This Podcast Will Kill You - Ep 222 Vitamin K: Calling the shots

Episode Date: September 22, 2026

Shortly after birth, many newborns are given vitamin K to help their blood clot properly and reduce the chances of hemorrhage. Increasingly, especially here in the US, parents are refusing this life-saving intervention, leaving these babies more likely to develop deficiency bleeding which can lead to life-long brain damage and death. In this episode, we explore the many dimensions of vitamin K: how it acts in our bodies as an essential compound, when we discovered the clotting properties of this vitamin and applied that knowledge to prevent catastrophic bleeding in newborns, and why some people are turning away from this life-saving injection. You’ve seen the headlines, now tune in for the full story. Support this podcast by shopping our latest sponsor deals and promotions at this link: https://bit.ly/3WwtIAuSee omnystudio.com/listener for privacy information.

This is exactly right. The first-hand account contains some descriptions that listeners might find upsetting. Please listen with discretion. Olive was breathing and her heart was beating, but she was otherwise non-responsive. She was fitted with an IV, had blood drawn, and even had a lumbar puncture to help the doctors figure out what was going on. It turned out there was blood in the fluid that they pulled from her lumbar puncture. The pediatric intensivist came and asked me if we had given our daughter a vitamin K shot at birth, and I just stared at him and said I had no idea. The doctor explained that a clot had

developed that was placing immense pressure on Olive's brain. Not only that, but there was bleeding on the back of the right side of her brain as well. The water pockets that are within the brain were completely destroyed, and the tissue on the left side of the brain looked damaged. He said that the lack of vitamin K in Olive's system resulted in her blood not being able to clot. Anything as small as putting her down in her bed could have caused this bleed. Since she couldn't clot, the bleeding didn't stop. Olive began clotting a little over an hour after they began her vitamin K treatment. Our decision now was whether we could have her undergo the risky surgery or see if the clot would resolve on its own. We felt the surgery was the best option, and it began just after 2 a.m.

Our little girl survived the surgery, and it was a success. This may be the hardest part of Olive's story that I will write. The part where I admit that what happened to her was nearly 100% preventable. And yet, it happened. It happened because she didn't receive her dose of vitamin K when she was born. I spent the first few days that she was in the hospital blaming myself. I ran through the situation in my mind, trying to understand why I would say no to something that would keep my daughter from being in this much pain. In all of the situation, unfortunately, it was largely accidental. That didn't stop me from feeling guilty, however, and only recently did I accept that although this happened to Olive, it doesn't have to happen to another person's baby. Olive was born in a

birth center. I loved the experience that I had there, and to this day, I hold no hard feelings against the wonderful midwives that were present when she was born. A few weeks before her birth, we went over the routine shots that infants are given in the hospital and decided whether or not Olive would receive them. For most of these, I knew my answer. But since I knew nothing about the vitamin K shot, I decided to do my research and then decide at the birth what I would do. When I began hemorrhaging after Olive's birth, the discussion of the shot was completely forgotten, and she ended up not getting it. After all, things that are deemed to be optional are probably not essential, right? There's debate about causing pain to a newborn by giving them a shot shortly after they are born.

All I can say for that is this. The pain that Olive endured from the results of her vitamin K deficiency is so much more than any pain she would have had as a result of a quick shot at birth. And although some argue that the shot is an unnecessary medical intervention, the number of medical interventions that will occur if your child has a brain bleed when they stop clotting are substantially more significant. What it comes down to is that giving your child, a shot of vitamin K at birth, is a small price to pay, especially when the cost of rejecting the shot can be severe brain injury and death. I can't change what happened to Olive, but I can try to prevent it from happening to another baby. Yeah, I found that story actually on the CDC website on,

It's like one of the stories of vitamin K deficiency and what can happen. And it's called Olive's story. If you like, that's excerpted from that. And so if you'd like to read the full version, it is heartbreaking. It is awful. Yeah. Yep. And yet it is happening more and more these days.

And this is why these stories are so important. They're so impactful. Yeah. Just so that, yeah. Because if you don't know, then you don't know that that's a thing. that's a thing that can happen. Yeah. Yeah. Hi, I'm Erin Welsh. And I'm Erin Elman Updike. And this is, this podcast will kill you. And today we're talking about vitamin K. Vitamin K. Yes, we are. There's a lot to cover. There is so much to cover. This was a hard one to do. I think

emotionally. Yeah. I think hopefully everyone has been hearing about vitamin K lately. If you haven't, you'll know why people are talking about vitamin K if you haven't heard by the end of this episode. But it's largely in the context of newborns and vitamin K deficiency. So that's mostly what I'm going to focus on today. Yeah, same. Vitamin K has a lot of other applications besides being injections or oral drops at birth. But that's my story is also about like when we started to give vitamin K to newborns and how transformative that was. Yeah, I'm really excited for that. But we have some other things that we have to cover before we get into the meet of this episode, Aaron.

We do. It's quarantine time. Quarantini time. Hold on. I have my notebook. Oh, good. Because I don't remember what we agreed on. I know.

It is called the quarantini for this week is called Flip, Flip, Flip, Flip. Here we go. Thicker than water. Thicker than water. Thicker than water, that's right. Like blood. Yes, blood is thicker than water. Yes, it is.

Vitamin K makes blood even thicker, but not too thick. Not too thick. We'll get into all of that. In thicker than water is lime juice, pomegranate juice, blood to make it look like blood, orange juice, club soda. I can't read my own handwriting. It's terrible.

I'm not even that kind of doctor, and it's horrific. And if you want to make it extra thick, we have an optional note here that you could add chia seeds or cillium husk just to gloop it up. Just to glute it. I would not recommend it, but you're welcome to. You are welcome to. I mean, you know, exercise your free will.

Exactly. Polymogenet juice also a moderately good source of vitamin K. So there you go. There we go. You'll find the full recipe for that delicious beverage on our website, this podcast will kill you.com, and our social media channel. So make sure that you're following us over on the sochi's. On the Sochi's. That's an excellent, excellent use of your free will to abbreviate and extend in that way.

