What's the Deal with Gluten?

Emily: [00:00:00] Perry preparing for this week's episode. I was thinking about the kinds of foods that I love, and I wanted to ask you a specific question about food. If there was one food you would be sad to lose, like, and not alcohol or coffee. Like, not a, not a like fun food, but like a real regular food. What is like the one thing that you would cry if you lost?

Perry: [00:00:32] Pez. Cherry flavored Pez. Sorry, that is a deep cut. That is one of my favorite quotes from Stand By Me. Uh, no. My my real like a food that if if it was like, no, you can't eat this anymore. This will now kill you. Probably, like, I don't know, like pasta bolognese. That's [00:01:00] probably like pasta with meat sauce is my happy place. Happy place.

Emily: [00:01:04] So I was thinking about this because mine is definitely bagels. Uh, but then like my second one is bread and my third one is pasta. Like I every single thing on my list has gluten. Everyone.

Perry: [00:01:16] Yeah. If if you had celiac disease.

Perry: [00:01:19] I would be so sad.

Emily: [00:01:20] I would just be eating rice all the time. And, uh, I think that would make me sad. So I'm. I'm glad I am not sensitive to gluten.

Perry: [00:01:29] Well, there are a lot of people out there, unfortunately, who are. There are a lot of people out there, maybe who think they are and might not be, which we're going to dig into a lot in today's episode on one of our favorite proteins, which is gluten.

Perry: [00:01:45] We love.

Emily: [00:01:45] It. Let's do it. I'm Emily Oster. I'm an economist and a data expert.

Perry: [00:01:52] And I'm Perry Wilson. I'm a medical doctor.

Emily: [00:01:55] It's Thursday, August 6th, 2026. And this is Wellness Actually.

Perry: [00:01:59] Because [00:02:00] you're getting a staggering amount of health and wellness information nowadays from every source imaginable. And some of it is awesome.

Perry: [00:02:08] And.

Emily: [00:02:08] Some of it is, well, actually bullshit. Fortunately, we're both people who know how to read studies, how to parse the data, and can tell you what's worth thinking about and what you can safely ignore.

Perry: [00:02:21] But before we dig in a note that this podcast is for educational purposes and should not be construed as medical advice. We don't know your unique situation, so talk to your doctor for personal health decisions.

Emily: [00:02:32] This week we're asking what's the deal with gluten? Perry and I will give the official smash or pass, and then we'll get to your question of the week. But first, let's do the health news roundup after the break.

Perry: [00:02:55] And we're back with our health news of the week. Emily, I want to start with [00:03:00] the great protein backlash. Uh, if listeners go back to her, what's the deal with protein episode? We talked a lot about protein having a moment. This was the macronutrient that everyone was into entire aisles at Costco dedicated to protein containing foods. And now we start to see some articles that are saying, hey, wait, if you eat a lot of protein, you're actually going to die sooner. Is it over? Is the protein party over?

Emily: [00:03:27] I don't think the protein party is over because let's just emphasize, if you don't eat any protein, you will actually die.

Perry: [00:03:34] This is true for a reason.

Emily: [00:03:35] You will die. But I find this. I'm going to tell you about the the science, but I also think there's something just so interesting about the psychology of how the news works here, that this gets covered because it's surprising. If people don't think protein is great, then you're really interested in publishing articles that say, oh, protein is great, protein is great. Surprise protein is great. Now everyone's like, I gotta have protein popcorn at Costco. It's not [00:04:00] interesting to publish an article that says protein is great. And so now the thing the media wants to cover is like, maybe protein isn't that great? Do you think of that?

Perry: [00:04:07] It's the the engaging contrarianism of.

Perry: [00:04:10] Engaging.

Perry: [00:04:10] Science communication.

Emily: [00:04:11] Totally. Okay. But this is the reporting that I saw on this week is based on a study. It's like a review study about data primarily on yeast, although they do have some mouse data. There's very little if no data on humans here. And they have an argument about protein restriction. This is actually a set of people who are very interested in calorie restriction for lifespan extension, which is an interesting space where most of the evidence is also in mice. And I want to read you just one sentence, because for me, this sort of summarizes like why I think you shouldn't probably learn much from this, which is a quote from the paper like calorie restriction. Protein restriction improves healthspan [00:05:00] and increases the lifespan of yeast, flies and rodents. It does not mention people, and I think we should not port this to people just yet.

