Today, you’ll learn about whether the cyanide in apple seeds could do you any real harm, how working out in the morning and at night are both beneficial but in different ways, and how researchers have found evidence that patients with long Covid may often have fragments of the virus lingering in their gut.
Today, you’ll learn about whether the cyanide in apple seeds could do you any real harm, how working out in the morning and at night are both beneficial but in different ways, and how researchers have found evidence that patients with long Covid may often have fragments of the virus lingering in their gut.
Snow White wasn’t far off with the poisonous apple.
What time should I work out?
“Is It Better to Exercise in the Morning or Evening?" by Gretchen Reynolds
● https://www.nytimes.com/2022/01/19/well/exercise-timing.html
“This is the Best Time of Day to Work Out, According to Science" by Jamie Ducharme
● https://time.com/5533388/best-time-to-exercise/
An even scarier kind of ghost?
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Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/cyanide-seeds-workout-when-covid-but-ghosts
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 whether the cyanide in apple seeds could do you any real harm, how working out in the morning and at night are both beneficial but in different ways, and how researchers have found evidence that patients with long Covid may often have fragments of the virus lingering in their gut.
CALLI: Without further ado, let’s satisfy some curiosity!
[SFX: Whoosh/Intro Music]
NATE: Hey Calli, have you ever heard of how apple seeds can be poisonous?
CALLI: Of course! And not the Snow White Evil Witch kind of poisonous either. My mom used to warn me about eating apple cores, apple seeds. They contain cyanide, so you’ve really gotta be careful.
NATE: Okay, so that there is the thing I’m talking about, apple seeds and cyanide, but the truth of it isn’t exactly how you were told. Apple seeds, and many other fruit seeds, contain a molecule called amygdalin, and—like your parents may have warned you about—that can release cyanide if ingested.
CALLI: Sounds like you’re saying my mom was right. So the cyanide’s not in the apple, but this amygdalin becomes it if ingested? Seems like you two are saying the same thing.
NATE: Absolutely, yes. But, she’s still maybe overreacting. While the existence of the cyanide in the apple seeds is not an old wives’ tale, it would take a LOT of work for you to actually feel the negative impacts of eating them.
CALLI: Ah, I see, I see. But, wait, go back a sec. Apples have been getting all the bad press, but other fruits have this as well?
NATE: Apple seeds, watermelon seeds ... the pits from apricots, peaches, nectarines, and cherries ... and even almonds and some beans!
CALLI: All of these things are poisonous? How am I not dead yet? I’ve swallowed plenty of watermelon seeds. Who has the time for spitting all those guys out? Not me.
NATE: I used to think I’d grow a watermelon in my belly if I did that. Possibly scarier than being poisoned. But, yes, all those fruits and seeds, and some beans, yes, have amygdalin. Each molecule of it has a sugar and a nitrile group. When these amygdalin molecules are digested, they release their nitrile group as, you guessed it, cyanide.
CALLI: Ah, I see. That’s kind of crazy that you can digest something else and it turns into poison!
NATE: For sure. Cyanide is super scary, it causes nausea, fever, headaches, lethargy, and fatal doses can kill you within 5-10 minutes as they cut off oxygen to your cells, causing damage to your heart and brain instantly.
CALLI: I’m going back and forth here and whether I think it’s okay to eat an apple core.
NATE: It’s fine, it’s fine. Because all that stuff about cyanide is true, but for concentrated, lab-synthesized cyanide. The cyanide from these fruit pits and seeds just gets flushed out of our systems during digestion. It's even been used for things like pen ink since 1782.
CALLI: So it's not possible for it to kill me?
NATE: Well, it's still possible. It’s just not gonna happen. Apple seeds have 3 grams of amygdalin per kilogram of apple seed. It’s way too little to do any damage. Though, other, tougher-to-digest pits can have more. Apricots for instance have fourteen grams of amygdalin per kilogram of pit.
CALLI: And this whole time we’ve been slandering the apple! Man, they’ve gotten a bad rap since that whole Garden of Eden thing.
NATE: I know, right? laughs. For pits though, the amygdalin is only released if they’re crushed up and ingested. So is eating a ground up peach pit a good idea? No. But you shouldn’t be afraid of peaches. And the amygdalin can’t make its way through the flesh of the fruit either.
CALLI: Well what about those smaller sources? Cherry pits or our classic apple seeds?
NATE: Cherry pits pass right through us, and they’ll only let out amygdalin if they're cracked open, which our teeth really can’t do anyway. And say, worst case scenario, you chew up a bunch of apple seeds, you’d need bushels of apples to make something deadly. Think on the scale of a super dry smoothie made up of only apple seeds. Say, nine-hundred apple seeds. That could probably kill you.
CALLI: That sounds like the worst, and last, smoothie of a lifetime.