On our website, there's lots of things you can find, transcripts, links to things like merch, bookshop.org affiliate page, Bloodmobile, contact us form, first-hand account form, other things like that, check it out. And if there's no more business, let's get straight to business. Let's do it right after this break. You've heard the chaos. Now you can see it. Do we want to jump right in? Watch all your favorite podcasts from start to finish right inside the free IHart Radio app.

Make some noise. Wooee! Catch every laugh and eye roll on shows like Bestie Listen, Hey Jonas and Las Culturistas. Now with full video. I'll just leave that there. It's the same hosts and the same chemistry with all the hilarious moments you've been missing right on your screen.

Open the free. her radio app, search video podcasts, and tap watch. So the story of vitamin K, like we mentioned, it has a lot of different parts that we could go into. But the main one that I'm going to focus on today is vitamin K in newborns, because it's a huge part of the vitamin K story. But this is, this podcast will kill you, so I can't just do that one thing. And I think to really understand the vitamin K and newborn story, we have to first understand what vitamin K actually is. and what it's doing in our bodies. Yeah.

And then we can look at why newborns are so weird and, like, different than adults and what we can actually do about it. I also know that a lot of people listening might be hearing a lot about vitamin K in a completely different context. And that is the world of supplement bros who can't stop talking about K2. So I promise we can talk about that at the very end. Okay. Okay.

Okay. Okay, too. Okay, too. All right. So what the heck is vitamin K even? Vitamin K is a vitamin. It's a fat soluble vitamin. And we've talked about vitamins a lot on this podcast. They're basically just something that is essential for life in minute quantities. And they are substances that we use as either like enzymes or cofactors in a lot of our biological processes. Much of the time we have to get vitamins through our diet. And that is also true for vitamin K. And a fat soluble vitamin, just means that we have to have fat in our guts while we're absorbing that. Like, it won't absorb without fat present. And we don't just, like, pee it out the way that we pee out water soluble vitamins. We can actually store it a little bit in our body. And it turns out that vitamin K isn't actually

just one single thing. It's multiple different compounds. The most common one that we use in medicine and that we have and that we get from our diet is vitamin K1, which is also called phyloyal. iloquinone. And this comes from plants. We get it from like leafy greens and fruits and other vegetables. And then there's vitamins K2. Vitamins because there's more than one of them. More than one K2. More than one K2. It's quite confusing. These are called menacoinones. And they're produced by bacteria. There are so many different types of bacteria that can produce so many different variants of these menacoinones that are collectively vitamin K2. That makes sense? Sure. They've got like different MK4, MK7, 11. We don't need to do that. We get these from the bacteria in our guts, which make our own K2. That's quite exciting. I really is. I really liked learning that. I love that. We also can get K2 in our diet from food sources like bacterially fermented foods. So a lots of types of cheeses, Nato, which is like a Japanese fermented soybean, and other foods as well. And in the plants and bacteria that produce vitamin K, the vitamin K is very important for them as well. It's like a substrate for electron transport, but we can ignore all of that and just focus on what vitamin K is needed for in us humans, all right? And it turns out that it's actually important in a really wide range of biological processes, but ultimately it does just one single thing. And that is that

vitamin K acts as a co-factor. So it's like an integral part of an enzymatic process in our body, but it's not getting used up in that process. So it's kind of like a wrench that tightens a bolt on certain proteins in our bodies. It's a tool. It's a tool. Yeah. And it's a necessary tool. Because what it does is a process called carboxilation, which basically just means it adds on a carbon dioxide to a specific amino acid called glutamic acid. And it does this on a bunch of different proteins in our bodies that we collectively call GLA proteins. But we can avoid a lot of the biochemistry if we just think of it as that wrench and think that there's a bunch of different proteins in our body that basically cannot take their final active form, cannot get wrenched

into the correct configuration to be activated without the presence of vitamin K. It's like the finishing touches. Exactly. But crucial finishing touches. Crucial finishing touches. Not just the paint on the walls, but like the couch in your room. That's a terrible analogy. We'll workshop it.

We'll work on it. So what proteins you might ask? There are quite a number. And we're probably going to learn even more of them as we continue to research vitamin K. But we know already that vitamin K is integral in the activation of a protein called osteoketal. which is involved in our bone mineralization and remodeling. Another protein called matrix GLA protein, which is found in all of our vascular tissue and our heart and our lungs and our kidneys.

And it's actually involved in inhibiting tissue calcification. So that means this protein makes sure that calcium doesn't get deposited in places that it doesn't belong. And then there's other proteins like the ones in our bone mineralization that makes your calcium goes where we want it to go. All right. Calcium placer, yeah. Big time. Calcium and vitamin K, this is really cool. There's people who are really excited about it. But the way that most people know about vitamin K is that it is very involved in our

clotting cascade. People may or may not remember many years ago when we did an episode on hemophilia. If you do, you must be in the teeny tiny minority. If you do. And I don't count myself as one of those. I don't remember anything. Thank you for listening for this long because, wow. That was a long time ago. It was a long time ago.

But basically, our blood clots via a pretty complex system where there are kind of like a chain reaction of proteins, which one protein has to be activated in order to activate the next protein, which activates the next protein and so on and so far. in order to form a blood clot whenever we have any type of tissue damage. There are at least 12 different factors, 12 different proteins, we call them factors, that are involved in this clotting cascade. And the presence of vitamin K is essential for the activation of four of these factors, factor 2, 7, 9, and 10. And it's also responsible for the activation of two anticoagulant factors, which are called protein C and protein S. Isn't that interesting?

It's just got its fingers in everything. Every aspect of our coagulation process. Okay. And overall, vitamin K acts as a pro coagulant. So without vitamin K present, you will bleed more. And like, honestly, if you have no vitamin K, you're just going to continue bleeding. You'll never be able to fully clot, which is a huge problem. And so the single most well-studied consequence of vitamin K deficiency is bleeding. Even though it can also result in the malfunction of other proteins that are involved in bone density, cardiovascular health, the place that we know the most about vitamin K is its effect on bleeding. And the place that we hear about it really often, especially these days, is in newborns. Why is that the case?