Perry: [00:05:12] Uh, mice aren't people, although, you know, I want nothing but the best for at least yeast, who, you know, for the gluten episode in particular, where, you know, we need our good friend, uh, Sarcomatosis cerevisiae for many of our yeasty bread products. Yeah. It's true that severe calorie restriction, uh, does extend the lifespan of a variety of animals, ranging from single celled organisms up, through, up through mice. And we don't know if it happens in people because you really need people live a long time anyway. And so you need and we're talking calorie restriction on the order of like the equivalent of like 1200 calories a day forever. I mean, it's really you're in a starvation state. And my thought about these kind of studies is like, even if [00:06:00] true, this is not a life worth living. Um, so, you know, if we can find the mechanisms downstream of the calorie restriction, like if it, oh, it upregulates some hormone that like, and we can just give the hormone great, do that research. But, um, you know, I'm not, I don't if, if eating 1200 calories a day gets me to 120, I don't wanna be 120.

Perry: [00:06:20] Right.

Emily: [00:06:21] Totally. I could not, I could not agree more. Okay. Uh, next up, can we talk about Ebola? Unfortunately, the Ebola outbreak in the Democratic Republic of the Congo has gotten worse. It's now the worst ever. What is going on? And is this something people should be worried about outside the DRC?

Perry: [00:06:42] Yeah. I'm glad that you brought this up. You know, we talked about the Ebola outbreak a few times when it was first emerging. And then these things do have a way of falling out of the news. And you might think like, oh, I guess that's not an issue anymore. Um, but it very much is. As of the 30th of July, there were 3605 [00:07:00] confirmed cases, including 1587 deaths. That's a case fatality rate of 44%. That's obviously very bad. And the W.H.O. says the outbreak is actually intensifying. They've documented sustained chains of transmission across multiple parts of the Democratic Republic of Congo, as well as some cross border movement. There were cases in Uganda which has done a little bit better with containment than the DRC. There were a couple of cases that were treated in France, didn't, uh, didn't get acquired in France. Um, one of the really concerning things I found was a recent study which showed that maternal mortality was increasing in the DRC, not directly because of Ebola, but because pregnant women are avoiding hospitals when they're giving birth. And so because of the risk of Ebola. And so you see young mothers dying, you know, this is concerning on a humanitarian level because it's a humanitarian crisis, and [00:08:00] it's a place where the proper provisioning of some standard public health measures could do a lot of good. Is it concerning in terms of if you live in Connecticut or Rhode Island? No. You know, Ebola is certainly transmissible by body fluids, but, uh, we haven't seen really sustained transmission out of the DRC. And there's a lot of monitoring and, and whatnot. So I'm not worried about that. There are some vaccines in the pipeline which might make a dent. But most important, just to remind people, this is still happening and happening more than it was before, actually, even though you're not hearing about it too much.

Emily: [00:08:36] Absolutely. Okay. In better news, it seems like viagra might help prevent cancer in addition to being super, super fun.

Perry: [00:08:47] Uh.

Emily: [00:08:48] So the, the result in this, at least in this article, is that men taking viagra before their cancer diagnosis had an overall higher cancer survival. [00:09:00] And I think there are some, you know, like always in these articles, there's some made up suggested mechanism which could or could I mean, a little bit of a just so story. You know, this is not a randomized study. What do we think is driving the results here?

