I Drink Your Blood Type

keep dancing. And unlike typical vampire nightclubs, we separate the herd by blood type for your convenience. At Blute, you will feast in the certainty that all human partiers and our medievalist to prove thrown room are Type A B and our foam dance party room runs on type old negative exclusively guarantee. So don'tly blood chance club flood. Look for us on Vampire You help, and don't forget to leave a review. Welcome to Stuff to Blow Your Mind,

a production of I Heart Radios How Stuff Works. Hey you, Welcome to Stuff to Blow your Mind. My name is Robert Lamb and I'm Joe McCormick. Hey, it's still October. That means we're partying. That's right. It's Halloween, and Halloween means blood. It also means vampires. As I think everyone probably got the idea from from the title this episode and from the cold open that we just inflicted upon you.

You know, what I was just wondering is whether in the month of October people actually, like in the industry, you can see a spike in demand for Caro syrup or general you know, corn syrup products and and red food coloring, is the demand for fake blood enough to make a dent in an otherwise massive agricultural or industrial food product. Well, I mean it depends. I mean a lot of po're just gonna buy a bottle of fake blood. They're not going to bother to mix their own. I

guess that's true. You know, I bet mixing your own is cheaper though. Oh I'm sure it is. But not everybody has the skill to create a you know, a good batch of Kensington gore. Uh. I remember when I was a kid, I was trying to make fake blood and I did it by mixing red food coloring with water. And that was how I discovered that blood is thick. Yeah, I mean, it's far better just to shoot it all

in black and white and use chocolate syrup. But even that gets a little little little pricy, I imagine, And also it's gonna know, just attract a bunch of ants. But yeah, when you think Halloween, you think monsters, you think vampires, and of course you think blood. Now, blood hasn't really changed in the course of human history, but our understanding of blood has. Blood Letting used to be

a lot more common, right, yeah. Uh, and sometimes sometimes vampire tails change to reflect some of the new ideas regarding blood. Oh yeah, Like I'm sure you can see vampire lore being affected by, say that the four humor theory when that was in vogue, like the idea you could have a sanguine personality that might be caused by

an excess of blood in the body. I'm sure that that makes them specially juicy targets for vampires or something that you're gonna mean, there's like there are there are four different vampires for each of the humors, right, oh right, so you get the black bile vampire and the worst kind of vampire to be because it's so bitter. So yeah, the ideas of what blood is may change, But of course there's first of all, the simple notion that blood

is food. Various human cultures include the consumption of animal blood in one form or another in their cuisine. Blood sausage is one example of that. Blood tofu and in certain Chinese cuisines is another example. Never heard of this blood tofu? Yeah, look aout made from blood? Blood? Okay? Uh? And then there's the idea of blood is this is a fluid that contains our vital life force. Right, this is a classic of the vampire trope. Uh. And then

naturally we do need blood to survive. But traditions have you know, tend to go above and beyond biological fact and stressing this. Oh yeah, the blood takes on a kind of magical essence. It's the you know, the ecore of the human. Uh, there is I think you can see this often when there is emphasis on monsters and

other creatures having differently colored blood than humans do. Like their blood isn't red, it's green, and that shows that there's some different there's some kind of different essence to them. And then there's also all kinds of beliefs about um, you know that your affinity for your family is based on the metaphor that you share blood, which is funny because you might not necessarily share physical characteristics of blood. You might not have the same blood type as either

one of your parents. But there's this idea that you're bound by blood and that I think that takes on a more kind of a magical kind of quality in people's minds. Yeah, this idea that there's this bloodline flowing through the centuries. Um. I do have to say, I love a creative blood color, and some in a monster or so certainly in like a Star Trek Alien type of scenario, if there's only so many colors, like what

you mean, like purple blood or what? Oh yeah, wasn't it Star Trek the Undiscovered country where the Klingons had had pink blood like looks like pepto bismal. Oh. I always chalks that up too bad early c G I, because they're in their blood c G I, And that movie is like really early c G I floating around in the zero G environment after the AA it is really impressive. Well, it looks terrible now, but that movie still holds up. Is one of the better of the

Star Trek movies. Now, in modern times, you'll often encounter vampire stories that invoke blood banks and and uh and blood drives sometimes uh and sometimes you'll even see recognition of blood types, and generally this amounts to which blood of vampire finds most tasty interesting. I don't think I'm

very familiar with it. Well. I am familiar with, of course, blood banks and blood drives, because I remember when I was a kid and my family would go to the beach and we get Sci Fi channel on the TV. I'd watch that show Forever Night, which is about a good guy vampire who is also a cop, and he keeps a refrigerator full of like blood bank style blood bags. I guess he drinks those in order to not have to kill people because he's good. Oh man, Forever Night.

I never watched Forever Night, but it's one of those Canadian series where a lot of times I'll watch another Canadian series and I'll look it up and it's like, oh, this person is from Forever Night. Forever Night is the like the beating heart at the center of Canadian drama from that period of time. Yeah, I mean I never saw that much of it, but in the episodes I saw because he's a good guy. He doesn't drink from

next he drinks from bags. There's um there's a Tales from the Crypto episode that called the Reluctant Vampire that started Malcolm McDowell as as the titular Reluctant Vampire and also had just an all star cast. Of course, like all those episodes, just an embarrassment of riches generally squandered on some sort of in a sappy, bad taste kind of plot. But this was this episodes pretty good. But in that one he's depending on a blood bank as well.

But then occasionally like meeting real live hosts to prey upon, and he ends up asking them a lot of questions about, you know, if they had dental surgery recently, that sort of thing. But but he he never asked them about their actual blood type, dental surgery. Wait, like he fears the amalgam in their teeth or something like they might have silver and if he just needs to have a good you know, pacent you know, biomedical history before he

uses them as his prey. Fair enough, now, of course, the the HBO series True Blood features vampires that have a clear preference when it comes to blood type and they use the synthetic blood product that's labeled and bottled called true Blood, which is in the show available in in different types, so you can get your oh negative true blood bottle you if you prefer a B, they

have a B as well. Oh so all the I haven't seen true Blood, but all these vampires are of the Forever Night type where they don't drink from p all. They drink from bags they're supposed to because it's basically like vampires are out amongst us, uh, and we're living alongside each other. They have kind of their separate government.