Yeah. The vast majority of us grown adults, or even my incredibly picky toddlers who eat nothing healthy. Chicken nuggets. Chicken nuggets. Chicken nuggets. Mac and cheese. Okay. Things that are orange or white.

Yes. Orange if you're lucky. Yeah. Even they get an adequate amount of vitamin K in their diets. Is it because it's just, well, okay, I have questions about this. Give it to me. Okay, before we get into newborn bleeding, yeah. Quantities of vitamin K, dietary, like, is it, how likely is it that you will become deficient?

How much do you actually need? What is the range? What is the sufficient amount? Yep. You know, like, what is the actual risk for adults becoming vitamin K deficient without some other sort of underlying health factor going on? Very minimal without some other underlying health factor going on. Okay. The recommended daily intake of vitamin K is one microgram per kilogram of body weight.

So if you weigh like 150 pounds, that's 68 kilograms, so you need 68 micrograms of vitamin K. That's like a small spinach salad. It's like a half of a cup of broccoli. It's like a couple of kiwis. It does not take much to get the daily recommended amount. And because it's fat soluble, even if you're not getting it every single day, if you have a big fat spinach salad or like a kale smoothie or, something like that, you're getting a ton and your body's going to be able to use that for at least a few

days. Okay. A question well, so then why are the podcast bros and the supplement bros obsessed with K2? Why are they such a question? So that because it's a moneymaker. But then the other question I have is excess. So is there

a cutoff point where your body's like, we're not storing anymore or does it continue to deposit until like can things get bad with coagulation? It's such a good question. We don't have a firm answer on that, largely because it would be very difficult to overdo it just by eating. Your body's going to absorb how much your body's going to absorb. And it's all going to be sort of like physiological levels because if you're eating foods that are, you know, just fruits and vegetables and even processed foods aren't like supplemented with vitamin K in general because we don't need vitamin K supplementation.

If you are taking really high-dose supplements, then yeah, it's possible that you could become overloaded with vitamin K. So far, we haven't seen data that suggests that that makes you more likely to have blood clots. Why is it just because our body is really good at regulating that clotting cascade? Maybe. So it might just be that. Could there be other downstream effects if you overdose on vitamin K, possibly? But at least at this point, we don't.

We don't know. You're also getting it from your own gut. microbiome, right? Like our guts are making K2, which is really interesting. But I really, really want to know why K2 is being pushed. We'll get there eventually. Okay. Tell me. Okay. It's because people are very interested in the interplay between vitamin D and K2. And so there is a growing amount of data that it's possible that if we supplement with vitamin K in addition to, vitamin D and K2 seems to be more involved in the bone and vascular health than K1, which is more strongly tied to our coagulation cascade.

Okay. And so the thought is that maybe if we add vitamin K to vitamin D supplementation, we might be able to prevent something like osteoporosis. We might be able to improve our vascular health and reduce bad cardiovascular outcomes, like heart disease, heart attack stroke. So far, the data is no. We don't have data that those things are true. We can't prevent osteoporosis with K2, and we don't have enough data to say that it does improve cardiovascular outcomes.

But that's the reason that people are excited about it because theoretically, you could. But again, because people are mostly not deficient in vitamin K, it's the same story with supplementation. We don't need to supplement then. Right. Okay. Okay. So like it's based on an actual physiological possible relationship, not firmly established, but the supplementation has no support. There's no evidence that supplementation is necessary for most.

people. So, yeah. Newborn bleeding. Newborn. Let's get back to it. Okay, so adults, toddlers, humans in general are not likely to be deficient in vitamin K for the most part. Newborns are very different.

Newborns, every single one of them, are born with very low stores of vitamin K because vitamin K does not cross the placenta very efficiently. Even if you are taking vitamin K supplements during pregnancy, it does not substantially increase vitamin K-dependent factors in the newborn. Additionally, though this probably pays a much less role, their gut microbiome is not yet mature. So they're not making any substantial amounts of K2 themselves. And interestingly, even the first year of life, their concentration of vitamin K2 from their gut bacteria is pretty low.

So functionally, it's really not playing that big of a role. And this is the real kicker. Vitamin K is found at incredibly low concentrations in breast milk. So newborns are born physiologically deficient in vitamin K. Their stores are going to decrease over the first few days of life. And the breast milk that everyone recommends that babies are fed because it is considered the best option for all newborns, if it's possible, is deficient in vitamin K. Yeah. The amount of vitamin K in breast milk really can vary.

But on average, it's about 2.5 micrograms per liter of breast milk. Whoa. And babies, especially newborns, are getting literal milliliters the first few days of life. Right. And even as they get to be between one and six months old is when they're like maxing out the amount of breast milk that they're going to get, it's about 24 to 30 ounces a day that babies are getting. So that's like 700 to 800 milliliters. So on average, breastfed infants are getting less than one microgram per day in the first six months of life. That's not enough.

That's not one microgram per kilogram. They're weighing three and a half kilograms at birth and then going up from there pretty rapidly. So they are deficient in vitamin K, which means that newborns, all of them, every single one, are at very high risk for what's known as vitamin K deficiency bleeding. And that is why we talk about vitamin K and newborns. There are multiple different kinds of vitamin K deficiency bleeds that we see in newborns. They can happen really early, which is like in the first 24 hours of life. If this happens, it tends to be quite severe. It can be an intracranial bleed.

