Speaking of Psychology - Why We Like the Foods We Like (SOP86)

Episode Date: July 31, 2019

Why do some people scarf down anchovies by the pound while others recoil at the thought of a tuna fish sandwich? Why do the textures of certain foods, like mushrooms, turn people off? Not only is taste a biologically complex experience, it is quite psychological. Our guest is psychologist Linda Bartoshuk, PhD, an international leader in taste research, who is the Bushnell professor of food science and human nutrition at the University of Florida and director for psychophysical research at the university’s Center for Smell and Taste. APA is currently seeking proposals for APA 2020 sessions, learn more at http://convention.apa.org/proposals Learn more about your ad choices. Visit megaphone.fm/adchoices

Welcome to Speaking of Psychology, a biweekly podcast from the American Psychological Association. I'm your host, Caitlin Luna. Why does some people scarf down anchovies by the pound while others recoil at the thought of a tuna fish sandwich? Why do the textures of certain foods like mushrooms turn people off? Not only is taste a biologically complex experience, it is quite psychological. Our guest for this episode is psychologist Dr. Linda Bartaschuk, an international leader in taste research, who is the Bushnell professor of food science and human nutrition at the University of Florida and director for the psychophysical research at the University's Center for

Smell and Taste. She's known for her discovery of supertasters, people who have more taste buzz than the average person, her work on enhancing the flavor of tomatoes, and for discovering a condition known as Burning Mouth Syndrome. Dr. Bartaschuk is joining us via Skype from the University of Florida. Welcome. Hi. So it may be surprising to people that taste is as psychological as it is biological. Can you explain how taste is studied from a psychological perspective? Well, taste is both biology and experience. And it's psychological because of the learning that we do. We learn to like things. Some of our liking or disliking is built into the brain, but most of it is learned. Does that explain why some people like very polarizing foods, like vegetamite, durians,

those really stinky cheeses. Is that genetic, cultural, or is it based on personal preference? A lot of that is early experience. They learn to like it very early. Their culture promotes it. They learned it from their parents. And what we learn to like when we experience it very early in life sticks with us. And so what if you hated, say, broccoli growing up, but now all of a sudden as an adult, you can't get enough. Are there changes in the taste psychology over time? The changes over time, some of it's biological, again, there are changes with aging, but most of it is just the experience you accumulate and probably you didn't switch from disliking broccoli to liking it a lot. It was probably gradual. And it probably happened because you paired broccoli with a lot of things you did like. And so you learned it almost accidentally as you were eating things you liked a lot. And so what causes certain food textures to bother? people. You know, for example, I like bananas, but sometimes the texture just makes me want to gag. No, texture is interesting. In fact, if you lecture to students and you mention texture

and you say there are textures, some people don't like, you can actually watch people's faces get red in the audience. It's embarrassing. It's emotional. And we don't understand that very well. For example, you know the little curly thing next to an egg yolk? I can't stand that. If I get that with my egg, I don't want to eat the rest of it. And I don't generally admit that because people think it's a little weird. Texture reversions are considered rather strange. We don't talk about them much. But they are quite common, though, you said, right? They're very common. And why is really a puzzle because they don't really have nutritional consequences. So something else is going on, and that is something that hasn't been studied much. I'd really like to know more

about it myself. Many of us probably have that person in our lives who only likes, or maybe we are that person who only likes brown food or white food, so that's pasta, potatoes, chicken, or whatever. So what causes people to be picky eaters? Wow. Picky eaters is really a loaded subject, especially with parents. Occasionally, I have a parent or grandparent bringing a child to me because they're upset because the kid is a picky eater.

And they think the kid must be a supertaster. and that explains it. So they come to me in the hopes that I can verify that there's something going on. The truth is we're all picky eaters to start with. We learn to accept things, but if you look at the way we acquire preferences from the time we're babies, for example, vegetables are really, really slow to develop preference for. And one of the reasons is you don't get much immediate reward from a vegetable. things that have fat in them, you get an immediate calorie load, things that are sweet or salty,

you've got hardwired liking built into your brain. But vegetables don't buy you much. So we really are acquiring our liking for foods, one food at a time, except for sweet and salty, which we like as soon as we can perceive them. And that learning liking just takes time. Now, why does some people develop such dislikes? That's actually a wonderful question. And part of it can do with gastrointestinal illness.

For example, if a small child tends to get nauseated frequently and throw up, anything that you eat when you're experiencing nausea is likely to be learned as disgusting very, very quickly. It's one trial learning. So sometimes people have aversions to it. a lot of foods because they got sick a lot as a baby. When you don't have that kind of history or can't remember it, sometimes it can be very puzzling to explain. But I'll tell you, one thing don't do. If you've got a picky kid, don't bug them about it.