We have ours, and there's like a treaty that says they're only going to drink their synthetic blood products or you know, consenting adult humans that wish to have their blood drained that sort of thing. Okay, it's kind of a mixed bag, but it it also has a wonderful cast and Dennis O'Hare in particular was a real standout playing this character who was the King of Mississippi. Stephen Root also showed up at one point and it was great.

Steven Roots wonderful. Yeah. Um, there's another movie at this time that I ran across that was interesting that invokes

blood Types nine the Return of Doctor X. No. I I was not even familiar with this at all because it stars Humphrey Bogart as an evil doctor yeah, who's been brought back to life because this is a sequel, uh in this in this movie is brought back to life with synthetic blood, and he has to find TYPO victims and drain their blood and use it in order to stay alive because his syn synthetic blood cannot replenish itself. This was a few years before The Maltese Falcon and Casablanca.

In case anyone's wondering, you know, I like, I really like Humphrey Bogart as a villain type character, or at least as a very dark and troubled character, as opposed to well, I don't know. You might say that he has shades of villainousness in his detective stories and in Casablanca, but in movies like a Lonely Place, or he plays this like scary, abusive creep or in Treasure of the Sierra Mare. I guess you could say also, I think Bogart actually makes a great villain, and I wish you

had seen him as a villain more often. So I want to see this. Yeah, and now, of course Dr X is no typical vampire. Generally, the you know, the models very much parasitic in nature. Perhaps a vampire can taste the difference amid blood types in the same manner that a wine connoisseur can taste things in the wine that others can't, or at least can, you know, claims to have that ability. I love you. You've got some

skepticism about the smell, yea. I want to come back to it at some point because I feel like there was an old episode of the show where we we looked at one of these studies that was a real um don't I mean, I don't even know that what extended was a true study was just kind of a guy who got your exercise with wine experts, like tricking them into saying one wine was another and and and

so forth. But I think there's I'd like to to give the topic due diligence sometime and really get into like because sometimes the you know, the idea of priming and you know, bringing in some of prior knowledge to

your experience of the wine. Uh, you see people talk about that is if that's a you know, a negative, you know, But I mean that's part of your appreciation of any kind of food product or or certainly a wine is knowing where it came from and making connections, and if some of the connections or maybe partially imagined or exaggerated based on your prior knowledge. I don't think that's necessarily a bad thing at all. Have you been to any of these places that do wine style tasting

notes but for oysters, Um, yes, I have. I'm all in on that. When I have the oyster, I'm like, yes, I take yes, that's right, salted melon. Yeah, I mean the cases like that, they're providing me with this the specific terminology and descriptive language that I don't have, uh, you know, regarding oysters or or certainly wine or what have you. And again and then I can I can look for those things in my my taste sensation that

I'm experiencing right now. Once they give you the words for it, you can kind of find it in the sensation void With With most cases of fictional vampires, though, yeah, they're I think we can we can assume that, yeah, maybe they could taste some sort of difference in the

blood type. You know, they're essentially parasitic. They're they're digesting the blood now, and since they're digesting the blood, you know it's not gonna matter, um you know what kind of what type of blood it is, because they're digestive system is going to break down all those troublesome proteins. But then again, I don't think I've ever seen outside of doctor X here, I don't think I've encountered a vampire or vampire like creation that can only use one

particular blood type. Well, if you imagine vampire physiology a little bit different, like you're saying that they just use a normal style digestive system, break it down for the nutrition in it. What if it's that the vampire drinks blood in order to have blood, So like when the

vampire drinks blood, they're essentially getting a blood transfusion. In that case, maybe the vampire would need, in fact to have a compatibility test for the right kind of blood because drinking the wrong kind of blood could give them

an immune response. Yeah, that would I think that could make sense because it also would would line up with some of these descriptions from folklore where they would dig up the body of the vampire and it would be just just just thick and bloated with blood, like every you know, all its entire all of its flesh is just just completely ballooned up with the stuff. You know, you're saying that's the swelling of the allergic reaction. Yeah, maybe,

so maybe that's the that's the explanation. Well, maybe we should get into how blood types actually work, because I realized not too long ago that this is something I should know, and I actually didn't, so I had to go and read up about it. Yeah, it's it's easy to go through life without knowing the explanation for it, and just and hopefully just knowing what your blood type is, but not necessarily what that means. Right, Well, should we take a break first and then come back and talk

about the blood type basics. Let's do it. Thank thank alright, we're back, all right. So, if you know your blood type, or if you've seen blood types listed before, you generally will have seen a letter followed by a plus or minus sign and that letter is probably going to be A or B or a B or Oh. But so okay, you know they're at least several different types of blood, but you might not know what they do. In fact,

there are actually many different blood type families. I think the known number of human blood group systems is now somewhere in the forties. So there are tons of different ways of classifying and grouping blood. But the most common and most important blood group types to discuss are the A, B, O blood group system and what's known as the R H factor. Now you've heard of these before, but what

do they mean? Simply put, blood type refers to which category of antigens you will find on the outside of your red blood cells, and that in turn determines how your body's immune system responds to different types of blood from other donors because of the antigens on the outside of their red blood cells, and also how other people's bodies would respond to your blood if you if given a transfusion from you. By the way, Joe, before we go any any further, what is your blood type? I

almost answered, but then I stopped. Should I reveal my blood type on air? I wonder? I'm getting flashes of some future like cyber scenario where I regret sharing this information publicly. Well, I can't think of a way people would use it against us. I can think of a way Facebook will use it against us. Okay, Well, don't have to reveal if you don't want to. You want to reveal yours, Well, I mean, I don't mind saying that I'm I'm typo negatives. Oh nice, just like the

goth industrial band of the same name. Well, you also have a rare and important blood group, as we'll discuss as we go on. Yes, and we'll we'll just consider Joe's blood type to be of what blood type enigma will we'll lead into the listeners to imagine what it might be blood type question mark equal sign Yes, okay. So red blood cells, we know they serve the function of traveling through the body and transporting oxygen molecules to

body tissues, and they also carry away carbon dioxide. And so the outsides of the red blood cells in your body will have these little molecules on the outside of these structures made of molecules, uh that on on the top layers of these structures consist of various types of antigens that the and of course, an antigen is just something that your body's immune system can recognize as a threat and react to. And so your red blood cells can have either a antigens, be antigens both or neither.