NATE: See? Poisonous. In reality though, it really shouldn’t be an issue. The only exception is…
CALLI: Exception?! Nate I was finally calming down!
NATE: …is for children Calli.
CALLI: Nate, what? I’m scared again!
NATE: Small kids should be warned to not eat apricot seeds, it's exceedingly rare, but if a child were to eat a few apricot pits, there is the potential for some harmful effects.
CALLI: Forget poisoning, I’d be more worried about how they made their way out over the next few days. Apricot pits are large and ... sharp!
NATE: Oh that is such a good point.
CALLI: Okay, so it’s still a good thing to tell your kids to avoid eating all those seeds.
NATE: Yes.
CALLI: And if The Evil Witch were going to poison Snow White ...
NATE: She’d probably need to get her to eat somewhere around a thousand apples.
CALLI: That’d be good. I think Snow White would stop eating them before she had a problem.
NATE: Yeah, my daily limit on apples is around five hundred.
[SFX: Whoosh]
CALLI: You know how my absolute favorite thing to do in the morning is hit the gym and get a good sweat in? And how you never answer my calls when I need a workout buddy?
NATE: I don’t answer because I’m sleeping! The true best time to hit a workout is right before you go to bed.
CALLI: Well a new study shows that both of us could be right, depending on the situation.
NATE: I can’t wait to hear all about how working out at night is the best time. I will ignore the rest.
CALLI: A team put together trials with lab mice to determine how working out at different times affected their metabolism. They tracked hundreds of changes throughout their molecules and genes. And, the study uncovered some interesting data on fat burning.
NATE: The only thing, and I mean the ONLY THING that would get me to workout in the morning is if you told me it helps burn more fat. Or if there were donuts at the end of the workout.
CALLI: Those two things sound contradictory.
NATE: I burn more fat, I can eat more donuts - the math seems pretty simple.
CALLI: Well a previous study in 2019 did show that men who worked out in the morning did shed more fat than their evening counterparts.
NATE: But didn’t other studies the same year find that morning workouts could negatively affect blood sugar spikes?
CALLI: That is correct. None of these studies went far beyond the surface and into the full molecular changes that may be at play.
NATE: Okay so the scoreboard is still zero-zero in my book.
CALLI: But this new study examined as many observable changes as possible in the mice.
NATE: Like how cranky the morning mice were?
CALLI: Okay, fine, they didn’t monitor that. But overall they found that the mice working out in the morning relied more on fat than blood sugar for energy. Whereas the opposite was the case in the evening mice.
NATE: So working out in the morning burns more fat, and the evening could provide better blood-sugar control.
CALLI: Which interestingly does line up with the human studies. And the morning group had identical changes in different organs, but that wasn’t true to the same degree for the evening group. So, maybe morning exercise has your organs communicating more with each other than when you work out at night.
NATE: One thing’s still bugging me about this study though - can we really apply the same information learned from mice to humans?
CALLI: Researchers do believe there’s some overlap in our metabolic systems where the information could apply. Mice, humans, and all living creatures follow a consistent twenty-four hour rhythm. Recent studies have even shown that this clock is wired all the way down into our cells to coordinate our biological operations. Things like our body temperature, hunger, heart rate, and even cell division are controlled in patterns throughout the day and night.
NATE: And these clocks are somewhat changeable according to our lifestyles right?
CALLI: Definitely! Our internal clocks are very responsive to things such as sleep habits, eating times, and especially light and darkness. Hence why daylight savings can sometimes mess with us for a few weeks until we adjust to the new sunlight hours, or why looking at our phones right before bed can disrupt sleep cycles, which I learned from you recently.
NATE: That’s right. No more TikTok before bed!
CALLI: It should also be pointed out that the study was pretty limited as they only monitored one session of light to moderate jogging for exercise. The control group was only male mice as well so we don’t have any data as to the effects on a female set. The important takeaway is that the study doesn’t account for different types of exercise, how the timing of our diets factors in, or whether our chronotypes - our inclination towards being early risers or night owls - impact our molecular systems.
NATE: So really it just seems like the optimal workout time is whatever works best for your own personal clock.
CALLI: That’s the prevailing wisdom. I say if you’ve got something that works for you, keep it up! There are other studies that have shown a possible improvement in brain function throughout the day from morning workouts. While others still have found that nighttime workouts can help reduce certain hunger-causing hormones. So there’s benefits to both in the long run, just different ones. Eventually, we may have enough data to determine what’s best for each individual, their circumstances, maybe even for their specific health concerns.
NATE: But in the great debate, it seems it’s win-win.
CALLI: The only thing for sure is, that you see benefits when you work out, whenever it is that you can.
NATE: Either way, I’m going to keep sleeping through your 5AM calls.
[SFX: Whoosh]
NATE: Have you heard of long Covid?
CALLI: Yes! It's kind of freaky, the idea that this infection could stick with you for weeks, even months after you originally catch the virus.