Don't insist they eat things they don't like and don't make a big fuss about it because you're going to create a problem that you're then really going to require professional help to solve. So if you do want to get a picky eater to eat more vegetables or fruit, let's say, but might be difficult, is there a way you can try to, instead of forcing them to eat something like that, you know, find a way to show them how good it can taste or hide vegetables or fruit in other foods? Is that possible? You know, one of the best ways to get a kid to try something new to eat is to have another kid at the table eat it. Now, when that's not practical, there is another

solution. For example, you want a kid to eat broccoli. Serve it with something good on it, like sprinkle a little sugar on it, put something fat on it, add butter to it, add cheese. The beauty is that our learning theorist experts tell us that the kid will acquire a preference for the flavor of the broccoli because it's paired with something that's really highly liked. Later on, when you take that highly liked substance away, the flavor preferences remain. So you can actually condition a preference to something like the flavor of broccoli by adding sugar to it. And later when you take the sugar away, you still have the broccoli preference. That must be an interesting taste to have some sugar on your broccoli, right?

Well, you know, dietitians tend to be very bothered by the instructions like this. But sugar is not the evil that we tend to make it out to be. We evolved with sugar. Frankly, artificial sweeteners worry me a lot more. How come? Why do you think they're so much worse than regular sugar? Well, first of all, they have a lot of toxic. is associated with them. It concerns me that we tend not to pay attention to some of the

literature about this. For example, cyclimate was taken off the American market because it was found to be carcinogenic. Well, it turns out that probably wasn't correct, but saccharin is known to be mildly carcinogenic, and there it stays. Because at the time, people tried to get it off the diet. it was about the only artificial sweetener out there. And people who thought they needed artificial sweeteners really raised a row about it. So it's probably almost better if you can, I mean, unless you're diabetic or some other physical need to have regular sugar on your food. Just don't have a lot of it.

Be careful about the quantities you eat. But a certain amount of sugar is really not a bad thing. You're right. If you're a diabetic, then you have to worry about it. This is one of the reasons that I'm interested, very much interested in research that might lead us to a sweetener that really is safe. I'm happy to tell you we're doing that right now. We're working on volatiles. Now, a volatile for people who aren't training chemistry. It's a compound that can be in gaseous form. Like you sniff something, a flower, the compounds that you're

smelling are volatiles. They're in gaseous form. The compounds that we sniff when we smell a fruit and are so pleasant, those are volatiles. Now those compounds, when you bite into that fruit, those compounds actually go in your mouth and they rise at the back of your mouth through a space up to the back of your nose. Think about post-nasal drip. That space that the post-nasal drip comes through

is what volatiles rise through. And so a volatile can bite in and the odorant, a volatile can rise at the back of your mouth and go into your nose from the rear. Now, when your brain detects a volatile coming in that path, it sends it to a part of the brain that also handles taste. And the two interact there. And there are some volatiles that actually intensify the taste message.

That's fascinating. And you, we raised a lot of really interesting points that I want to address in a couple different questions here, but just to wrap up the section about picky eaters, you know, why are some people more adventurous than others on the flip side of being a picky eater? Well, first of all, being adventurous is a more general characteristic of personality, and I honestly don't know what makes us more adventurous.

But if you want to become more adventurous in food, you have to go out and try new foods. This is something that I run into when I see a patient who's got taste damage and they can't taste things as well as they used to. I urge them to go out and try a lot of new things. And part of that is in the hope that they're going to find a few things. sensory inputs that are still going to be really good. But there's a hidden purpose to that. The hidden purpose is the more things you try, the more things you give your brain an opportunity to learn to like, you eat something. And the sensory signature of that, actually, the retronasal

olfaction, that message I was telling you that comes up the rear of the mouth, that is the signature of the food, the flavor of it. Your brain records that. And if that flavor is, coming into the brain at the same time, calories are coming in through your stomach, your brain is going to tell you to like that flavor. So the more different things you eat, the more unusual flavors you are pairing with calories and your brain is going to make you like them. That's fascinating. So there are ways to enhance what you like to eat just to give it a shot and try it and see if you can like it again. Okay. That's really interesting. The more you explore the food world, the more things you're going to learn to like. Now, you have to be careful.

because if you start out really disliking a lot of things, you can then expose yourself to things you don't like. And sometimes it'll backfire and you'll get to like it even less. So it's better to start off neutral and pair something with calories or good taste like sweet or salty and your brain will make you like it. And we've talked about smell a little bit. So can you talk about how integral smell is to the full sensory experience of food? So, you know, anyone who's ever had a cold, which is probably everyone who is listening,

can attest to how bland and basically terrible food tastes when they're sick. Well, I mean, that's actually a myth. The notion that you can't perceive the flavor of food when you got a cold, there are some people that do lose the ability to smell because the area that the odorants have to go through to get to receptors get swollen from a cold. And the odors just don't get through the area. But that's not true for most people. For example, I don't lose a sense of smell at all when I get a cold. And I think most people don't.

But unfortunately, there is a fairly rare condition where the virus itself can damage the olfactory system. And those people do lose smell with a cold, but it outlasts the cold. Oh, okay. But just smell in general. How is it, how integral is it to enjoying and tasting your food? It's extremely important. And let me first distinguish between taste and taste. smell because I think it's easier to understand all this if you really get that distinction.