If your red blood cells just have A antigens, just these A antigen molecules on the outer layer, you have blood type A. If you have just BE antigens, you have blood type B. If you have both your blood type A B, and if you have neither, you are blood type Oh all right, I think that's pretty straightforward. So really, yeah, they're they're like two critters at play here. You can have either one, both, or neither. Now, of course,

blood types are genetically inherited. You get them from your biological parents, but your a bio blood type is based on interactions between a number of dominant and recessive genes. So the correlation between your parents blood types and your own blood type can be kind of confusing. It can, for example, happen that your blood type might be different from both of your parents blood types because of a

dominant recessive interaction. Um. But if you want to work it out, you can look up inheritance matrices for blood type online. These are easy to find, right, Or you can just do like most families do and just put your blood in a petri dish and just go around in a circle and put a hot wiring a bit. That way, he can find out whose family and who's definitely not well. It's funny how how close that that scene in the thing is to some of the early tests that were done to figure out what was going

on with blood types. Get into that in a minute. Um, So again, why does it matter which type of blood you have if you're going to receive a blood transfusion. Well, again,

it's because of your immune system. So within your body, you've got in your blood plasma, you have white blood cells, and you've got antibodies that were kind of like defense drones latching on to certain types of antigens that they encounter things in your body that seem like they might be some bit of dangerous foreign material in the blood. And of course the main thing you'd be worried about,

there are some kinds of germs. Right now, generally we don't have antibodies that will attack our own red blood cells. So if you have blood type A, meaning you've got these A antigens on the outside of your red blood cells, your immune system will not attack A antigens because you know you need to not attack them. They're they're going to be abundant throughout you. But it probably will attack

BE antigens and vice versa. So generally your immune system will attack whichever of these little molecules on the outside of red blood cells you don't naturally have. So it works out like this. If you have type A blood, your immune system will attack BE antigens. If you have type B blood, your immune system will attack A antigens. If you have type A B blood, you have both antigens, so your immune system will attack neither of them. If you have type O blood, you have neither antigens, so

your immune system will attack both. Following so far, yeah, I think I think it's pretty straightforward for everybody. So it's basically you know the starbillied sneeches, except a little more complicated, like like you know three or four different tribes of sneeches, right. I mean this means that when you donate or receive a blood transfusion, you don't always just need to match the same type between donor and recipient. There are these inherent asymmetries and who can receive what

types of blood. For example, if you have a B blood, you can receive blood from any other type. You can receive A blood, you can receive B blood, you can receive A B blood or OH blood. It doesn't matter because you don't in your blood plasma have antibodies to attack any of those other types of red blood cells. And for this reason, type A B is the universal

recipient class. But if you donate A B blood, that blood can only go to a recipient who is also a BE because that recipient otherwise is going to have immune system reaction to one of one or both of those antigens on the outside of those cells. Now, on the flip side, type OH blood, which has neither A nor BE antigens, is the universal donor class. You can give type OH blood to people with A B, A B,

or OH and it will usually be fine. Now I think we should say that these donor you know, these donor safety statements are for most cases, these are like, on average, they'll be better. They're always kind of like anomalous reactions people can have to any type of protonation, and and and and that also gets into the fact that all things being equal, an exact match is always preferred, but certainly in an emergency. Uh, that's when you see cases where where you know the universal donor can come

in exactly. And that's a one reason A common practice in modern hospitals and clinics today is to collect blood from a patient in advance of a preplanned surgery or

procedure in which a transfusion might be necessary. So if you're going in for surgery these days, they'll usually take some of your blood, you know, the day before, the week before the surgery, and that way, if you suddenly need a transfusion, if there's some emergency during the procedure, you can receive your own blood, decreasing the chance of an immune immune reaction or any other compatibility issue. It's not that you're octor is of secret vampire right and

just needs a taste before things get going right. But there may be times when somebody needs a blood transfusion and there's none of their own blood on hand to give them, so they need blood from a bank, they need blood from a donor, from a reserve of pre stored blood. That's they're waiting for somebody who needs it now. We should also say, on top of the A B O system, there's also the r H factor, which is just yet another type of thing that you would find

on the outside of red blood cells. This time it's a protein UH that's known as the recess factor r H factor after the recess monkeys from which it was originally studied and isolated. Uh, and it works sort of the same way. Basically, there are only two options with the RH factor factor. Either you have these proteins, meaning your r H positive, or you don't have them, meaning you'r RH negative. And the RH factor is noted with a plus or a minus sign after your A B

O type. So the true universal donor is actually not just blood type OH, but blood type O negative, and the universal recipient is not just type A B but type A B positive. Now that's the simplified version, but it also gets more complicated because the blood donor and recipient compatibility is very based on whether you're talking about

like red blood cells versus plasma. Like your red blood cells contain the antigens for your blood type, but your plasma will contain the antibodies or potential immune response correlated to your blood type. So most of what we've been talking about so far has been for the red blood cells that would be donated or received. But yeah, so again, so you mentioned your type of negative. You are the universal donor, Robert, You're you're you're kind of human gold. Well,

I do have to stress it. I think that is we have to be careful about overstating that, not that I'm gold, because obviously I don't want people to harvest my blood without my consent. I do try and give give blood, um, you know, a lot when whenever there's a blood drive and I'm allowed, you know, to do so. But but but also nobody out there who is like a B needs to to feel like, oh, well, my blood is not as valuable. I'm gonna sit this one out like they don't really need my blood because I'm

not a negative. Like, No, your blood is still really important because again, all things being equal, they're going to try and do as as close of a match as possible. Yeah, that's totally right. All all blood is valuable, All all blood is beautiful, and maybe all blood is delicious? Uh? Should we? So let's let's talk a little bit about that.