NATE: Yeah, totally. Well, I’ll be honest. This isn’t any less freaky. New studies may be pointing to a cause. Researchers have found pieces of the coronavirus itself lingering in the gut long after initial infection. They think these lingering “ghosts” might explain some of the symptoms of long Covid.
CALLI: Oh, that's fascinating. But what are these pieces doing in the gut? I thought most of the issues with this infection were respiratory? Like, in the lungs?
NATE: Right, of course. That was the early take on Covid. At first, it looked exclusively like a respiratory illness, but it didn’t take long for some patients to start complaining about gastrointestinal issues like diarrhea and nausea.
CALLI: Okay, so it’s not just the lungs in the end.
NATE: Well, it’s important to look into it, so when these complaints started popping up more frequently, researchers started broadening the scope of their work, and looking into the gut.
CALLI: So what did they find?
NATE: As you may know, Covid, like other viruses, uses these things called spike proteins to bind itself to receptors on certain human cells and invade. These receptors are the key to the infection. They essentially open the door for the virus.
CALLI: Why are the receptors doing that?
NATE: They don’t mean any harm, and they usually perform important functions, like regulating inflammation in response to injuries, but the spike protein confuses the receptor, and they bind together. Then the receptor helps merge the virus with the cell. Once inside, the virus dumps its genetic material into the cell and hijacks the cell’s resources to replicate itself.
CALLI: Those receptors are causing a lot of trouble.
NATE: Indeed. But, in this case, they’ve also kinda helped the researchers out.
CALLI: How so?
NATE: Well, it was these receptors that the researchers found when they started looking for Covid in the gut. Finding those receptors led them to realize that the other gut-related symptoms, the nausea, the diarrhea, they weren’t coincidental. They were probably Covid too.
CALLI: So, they’ve had evidence that Covid can affect the gut since then.
NATE: Yes! But now, they're learning that the gut might also be a major reason for long Covid.
CALLI: Can we define long Covid? I’ve heard of it plenty but want to make sure we are on the same page.
NATE: Sure, it means having any symptoms that last beyond 12 weeks after your initial covid infection. That can mean a lot of things, because there are more than 200 associated Covid symptoms. Some of these are pretty mild, but others can be debilitating and scary, like a series of tiny blood clots.
CALLI: And some of these symptoms happen in the gut as well?
NATE: Well, many of these long Covid patients were still having gastrointestinal issues. Months of discomfort, diarrea, and vomiting issues among other things. So again, researchers dove into their gut. This time, they looked at what the gut produced, their stool.
CALLI: It’s always poop.
NATE: With the gut, it is.
CALLI: So, what were they looking for?
NATE: They wanted to see if the long Covid patients were ... expelling the ghosts I mentioned before. And sure enough they were! Researchers found bits of Covid RNA in patients' stool four months after infection, and for some patients, up to seven months after.
CALLI: Was that every patient they looked at? Are we all expelling the virus or fragments of the virus?
NATE: The study looked at the stool of 46 participants who had had mild Covid. 32 of them had viral molecules in their gut seven months after the infection, and two thirds of those patients had long covid symptoms.
CALLI: Oh, interesting. So, there’s some correlation it seems. That's a long time to have GI issues. So can we say that this is the cause of long Covid then?
NATE: No. Researchers still have to do a lot more testing to nail down whether these Covid ghosts are the cause of long Covid. But it does mean that they are getting closer to understanding it.
CALLI: But they know it has something to do with the gut?
NATE: Actually no. This study only focused on Covid and the gut. They haven’t yet ruled out other places in the body. There are a few other studies still ongoing. They haven’t yet been peer reviewed, but scientists have begun to see evidence of RNA lingering in other organs as well. Places like the heart, eyes, brain, and breast tissue. Maybe for up to 230 days—interestingly, that same seven or so months—after initial infection. Again, ongoing research, not yet peer-reviewed. But our knowledge of long Covid is expanding as scientists look deeper into it.
CALLI: Well let's keep hoping the research goes well, and we can all get beyond this.
NATE: Amen to that.
[SFX: Whoosh]
NATE: Let’s recap what we learned today to wrap up.
CALLI: It's not an old wives’ tale, apple seeds, and the pits and seeds of other fruits, really do have cyanide in them. And while, theoretically, it could kill you, it would take more chewing than the human jaw may even be capable of. Your fruit is safe. Just be sure to put some limit on how many fruit seeds your kids eat.
NATE: New research shows potential benefits for both morning and evening workouts. And while the best strategy is following your own personal internal clock when it comes to timing your workouts, some research shows unique health benefits depending on when you do it.
CALLI: New research has found that even months after initial infection, the evidence of covid 19 still lingers in our guts. These “ghosts” of the infection, fragments of the virus’s RNA, might help us better understand and battle long Covid.