Taste is what's coming from your tongue. Sweet, salty, sour, bitter, umami, if you buy the advertising stuff coming from places like Kajunomoto, which I do not. But the four basic taste, sweet, salty, sour, bitter coming from your tongue. Now, when you sniff with your nose, you're bringing volatiles, odorants, in through your nose, they have to go through a very small opening And that opening is what gets swollen during cold for some people. But once the volatile goes through that opening, it hits the receptors and sends a message to the brain. And that's smell. That's what we sniff from the outside world.

But the nose has a second job. And that second job is you put food in your mouth, you bite into it, you chew it, you swallow it. And swallowing forces those volatiles up that passage at the back of the mouth that I mentioned. Now that input is going up and it's hitting, going to. through the same small opening going to the receptors. So you've got a molecule that you could sniff and it comes into your nose one way and that same molecule can go through a different pathway if you get it from your mouth. But the brain pays attention to the difference and it sends the input to different places in the brain. So when you sniff, the input goes to one area and we call it smell.

You put food in your mouth, chew it, swallow it, and that odorous input goes to another part of the brain, and actually that input is what produces flavor. And flavor is going to the same part of the brain as taste, and they can interact. That was what I was mentioning earlier. Now, here's the key thing. We are hardwired. Our brains are wired to make us like sweet, sour, well, not sour so much for most people, but sweet, salty, and to dislike bitter. That's hardwired. But liking smells is entirely learned in humans. At least that's what we think so far. If there are any smells that we're born loving, we haven't identified them yet. Well, that's fascinating. So put this together for food. You've got taste, which is giving you hardwired affect plus or minus, and you've got

smell, which is giving you learned affect. And that depends very much, and almost entirely, in fact, on your experience. Put it together and you've got food. It's complicated. Yes, it's very complex. And also, smell and taste is known to evoke powerful memories. So can you explain how that works as well? Not taste. Oh, not taste. Okay. It's smell that produces those memories. We call it the Proust effect, because Proust wrote about his Madelens with tea in his, I think, aunt's kitchen. And they brought back all these evocative memories. So yes, we associate emotion with smell very, very powerfully. and in fact it may be the most important phenomenon and maybe with the exception of being able to identify food by smell but having affective reactions to it controls a huge amount of our food behavior

and going back to speaking about food in itself you know why do some foods like say fish sauce or anchovies like I mentioned so on their own most people don't like or many people don't like but if they're added to something they suddenly become delicious so like in Vietnamese food a fish sauce really enhances the flavors or an anchovies in a Caesar dressing can really make it taste really good. You explain how that works? Yeah. A lot of it's simple concentration.

That is, when you taste pure fish sauce, you're really getting a full dose. When you add it to food, it's both diluted by the food and it's diluted by the other sensory experience. That is when you put a whole bunch of tastes and smells together, they suppress each other. And what you end up with is an experience that is certainly not the linear sum of all the things that went into it. For example, imagine when you make a beautiful Chinese sauce to have on dumplings. You have soy sauce, maybe you add if you really love salt, salt, sugar, a little vinegar, you put all that together. And if you added those tastes and smells linearly, it would knock the top of your head off.

So they suppress each other. So what happens when you eat food is it's all kept within a reasonable intensity domain. So it's really those chemicals reacting together and working together that make them taste really good once they're all mixed. Absolutely. And also you learn the mixture sensation. That is one of the beautiful things our brains do is to record information about what we've eaten before. And those are saved almost as like templates in the brain. So for example, look at bacon. You eat bacon, it's got protein in it, it's got fat in it. Those are two things that your brain perceives as really good. So it's going to make you love the flavor that comes in with bacon.

Now, that flavor is actually a composite. It's a lot of salt. It's a variety. I mean, dozens of different volatiles make up the smell and the flavor of bacon. You put those all together, and they produce a template of certain sensory signature that's stored in your brain. And the next time you eat bacon, you're going to recognize it very quickly. Yeah, and people go wild for bacon these days, it seems like. Well, look what it's got in it.

That protein, what's not to like? Exactly. Add a little sugar maybe from pancakes or something, maple syrup. Dangerous combination. And why do some people, can they tolerate super spicy foods? Like they can add the hottest hot sauce to their chili and love it or eat these ghost peppers and all sorts of things like that, but while other people can't even stand a hint of heat, some of my family members are like that, no heat at all on their food. Why is, why can some

people eat really hot food and others can't? Some of it's genetic. For example, taste buds in your tongue are surrounded by a basket of pain fibers. So the more taste buds you've got, the more pain your tongue is capable of perceiving. Now, the number of taste buds you're born with is, under genetic control, at least in part. There may be several factors. So if you're born with a lot of taste buds, we call those people supertasters. You're also born with a very large number of pain fibers. And so you're going to feel the burn of a pepper about three times as much. And I love watching the food channel and you watch these pepper eating contests. The person who can eat that really powerful pepper, there are two factors. One of them is, they're probably.