The blood serum clumping test we mentioned earlier. Now, the Austrian immunologist and pathologist Carl land Steiner, who I keep accidentally calling land striders, stop me if I do get

get dark crystal brain. But Carl Landsteiner, uh, he discovered the primary a bio blood groups around the year's nineteen hundred or nineteen o one, and at the time, doctors knew that blood transfusions could be very dangerous, could kill patients, They caused adverse reactions and the recipient um and you know, up until around this time that it was a good reason why blood transfusion wasn't done much. It was considered sort of a risky, experimental kind of thing, not not

like a standard medical intervention. Yeah, I realized I probably bring this show up every time we talked about the history um of of of surgery. But the the excellent cinemax series from Soderberg the Nick there's one scene in which they attempt a blood transfusion um to save a patient and the patients is just killed on the operating table. Yeah, I mean, yeah, that would have been a reality at

this time. Like if you so, there were surgeons who tried to experiment with blood transfusions because patients died all the time for from blood loss, and so you know, if you could find a way to get blood into them to save their life, that would be great, And sometimes it worked, but a lot of times it didn't, and it if it didn't work, there were chances it

could go catastrophically bad and could kill you. Yeah, but they think they begin to realize, yeah, there's some there's some code in the blood, there's some there's something here. There's a reason that it works sometimes but not other times. We just have to figure out what that is. Yeah. Now, one of the things that doctors of the time observed is that you could see this if you just mixed together blood samples from different patients in uh in, in

dishes or in tubes. Sometimes when you mix together blood samples from different patients, you would get what was known as a glutination, which is where the red blood cells I'll start to clump together. That's not good if that happens inside your body. Right, So it's clearly that's a major thing that must be happening in these cases where you give humans a blood transfusion and it goes really wrong. And yet while we knew these negative reactions could happen,

we didn't know exactly why. And land Steiner comes in here.

He figures out that this adverse reaction to donated blood was because the recipient's immune system in the plasma is attacking the new blood cells like they were germs, and land Steiner figured out that these immune reactions were correlated to four are categories of antigen profiles in red blood cells, which now from from which we've now derived the first he discovered the A group, the B group in the O group, and then a little bit later he discovered

the A B group also. But as I mentioned earlier, there are these other blood factors, and Lensteiner discovered several of those as well, such as like m in and P factors, And he was also involved in research decades later that led to the discovery of the RH factor. Again, that's like the plus and the minus sign. After you see the most common blood types in the A B group or the A B O group. Uh. And Lnsteiner eventually won the Nobel Prize for his research, which was

essential to making blood transfusions safe and commonplace. So this was like very important work in the history of medicine. Yeah, I mean, this is one of those technical surgical technologies, medical technologies that it's hard to imagine, like modern medical science without the ability to give blood transfusions. Right. Um, But there still is an underlying history here, something that we haven't fully solved yet. Why do we have different

blood types. Like what evolutionary pressures, if any, brought about these different uh, these different antigen structures on the outside of red blood cells. This is still to some extent and unsolved mystery and human evolution, but I think, at least as far as I've read, there are some indications that the evolved differences in blood types may have something to do with different pressures related to immune response and protection against disease. Yeah, that's that's that's what I'm getting

from from from the information I was looking at here. Um, So let's get into this the idea that in a sense, there are powers in the blood or or more specifically, I guess that that different blood types bring with them different uh immune strengths and in some cases perhaps immune weaknesses. And you know, this is a very common thing to

find in human evolution. A lot of times you see different population groups with slight differences and you want or why, And it's because of some local parasite that people's ancestors evolved to u to resist. And so let's let's talk about parasites here. The real blood drinkers, the real dangerous vampires, uh not count Dracula, but the but the mosquitoes that drink human blood, that hunts for our blood and spread

a host of deadly diseases in the process, the real vampires. Yes, so you know you may have heard before, you may have read this before, that mosquitoes prefer typo blood. I don't know if I had heard that, But once you start looking for it, you see it all over the place. Uh. And more than that, you probably read it in any number of articles in in very trustworthy publications. Uh. And it's it's been widely reported. Yeah, that people with TYPEO are bitten twice as often as people with Type A,

while Type BEE falls somewhere in between. Okay, so wait, you get bitten a lot by mosquitoes. I mean I do. I was been numerous times yesterday actually who researching this because I was working out on the porch and then it grilled in the afternoon, and I was thinking like, well, you know, I surely get attacked by them a lot. But then that proves it. But yeah, that's hardly proved.

That's just like if any time you're bit my mosquito, fed upon my mosquito, you know that's that's one time too many, right, So, uh, A lot of these articles, though there they end up pointing to a two thousand and four study from the Journal of Medicine Etymology from two thousand four from Cheray at All, which found that quote, blood group OH subjects attracted more UH mosquitoes than other blood groups BE A, B, and A. But we're significantly

more attractive than blood group A subjects in sixty four human landing tests. So, um, yeah, this one's this. This one is cited a lot. I'll come back to that in a second, but I want to point out that the Smithsonian magazine has an article about about this, and they point out that, you know, based on genes, about P will secrete a chemical signal that broadcasts their blood type, about fifteen percent do not, and mosquitoes are apparently more

attracted to secret ors. Now. To be clear, though, there are plenty of other factors here at well that play into whether mosquitoes will swarm to you. They don't care about gender, hair color, or pigmentation, but they can be attracted by the big one. One of the big ones

is carbon dioxide. Sweat. High body temperature is a big one. UH. Certain skin bacteria, ethanol excretion, and sweat due to beer consumption, yeah, pregnancy apparently as a factor, but that seems to come down to just carbon dioxide and warmth, like increased carbon dioxide and warmth, and then also dark clothing, which that's one that matches up. I found with my experience killing mosquitoes is that they'll be attracted to dark things I'm wearing.