Perry: [00:09:15] This is one of those things where you have one paper. This is uh, this came out in cancer, the journal Cancer Research. And they were looking actually most of the papers in cell culture and stuff, looking at the effect of, uh, viagra and statins. So cholesterol lowering medications on cancer cells. And you know what sometimes we'll do in science when we have a very sort of wet lab technical paper, like we did some cell work and blah, blah, blah. And you sort of are looking at the results and you're like, okay, this is interesting to us in our little field, but maybe it's not super compelling to the rest of the world. So what we're going to do is we're going to tack on some kind of epidemiology study. And so, so they have all this kind of rather elegant work in cell culture looking at cholesterol [00:10:00] synthesis, which if that's what you're interested in, please check it out. And then they're like, and by the way, we looked in this huge data set and men who take viagra before they got cancer had a better overall survival. And that's, that's literally it. Like it's, it's really a paper about cell culture. But of course, that is what's generating, you know, dozens and dozens of news articles. Their proposed mechanism is that viagra has some effect of limiting cancer cells access to cholesterol. And cells need cholesterol to do a lot of work. And if they don't get the cholesterol, maybe they don't live as long. You're right. This is a a just so story. There are plenty of reasons to think that men who have access to viagra might have better contact with the health care system, maybe be even more health literacy might be in different socioeconomic status, all sorts of things that might improve outcomes after a cancer diagnosis.

Perry: [00:10:49] Might.

Emily: [00:10:49] Have better social support. I mean, it may be the case that their access to viagra is so they can use it to have sex with a partner, and that that having a partner to support you [00:11:00] in a cancer diagnosis may improve your survival.

Perry: [00:11:02] Another excellent point, but just to underscore how headlines can be misleading, I actually read the article, you know, which is like, I sometimes wonder if the, the science reporters actually look at it. And, um, it actually only shows a significant effect among men taking statins. So, so they looked both at, as I said, statins and viagra. And, and the significant effect was in men who take statins prior to their cancer diagnosis live longer. Um, and then they looked at men who take statins and viagra and saw a similar benefit, but like the statins were still there. And then when they looked at viagra alone, there was no significant benefit. So I'm like, all right, so it's the statins.

Perry: [00:11:46] Conclusion.

Emily: [00:11:47] Statins and viagra together or something.

Perry: [00:11:49] Yeah, I don't know. Anyway, viagra is a great and useful drug for many things. I'm not sure that it's um it's curing cancer though. Sorry, Pfizer.

Perry: [00:11:59] Yeah.

Emily: [00:11:59] Sorry [00:12:00] folks. Great cell work, poor epidemiology.

Perry: [00:12:04] All right.

Emily: [00:12:05] That's it for the health news of the week. Now what's the deal with gluten?

Perry: [00:12:10] All right, Emily, there's as soon as this episode was added to our list of upcoming episodes. I knew exactly what clip I wanted to play for you. So, um, please listen to this.

Seth Rogan: [00:12:23] Look, man, if you stopped eating gluten, you'd feel way better all day. Whenever you feel shitty, that's because gluten.

Jay Baruchel: [00:12:29] That's not true. Who told you not to eat gluten?

Seth Rogan: [00:12:31] It's just true.

Jay Baruchel: [00:12:32] You don't even know what gluten is.

Seth Rogan: [00:12:34] Gluten is.

Jay Baruchel: [00:12:35] No. You have no idea what.

Seth Rogan: [00:12:36] You do know what gluten is. Gluten's a vague term. It's something that's used to categorize things that are bad, you know, calories, that's a gluten fat. That's a gluten. Gluten means bad man. And I'm not eating it.

Perry: [00:12:53] All right. That's Seth Rogen and Jay Baruchel from, um, great movie. This is the end. And [00:13:00] for those of you there driving in a car in California at the end, they end up at a Carl's Jr and are eating like delicious looking burgers, obviously with with bread containing gluten. I just thought this was the most emblematic thing we could start the episode with.

Emily: [00:13:16] I love it, and I think I particularly love it because this is how many people talk about gluten as sort of this like nefarious, like, well, you're bloating, diarrhea, too much poop, not enough poop, not feeling good, tiredness. It must be gluten. It's like, I guess like gluten. It just means feeling badness, but gluten is actually a specific thing.

Perry: [00:13:43] Yeah. And so we need to talk about what is gluten. So let's start there. Gluten is a protein. In fact, it's two proteins gliadin and glutenin. And it's the primary protein in wheat. It's also found [00:14:00] in barley and rye. And it is the sticky stuff that polymerises when you make dough that makes your dough all stretchy. And amazing. You know, when you are rolling out pizza dough and it springs back, that's a gluten. When you are baking your bread and those air bubbles get trapped, the air bubbles or the carbon dioxide bubbles that the yeast are generating get trapped in the sticky bread dough. That's a gluten. There really is no other grains that have that. And because of that, it's really hard to make chewy, stretchy, delicious doughs out of things like rice flour. Unless you put in an additive like guar gum or xanthan gum or some other binder. But gluten is a natural binder in wheat, and without it, life would be a little bit more sad.