It could be bleeding really from anywhere, but these tend to be really catastrophic. Not very common. The classic vitamin K deficiency bleeding happens in the first week of life, so between one day and seven days old. This is often less severe. it might manifest as like skin bleeding, maybe bleeding after a circumcision that doesn't stop or maybe bleeding from the umbilical stump. It could also be GI bleeding. It could also be brain bleeding. But this one probably tends to be a little bit less severe than the other two. And then there's late vitamin K deficiency bleeding, which happens after one week and up to about six months of life. Okay. Late bleeds are very often

severe. About 60, up to 60% of the time, they are intracranial, which means in the brain. And depending on what year or what country or where you look at the data, mortality rates can be between 50 and 60%, though a lot of time modern rates of late vitamin K deficiency bleeds are about 20%. And what's scary about these is that there often isn't a warning bleed. So there's not something to let you know that something bad is about to happen. There's just a sudden catastrophic bleed, whether that's black or bloody stools, whether that's just seizures or unresponsiveness from a sudden brain bleed. And this used to happen quite frequently. Yeah. Although because none of this is notifiable, it's actually really hard in the literature to get good numbers on this.

usually the incidents that's reported of early and classic bleeds, so those first two categories, ranges from like 250 to almost 1,700 cases per 100,000 live births. So like not that uncommon. And then late vitamin K deficiency bleeding has always been considered less common, but still about four to seven per 100,000, though some papers cited up to 80 per 100,000 for late bleeding in some countries. It seems variable. And like, I have some historical data. Yeah. But it is, yeah. And also I think that like it's only been more recently that we have split these into these three different types. And so it's all been kind of like lumped together. Right. Exactly. And like this was the reality for babies across the entire globe before we figured out, which you're going to tell us all about, Erin, that this is actually entirely preventable. Maybe not 100. 100% preventable, but very preventable. Yeah, like pretty, pretty dang close to 100%.

Pretty dang close. Pretty dang close. There's two different ways that we can prevent vitamin K deficiency bleeding. Both of them just involve literally giving the baby vitamin K. That's it. That's all that we have to do. It's very, very easy to do. In the U.S., since 2003, and actually in almost every place across the globe, including

most major medical societies and public health organizations, the recommendation is to do this by intramuscular injection, one single dose of an injection of vitamin K. What that does is it provides a steady supply of vitamin K for the first several months of life. And this reduces the risk of bleeding to almost zero. Yeah. It goes down to about point four, especially for late vitamin K bleeds, to about 0.4 per 100,000 babies born from 4 to 7 to 80. Babies who receive no vitamin K prophylaxes are 81 times more likely to have a late lead. So that is the recommendation almost everywhere. Some places, though, use oral administration, and that is an option.

It still can significantly reduce the risk of bleeding. but it is not as effective as the injection. And it's for a bunch of different reasons, which we don't like fully have a good grasp on. It's in part because there's not a clear consensus on the dosing schedule and frequency. We do know, though, that it requires multiple doses to be administered.

And that's harder to. It's harder to do. When you have to do things multiple times, go back multiple times, maybe you can't, maybe it, yeah. Right. Or maybe you have to do it at home. And you're dealing with a newborn. That's not easy.

ask how often my baby got vitamin D. Not as much as they should. It also, like, there can be issues with absorption for a number of different reasons, whether it's because you give it on an empty stomach or baby spit up right afterwards or they just spit it out because it tastes bad. So we might not actually get in as much as we think that we're getting. And then there's also the fact that some babies separate from this will end up having billy issues that go unidentified.

And that can substantially affect the. absorption and the function of the oral vitamin K, much more than the intramuscular dose of vitamin K. Okay. So this is still an option in some countries, including a lot of places who say, we're going to recommend the injection. But if you really don't want the injection, then we have an oral formulation that's available.

And there are other countries that used to use oral and then switched back to doing intramuscular because the data was very clear that when you do oral, you have more. bleeding. Yep, yep. In the U.S., there is no oral formulation that is available. So there is no FDA approved. There is no formulation that has actually been looked out by regulators, approved by regulators, and is available for administration. In the U.K. and in many countries in Europe, there are oral formulations that are available, but that is not the case in the U.S., which means that if you are using an oral form of vitamin K in the U.S., you are getting it either from another country somehow, which does have regulations, or you're getting it from the supplement

market, which we all know is entirely unregulated and you have no idea what you're getting or how much you're getting or how much your baby is getting. We also don't have official recommendations from any of our major medical societies to say what our dosing schedule would be if we're going to use oral. Other countries do, but the U.S. does not. And that's again, interesting. And it's like, and this is beyond the scope, but just like, you know, know, is there a good argument for having oral drops or will it lead to still like similar rates of bleeds or still risk of bleeds? Will it actually help capture the people who are refusing the shot? The shot, exactly. What do we do? Is it meeting in the middle? Is that meeting

in the middle sacrificing safety for the, of the newborn? Right. And it's hard because we just really don't have a lot of data on this because vitamin K deficiency bleeding is not a reportable condition. It's not a notifiable condition, which means that we're not capturing any data on how many babies are having these bleeds. We also don't know how many people are not getting the vitamin K injection or in other countries how many are opting for injection versus oral. These are things that are just not being studied on a large scale, which makes it really, really hard for us to make evidence-based recommendations. Though the evidence is unequivocal that the I am in. injection is more effective than any of the oral doses that are given, essentially.

And incredibly safe. Incredibly, unbelievably safe. So are there any side effects that are reported with the vitamin K in intramuscular injection? Intramuscular injection. You can have local site effects. So you might have redness. You might have swelling. You might have a little bit of pain or tenderness where you get the injection.

And Erin, that's about it. There is a warning on the box about anaphylaxis, which of course is an allergic reaction, that anyone can, in theory, get to almost anything. However, there has only been one case of anaphylaxis that was reported after an intramuscular injection of vitamin K, and it's unclear if it was actually from the vitamin K or not. Any other case of anaphylaxis is from an IV injection, not from an intramuscular injection. And it only has happened in adults, not in newborns, who don't get an IV. they get an intramuscular injection. So really, no, there's no substantial risk to giving the IM shot, no long-term risks. It's just the risk of bleeding if you don't get it.

And that risk is so rare. It is so severe when it does happen. That's vitamin K, Aaron. Tell me everything about how we learned all of this, about how we got here. Okay. Okay. You've heard the chaos. Now you can see it.

Do we want to jump right in? Watch all your favorite podcasts from start to finish right inside the free IHart Radio app. Make some noise. Wooee! Catch every laugh and eye roll on shows like Bestie Listen, Hey Jonas, and Las Culturistas. Now with full video.

I'll just leave that there. It's the same hosts and the same chemistry with all the hilarious moments you've been missing right on your screen. Open the free IHard Radio app. Search video podcasts. Stories of science and medicine are often criticized, rightly so, for presenting these narratives where progress marches forward, never backward. Miststeps or overlooked cues rarely featured prominently, and the cost or rejection of this progress is not often considered.