not a supertaster so they don't have the biology to perceive the pain as intense. But in addition, capsaicin is the compound that makes all chili peppers burn. And capsicin desensitizes pain receptors. So if you habitually eat chili pepper, you're desensitizing the pain receptors on your tongue. If you'd like to prove that yourself, go for a vacation, go for two weeks or so without eating any chili pepper, then come back and eat the amount you're used to eating, it will burn. And that relates to your taste buds regenerating over time, correct? No, there's no, regeneration is a natural part of the taste system, and all of our taste buds die off and regenerate. They don't even have a very long taste life. And burn doesn't actually

damage anything. I mean, it produces a powerful sensation of burn. But for the most part, things like capsaic and chili peppers do not actually produce any damage. But you said you just become desensitized to them over time. Yeah, you don't feel the burn. And that is really fun. For example, suppose you go to a restaurant and you order a hot dish and it's too hot for you. Fill your mouth with it. Really let the burn hit a maximum.

And then sit and chat for a few minutes. You can drink ice water to keep the burn down while you're doing that. and the burn will naturally fade away in 10, 15 minutes. At the end of that fade, put the hot food back in your mouth, and it won't burn as much. You can desensitize your pain receptors on your tongue that fast. Wow, that is fascinating. I thought it would be like a gradual process, but it can be over the course of one meal. Nope, it can happen in really in minutes.

And speaking of the supertasters you just mentioned, so those are people with more taste buds. And while this sounds like a blessing in some ways, you also found that that may not be the case. So can you explain why? Well, it's, in terms of eating food, there's one thing about being a supertaster that really is wonderful. We discovered this fairly recently. That is the pleasure you get from your favorite foods is more intense if you're a supertaster. Now, we don't know why that is. This is why I think there's more to being a supertaster than just taste buds, because pleasure is happening in the brain. So something in the brain is different with supertasters,

and they're getting more pleasure from their favorite foods. Now, that isn't the blessing you might think because the supertasters don't have quite as many favorite foods. There are also a lot of things they don't like to eat. They tend to be pickier eaters because they're very sensitive to bitter, for example. They don't like certain texture. Now, that's a case of where texture, there is certain, amount of biology in it, and texture is more intense to supertasters so they can be put off by it.

Yeah, and so for those supertasters, they may not be likely to eat said bitter things. Maybe they're not eating some of those cruciferous vegetables like Brussels sprouts and those things that can be very good for you, by the way. So that's the second piece of this. Your diet has, it involves risk factors for diseases. And one of the reasons we're very interested in the fact that there are supertasters is that their diets are affected. They don't choose to eat the same foods. And because of that, it changes their risk factors.

So, for example, colon cancer, one of the risk factors is fiber in your diet. Well, supertasters don't like eating highly textured foods as much as others. They eat fewer of them. And so they actually are at a slightly higher biological risk for colon cancer. Now, that's a small difference, but it's big enough that you can actually see it. We did a study, for example, looking colon polyps. Colon polyps are risk factor for colon cancer, and they're produced in people who don't consume enough fiber.

And if you look, in fact, at supertasters and people who are not supertasters, they have different number of colon polyps. The supertasters have more. switch to something else like head neck cancer. Now the risk factors are consumption of alcohol and smoking. And supertasters don't drink as much alcohol. They don't like it because it burns their tongues and doesn't taste very good. And they also don't like to smoke for sensory reasons as well.

So the supertaster is an advantage when you look at head neck cancer. And is there's a genetic component to being a supertaster? is. We don't know how big it is. Nobody's done a family study on it yet, but it certainly is genetic. For example, if you look at the tongues of identical twins, they're going to look very, very similar. By the way, you can look at the tongue and see whether somebody's a supertaster. And your listeners can do this by going to the supermarket and buying blue food coloring. Bring it home, swab it on your tongue with a cue tip, and swallow a couple of times to move the dye around. your tongue, best to do it in a magnifying mirror with a flashlight. And what you'll see are pink

circles against a blue background. Those pink circles are fungiform papilli. They're structures that hold taste buds. And you'll see that some people have a huge number of them. Their tongues look like they're absolutely tiled with these pink circles. And then there are others like me. I'm not a super taster. And for me, those pink circles are like polka dots. There's a lot of space between them. So you can see by looking at the tongue whether you're really an extreme supertaster or not. You can't really see it. Most people are in the middle, but you can see it with the extremes. That sounds like a fun experiment to do at home.

Oh, it's wonderful. Kids love this, by the way, for science projects. Yeah, that's a great idea. And how would being a supertaster relate to weight? I mean, you talked about, and possibly obesity or being overweight. You talked about maybe being a risk factor for not consuming enough fiber, but could it also relate to someone maybe being more overweight or obese because they might not be eating some of these healthier foods that aren't as tasty?

Wouldn't you think so? We thought so early on, but in fact, obesity is not really connected with supertasting. If you look at weight differences, you can find some groups of people where there might be a slight weight difference. And when there is, usually the supertasters are thinner, but it's not a very big effect. Okay. That's interesting. I want to also touch on a point you mentioned a little while ago.

