavioral issues, but the dreaded “sugar rush” from junk-food might just be junk-science. Research shows that the developing brain, and new stimuli, are more responsible for a rush of energy than any candy bar.

NATE: MRIs can be used to help us understand how our brain’s structure and activity affects our traits and mental conditions. By combining the data from smaller studies, researchers can build larger studies to get real, meaningful, results.