And then if I'm killing them, say in a bungalow, they're going to go to the dark corners of the bungalow to try and get away from me. Well, I wonder if it's because out on a warm day, dark clothing gets hotter. Yeah, that's true. They're attracted to heat. Yeah, again, heats one of the big ones. Now, the notion that mosquitoes prefer type of blood did not hold up for long.

The study was was criticized for statistical problems. Uh. Joseph conelan technical adviser of the American Mosquito Control Association, has dismissed this as a as as as not being that that big of a factor or not being a factor at all. But but you still see it decided quite a bit. But as far as I can tell, uh, based on the research here, I don't think blood type really plays into whether or not a mosquito is going

to feast on your blood, or certainly it's not. It's it's it's not going to compare to the other factors that are going to dictate whether or not you're going to be fed upon. Now, on the other hand, there does seem to be evidence that people with type OH blood are protected from the most severe forms of malaria.

According to a two thousand fifteen Swedish study, a protein sucree did by malarial parasites only bonds weekly with type O blood cells, but bonds strongly to A As a result, type of blood is more prominent in malaria plague regions. The researchers from the Caroline Esca Institute point out that roughly half of Nigeria's population has type of blood. And by the way, this is UH. This is how it

breaks down. In the United States. According to the Red Cross, UH OH positive blood, you'll find UH forty seven percent among African Americans, thirty nine percent among Asians, thirty seven percent among Caucasians, fifty among Latino Americans, and then OH negative four percent among African Americans, one percent among Asians, eight percent among Caucasians, and four percent among Latino Americans, So having type O blood with the positive rh factor

is much more common. Yes, yeah, and and certainly you see like in the the the American the African American population used, do see that significantly higher um rate of O positive blood likewise with Latino American blood as well. So I think these are some of the key statistics that people are focusing in on when they're making a case for uh, you know, the blood type having this uh,

this immune factor. You know that this is the reason you find these different blood types and different human populations the result of your more recent ancestors being exposed to

more malaria risk. Ye. Now, on the other hand, people with type OH blood tend to become more severely ill from cholera compared to other blood types, and according to a two thousand sixteen study from the Washington University School of Medicine, it maybe due to the way that blood type influences how strongly cholera toxin activates intestinal cells, leading to diarrhea. Oh. Yeah, I was also reading about some evidence that there may be different responses to norovirus having

to do with blood types. Well that, yeah, that would make sense too. Um. I've also seen A A B and A by link to higher risk for coronary heart disease, but I didn't. I didn't look into that U super closely. I'm not sure how much of that is really ironed out, or or to what extent is correlation. I think type A blood is associated with greater risks for some types

of cancers. Now, of course, as we stressed already, one of the most important aspects of type of blood remains that it is a universal donor, meaning that an emergence in an emergency, it can be used with the lowest risk of series reactions for all blood types. And so as you might imagine, it would be ideal to be able to transform any blood type into a universal donor, right uh. And I suppose our vampires would would very much like that as well, if they indeed prefer um

oh oh negative and no positive blood. And one of the ways that this could be achieved is by using bacteria enzymes to clip away sugars that give red blood cells their type, but it's ultimately not a very effective method. But recently this year, in fact, researchers at the University of British Columbia found two types of enzymes in the human gut biome that that can transform blood types essentially

into O UH into O type blood. One converts the antigen to an amine and the other removes the antigen completely. But a lot of work remains to be done in this area before anything like a human test uh this would be possible. But it does show how we could very well come to a you know, a day in the future where when you give blood that blood is then can then be altered so that it can be

more broadly used. Now, we alluded to this earlier, but there are also tons of just edge cases where things get more interesting and more complicated than the blood type groups we've been talking about so far. Like there is what's known I think is like the Bombay blood type group where uh, this is a relatively isolated phenomenon but um, but people who are not type A, B, A B or OH and can only receive blood from each other.

All right, on that note, we're going to take a quick break, but when we come back, we're going to get into some blood myths than all right, we're back. So you know, we started off this episode talking about vampires drinking blood, and we touched on the idea of

vampires being sort of like wine connoisseurs. So what if you had an elder nos Ferato style vampire holding up a goblet of blood and you know, sniffs it, SIPs it, and then starts just uh, you know, ranting about and raving about how oh you can tell that this one, this one came from a hunter, one came from a you know, a fierce lover. Uh, and I could taste it. This has notes of big mac, notes of barbecue sauce.

But getting into this idea though, that that blood could in any way inform the vampire about the personality of the individual that it came from. Uh, you know, that would seem to get into uh into supernatural aspects about blood for sure. And yet well we also see this idea of you know, moving among the living in our real world. Uh, this idea that personality is somehow tied

to blood type. Yeah, it's a somewhat popular form of personality assessment in Japan these days that's based on blood types. So in some Japanese magazines and TV shows and stuff, you'll find what are essentially blood type horoscopes. Or for how about this blood type relationship compatibility charts, Like if you know, you to figure out if you've met the person who's right for you, look up their blood type

on this chart and see how it correlates with yours. Uh. And this is all predicated on the belief that blood types concern more than just the proteins and antibodies and stuff in your blood, but that they actually determine important aspects of your personality, much like the zodiac signs in

