# What is an allergy?

An episode of [Science for Kids / Science's Not Boring: The Kids Science Podcast](https://invisiblenetwork.ai/podcast/1896928296), 17 Aug 2026, 12 min.

Audio: https://www.buzzsprout.com/2624612/episodes/19623725-what-is-an-allergy.mp3

Have you ever wondered why a yummy peanut butter sandwich is just a snack for you, but super dangerous for someone else? Welcome to the wild world of allergies! Join Mira and Finn as they shrink down to discover what happens when your body's immune system gets totally confused and sounds a giant false alarm! You'll meet the body's microscopic security guards—called mast cells—that are packed full of tiny chemical water balloons just waiting to pop! Find out how an amazing secret military invention from the 1970s transformed into the life-saving EpiPen we know today. Plus, travel all the way to Israel to uncover a mind-blowing medical mystery about baby peanut puffs! Could eating peanuts as a baby actually stop you from being allergic later on? Discover how scientists literally had to rewrite the medical books in this epic, sneeze-tastic episode of Science is Not Boring! Get ready to explore the amazing science inside your own body!

## Transcript

[0:46] SPEAKER_00: Welcome to Science Is Not Boring by kidopoly.com.
[0:49] SPEAKER_00: I'm Mira.
[0:50] SPEAKER_00: And I'm Finn.
[0:52] SPEAKER_00: Before we start, a big hello to Hazel, who is seven and lives in Dublin, Ireland.
[0:57] SPEAKER_01: Hazel loves Science is Not Boring, and she asked us an amazing question.
[1:02] SPEAKER_01: Why do some people have allergies?
[1:05] SPEAKER_00: What a great question, Hazel.
[1:07] SPEAKER_00: This one is exactly for you.
[1:09] SPEAKER_01: Yeah, because for me, a peanut is just a yummy snack.
[1:12] SPEAKER_01: But for some kids at my school, it's super dangerous.
[1:16] SPEAKER_00: Exactly.
[1:17] SPEAKER_00: Today we are finding out why a body would attack a peanut, why allergies seem more common than they used to be, and what an EpiPen actually does.
[1:26] SPEAKER_01: I heard a wild fact, Mira.
[1:28] SPEAKER_01: Are there really 220 million people globally with food allergies?
[1:34] SPEAKER_00: Yes, it's a massive number.
[1:36] SPEAKER_00: In the United States alone, about 33 million people have food allergies, which means one in 13 children has one.
[1:44] SPEAKER_01: Whoa, one in 13?
[1:46] SPEAKER_01: That's roughly two kids in every single classroom.
[1:49] SPEAKER_00: Exactly.
[1:50] SPEAKER_00: But for a long time, the advice doctors gave to prevent these allergies was completely backward.
[1:56] SPEAKER_00: We literally had to rewrite the science books.
[1:59] SPEAKER_01: Backward?
[2:00] SPEAKER_01: What do you mean?
[2:01] SPEAKER_01: And what actually is an allergy anyway?
[2:05] SPEAKER_00: To understand allergies, we have to travel back to the year 1906.
[2:10] SPEAKER_00: An Austrian doctor named Clemens von Perkett was treating children in a hospital.
[2:15] SPEAKER_00: What did he see?
[2:17] SPEAKER_00: He noticed that some children's bodies reacted terribly to harmless things, like standard medicines or ordinary foods.
[2:25] SPEAKER_00: He realised their bodies had an altered reaction.
[2:28] SPEAKER_00: So he had to make up a new word for it?
[2:31] SPEAKER_00: Yes.
[2:32] SPEAKER_00: He combined two Greek words, alos, which means other, and ergya, which means action.
[2:39] SPEAKER_00: Altered action.
[2:40] SPEAKER_00: Allergy! He invented the word allergy! Spot on! An allergy is basically your immune system getting confused.
[2:49] SPEAKER_00: Your immune system is an elite security force protecting your body from germs.
[2:54] SPEAKER_01: Yeah, with white blood cells acting like tough security guards.
[2:58] SPEAKER_00: Exactly.
[2:59] SPEAKER_00: But there's a very special type of guard called a mast cell.
[3:03] SPEAKER_00: You have billions of these mast cells hiding out right where your body meets the outside world.
[3:10] SPEAKER_00: Like your skin, your lungs, and your gut.
[3:13] SPEAKER_00: What are they guarding against?
[3:15] SPEAKER_00: Bugs?
[3:16] SPEAKER_00: Close.
[3:16] SPEAKER_00: They actually evolved millions of years ago to protect humans from dangerous parasites.
[3:22] SPEAKER_00: Inside every single mast cell are tiny sacs called granules.
[3:27] SPEAKER_00: Like little storage backpacks.
[3:30] SPEAKER_00: More like microscopic water balloons.
[3:33] SPEAKER_00: And they are filled with a powerful chemical called histamine.