Emily: [00:14:50] Yeah, and the higher stretchier like kind of more stretchy bread flour. When people say it's a high protein flour, it is because [00:15:00] it has more gluten. That is the protein that we are discussing.

Perry: [00:15:02] Oh that's right. And yeah. And if you're if you're not baking your bread with bread flour, switch right away. It's, it's more unctuous.

Emily: [00:15:09] Okay. Uh, cooking with Perry, that's our next episode. That's our new podcast.

Perry: [00:15:14] Um, I make a lot of bread. I do.

Emily: [00:15:16] Perry makes. Oh. That's good. You have a sourdough starter. Are you a person?

Perry: [00:15:20] Okay, we're going to talk. Can we table sourdough? I have thoughts. I have many thoughts on. So we will get to sourdough, folks. We'll get there. But, um.

Emily: [00:15:27] Some other things before that, let's say before we get into this, some other things do have gluten in them. Soy sauce, um, often salad dressings, malt vinegar. So actually a lot of, if you are a person who is gluten sensitive, there are many things that have gluten. Although bread and bread products are the primary, the primary ones. Yeah. So when we were thinking about this episode, the setup for me here is there is a real set of issues associated with how people process [00:16:00] gluten. Like many food sensitivities, this is something that some people have a sensitivity to, and we want to start talking about that. But in the influencer wellness space, there is a much wider discussion about gluten sensitivity. And if you look at some numbers, you know, the Nhanes says there's like 2% of people who, you know, don't eat gluten at all. But in other surveys, like 30% of the people in the US say they limit their gluten intake. And about 10% of people worldwide identify as gluten sensitive. But something like 15 to 30% of those have symptoms that are triggered. So there's a disconnect here, I think, between how people talk about gluten and the sort of scientific diseases that are actually gluten sensitive. And I think that's, that's like the interesting thing to unpack is what is real. And then how much do you want to extend the [00:17:00] existence of celiac disease into everybody should stop eating so much bread.

Perry: [00:17:05] Right? An analogy might be, you know, there are people with peanut allergy. They truly could die if they get any peanut product. And then if we had people who were like, oh, I don't have a full blown peanut allergy, but I'm peanut sensitive. You know, peanuts make me feel bad. And we need to explore that aspect because that's actually what the vast majority of people who are avoiding gluten are avoiding gluten for. And we can start by like, we can kind of buzz through the easy diagnoses. Not easy, but like the confirmed gluten diseases. And I think obviously we have to start with celiac disease.

Emily: [00:17:40] Celiac disease broadly is a disease that in which people cannot tolerate gluten. Tell me how we know about it.

Perry: [00:17:48] Uh, fascinating. We've known about it for centuries. The oldest reference I found was 300 A.D. and what celiac disease presents, as is a chronic disease of [00:18:00] the the bowels. Celiac literally means belly in like ancient Greek or something. So celiac disease, just like belly disease, not very descriptive, but it's not just that, you know, in kids, it typically presents as, as GI symptoms, malnutrition, failure to thrive, like so growth limitation and stuff. And for a long time, it was really thought to be a disease of children. We now recognize that celiac disease can present in later life. And it's actually quite easy to diagnose. But you have to think of it first. And celiac is one of those great imitator diseases. So, you know, yes, it gives you GI upset diarrhea, uh, you know, excessive gas and things like that. But so do a lot of things, right? It can also cause joint pain. Um, it has a very characteristic rash called dermatitis herpetiformis. Sort of a vesicular, intensely itchy rash on the extensor surfaces of the arms and legs and stuff. A lot of fatigue, anemia, [00:19:00] osteoporosis.

Emily: [00:19:01] And so these are like, so, I mean, this isn't there's an issue with a disease like this where. Right. These are such generic symptoms. People come in, they say, I'm not feeling good. I've got bloating and diarrhea. I have a weird rash. I've got some anemia. A lot of people are anemic. A lot of people are tired. Rashes.