And the outcome of these stories is that, you know, scientists are rewarded for their perseverance and insight with this knowledge that has the power to transform the world. world. And that's where the story ends. For some topics, that might be an accurate, if not entirely complete narrative. You know, you could certainly tell the story of vitamin K that way. There's a strange observation, which leads to more research, which leads to scientists discovering a new vitamin that can help with blood clotting, saving lives, and preventing injury and death, especially in newborns. True. True. That is the story. Okay. But as we know today, there is way more to that story. The misinformation and fear surrounding this life-saving intervention that leads parents to refuse the shot for their baby. The challenges with access to vitamin K in many

low and middle-income countries around the globe, which limits its use, the story of vitamin K shows us how scientific progress can truly transform the world, make it a better place, but only if that knowledge is applied. Yes. Today, I'm going to tell both parts of the vitamin K story. So the first dealing with how we learned about vitamin K and how we began to use it in medical settings. And the second exploring how this progress has been increasingly rejected or how this progress has been unevenly applied, sometimes leading to deadly consequences. Erin, sometimes is really no better way to start than with a quote. I love it when you start with a quote, Erin. Okay, this is a little bit of a long one.

Strap in. Quote, hemorrhagic symptoms frequently had been seen in infants, in patients with obstructive jaundice, in experimental animals maintained on simplified diets, and in cattle eating moldy sweet clover hay. All these circumstances added up to a first-class mystery. Why should cleanliness at times lead to an apparent deficiency in infants receiving breast milk, traditionally the most complete of foods? What was the connection between bleeding and jaundice? Why did chicks develop a scurvy-like deficiency disease that was cured by fresh greens when chickens were not reported to need vitamin C? What was the anti-hemorrhagic fever apparently absent in fish meal that was present in meat meal? How could an anti-hemeragic agent be present in green leaves if sweet clover hay actually caused hemorrhages?

Now, of course, we know that a common factor in all these conditions was vitamin K, end quote. I love it. It's good. I mean, it's all of these different. Everything. Here it is. You got warfarin thrown in there. I was going to say, we're not going to get into warfarin today, but someday we will tell the story of sweet clover hay and warfarin and cows and all that. But yeah, it's got the breast milk connection, how bacteria are actually helping us with this vitamin. It's interesting. So much. That quote is from a 1975 paper by H.J. Almquist about the early history of vitamin. K. And honestly, it's like a pretty delightful read because Almquist was actually heavily involved in this research. And he gets a little personal and he adds his little flare. And he definitely still seems annoyed almost 50 years later that he didn't get the credit that he felt he deserved for his role in vitamin K discovery. Okay. But we'll get to that. A little trauma. Exactly. I love it. But the reason I try. chose that quote is because I feel like it really brings home, A, how widespread application vitamin K has in so many different areas, and also how the discovery of this vitamin connected the dots of so many longstanding questions in medicine. So how was it discovered? We start, in fact, with cholesterol.

That's so funny. Recent topic, yeah. In the 1920s, a Danish researcher by the name of Henrik Dam was trying to understand how sterols were made. And so he was like, what are the things that you actually need in order to make cholesterol? And he was using chicks fed on fat and cholesterol-free diets, and he noticed that they developed these large hemorrhages under the skin. And he reported this in a 1929 paper. But he had no idea why, like why these hemorrhages were happening. The chicks could still make cholesterol. So it wasn't because of that. And the mystery deepened when a couple of other research groups saw something similar in chicks fed on a diet of fish or meat meal where the fat had been removed or where there were no greens. And it kind of looked like scurvy,

but as the quote mentioned, chickens can make their own vitamin C. It's just like, you know, how we can't, guinea pigs can't. Check out our scurvy episode. It's just us in guinea pigs is such a good episode. It's classic. It's classic. If we do say so ourselves. It is one of our longstanding, like, favorite episodes. Whenever somebody asks us, what are your favorite episodes? Scurvy's still cunt up. Yeah. But so they were like, okay, so it's not vitamin C, but maybe it's another vitamin deficiency.

But in follow-up experiments where they supplemented with the vitamins known at the time, the hemorrhages didn't stop. They couldn't do anything. When did they stop? When the chicks were fed plant material and things like hog liver. as an example. Okay. Apparently a great source of vitamin K.

Yep, it is. They still weren't exactly sure what the substance was. And so Dam concluded, well, it's got to be as yet undescribed fat soluble vitamin. And he proposed

that it be given the name vitamin K, K for coagulation. I love that. That's how it's spelled in German and Scandinavian languages. I love that, Erin, because I always just assumed,

which I think is true for some vitamins that they just named them like ABC, D, FG, all the way to K, but it's K for collagulation. Like at one point they were like, you know what, we've got, we've got better, a better system. Right. Yeah. And so this though, this is the part where Almquist, who's the author of that paper from the quote, he felt he was overlooked.

So what happened, drama, is that his research group submitted a paper with basically these same conclusions. He was like, there's this new fat soluble vitamin. It was produced by bacteria. But the paper got rejected because another group at the same university, which I think was UC Berkeley, they had reported very different findings. And they were like, no, it's got to be something else. Like it's not that. It's not a deficiency.

Whatever. And the university allegedly was like, okay, you got rejected. Do not resubmit this until we get this internal argument figured out. And in the meantime, Dan published his findings. And they were working totally independently. Like it was going to happen no matter what. Yeah. But it was only after those findings were published that Almquist was able to get his group's work published.

Oh my goodness. Which is annoying. That is annoying. That's like some real internal politics. Yeah. And I think like annoying gets pushed to infuriating or like lifelong the thing that wakes you up in the middle of the night when Dam later got the Nobel Prize in 1943. Not a small thing. This guy got, it could have been me.

I mean, it's also, it's, I don't know if it would have been him because also Dam did a lot of work on discovering, you know, figuring out's role in human physiology along with another guy, Edward Doissie. But it is really frustrating. And Dam, I think, wrote to Amquist and was like, I saw your great work and I saw that you were doing it at basically the same time. So, oh, I love that. Yeah. There was at least that acknowledgement. Anyway. Yeah.

