Today, you’ll learn about how metal was discovered to be able to heal itself, a potential cure for sensitive teeth, and the truth about sports supplements.
Today, you’ll learn about how metal was discovered to be able to heal itself, a potential cure for sensitive teeth, and the truth about sports supplements.
Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/healing-metals-sensitive-teeth-sports-supplements
Healing Metals
Sensitive Teeth
Sports Supplements
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[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 metal was discovered to be able to heal itself, a potential cure for sensitive teeth, and the truth about sports supplements.
CALLI: Without further ado, let’s satisfy some curiosity!
[SFX: WHOOSH]
CALLI: As long as humans have been using metals to build things, we’ve had to deal with metal fatigue, which is what happens when miniscule cracks in metals start to grow into not-so-miniscule cracks. But researchers studying metal fatigue have just made a totally accidental discovery that could change the way we understand metals. Turns out…metal has the ability to heal itself.
NATE: That…sounds crazy. I’ll be honest.
CALLI: That’s what made it so unexpected. So let’s talk about metal fatigue for a second, because it’s a massive problem that engineers spend a huge amount of time trying to solve.
NATE: I’ll say. I’m not so eager to drive over a bridge with metal fatigue, know what I mean?
CALLI: Bridges are actually a great example. So fatigue starts as these tiny cracks that grow when the metal is put through repetitive stress.
NATE: Like the thumping of a million car tires over a bump on a bridge.
CALLI: Exactly. And we think of metal as being incredibly strong - and, of course, it is. But over time, those tiny cracks expand and make the metal weaker and weaker. By some measures, up to 90% of metal fatigue is caused by this kind of fatigue. So when the bridge is closed and you have to take a detour - you have fatigue to thank.
NATE: Fatigue just became my mortal enemy.
CALLI: And you’re not alone. To keep this from happening, they have to build in a ton of extra safety features and overdesign the heck out of any structure that relies on metal for its strength. That’s where our researchers come in. Brad Boyce, one of the scientists involved in the report, said he and his team were conducting an experiment to see how metals perform under repeated stress…
NATE: …the stress test…
CALLI: Yep. Normal, everyday stress test where the researchers were trying to see how the cracks in the metal grow over time. Except they were looking at a piece of platinum at the nanoscale through an electron microscope. They were tracking these microscopic fatigue cracks, expecting them to get worse. But…to their surprise…one of those cracks didn’t get bigger. In fact, it just sort of…healed itself.
NATE: You mean it closed up like it was some kind of wound?
CALLI: That’s exactly what I mean. They were absolutely stunned. Not only did it heal - it left no trace of the crack behind.
NATE: Healing metals have no scar tissue.
CALLI: None. And other cracks formed - but not in that spot. In other words, once the crack healed up, it was like it had never happened.
NATE: Sooooo…this feels like some kind of alien technology. What’s really going on here?
CALLI: To be honest, they aren’t totally sure. Back in 2013, another researcher created a computer simulation that hypothesized that this was possible, but no one could ever prove it until Boyce and his colleagues saw it happen before their very eyes.
NATE: Is this something we can use one day? Like…can we build bridges that just sorta heal themselves so I don’t have to deal with detours anymore?
CALLI: The big question. They aren’t sure. But the thing is, before they watched this happen, the idea that metal could heal itself was totally unthinkable by most scientists.
NATE: So now I guess they have some new thinking to do.
CALLI: Right. And that new thinking could lead to new research. And from there, the only limit is gonna be their imagination.
[SFX: WHOOSH]
NATE: Do you ever dip into an ice cream cone and recoil in pain when that icy cold hits the wrong tooth?
CALLI: Actually yes, I mean, I really love ice cream but I don’t eat a lot of the stuff anymore because it’s just really painful. My teeth are sensitive.
NATE: Well…for you and anyone who’s experienced it, it’s a real pain in the tooth. And there hasn’t been any real cure for it, either.
CALLI: Wait - I thought there were toothpastes you could use that cure tooth sensitivity?
NATE: Just about every treatment out there treats the symptoms, not the cause. They work to desensitize the nerve, or else temporarily fill in little holes leading to the nerve. But either way, those treatments don’t really last.
CALLI: Ahh. Gotcha. So that means I might just have to stay away from ice cream forever?
NATE: There was never a cure before…but I’ve got good news for you. Scientists think they may have figured out a way to treat tooth sensitivity once and for all, and all it takes is a couple little pieces of candy.
CALLI: Wait, candy is notorious for causing toothaches.
NATE: Okay. So let’s talk teeth for a second. We all know that we’ve got these nerves in the middle of our teeth. But in healthy teeth, those nerves are surrounded by this stuff called dentin, and the dentin is surrounded by enamel.
CALLI: The enamel is the stuff that can wear away, right?
NATE: Totally. It’s super hard, but it’s got its softer spots. Whether you grind your teeth or eat food that eats away at the enamel, it can thin out. Once that happens, these tiny tubules in the dentin can open up, giving heat and cold a one way ticket to your nerve.
CALLI: It hurts just thinking about it.
NATE: Yeah. Not great. So the thing is, once that enamel goes away…it’s just gone. Enamel isn’t a living tissue, right? So it’s not like it can just grow back.
CALLI: So that’s why there’s no cure for tooth sensitivity?
NATE: Exactly. At least there wasn’t. But researchers at the University of Washington are working to change that by creating a biomimetic. That’s just a fancy way of saying that they want to create a process that mimics what happens when minerals form on our teeth.