And you're talking about getting food poisoning or getting sick on some food, maybe as a baby. But, you know, this can happen throughout your life. So say you've got food poisoning from some food and you feel like you can never eat it again. Is there any way to overcome that? It's hard. Not making yourself sick? It's hard. It's one trial learning.

Consider, for example, a cancer patient who's going to get radiation therapy or chemotherapy. and some of these therapies make you nauseated. So that nausea is going to condition onto foods and make a lot of foods become disgusting. So picture the cancer patient surviving cancer, going home, hoping to eat his or her favorite meal, biting into it and finding it disgusting. This is rough. And one of my tasks in the clinical world is to talk to patients like this and explain that In fact, this is the biology of food aversions.

The way to get over such an aversion, it's a conditioning effect, so you try to extinguish it. That is, try to eat the food that you've had trouble with when you're really feeling good. And if you're lucky, and you repeat this a few times, you may be able to extinguish the aversion. But I have to tell you, it's rugged. I developed an aversion to maraschino cherries, sitting, eating them in the best. back of the car, driving to California on a vacation, I was reading comic books and I was car sick. That aversion is so powerful that I cannot eat those things today. If I get one on a plate, I hope nobody's looking and I just shove it off the edge. I don't even want to see it.

Yeah, so it's so tied into, like we're talking before about, you know, the smell and the whole experience is tied into your memories. And if that nausea memory is so strong, it's very difficult to overcome that. Very, very difficult. Does that same principle apply to Savior trying to get yourself to like some food that you want to like but struggle with, whether that be mushrooms, Brussels, sprouts, that sort of thing? Can you apply that same technique? It's easier to learn to like a food than it is to get over an aversion. That is, if you're completely neutral to something, as I said before, your best bet. First of all, simple exposure will help.

That is just eat it a few times. Don't eat a lot of it, but just eat it. You'll probably find yourself coming to like it. But if you want to speed that up, like with a kid who's finicky, put something good on it. It's like we said with the broccoli, sprinkle little sugar on, put some cheese on it. It'll help. And speaking of disgust, we kind of touched on that as well. Are there any foods that discussed nearly everybody?

I mean, I know that we've talked before about some of these foods that are cultural, It's something people had growing up, like vegemite or durians. But is there anything that's universally panned? You know, the person to ask about that is Paul Rosen. He's the disgust expert. And I think he has found that there are disgusting foods that are disgusting to a lot of people. And they often have an animal origin like feces or a decaying body, something like this. So there are certain things that we do culturally tend to be really disgusted.

But then again, disgust is also learned by these conditioned diversions. It's very easy to develop a disgust for something if you've eaten it and gotten sick. I did this to myself on purpose once. I was coming down with a flu and I was nauseated. I drove home and I always go by Kentucky fried chicken, so I stopped off and bought my favorite, all dark meat, extra crispy and ate it while I was nauseated. Now, I knew what I was doing, but I still developed. the aversion. And it was very powerful. For a while, I found myself not even driving by Kentucky

fried chicken. And even now, if I want extra crispy, all dark meat, I buy it at Popeyes. I don't go to Kentucky Fried Chicken. So these aversions are powerful, and they take over. And it's important to have some compassion for people who've experienced these. And this is one of the things I feel about people who have real food dislikes. It's not something to make fun of. It's something that produces real distress. And I really don't believe in giving kids a hard time if they don't want to eat something they find disgusting. Yeah, you do raise a good point.

I mean, instead of some people, you know, are picky eaters for whatever reason, it might be stressful for them to go into a situation like a party or a restaurant where they struggle to find something they like and don't want to also be singled out in the crowd for getting something, quote unquote, boring. So yeah, that's a good point, though, to be sensitive to that and try not to push people. Because like you said, it does have a stress component to it. By the way, a food anthropologist told me a wonderful excuse to make if you don't want to eat something, suggest you have an allergy to it or that that particular food is something that makes you sick. Mostly, that's a social explanation that works for people. And I actually

have seen some children who turned out to be extreme supertaste. and I took pictures of their tongues and gave them copies to take back to show their friends and told them that they've now heard from an expert that it's not healthy to eat foods you don't like. That's a great idea. It makes the kids feel a little better. I love that. I'm not sure their parents agree, but I think it's important.

Yeah, like that. Speaking of children, children seem to be more sensitive to food than adults. Is that true? and does taste change over a lifespan? That's a wonderful question. The truth is we're all born neophobic. That means we're worried about anything new. And that's a very important survival characteristic.

You want to watch out for something you don't know anything about. You don't want to eat it unless you've learned it's safe. Well, in our culture, we learn it safe because our parents tell it. You know, even animals do that. For example, a rat pup will sniff its mother's mouth to tell what she's been eating. And that rat pup is very likely to go off and eat the food that has the same smell. So we socially teach people how to eat things that are safe. And culturally, we even label our food to make it safe.