[3:37] SPEAKER_01: Chemical water balloons?
[3:39] SPEAKER_01: That is so cool.
[3:40] SPEAKER_00: When a mast cell spots a real threat, it pops those balloons.
[3:44] SPEAKER_00: This is called degranulation.
[3:47] SPEAKER_00: The histamine floods the area to flush out the invader.
[3:51] SPEAKER_00: Kind of like a super intense washing machine cycle.
[3:54] SPEAKER_00: Behold Weep and Sweep move! That's a great defence strategy.
[3:58] SPEAKER_00: It is great for parasites, but in a person with a peanut allergy, those mast cells get very confused.
[4:05] SPEAKER_00: The body looks at a harmless little peanut protein and sounds a totally false alarm.
[4:11] SPEAKER_01: It thinks a regular old peanut is a giant dangerous parasite.
[4:15] SPEAKER_00: Exactly.
[4:16] SPEAKER_00: The immune system creates special wanted posters called IgE antibodies.
[4:22] SPEAKER_00: These antibodies stick onto the outside of the mast cells, warning them to look out for peanuts.
[4:28] SPEAKER_01: Oh, I bet I know what happens next.
[4:31] SPEAKER_01: The person eats a peanut and the guards go crazy.
[4:35] SPEAKER_00: You've got it! The mast cells see the peanut protein, sound the false alarm, and instantly degranulate.
[4:42] SPEAKER_00: Millions of chemical water balloons pop at the exact same time.
[4:46] SPEAKER_01: Whoa! That's a massive flood of histamine all at once.
[4:50] SPEAKER_00: Yes, and that much histamine triggers major changes.
[4:54] SPEAKER_00: It tells the blood vessels to quickly widen, which causes swelling, and it tells the smooth muscles around the airways in the lungs to tighten up.
[5:03] SPEAKER_01: That sounds like it could be really scary.
[5:06] SPEAKER_01: Is that why their throat might feel tight or their skin gets itchy?
[5:09] SPEAKER_00: Yes, exactly.
[5:11] SPEAKER_00: This severe body-wide reaction is called anaphylaxis.
[5:15] SPEAKER_00: Because the blood vessels get so wide, the person's blood pressure drops rapidly and the airways close up to try and block out the invader.
[5:23] SPEAKER_00: But the invader is just a snack.
[5:26] SPEAKER_00: How do doctors stop the false alarm safely?
[5:28] SPEAKER_00: They use a super powerful medicine called epinephrine, which is basically pure adrenaline.
[5:35] SPEAKER_00: And the way they deliver it is an amazing piece of engineering called an EpiPen.
[5:40] SPEAKER_01: I've seen EpiPens in the nurse's office.
[5:42] SPEAKER_01: They look like big plastic markers.
[5:45] SPEAKER_01: But what's inside them?
[5:47] SPEAKER_00: They are brilliant inventions.
[5:49] SPEAKER_00: Back in 1973, a mechanical engineer named Sheldon Kaplan was working for the military.
[5:56] SPEAKER_00: The Pentagon asked him to invent a way for soldiers to quickly inject life-saving antidotes on the battlefield.
[6:03] SPEAKER_00: Wait, the EpiPen started out as secret military technology?
[6:08] SPEAKER_00: It did! Kaplan invented a spring-loaded gadget he called the Combo Pen.
[6:14] SPEAKER_00: A few years later, a man named Rick Torin, whose daughter was highly allergic to bees, helped adapt Kaplan's military invention for everyday allergies.
[6:24] SPEAKER_01: That's so smart! So instead of a complicated needle and glass vial, you just have this one tube.
[6:32] SPEAKER_00: Exactly! You firmly thrust the epipen against the person's outer thigh.
[6:37] SPEAKER_00: Inside, a hidden spring instantly activates, launching a tiny needle into the muscle in a fraction of a second.
[6:45] SPEAKER_00: It automatically pushes the exact right dose of epinephrine into the body.
[6:50] SPEAKER_00: And what does the epinephrine do once it's inside?
[6:53] SPEAKER_00: It works like a magic reverse switch.
[6:56] SPEAKER_00: Remember how histamine widened the blood vessels and closed the airways?
[7:01] SPEAKER_00: Epinephrine instantly opens the airways back up and tightens the blood vessels, so blood pressure goes back to normal.
[7:09] SPEAKER_01: It literally turns off the false alarm.
[7:12] SPEAKER_01: That is a total lifesaver.
[7:14] SPEAKER_01: But Mira, it feels like way more kids have allergies today than when our parents were little.
[7:20] SPEAKER_01: Why is that?
[7:21] SPEAKER_00: That's been a huge mystery in science.
[7:24] SPEAKER_00: For decades, doctors told parents to keep peanuts far away from babies, hoping to protect them from developing allergies.
[7:32] SPEAKER_00: But it turns out that advice might have been completely backward.