CALLI: Okay so they’re trying to trick our enamel into regrowing?
NATE: Sort of. They found a peptide - which is just a chain of amino acids - that played a huge role in the natural development of human teeth. It’s called sADP5, and it basically snatches up calcium and phosphate ions and uses them to build up minerals in the teeth.
CALLI: Like a tiny bricklayer building a wall against ice cream.
NATE: That’s a very cute image, actually. And yeah - it’s kinda like that.
CALLI: So where does this candy that you mentioned come into play?
NATE: The candy is how they send that peptide to the teeth.
CALLI: There’s no way.
NATE: Yes way. They found that after a few rounds of treatment with this new method, tubes in the dentin had been remineralized, and those fast tracks to the nerve? Closed up.
CALLI: That is super cool.
NATE: Not only that, but tests showed that the new mineral layer was actually harder than normal dentin and that it wasn’t going anywhere. In other words…
CALLI: …it could be a permanent fix.
NATE: Yep. And they can deliver this peptide in a piece of candy - sugar free, obviously - or in mouthwash, toothpaste, dental gels. You get the idea.
CALLI: Sounds like ice cream might just be back on the menu.
NATE: Well…as with all new wonders, more research is needed. But at least for now, all signs point to mint chocolate chip in the not-too-distant future.
CALLI: Aw, you even know my favorite.
[SFX: WHOOSH]
CALLI: Have you ever used sports supplements to keep in shape?
NATE: Me? No way. Believe it or not, these enormous muscles are aaaaall natural.
CALLI: Right. Well, if you did use sports supplements, you wouldn’t be alone. By some estimates, the supplement industry is crushing it with over 55 billion dollars in sales every year. That includes multi-vitamins, of course, but the fitness supplement portion of that total is still pretty huge.
NATE: Huge like my pythons, right?
CALLI: Okay, you can’t refer to your arms as pythons, just saying. So, you’d think that people are scooping up these supplements because they’ve used them and seen the proof that they work, right? Well…a new study has found that nearly 90% of these supplements aren’t what they say they are.
NATE: 90%?! Okay. Hang on. I know what multi-vitamins are. But what, exactly, are sports supplements?
CALLI: Great question. Most of the 95,000 or so supplements that are on the market advertise some kind of positive effect on your health.
NATE: Sure. Vitamin C and zinc for immunity, calcium for your bones, probiotics for gut health.
CALLI: Exactly. But sports supplements go a little further and promise to increase your ability to perform.
NATE: Like…performance enhancing drugs?
CALLI: Kinda. Except as advertised, they don’t use typically banned substances. So instead of something like steroids, these are botanical ingredients that do things like stimulate muscle growth, or make you more alert.
NATE: Gotcha. I can see why they’d be so popular.
CALLI: Yeah! So Dr. Pieter Cohen and his colleagues at the Cambridge Health Alliance in Massachusetts decided to test some of these supplements to see if they actually contained what they claimed. The results were not great. Turns out that about 89% of the products they tested weren’t accurately labeled. A whopping 40% of these products didn’t even contain a trace of the ingredient they advertised.
NATE: So they’re just, like, sugar pills or something?
CALLI: That’s where it gets even worse. 12% of the tested products actually contained ingredients that had been banned by the FDA because they aren’t deemed safe to ingest. Some of these ingredients can actually cause heart failure.
NATE: Yikes. Isn’t that illegal?
CALLI: Obviously, if a substance is prohibited, you’re not supposed to put it in your product. But this is where the supplement business gets a little sneaky. The FDA doesn’t categorize these supplements as drugs - they see them as a subcategory of food. With drugs, the manufacturer has to do all kinds of testing to make sure their product is safe and does what it’s supposed to do. But with food, well…that’s a different story.
NATE: In what way?
CALLI: With food, if the manufacturer says it’s safe, then the FDA allows it to go on the market. They only ban it AFTER it causes someone to get sick.
NATE: So that means that anyone taking these sports supplements probably doesn’t have any way of knowing exactly what’s in them, and they’ll only know if it’s dangerous after they get sick from it?
CALLI: That’s what this study is suggesting. It’s worth noting that this study only looked at 57 different supplements. But while the sample size was pretty small, the results were still pretty shocking.
NATE: So…should people just stop taking these products?
CALLI: Dr. Cohen recommends choosing products that are USP or NSF certified - these supplements have gone through rigorous testing to ensure that they are what they say they are. But the biggest bit of advice is to just be cautious. When it comes to fitness, there really are no quick fixes.
NATE: That’s right. Just ask old Lightning and Thunder over here.
CALLI: Are you referring to your biceps?
NATE: Obviously.
CALLI: Is it obvious?
[SFX: WHOOSH]
NATE: Let’s recap what we learned today to wrap up.
CALLI: Scientists studying metal fatigue were shocked to find that a tiny crack in a piece of metal had healed itself. The totally unexpected finding could have huge implications for how engineers design and construct everything from buildings to bridges.
NATE: Sensitive teeth got you down? Well researchers have developed a potential cure for tooth sensitivity in which a lozenge delivers a peptide that mimics the development of minerals in the formation of teeth. In other words, it makes our teeth harder so we can eat ice cream without feeling the pain.
CALLI: A new study has found that a whopping 90% of sports supplements don’t accurately list their ingredients. 40% didn’t even contain the main ingredient advertised on the label, and 12% of them actually contained prohibited substances, some of which could even cause heart failure in extreme cases.