That's what spices do for us. For example, typically, if you want to eat a food that reminds you of your homeland, if you're an immigrant, for example, you use the spices from home. And you put those even on a novel food, and you can make that novel food seem like it belongs more to that culturally safe food you grew up with. That's a great idea. I never thought about that. This is a learned behavior. I was also reading somewhere as I was researching this that babies in the womb might like, so if this example of the mother ate garlic, the baby can tolerate garlic and breast milk after they're born because they were able to taste it in the amionic fluid.

You're talking about Julie Minello's work. That is brilliant research. Yes. Julie has shown that both volatiles that a baby can detect in amniotic fluid as well as in mother's milk will carry valence. That is, if you get mom to eat something special like carrots when she's pregnant, you may find that your newborn baby is more interested in eating carrots than if they never had the exposure. So amniotic fluid and mother's milk are ways to get an organism to like foods, both other mammals and humans. Yeah, that's really interesting. I'm actually pregnant right now, and I've been eating a lot of carrots and garlic.

So hopefully that bodes well for an adventurous eater in the future. We'll see. I guess I can keep you updated on that. Is there, does any specific gender have a better palate? I've heard anecdotally so that women have a better. palettes, they're better at tasting wine and all the different notes you can get off a glass of wine. Is that true? There's some truth to that. First of all, women have a more sensitive sense of taste, which is pretty fascinating. And if you consider the fact that what women eat affects a fetus, there's real biological wisdom to that. But more, remember that women, especially in our culture, and actually most cultures, have more experience in the kitchen. So they've learned. more about smells in particular. So having a woman be, say, a better wine taster probably has

something to do with the fact she's learned to identify so many odors because she's had more exposure to them. Now, anybody can get that exposure. And this is what wine tasting is all about. If you learn to become a better wine taster, the way you learn that is you learn to recognize specific volatiles that are associated with the things that are likely to be found in wine. Yeah, that's the interesting part of that. I have a friend who's into wine and he does some, you know, wine tastings for friends. And there's this wheel that talks about all the different tastes. And some of them can be amazing, like a fresh strawberry. Some of them can be downright disgusting, like cat urine that was on the wheel or rubber, you know, that kind of thing, that things you can taste in

wine. And I was just have what I've gotten through, you know, re-osmosis through the years is just that if you are into wine tasting, you want to sniff things like tobacco, leather, chalk, all these things so you can identify those flavors when you're, when you're sniffing the wine, when you're tasting it. That's right. And that wine aroma wheel is Anne Nobles. She's an expert in both the chemistry and psychophysics of wine. She's retired now. She's out in California. And she's the one that put real science into a lot of that. Yeah, and it's very fascinating. Like I said, I had no idea because I was thinking, you see these charts that say you can taste chalk or smoke in wine and like, like, how do, I guess we all know the smell of chalk from me growing up or whatnot, but of all

the things, like, yeah, you have to kind of re-sniff that to be able to identify that in a glass of wine. But I didn't realize if you're training yourself in that, in that area that you should be smelling a lot of different things. That is correct. And you've, I want to talk about some of your research you've done. You've been involved in work to enhance the flavor of tombs. tomatoes. So why tomatoes? Well, we started with tomatoes because my colleague, Harry Clee, is one of the world's experts on tomato volatiles. And we began with the tomato because we wanted to make it more palatable. Now, I don't know if you've eaten supermarket tomatoes recently, but they leave a lot to be desired. Most people have a memory of a tomato that was really wonderful and a lot better

than what you can usually buy in the supermarket. Well, part of the reason for that, is that we have raised tomatoes to ship. And if you want to breed tomatoes to have good shipping characteristics, you're not paying much attention to their flavor. So Harry wanted to make tomatoes more palatable, and also, tomatoes are healthy. So if we make them more palisible, can we improve the diet by getting people to eat more of something like a tomato

that's a healthy thing to eat? Well, it turns out it's not a very difficult problem. You really want to know what it is in the tomato that makes it like. Well, you do the chemistry on the tomatoes, and we actually grew at the University of Florida because we are a farm agricultural college, so we have farmland. We grew our own tomatoes and we grew heirloom tomatoes. Now, heirloom tomatoes, people think heirlooms are better tomatoes. They're not.

Airloom means they're genetically diverse. It refers to tomatoes that came before we started breeding and breeding. for shipping. Anyway, we grew heirloom tomatoes because they're genetically diverse. We did the chemistry on them, and we did the psychophysics. We measured both what they tasted and smelled like, and we measured how much people liked them. Turns out, you put all that together, and you put it into a regression model, which we were helped with by our colleague, Howard Moskowitz, and this regression model actually will give you the formula for the great tomato. Now, we could have created the best tomato in the world, but actually that's really, really hard to do because

it cars a lot of chemistry. Anyway, what we did do is determine which constituents in the tomato contributed what to palatibility so that we could create tomatoes that were better. And actually, Herrickley did create such a tomato. It's called a garden gem. And if you want to get seeds and grow that tomato, send him an email message and send a donation to his lab and I'll bet he'll give you some of his rare tomato seeds. Anyway, why did we start with tomatoes? Because they were there and it was easy. But we've now done the same work with strawberries and oranges and peaches and blueberries. And we know a very, very great deal about which constituents in fruit make them liked better. And we also know which volatiles in the fruit contribute to sweet.