I can understand why that would have trickled into this paper that he wrote almost 50 years later. But from that first observation in 1929, Dam and other research groups worked on characterizing the structure and the mechanism of vitamin K, which was essential in understanding why it helped to clot blood and why bleeding was an issue when someone was deficient. And they also worked on purifying in synthesizing vitamin K, finding its different forms, blah, blah, blah. all of this work helped move this knowledge from the bench to the bedside. Yeah. And it kind of happened in record time for medicine. And the effects of this, the impacts were immediate and transformative. For all of human history, if a newborn began to hemorrhage, there was nothing that anyone could do.

They simply had to stand by helplessly and hope desperately that the bleeding would stop. The journal entries from physicians dating back hundreds of years reflects the despair that they felt as a newborn that they were taken care of without any apparent trauma bled to death. It was seen as a curse, as God's wrath, as the mother's fault, and later as an issue with the blood's ability to clot. Like was this some sort of thing that just was this newborn specific they inherited. And the diary entries, like, I found a paper that has a bunch of these. And it is like, it is awful where they're just like, I don't know why this is happening. I don't know why. You know, we did everything we could.

Yeah. And you mentioned Aaron a few statistics, and that's what I found too. So they vary. But before vitamin K prophylaxis, it's estimated that roughly 2% of newborns experience severe bleeding after birth. Wow. Yeah. Yeah. When news of this coagulation vitamin broke, many obstetricians and pediatricians immediately saw the life-saving application that it could have in a newborn. And so when it became available, when it was synthesized and there was, you know, you could purchase it, they put it to use. As early as 1939. So this was, he was like, oh, there's something going on in chicks in 1929. 10 years later, it's on the shelves. Wow. And pediatricians, obstetricians began administering the vitamin to newborns, and they found that it cut the coagulation time in half.

And it halted hemorrhages in newborns. So to give you an idea of just how popular this practice became and how quickly, there was a paper published in 1944 by a physician in Sweden. And it's titled Vitamin K as a prophylactic in 13,000 infants. Wow. So they were just like, we're doing this. They were like, let's try this. is to go ahead. And what they found was that death from bleeding dropped from 2% to 0.45%, which was a 78% decrease. Wow. And this was not an invasive or expensive intervention. Vitamin K was cheaply available and easily administered.

Dosages still had to be worked out, but these results were more than promising. They demonstrated the life-saving potential of this vitamin. By the 1950s, many hospitals around the world, routinely administered vitamin K at birth. The American Academy of Pediatrics began recommending it in 1961. Some countries used oral vitamin K, others injected it intramuscularly, and over the years, the evidence just continued to mount for the practice, dramatically decreasing the risk of hemorrhage after birth. Enthusiasm and momentum are great.

But too much of a good thing can be dangerous. And so it was with vitamin K. So remember in this post-war era of scientific research, informed consent, IRBs, patient protections, they weren't really on people's radar. If there was sound scientific logic and animal trials had appeared safe, it was kind of on the menu. Quoting from pediatrician Ethel Dunham in 1948, quote, since the vitamin does no harm and may do good, it is probably best to give it to all premature infants immediately after birth, end quote. And so that is kind of, that was the logic that a lot of these trials, a lot of this just routine administration was based on.

The earliest trials with vitamin K prophylaxus in newborns had started with small doses, ones kind of similar to the ones that we use today. And when those appeared successful, some thought, well, okay, if a little vitamin K is good, then more would be better. Can we bring this risk of bleeding all the way down to zero? Right. In the mid-1950s in the UK, some premature babies who are at higher risk of hemorrhage were given doses as high as 60 milligrams of synthetic vitamin K. That's a lot. It's a lot. Most were totally fine, but physicians noted a rising incidence of severe jaundice, hemolysis, and carnictoris, which is jaundice-related neurological damage within these infants that received these super-high doses and several infants died.

The formulation was pulled and doses went back down to one milligram for both term and premature babies. Just like I said at the top, science and medicine, it's not just a forward march of progress. And stories like this can't be overlooked or downplayed because the fallout was significant. Even though the doses reverted to what had been established for decades as safe, this situation really shook the confidence in vitamin K. And it led people to question whether the intervention. was worth it. So for example, among the over 16,000 babies born in one week in 1970 in Great Britain, only 20% received vitamin K at birth. Wow. Gradually uptake increased, although unevenly. So in the U.S., where it was more common to administer vitamin K intramuscularly, rates of newborn

hemorrhage dropped substantially since the American Academy of Pediatrics recommendation in 1961. and by the 1980s had become super rare, these rates of bleeding. In other regions like the U.K., where oral administration had become increasingly popular, there was an increase in haemorrhagic disease, thought to be tied to the switch from intramuscular injection to a focus on oral administration, as well as the focus on breastfeeding exclusively. Yeah, which is such an interesting part of this story that I think is often overlooked. It is, it is.

But much of the progress made since the megadose scandal of the 1950s was about to be challenged. In the early 1990s, two studies out of the UK linked intramuscular vitamin K to an increased risk of leukemia later in life. And naturally, the reaction was swift and strong. Some countries changed recommendations, like they made oral the standard and intramuscular only for those at highest risk. And that led to a pretty big drop in intramuscular. prophylaxis rates. So in Britain, for example, 58% intramuscular in 1988 to 38% in 1993. Yeah. Huge, huge change. Huge change. And expectant parents questioned the safety of any vitamin K for their newborn. And these fears were understandable. But unfortunately, the studies that they were

based on were deeply, deeply flawed with small sample sizes and inadequate controlling for other variables. Following their publication, a bunch of other research kicked off to try to characterize this purported link between vitamin K, injection, and leukemia, and no link has been found in any subsequent research. By the late 1990s and early 2000s, the question of intramuscular vitamin K and leukemia was firmly settled with large, large meta-analyses and a working group of the WHO tasked with reviewing all of the evidence, ultimately concluding that, quote, there was inadequate evidence in humans and experimental animals for the carcinogenicity of vitamin K substances, end quote.