[7:36] SPEAKER_01: Backward?
[7:38] SPEAKER_01: You mean keeping babies away from peanuts was making it worse?
[7:42] SPEAKER_00: It looks that way.
[7:43] SPEAKER_00: The big clue came from a scientist named Professor Gideon Lack from King's College London.
[7:49] SPEAKER_00: He was giving a speech in Tel Aviv, Israel, and realised that Israeli children almost never had peanut allergies.
[7:57] SPEAKER_00: Why?
[7:58] SPEAKER_00: What were they doing differently in Israel?
[8:00] SPEAKER_00: He noticed that Israeli babies eat a super popular snack called bamba.
[8:06] SPEAKER_00: They are little puffed corn treats made with peanut butter, and parents give them to babies starting when they are just 4 to 11 months old.
[8:14] SPEAKER_00: So they were eating peanuts right from the start?
[8:17] SPEAKER_00: Exactly! To prove this was the reason, Professor Lack set up a massive experiment in 2015 called the LEAP Study, which stands for Learning Early About Peanut Allergy.
[8:30] SPEAKER_00: They studied 640 babies for five years.
[8:34] SPEAKER_00: Did it work?
[8:36] SPEAKER_00: Did the peanut puffs protect them?
[8:38] SPEAKER_00: The results were mind-blowing.
[8:40] SPEAKER_00: The scientists found that feeding babies peanut snacks early in life safely trained their immune systems to recognise the food as harmless.
[8:49] SPEAKER_00: It reduced the chance of developing a peanut allergy by an incredible 81%.
[8:56] SPEAKER_01: 81%?
[8:57] SPEAKER_01: That is a gigantic difference.
[9:00] SPEAKER_01: So their mast cells learn to just chill out.
[9:03] SPEAKER_00: Exactly.
[9:04] SPEAKER_00: By introducing the food early, the body learns it's safe nutrition, not a dangerous parasite.
[9:10] SPEAKER_00: It's one of the biggest medical breakthroughs in recent history, and it's already changing how kids grow up all over the world.
[9:18] SPEAKER_01: That is the coolest thing ever.
[9:20] SPEAKER_01: Science totally saved the day.
[9:23] SPEAKER_01: Again.
[9:23] SPEAKER_01: Alright Finn, time for the quiz.
[9:25] SPEAKER_01: Are you ready?
[9:26] SPEAKER_01: I am ready.
[9:28] SPEAKER_01: My brain is fired up and ready to go.
[9:31] SPEAKER_01: First question.
[9:32] SPEAKER_00: What was the name of the doctor who invented the word allergy in 1906?
[9:38] SPEAKER_00: Next one.
[9:42] SPEAKER_00: What are the immune system security guard cells called that release chemical water balloons?
[9:52] SPEAKER_00: Question three.
[9:53] SPEAKER_00: Who organisations event invented the spring-loaded auto injector for the military that became the EpiPen?
[10:04] SPEAKER_00: Here's number four.
[10:06] SPEAKER_00: What is the superhero medicine inside an EpiPen that opens up the airways?
[10:15] SPEAKER_00: Last question.
[10:16] SPEAKER_00: What country were the babies from who ate peanut puff snacks, which inspired the famous leap study?
[10:26] SPEAKER_00: Great job! Let's go through the answers.
[10:30] SPEAKER_00: The answer to question one is Dr.
[10:33] SPEAKER_00: Clements von Perkett.
[10:35] SPEAKER_00: For question two, they are called mast cells.
[10:39] SPEAKER_00: Number three, the answer is Sheldon Kaplan.
[10:43] SPEAKER_00: Question four, the medicine is epinephrine, which is like pure adrenaline.
[10:49] SPEAKER_00: And the final answer is Israel.
[10:52] SPEAKER_01: Wow! So allergies are really just our bodies trying too hard to protect us from things that aren't even dangerous.
[11:01] SPEAKER_00: Exactly.
[11:02] SPEAKER_00: Those mast cells mean well.
[11:04] SPEAKER_00: They're just a little confused.
[11:06] SPEAKER_00: And thanks to science, we have brilliant tools like the EpiPen to keep everyone safe.
[11:12] SPEAKER_01: I think mast cells and EpiPens deserve five stars.
[11:16] SPEAKER_01: Hey listeners, if you love learning about allergies today, please leave us a five-star review.
[11:22] SPEAKER_00: Yes, just scroll down on your podcast app and tap those five stars.
[11:27] SPEAKER_01: It helps us out so much.
[11:29] SPEAKER_01: And don't forget to head over to our site, kidopoly.com.
[11:33] SPEAKER_01: We have tons of awesome learning games and activities waiting for you.
[11:37] SPEAKER_00: If you want your name shouted out on the show like Hazel, or just want to tell us your favourite science fact, send us an email at hello at kidopoly.com.
[11:47] SPEAKER_01: See you next time on Science Is Not Boring.
[11:50] SPEAKER_01: Bye everyone.

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