Perry: [00:19:18] Yeah, yeah. So your doctor actually has to think about it. But the good news is if you think about celiac disease, it's a blood test. There's a screening blood test anti-tissue transglutaminase antibody. It's 95% sensitive and specific. That's not perfect. You do need a confirmatory biopsy test, which is done by endoscopy. But like broadly speaking, if you think about it, you test for it and you're you're well on your way. Historically, it's really interesting that although the disease has been known about for two millennia, it was only in World War Two that they figured out what the cause was. So celiac disease is a classic autoimmune disease that is due to a genetic susceptibility. So it's largely genetically [00:20:00] mediated, but it has an environmental trigger. And for all this, until World War II, it wasn't clear what the environmental trigger actually was. And it was a Dutch pediatrician, William Carroll Dickey, who found that his patients, his kids with this disease got better during the Dutch hunger winter of 1944 to 1945, when they ran out of bread and then the allies airdropped bread into Holland, I guess, and the kids developed the symptoms again once they were eating bread again. So it was actually that long before we knew at least that it was a wheat product. I think it took a little longer to figure out exactly that. It was the gluten in the wheat, what the cause was.

Emily: [00:20:42] So the incidence of this has gone up over time. This is quite interesting. So if you think of this as a as a genetic disease within an environmental interaction over the past, um, it's gone up a lot in the past few decades. Some of that's going to be diagnosis and awareness, but some of that is aligned with the general rise in auto [00:21:00] immune diseases. Almost certainly this is not genetic drift. It's just not enough time for there to be genetic drift. So there is something going on in the environment or the food that we are eating. That means that more people are having this. The gluten that we're providing, the wheat, the foods that we're providing are more likely to trigger this in people.

Perry: [00:21:22] Yeah. And we actually know that it's a true increase again, because that blood test is pretty good to detect celiac disease. There was a study in the journal Gastroenterology in 2009, which looked at banked blood samples from Warren Air Force Base, where, like the privates had gotten their blood sampled in 1948 and 1954. And they went back to those old samples and tested them for this anti-tissue transglutaminase antibody, this diagnostic test for celiac disease. And some of them had it, you know, they probably weren't even diagnosed at that point in time, but they based on their blood, they had it. And, and that rate has increased over time. So we do know something's going on. [00:22:00] And here's where we should talk about sourdough.

Emily: [00:22:03] We should never a bad time to talk about.

Perry: [00:22:06] Is it the lack of sourdough?

Emily: [00:22:07] Why we should discuss sourdough just now.

Perry: [00:22:09] So, so some people are hypothesizing that our modern industrial bread making process is a problem here. And the reason is that in the old times, when we made bread and sort of with a slow fermentation. So think sourdough where it's like it takes 24 hours and I've made sourdough. I actually don't love it because it's so labor intensive. And I, I just like getting yeast from the store and it's easy, but you know, you've got 24, 36 hours over that slow fermentation process. The gliadin and glutenin proteins are broken down somewhat more by the yeast. And so they're potentially in a less immunogenic form. Modern industrial bread is made with a process called the Chorleywood process, which is crazy and incredibly fast. You can make one of those whole loaves of bread basically [00:23:00] start to finish. Takes about two hours.

Emily: [00:23:02] Now they do that.

Perry: [00:23:04] So I did, I did, I did read about it. They use a lot more yeast. They like mix the dough really fast and it actually gets hot as they're mixing. And they have to inject like cold water to keep it from getting too hot. I think they inject some, maybe some gas or CO2 in it themselves. But the bottom line is the yeast don't have much time to like do their breaking down of proteins thing. So some people are saying that like it's the old fashioned bread that that might.

Emily: [00:23:34] Be people say things though. Yeah, like speculative sourdough bread could be something you would enjoy, but that feels speculative to me. Uh, so there's a lot of evidence that autoimmune disease, other autoimmune diseases have gone up over time.

Perry: [00:23:46] This is also true. And we can't blame bread for everything.

Emily: [00:23:48] All right. Worth noting is that people often take quite a long time to be diagnosed, because this is not, uh, clear an average of 11 years between first symptoms and diagnosis. And so, you know, [00:24:00] if some of what we've described here seems like it's you, there is a test and a gluten free diet is truly curative, although you have to keep up with it over time.