Western astrology. Um. And though I think some Western characterizations of this folk belief maybe overstating its importance in modern Japanese culture, the popularity of books in Japan giving life advice based on blood type indicates that this is at least a somewhat or pretty popular belief. I guess it's always hard, Like I was trying to find a survey that had good numbers on this, but I couldn't find

anything that was very well sourced in English. But I guess it's always kind of hard to determine things like this anyway, because even if you ask people like, well, do you believe in uh, you know, astrology and the zodiac signs predicting your personality, or do you believe in blood types predicting personality? I always kind of wonder what stuff like this, like, to what extent do people really

believe in it? Like with astrology, I think there are a lot of people who do it, who participate in it, who are who sort of believe in it, maybe half ironically, but but they wouldn't say, take the advice of an

astrologer over the advice of their doctor. Yeah. We we got into this a little bit when we talked about the Chinese zodiac on a past episode of the show UH with with some of like the birth rate spikes in one sees in the auspicious year of the Dragon, and I remember some of the author's writing on this, we're pointing to not you know, not a situation where we had like a bunch of really hardcore um you know, Chinese zodiac enthusiast in these Chinese communities outside of Maitland, China,

where the the where the research was conducted. But rather it was the idea that you had the younger UH individuals with more of a casual acquaintance, more casual knowledge

of the zodiac. They were just kind of, you know, they're trying to make a big life decision and they there's a lot of information coming at you and you're probably getting second and third opinions and maybe get that fourth opinion from the zodiac, and all things being equal, maybe you give into that right that you can kind of that you can kind of engage with it and kind of let it partially guides you, even if you're not a die hard believer, or even maybe if you

wouldn't even admit to believing. I don't know, I do not think by the way, I mean we should go ahead and say this, there is any good evidence that personality traits are strongly or even moderately correlated with blood types. There may be a small number of extremely weak correlations,

but even that seems uncertain. I was just looking at one study by Kingo Nawata called no Relationship between blood type and personality evidence from a large scale Evidence from large scale surveys in Japan and the US in the

Japanese Journal of Psychology in two thousand and fourteen. The author here writes that the relationship between personality and the A B O blood type is popular in Japan, but there has previously been no empirical substantiation for the belief, and so this study is a secondary analysis of data collected from more than ten thousand American and Japanese subjects in the years two thousand four and two thousand five, and of sixty eight personality traits or items assessed, there

was no significant difference between blood group types for sixty five of those sixty eight traits, and I guess small effects observed for the other three, which could still turn out to be errors. So basically, at best, the author rights quote blood type explained less than zero point three percent of total variants and personality. These results showed the

non relevance of blood type for personality. So the bottom line is that the relationship between blood type and personality seems to be somewhere within the range of extremely weak to nonexistent. And yet you will find plenty of popular books on this subject. You'll find websites that offer you know guides. I found stuff even in English. I guess uh for helping people get acquainted with Japanese culture and showing you know stuff about like blood type compatibility between

different personalities. I guess we'll refer to that more in a minute. But apparently much of the interest in blood type personality stuff comes from a series of books beginning in the nineteen seventies by a Japanese journalist and named Massa Hico Nomi. And this was not a guy with any scientific credentials, by the way, But there are a

ton of books by different authors on this subject. Apparently up until the present day, this remains sort of a popular genre of life advice, you know, when it comes to things like life advice and and and ultimately some of the more supernatural, uh, you know, things we turned to be at a you know, astrology or something else. Uh. I think you know a lot of it is just coming from this idea that you know, people, I think,

you know, you just feel paralyzed by choice. You need something to guide you should be at the stars or the secrets in your blood or whatever is being you know, related to you. And uh and yeah, I mean I understand that it can feel it can feel liberating to have have something tell you you know, what you should do, or to just sort of back up some sort of core belief about yourself. I think there's another thing at work here that lines up perfectly with that, and I'll

come back to it in just a minute. But I wanted to look specifically, like, well, what are the blood types believed to be correlated with like, if you believe in this, what what does it tell you about yourself? Uh? It seems complicated, somewhat variable, Like I was finding different descriptions of the blood type personalities that didn't seem to exactly match up with each other. Though I find this is the same thing when I look at personality assessments

due to the due to the zodiac signs and astrology. Um. But according to a BBC article I was reading by Ruth Evans on the subject, UH just gives a list of examples. Quote. According to popular belief in Japan, type a's are sensitive, perfectionists and good team players, but over anxious. Type OH is our curious and generous but stubborn. A B is our art but mysterious and unpredictable, and Type

B is our cheerful but eccentric, individualistic and selfish. Um. And also to add to that, roughly forty of people in Japan are type A, about thirty percenter, Type OH, about twenty percenter Type B, and about ten percent or Type A B. I also found a chart for blood types with positive traits and negative traits core related here from a website called Tofugu, which I think is like a it's an English language website for people who want to uh maybe travel to Japan and learn about Japanese culture,

and it's sharing a bunch of stuff here. Like it says that people with blood type A, uh, they're positive traits are that they're earnest and their neat, but they're negative traits are that they are stubborn and they're anxious. People with blood type oh, here you go, Robert. You are easy going and you've got leadership ability. Well, I think I have one of those things, not the second one. But you're also insensitive and unpunctual. I think I'm very

sensitive and I'm semipunctual. So yeah, I don't think that lines up with me at all. But it also says, uh, type B here is supposed to be passionate and creative, but also selfish and uncooperative, and type A B is talented and composed but eccentric and two faced. To that sounds really negative now, but but then again, we also have to look at the ratio, at least the presented ratio that one finds in Japan. So this probably becomes a situation where if you have blood types occurring at

certain percentages within a given culture. Then you can also match that up with social norms in a given culture. And since a B is amounting to just ten percent here, then yeah, you can go ahead and say that those are the eccentric in the two faced people for such a small section of society anyway, they're the artsy weirdos. And and so you might think, well, okay with that

more or less lines up. So the thing that I detect in this UH pretty much exactly the same way that I detected in UH in astrology generally, is that there's a good bit of the Fror effect to work here. Now, we did a whole episode about the Fror effect a few years back, and I remember very thinking, very fondly of that one. I think that was a lot of fun. But in short, this is a psychological phenomenon in which people have the tendency to interpret vague general assessments and

predictions as specific and high the accurate statements about themselves. Right, So you can say something that would apply to almost anybody saying, like, you know, oh, it turns out people with your blood type are it can be sometimes insensitive, but also are passionate about whatever you know, like give a list of characteristics and everybody will just say, yeah, yeah, that's me. But how do they know so much about me? Uh?