Even the International Association for Research on Cancer's, the what is it, the IARC, they have concluded there's no evidence in humans or animals for carcinogenicity of any formulation of vitamin K, including intramuscular. But it's one of those just like MMR and autism, like once the cat's out of the bag, it's really hard. Earworm, you hear vitamin K, you think leukemia, you hear vaccines or MMR, you think autism, even though that's been long disproven. Long, long disproven for both cases.

Yeah. And so this lack of a link, that's great news. It is. It's wonderful, right? But it's a lot harder to respond to good news than bad news. And the world hasn't quite recovered from that seed of doubt that was planted in the early 1990s. While that additional research was being conducted to further investigate the link, many countries switched to make oral vitamin K the standard. And we know that it doesn't have as good support in preventing hemorrhage as does intramuscular injection.

Especially for late bleeds. For late bleeds. And it's harder to get those multiple doses, all of these different barriers. But the more lasting damage wasn't about formulation or administration. It was about trust. Yeah. Once again, confidence in vitamin K had been shaken. And it's never quite fully recovered.

But these last few years in the U.S. have seen an unprecedented increase in parents refusing the vitamin for their newborn. From 2017 to 2024, the rate of refusal nearly doubled. Yeah. From 3% to 5.8% overall. With some regions of the U.S. reporting rates even higher, some hospitals staggering. high refusal rates, those babies who didn't get vitamin K have an 81 times greater risk of developing deficiency bleeding. You mentioned that too, Erin. But I just wanted to reiterate because 81 times is such an enormous number. It's an enormous, enormous number. And I think that it is

grossly undervalued because it is still something that is rare. Right. And not well communicated. Exactly. Right. This, it's, it's, It's not just about deficiency bleeding. Oh, there might be a little bit of bleeding. No, that can lead to severe brain damage and a 20% or higher risk of death. Catastrophic, preventable outcomes. So the question is why? Why risk it?

There are many things that work here. So let's just briefly go through a few that the research has found. So when it comes to the reasons that people give, you could group them into three general categories. There's mistrust of medicine. a desire for natural, quote unquote, natural birth, and a preference for alternative medicine lifestyles. So for example, childbirth is seen as natural. And if an infant needed more vitamin K, then evolution or God would have given them more. And so any intervention is not seen as necessary. It's like interfering with the way that things should happen. And for some people who

plan to breastfeed exclusively, it's seen as insulting. Like you're telling me that I'm not enough for my child, I'm not making enough vitamin K. They're getting all they need from me. You don't need to give them anything else. And this often, this mindset often aligns with a preference for alternative medicine, and it leaves people susceptible to grifters like Dr. Joseph Mercola, who had for years told parents that vitamin K is unnecessary. He has now, as of early June, completely changed his tune due to the rise in babies dying from hemorrhage. Why is he saying no? He sells supplements and alternative therapies. All of this like Dr. Green Life, Dr. Green Mom supplements that you can buy on Amazon,

you're going to trust Jeff Bezos with your health? No. Yeah. And so there's like there's a lot of grifting out there. Yes, there is. And then there's just mistrust in medicine, right? Some parents feel that the benefits of vitamin K don't outweigh the risks or they believe that the shot contains toxins, that it might cause leukemia or allergies, or that it's distressing for the infant to get a shot right away. And vitamin K, this is not just about vitamin

K, right? This is not the only victim of mistrust. Parents who refuse vitamin K are also much more likely to reject vaccines and eye ointment post-birth. If we want to meaningfully increase vitamin K uptake, we have to consider not just these reasons for refusal, but also who's doing the refusing and where they're getting their information. Studies examining this found that refusal tends to be much higher among white people, college educated, over 30, and are more likely to have a planned home birth or at a birth center and a desire for a quote-unquote natural birth experience. The medical professional they interact with throughout pregnancy and birth might also play a role in whether they refuse vitamin K. So, for example, one study in New Zealand found that

100% of the doctors surveyed thought vitamin K should be given to all infants compared to 55% of midwives. Fascinating. Yeah. And 26% of those midwives would not give it to their own children and felt that it interfered with the natural birth process. A similar trend was found in Canada, where births attended by midwives were eight times more likely to have vitamin K refused compared to physician attended births. Wow. Yeah. And it's a huge problem when your trusted source of medical information is telling you to refuse a life-saving intervention. Right.

Is not going based on evidence-based guidelines. Yes. Yeah. I mean, and these are two studies. There's some generalizations in there. But I do think that what it shows are opportunities. You know, if this is where the information is not, the accurate information is not getting to a patient who needs that information to make informed decisions, then that's an opportunity. Maybe that's where we try to educate more. To improve the gap.

Yeah. But even if a parent is urged to get the shot, whether it's from whatever medical provider they're seeing, whether it's a midwife or a physician, the risks of not getting the shot rarely seem to be accurately communicated or, or well enough communicated. So there's research looking at parental refusal and found that most parents, whether they said yes or no, know that vitamin K is associated with bleeding but are not well informed of just how deadly and damaging this hemorrhage can be. Yeah. So it's like even if the information is there, it's not communicated effectively.

Right. Education, awareness, and empathy are all clearly needed to reverse this trend. being afraid for your newborn's health, for making sure you do the right thing, that's understandable, and it should be acknowledged. But we also need to make more visible the damaging, devastating consequences that can happen after refusing the shot. Some parents whose babies have died

or suffered brain damage because of not getting vitamin K are doing the incredibly brave thing of sharing their stories, saying, I made this decision, this is what happened, don't do what I did. This doesn't have to happen to you. Doctors are also seeing their newborn patients bleed to death for the first time in their careers. And they're ringing the alarm bells and working within their communities to try to raise awareness of this problem.