Perry: [00:24:09] Right? And for real celiac disease, I mean, a tiny amount of gluten will set it off. So this is like the real deal gluten free diet. And one thing we're going to say here is that for all of the conditions we talk about jumping straight to the gluten free diet is generally not the recommendation because it's hard and not easy. And you know, with celiac disease, at least we can test and make sure you have celiac disease and then put you on a gluten free diet, but you don't want to do that. You don't want to pull that trigger if you don't have to. Yeah.

Emily: [00:24:38] Okay. You can also be allergic to wheat to have a regular, just a regular person wheat allergy, just like you can be allergic to other foods. This is separate from a gluten allergy and would present with normal allergy symptoms. Difficulty breathing, principal anaphylaxis. So separate gluten celiac disease and wheat allergy [00:25:00] are not the same thing.

Perry: [00:25:01] Have you heard of wheat dependent exercise induced anaphylaxis? Have you heard because you're an exercise person Emily.

Emily: [00:25:09] I have I have not.

Perry: [00:25:11] So it's this weird phenomenon, um, which I like to say like, like we don't fully understand, but it might be one of those weird phenomena that I don't fully understand and other people do. So Allergists let me know. But but basically it's people who have a wheat allergy, but it only presents during exercise. And so it's like this weird combination where if they just eat wheat or they just exercise, it's fine. But if they do both in proximity and time, they develop anaphylaxis.

Emily: [00:25:36] Like it's not just like while you're running. It's not like if you run and eat a bagel, your bagel too close to them.

Perry: [00:25:42] No, I think I think it can be in your system, but that's sort of a weird one. And then there was a bizarre, um, Japanese facial soap wheat allergy incident that occurred with the cha no Shizuku soap, which was documented in epidemiology [00:26:00] circles. The short version is this was a soap that contained wheat. I don't know why. I guess whatever people put a lot of things in wheat and but for whatever reason, it was wheat in some kind of digested form that was pretty allergenic. And when people were putting it on their faces, they were getting it like they were inhaling it and doing stuff like that. There's there's a lot of evidence in the allergy literature that when you eat something, it's protective in terms of allergies, right? Like giving kids peanut butter when they're extremely young is protective. But when you get it in a different way, like if you if you inhale it or if it gets under your skin or something like that, then you can generate allergies. So this happened in a like a several thousand women in Japan developed wheat based anaphylaxis based on a soap. Very strange.

Emily: [00:26:45] That's extremely odd. Don't buy weird soaps. Don't wash your face with flour. I don't know, there's a few.

Perry: [00:26:51] I'm sure people do.

Emily: [00:26:53] Um, you probably do. I'm sure there's, like, a TikTok influencer whose whole thing is like flour face, and she, like, puts flowers on her face and [00:27:00] then covers it with one of these masks and then, like, stays on the airplane for like nine hours. And at the end, she's like, look at this. And then her face is just like a crumpled mask of, of dough.

Perry: [00:27:10] Oh, I'm gonna try to find this person. And if not, I'll have AI make it.

Emily: [00:27:15] Yes. Ai needs to make that up. Okay. There. Do we really need to talk about gluten ataxia? We're just going to get people freaked out that they're going to have neuron loss.

Perry: [00:27:26] Yeah. No that's okay. There's there's another rare condition that is gluten ataxia, which is another autoimmune condition kind of related to celiac disease, but it attacks your brain instead of your small intestine. And that's not great. Um, but this is this is pretty rare. All of this is just to say that yes, of course, like, like any protein that's out there, including peptides that you might be getting from China or other places, anything like that can be a potential allergen. Can, you know, your body is a complicated place and can induce strange symptoms and strange [00:28:00] disease states, but the vast majority of people don't have celiac disease, don't have wheat allergy, and certainly don't have gluten ataxia. Thankfully, what most people have or are a concern they have is non-celiac gluten sensitivity. And I guess that's what we need to get to after the break.