So it has more to do with transporting food than it is of the food itself. So, you know, I definitely have tasted some very disappointing tomatoes of the grocery store or when I have grown some outside, they're incredibly delicious. So it's fascinating that's really based on consumer needs in the grocery store. You know, the sad part about it is we've got the science to make almost anything we grow better. What you need to do is understand the economics. and you have to understand what the farmer is paid for and what he's going to grow. And unfortunately, a lot of farmers are paid for fruit or vegetables by wheat.

And we don't insist that they become, that they be very palatable. If we insist on that, the breeders and the growers can produce it. We just have to insist on it. And those may be the ones you, and they might be a little more ripe, so you might have to eat them more quickly. If you get them from the grocery store, that might come. into play a little bit, correct? Yeah.

Yep, that's called post-harvest. That is how you treat something is going to affect its flavor as well as the genetics of the plant. So you have to pay attention to all of it. Have you ever heard about how tomato juice tastes better on airplanes or people tend to order more V8 when they're on an airplane than they would on the ground? I've heard that and I know absolutely no good science that supports it. There are some papers on that, but they aren't very impressive. Maybe I haven't read them all.

But this notion is, I know, every so often it pops up online and it is not something that is generally understood and believed in by experts. So it's maybe more of a placebo effect. I'm not sure what it is. I shouldn't say absolutely it can't happen. There are the same kinds of stories come from submarines. The same things come from our astronauts. do things taste different to them when they're in outer space? Unfortunately, we haven't done a lot of research on that.

But in fact, there's not a lot of really solid evidence for it. However, if anybody's got some evidence, I'm happy to look. Yeah, that would be open up some new areas of research, too, like you said, if we're going into space, underground, that sort of thing. Maybe it's also people are just ordering Bloody Mary's or something. Or they wish they had a Bloody Mary on the plane? Well, I think that most of the people who are getting tomato juice on the plane, I mean, they're probably getting alcohol in it.

That probably has a little bit to do with their judgment. Yeah, that could be true too. It tastes better. For those experiments you're talking about with strawberries and oranges, is that because maybe strawberries are picked too soon? Because when I thought of like, you know, an orange or a strawberry, I typically thought, you know, if you get them at the right time of year at their grocery store, they're pretty good.

But is the same concern there with, you know, we're focusing on asking farmers to give it to us by weight and we're worried about shipping. We're not concerned about the taste. There's a lot of interest in making good things, making strawberries good. And wow, we know a lot about that now because we know which volatiles in the strawberries make them sweeter. And in fact, there are about 30 some volatiles in a tomato that all add a little bit of sweetness to it. Because those volatiles, when we bite into the strawberry, the message travels to the same part of the brain that codes for the sweetness of sugar. and those volatiles enhance the sweetness message in the brain.

Now, once you've identified those volatiles, you can take them out of the strawberry and put them in pure sugar and it'll get sweeter. So this is one of the things I'm very excited about right now because it looks like about the safest way to make a so-called artificial sweet that could possibly exist. We use volatiles that we've already been eating ever since humans were humans. and they're going to, if you pick the right volatiles, they're going to produce sweetness in the brain. Now, first of all, you can certainly breed for those volatiles in the strawberry, and you're going to produce strawberries that do not need any sugar. I have tasted some of these strawberries, and I'm telling you, when they're widely available, people are really going to like them.

But at the same time, we can put these volatiles in anything that we want to be sweeter, and we can make it sweeter safely for, let's say, diabetics. But there's something else about it that I'm very excited about. I've spent a lot of my career studying people who have taste damage. And one of the things about using volatiles to affect a taste message in the brain is those volatiles bypass damaged nerves. That is, if your taste nerve is damaged, you can't perceive more sweet from sugar because you don't have the nerve to carry the message. But if you consume sugar that has some of these volatiles in that enhance sweet, those are going to, the volatiles, the message is going to bypass the damaged nerve and increase the sweet message in the brain. And I'm happy to say that the early test with patients supports this. It looks like it's going to work. Would those enhancements be considered genetically modified?

No, no. Organisms? Okay. Nobody does that today. Well, not nobody. But the fact is there's so much prejudice. against genetic modified. And I have to tell you, I am not a supporter of that prejudice. If we want to feed the world, we want to use the best science we've got. And if we can genetically modify something to make it, put up, say, a vitamin in rice that's going to save children in the third world from going blind, I say all for it. And I know of no evidence that genetically modified organisms are in any way dangerous. I think that's a type of prejudice that's gotten into

the world. I don't know how it got there and I'm sorry it's there because I think it's doing a lot of harm. Yeah, I've definitely, I mean, there's a lot of arguments against it, but I've heard more than one person say your side of it and typically someone who's a researcher in the science field saying like if we can feed people out there who otherwise wouldn't be able to get the nutrition they need, then we need to think about that. We sure do. And also I wanted to touch on your burning mouth syndrome. So I'm sure most people who are listening have all burned their mouths on food and know how annoying it is. Your tongue goes numb and nothing really tastes great for a couple of days.