Some researchers and physicians are also pushing to create a registry, a national registry in the U.S. of vitamin K refusal and uptake so they can better track outcomes. because right now we're likely underestimating cases of vitamin K deficiency bleeding. Vitamin K has been swept along with the other medical interventions rejected in this post-pandemic world, where expertise has become a bad word. And as the anti-science, anti-medicine, anti-experty sentiment continues to grow, these preventable injuries and deaths will grow along with it. If once 100 years ago, the challenge was, with discovering and describing vitamin K, now it's about getting it off the shelves and where it

needs to go, a challenge that is far from solved. And so with that, Erin, I'll turn it over to you for some numbers on vitamin K around the world. Oh, Erin. I don't have much more for you, in all honesty, because like I mentioned, there's just not really good data on rates of vitamin K deficiency bleeding, certainly not globally, but even country by country. the rates are still cited as like what we talked about. Like most papers just mentioned the previous rates without prophylaxis. And we know that with prophylaxis, rates are often as low with intramuscular prophylaxis, rates are as low as 0 to 0.4 per 100,000 for late bleeds.

So very, very substantial decrease. They often don't report the rates of early and classic bleeds because it's, I think, essentially zero. And that's even true for oral prophylaxis. So oral prophylaxis does a really good job at helping to prevent those early and classic bleeds. But we still, depending on the study, because it's depending on the exact dosage that was used and what the, like how often it was given in all of the different routes of oral administration in terms of timing, the rates can vary from like reduced maybe one to one and a half per 100,000 to sometimes just as, you know, high as without any prophylaxis. So about four and a half per 100,000 in some studies for late

vitamin K deficiency bleeding. So I don't have like good global numbers. I do really want to emphasize because I see this all over social media. And it's kind of the same thing that we see with food dyes, which is so interesting. This comparison of, well, in Europe versus in the UK, they do things differently. They do the orals, which is so much gentler and more. quote-unquote natural. I mean, none of it's natural. Nothing in medicine is natural. And guidelines across the globe prefer and recommend strongly for intramuscular vitamin K. The difference is that some specific countries still primarily use oral, though most professional societies and like including European societies, the UK, the World Health

Organization, the Canadian guidelines, the Spanish Association, and then a lot of individual countries like Denmark, Spain, Australia, Belgium, New Zealand, they all recommend this intramuscular dose, but some of them have oral formulations that were approved by their regulatory bodies. So that means that they have guidance on oral administration of vitamin K. It differs widely country to country, but they at least have guidance that they can give if a parent does not want the intramuscular formulation. And that is not true in the U.S. There's plenty of arguments to be made, like, why is that the case? Should we have an oral formulation? Manufacturers are like, where's the money in an oral formulation? Because everything comes back to capitalism.

But the fact of the matter is that in the U.S., we do not have any safe and regulated oral regimen or oral drops available. And so the only thing that we have available in the U.S. is the intramuscular. And that is what is preferentially used across the globe. It is, yeah. So, yeah. Yeah. And like you said, Aaron, the really concerning thing is just how much refusals are going up. And we don't yet have data like good peer-reviewed published data on what this means for the rates of vitamin K deficiency bleeding. There was a ProPublica article that came out very recently that sort of has a lot of anecdotal stories of it.

And you can see anecdotal stories all across the news from physicians who. are seeing babies come in with bleeding who had never seen babies come in with bleeding before. But because it's still like happening now, we don't have published data and because it's not a reportable disease. And so it's not like hospital systems are necessarily collecting this data voluntarily and then reporting it out for someone to actually do a study on. So it's going to be years before we have data to show this. But that doesn't mean that babies aren't dying right now because of this. Yeah. So they are. They are. They are. And that's, what I have for vitamin K. I already told you about the vitamin K to D3 thing, so we don't have to

talk about that. And then everyone, we didn't talk about warfarin, aka Akumidin, but that is the medicine that we use as an anticoagulant because it blocks an enzyme that vitamin K needs to be recycled. So you know we got to do another episode someday. It's like the anti-vitamin K. It's an anti-vit. That's exactly what it is. The other thing that I don't think we mentioned, but I just wanted to add in case we didn't was that we talked about how breast milk contains relatively low levels of vitamin K and why exclusively breastfeeding is associated or is a higher risk of bleeding if you don't get vitamin K shot. That's because formulas tend to contain that have vitamin K.

Yes. So that's actually a really good point. So formula has really variable amounts of vitamin K, but overall like 10 to 100 times more than in breast milk. So babies who are exclusively formula fed tend to get. on average about 100 times more vitamin K than babies who are exclusively breastfed. And it's still recommended that babies are exclusively breastfed if that's available. Right.

Because of other benefits, right? And so it's, both are true. Right. Just, I just wanted to make sure that we mentioned that, like, there is a difference, you know, we didn't say anything about formula. Yeah. And it is still recommended that even babies who are going to be formula fed still get the vitamin K shot because there is still a risk of vitamin K deficiency bleeding, even in babies

who are formula fed. it's just lower than breastfed babies. I didn't know. Before doing this episode, I didn't know pretty much anything about vitamin K. It wasn't on my radar. Yeah, it's not for most people. I don't have kids. Yep.

But after learning about it, I am blown away by the simplicity and the power of this intervention. Yeah. And the lack of downsides. Right. It's really incredible. It really is. It genuinely is incredible. World-changing, if only we used it.

Medicine. Medicine. If you like to learn more. Yeah. I have a bunch for this. Yeah. Shout out three in particular. One is by the Almquist paper is pretty fun to read.

It's called The Early History of Vitamin K, published in 1975. Then in 2019 by Magid at all, newborn vitamin K prophylaxis, a historical perspective to understand modern barriers to uptake. And then also that pro-public article was, I don't know. You should check it out. It's a good read. It's good. I had a number of papers as well, too. One that's like really quite comprehensive, specific to newborns, is by Shearer from 2009 called

vitamin K deficiency bleeding in early infancy. It's just like a really good review. I have a number of papers that are about vitamin K more broadly in our body. I think my favorite one was probably by Oldenberg at all from 2008. That's called the vitamin K cycle. It's pretty detailed. So there's another one if you want a little less detailed. That's called, it's by Crennenberg at all from 2007 called Vitamin K, the Coagulation

Vitamin that became omnipotent. Oh, yeah, I read that one. Yeah, that's a good one too. So there's a lot. And then I also have a number of papers on the epidemiology and the paper that looked at the refusal rates that you had mentioned, Aaron, was just published this year. It was by Scott at all called Trends in Vitamin K administration among infants published in JAMA. So we've got all of that on our website.

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