This was demonstrated in this original experiment by this American psychologist named Bertram for when he had his students take a personality test and then he later handed back the quote results of their test and asked the students to rate how specific and accurate the characterizations from the results were to them individually, And for the most part, the students were like, wow, yes, this is really describing me.

In fact, four had handed back the exact same personality assessments to every student in the class, and there was no correlation between their answers on the test and the results they got. Obviously this probably led to lots of nervous laughter, but I think this certainly rings true. I mean, people are so hungry for personality tests and stuff. We we have a natural eagerness to interpret vague general statements as applying specifically to us in particular and being like, yoh,

yeah that is me. They got me. Yeah, I mean, and probably more so than ever with the you know, the sort of online live so many of us lead, you know, we want without actual personal interaction with someone. We want, we want something to tell us, some sort

of feedback mechanism. And so then when you're told, oh, well, your negative traits are that you're insensitive and your unpunctual, you may be inclined into instead of saying, oh, well, I'm actually sensitive, you know, um screwed off, you're gonna say, well, wait, in what ways am I insensitive? Like there's one right there, I just remembered one. That sort of thing. And that's

exactly what bertram for said. So he was assessing these results he found and he said, you know, what's going on here he thinks is a combination of what he calls universal validity and subjective validation, or I think he called it personal validation, but more recent research calls it subjective validation. And basically this means that, as for rights, the universal validity trade is that quote, virtually every psychological

trait can be observed in some degree in everyone. So like any psychological statement you could make, you can find examples in your own autobiography for which it's true. One of one of my my favorite examples of this. And I feel like, I mean, I'm certainly guilty of this as well. The misuse of the word sociopath u um, and when we've discussed sociopaths and psychopaths and what these

terms actually mean on the show before. But in a general sense, there is a tendency to just throw the word around at other people, but also at your own self. We are like, oh, my goodness, and I and my sociopath was was I acting like a sociopath the other day when I did this or the other? Uh? You know, we we have this tendency to lean into those terms for you know, either regarding ourselves or to mold our

perceptions of other people to fit them. A sociopath is somebody who behaves like a sociopath most or all of the time, as opposed to you who behave like a sociopath only some of the time a time. Yeah. Um. But the other thing, he says, that's paired with this, so every psychological trait you find to some degree in

almost everybody. But then he says, on top of that, there's subjective validation, which is that this is what you were just alluding to when you search through your own autobiography and your mental picture of yourself to judge whether a personality statement applies to you, You've been a huge number of memories and instances to draw from and no real way of judging whether a personality assessment statement applies

better to you than it does to other people. So imagine if I tell you, because of your blood type, you have a tendency to be generous but also stubborn.

Because of universal validity, almost anybody can think of examples of times when they were both generous and stuff burn And because of subjective validation, you'll have lots of opportunities in your memories to find examples of yourself displaying both of these traits, as well as difficulty judging whether you actually display those traits more or less than other people do.

I mean, because you know more about yourself than you know about all other people, you'll probably just have the tendency to find more examples of any trait within yourself than you would normally see in others. But I think,

especially if the traits are flattering. I think. But it also drives home just how if if an individual is given to narcissism, how easy it is to feed that narcissism, And likewise, if one is given to self deprecation or just outright depression, Like there's always going to be plenty

of stuff to feed that as well. Yeah, totally. But one aspect that I think is interesting about the blood type personality myth in particular as opposed to say Western astrology or the zodiac signs, is that it seems a little more biologically plausible, Like it's something about real genetic traits within the body. If blood type is a heritable biological trait, which it is, why couldn't certain aspects of personality be biologically inherited in some correlated way? Like the

idea isn't inherently implausible, it just doesn't seem to be true. Yeah, I mean it's it's it's leaning into the idea of the mind body connection, which is it is a reality. But but that doesn't mean that every invocation of the mind body connection is is scientifically authentic. Sure, well, I mean there are some there's evidence of some correlation between mammalian gut flora and personality traits. So uh so, like, if that could be going on, why couldn't blood type

be correlated with personality traits. It's not that it's impossible, it just does not seem to be the case. Now, another area that one will sometimes find some life advice tied up with blood type is in the domain of diet. Oh boy, yep. It's been argued that different blood types benefit from different diets, and idea was popularized in the book Eat Right for Your Type, written by natural path

Peter di Atamo. So basically it draws on this idea that like each blood type is kind of it kind of ties you to a specific archetype of of ancient human identity, which which is not true, right right, not true like our our blood types evolutionarily are traced back to our like ape like ancestors, that they go back that far. It's not it's not from like what profession your great great grandparents have, right, So like, for instance, it's it's presented that type a's are agrarians and they

need an agrarian diet that's essentially devoid of meat. Bees are no bads who can eat meat but need to avoid wheat, corn, lentils, etcetera. A bees are enigmas and they just have to avoid kidney, beans, corn, beef, and chicken. And meanwhile, typos are hunters and basically need to halio diet, so limited grains lagoons and dairy but less of protein,

so that would make me a hunter. Uh. But but then again, okay, so you know, one might say, well, okay, maybe with without leaning as much on this idea of you know, these archetypes, but maybe there is still something to it, because again, our blood is our body. It's part of our body, it's part of our system. Perhaps there is some connection between different blood types and different dietary requirements. Sure could be the case it, but it again does not seem to actually be the case. Right.