But for some people that doesn't go away. And so your lab uncovered the reasons why people suffer from this. So can you explain what the causes of burning mouth syndrome are and how many people might have it and how you can be treated? Burning mouth syndrome actually has nothing to do with damage in the mouth. Burning mouth syndrome occurs in the brain. It's what we call a sensory phantom. You can make a phantom in any sensory nerve in the body. Have you ever heard of a phantom limb? Yes. This is feeling and arm is there after it's been amputated. Well, you can have a phantom smell, a phantom taste, and a phantom pain in your tongue. So how does it happen? We think what causes it is, believe it or not, damage to the taste. nerve, the seventh cranial nerve, that nerve normally has two jobs. It both brings taste information to the brain, but it also terminates oral pain, maybe even pain on other parts of the body. Now, think about why that might be a good idea. Imagine an animal in the wild fighting to

survive with its teeth. It's going to get bitten on some occasions, and another animal might bite it. it might bite its own tongue, and if tongue pain stops it from eating, an animal's going to die. So a survival characteristic would be to somehow stop the pain of any kind of oral damage. Well, if the animal takes a bite of food and the food input, the sensory input, inhibits the pain, it's going to eat and survive. It looks like that mechanism connected the taste system to pain. So what happens is if you damage taste, you lose the ability of taste to inhibit pain. And essentially, pain turns on in the brain.

It's like you flip to switch and you can't reach it to turn it off. Now, how can you get rid of the phantom? And by the way, let me tell you how we discovered that the phantom was in the brain. If you had a burnt mouth, it would be easy to treat it. All you'd have to do is anesthetize the area of the burn. and the pain will go away. When we anesthetize the tongues of people with burning mouth syndrome, the burn gets worse. Why does it get worse?

Because the burn is only occurring in people with damage to taste. And when we anesthetize their tongues, we take out whatever taste was left and we make the effects of the damage worse. So the pain phantom in the brain gets worse. Now, that goes away when the anesthetic wears off, fortunately. but you don't have just burn phantoms in the mouth. You can have taste phantoms and you can have touch phantoms. For example, you could wake up one morning with a bitter taste in your mouth that never went away. Believe me, you would not be happy.

And so can it be treated? Yes, it can. And I can tell you, one of the reasons that I got so interested in this was my father had lung cancer when I was in college and his most distressing symptom was a metallic taste in his mouth that wouldn't go away. And we didn't know what to do for him at that time. But one of the reasons I got interested in Phantoms was to try to figure out how to help patients. It turns out we can use a medication that intensifies inhibitory neurotransmitters in the brain. It's called a GABA agonist.

And a GABA agonist will restore some of the brain. that inhibition from taste that was lost from damage, and it will reduce that burn phantom in about 60, 70 percent of patients. And I can't take the credit for that. That was discovered by Dr. Miriam Grushka, who is an oral pathology expert. Yeah, it sounds like a really troubling situation that can happen, but it's nice to know there's at least a solution for people, like you said, not just me burning mouth, having a metallic taste, or that's, I mean, that really can inhibit the quality of your life if you have a bad taste in your life. It's nice to know. mouth all the time. It is, it is awful. It's one of, it's one of the reasons why that's the

specialty area that I work on in taste pathology, because it probably produces more distress for patients than any other taste problem. Yeah, because the quality of, you know, the quality of life, the enjoyment of food, it's just everything. I mean, you're living with that every second of every day. It's just like having a disturbing taste in your mouth. Well, thank you so much for joining us, Dr. Bartich. This has been a really fascinating conversation and I'm probably going to head out to the grocery store and get some of that blue dye and test out that experiment you mentioned earlier today. That sounds like a lot of fun. Do you do that at parties? You know, the truth is I actually have done it at lectures. I take paper with me that is bitter to

super tasters and pick the people in the audience who think the paper is just awful and put blue food coloring on and let everybody look at their tongue. That's a lot of fun. That's a really great idea. a good thing to do with kids. But thanks again so much for your time. It's been a real pleasure speaking with you. I'm delighted. And thank you for being so well prepared. I really enjoyed this.

Before we go, just a reminder to let you know, we want to hear from you. You can email your comments and ideas to K-Luna at APA.org. That's K-L-U-N-A at APA.org. Also, please consider giving us a rating in iTunes. We'd really appreciate it. Speaking of Psychology is part of the APA podcast network, which includes other great podcasts like APA Journal's Dialogue, about new psychological research and progress notes about the practice of psychology.

You can find all of our podcasts on iTunes, Stitcher, or wherever you get your podcasts. You can also go to our website speakingofpsychology.org to listen to more episodes. I'm Caitlin Luna with the American Psychological Association.