So there there are, as far as I can tell, no studies that that back this up. Uh. There has there's been at least one study that has set out to debunk it. Uh. Two thousand fourteen study came out of the University of Toronto. They found that blood type had nothing to do with it, but rather, you know, it comes down to sticking to a reasonable vegetarian and low carb diet. Now, it's only a study of one thousand, four hundred study participants, but then again, there's not a

lot of research out there. This is one of the studies that does exist, and it certainly argues that there's there's nothing to this idea that diet needs to line up with your blood type. Yeah, and the basis of it on the idea of like humans as certain types of like natural professions and your blood that again, that's the basis is wrong. Yeah. Now on on the other hand, it's often pointed out that, you know, many people probably picked up this book, followed the dietary advice that was included,

and uh, experienced improvements in their health. Uh. And a part of that comes down to the fact that if you're, if if you do not have any kind of a managed diet at all, if you're perhaps eating poorly, and then you start, you know, eating a largely vegetarian diet based on your blood type, you're still going to you're gonna see a shift in your overall health because now you were following a diet, you're probably following a healthier diet. Now you might be using it. You might be employing

this diet for a reason that is not scientificallyvalidated. But the idea that you could cut down on carbs and eat more vegetables and improve your health, well, that's that's nothing. There's no superstition there. Yeah. I think I was reading one article that said that some research on this just found that everybody should follow the blood type a diet or whatever, like it didn't have anything to do with blood type. Is just that, like some of these diets

are going to be better than others. Yeah, but but again we come back to the fact that we can you can definitely see why this idea is appealing. Like, there is this idea that there is a there's essentially a code in your blood, there's a secret language in your blood. And now that we know that language, we can, you know, we can better prepare for our personality, for our we can better choose a diet based on this information.

But it's not really the case. I think the idea of diets tailored to an individual person and not not just the same diet for everybody. That there is something to that, but again, not that it has anything to do with blood type, right. I mean you're gonna have a host of issues there too. I mean people are gonna have different allergies of slay that are going to come into play. Um uh, you know, which is again just comes down to the complexity of our our our

immune systems for the most part. But imagine this were true and impart with what you were talking about earlier about technologies to change blood types. This would be leading obviously to a future where everybody is trying to get the Would it be cosmetic surgery, the elective surgery to transform their blood into the pastry group? Tho oh, yeah, well that would be a step beyond even what because I believe the research I was looking at was talking

about changing blood after it has been removed. But but then again, as long as we're you know, cranking the time machine forwards, I imagine, I imagine somebody is probably speculated on a time when you could you could make those alterations to a human being as well. Though I guess it'd be easier to change the blood, right, I mean, I guess. I don't know. How would you want it? If you were doing you're sending a crew out to another planet on a lengthy space uh journey. Would you

want everybody to have the same blood type? Would you want an array of blood types? My guess is that blood types would be a fairly low priority when selecting the crew. Sorry, that's a boring answer, unless you're going to the Planet of the Vampires. Oh what a great movie, in which case it could become a factor. Though I don't remember did that film actually have vampires in it or were they more zombies. There's sort of vampires. Yeah, yeah, it had these uh, these spirits inhabit. Oh man, what

a great movie. That movie's got killer costs to costumes are the main thing. I remember. Now you can watch the movie on mute and it's almost as good. Is that Mario Baba? Yeah? I think. Actually we just watched another Mario Bava movie last night. Yeah, we watched Black Sunday. You know that one. I know of it. I've seen it's got that very distinctive cover art, but I've never seen it. Oh, you should see it sometimes nineteen sixty.

It's black and white, super creepy, very u unusual to see a black and white movie from as early as it was. That's as gruesome and gory as it is, but in a good way. I would say pretty big thumbs up to Black Sunday. It's it's creepy and also funny. It's got a It's got this great professor character who just goes about smashing things, Like goes into an old ruin and there's a wind blowing through some organ pipes and he just smashes them with his cane and he

smashes a tombstone. Well, speaking of smashing tombstones, I think it's time to close this episode out. Okay, Uh so, I'm really it's also kind of surprised that we were able to do a vampire episode. Every time we do a vampire themed episode, I feel like, like, that's it. We've exhausted the vampire possibility and there's nothing else we can cover that's even vampire flavored. I really enjoyed our

vampire Clinic episodes last year. Those were good. Yeah. Yeah, I mean every time we we we dip back in to the vampire content, it's always it's always rewarding. But this one kind of took me by surprise. Uh. It was suggested that we do something on blood types, and then I'm like, oh, it's got to be vampire them and here we are. Wait, who suggested it? My wife suggested it? Oh okay, yeah she was. I was like,

I don't know where we're gonna record next week. We we gotta pick one of these Halloween topics and she was like, oh, we should do blood types and I like, well, yeah, that's that's true blood vampires, Halloween. It's perfect fit. And so there you have it. Obviously, we'd love to hear from everybody out there, because you all have blood. You all have experience with your blood, thoughts about your blood. Perhaps you have exposure to um, blood type based diets,

a blood type based personality tests. You've all bathed in blood at some point and and and in doing so noted the like the weird coagulations of the blood right and you realize, oh, they mixed. I requested, specifically requested on all a B bath and they gave me a little bit of A and a little bit of B. It's not the same thing, people, It's not the same thing. A vampire can tell uh. Also, maybe you've had a blood transfusion, you'd like to tell us about that as well.

As always, you can find us in the normal places, And if you want to support the show, the best thing you can do is to rate and review stuff to blow your mind wherever you have the power to do so, and be sure to subscribe to Invention as well. That's our other podcast. It is a journey through human techno history, one invention at a time. Huge thanks as

always to our excellent audio producer Seth Nicholas Johnson. If you would like to get in touch with us with feedback on this episode or any other, to suggest a topic for the future, or just to say hello. You can email us at contact at stuff to Blow your Mind dot com. Stuff to Blow Your Mind is a production of iHeart Radios. How stuff Works. For more podcasts from my Heart Radio is at the heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.

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