Emily: [00:28:26] Okay, we're back and we're going to talk about non-celiac gluten sensitivity, which is what many people seem to think that they have. And I will say this conversation a little tricky because there is no defined characteristic of sensitivity. So people often say that they're sensitive to foods, by which they mean some combination of I don't like that food, and I don't feel great after I eat that food. And it can be hard to think about outcomes in this case, if what you are saying as the sensitivity of the outcome of the sensitivity is just like I don't [00:29:00] feel, I don't feel great. Like I don't eat spicy food, I don't eat spicy food because the next day I feel really bad and I have a lot of problems in the bathroom. We don't need to go into it, but I would say I have a sensitivity, but it's not like a like a documented sensitivity. So I don't know. I think this is what people mean here is something different, something fundamentally different than I don't like to eat that food or that food doesn't agree with me. They mean something like, I am having a version of a celiac reaction to this food and therefore need to avoid it for medical reasons, as opposed to almost preferences. Does that make sense? It's such a hard distinction.

Perry: [00:29:43] Yeah, it it's tough. We do not have a diagnostic test or a clear biomarker for non-celiac gluten sensitivity. So in contrast, celiac disease where it's like, yep, blood tests, biopsy shows it, you know, these characteristic symptoms, people who are like, look, I feel bad. And [00:30:00] by the way, we should say feeling bad generally is in the GI system. People complain of bloating, diarrhea, sometimes constipation. Um, but also brain fog, fatigue, uh, depression, um, other symptoms that can be hard to pin down. There's no case definition for non-celiac gluten sensitivity. And more importantly, there's no blood test. There's no signal of immune activation like we can see in celiac disease and celiac disease. You can find the immunoglobulins that are directed against the proteins and things like that. We don't have that in this. This is not to say that this is not a real thing. And we can go. I think the, you know, there are always people who are going to be skeptical of this because it's like, wait, okay, you don't have a blood test. This is just someone kind of complaining that they get gassy sometimes. And we all get gassy sometimes. And who cares whether it's the gluten or not. So the thing I think to take home or an important set of studies that looks at non-celiac gluten sensitivity are blinded challenges. [00:31:00] So the way this works is you take people who, you know, believe they have gluten sensitivity for whatever reason, And instead of just saying, okay, go on a gluten free diet and see how you feel, in which case there's going to be a lot of placebo effect there, right? Like you're doing something, you're being proactive, you're eating different foods in general, you give them a blinded challenge where you, you know, at random, you give them either food containing gluten or food containing, uh, non-gluten.

Perry: [00:31:30] And basically when you do this, you find that, let's see, 16 to 30% of those who believe they have gluten sensitivity get the symptoms reliably reproduced in blinded challenges. Now there's two ways to look at this. One is to be like, oh, that's like glucose. No one has non-celiac gluten sensitivity, but that's clearly not true. I mean, some people obviously do, you know, up to 30% of people who believe they have some non-celiac gluten sensitivity can reproduce [00:32:00] it in a blinded challenge, which means something is happening even if we can't see it in the blood. But it's also really important to realize that there's 70% of people out there that don't have a non-celiac gluten sensitivity. And I think it's important to realize that there's a heck of a lot more in bread products than just gluten. And it's so critical to determine if you're sensitive to something, what you might be sensitive for. Because as we pointed out at the beginning, cutting out gluten means cutting out a lot of really great, a lot of really great things.

Emily: [00:32:35] Yeah. Let me just double down on this point about how we do these blinded challenges, because there's also some, I think, very nice, what people would call, uh, nocebo evidence. So in these kind of trials, they give people in this case who are potentially gluten sensitive, they either tell them that they're getting gluten or tell them that they are not. [00:33:00] So there's a difference in your expectations. And then they either give them gluten or not.

Perry: [00:33:05] Oh, diabolical. Okay.

Emily: [00:33:07] The the people who so they they find here is that, you know, there's significantly more gastrointestinal symptoms. If you tell someone that they're getting gluten and they get it than if you tell them they're not getting gluten, but they do get it. So there's a sort of like the expectation is driving it. And moreover, the people who think that they're getting gluten and are not getting it look like the people who think that they're getting it and get it. So the in this particular study, the expectations about whether you were going to get gluten were much more important than whether you actually got it in driving the symptoms. Now, again, that doesn't mean that there aren't people I mean, this is like one study and there's variation across people. It doesn't mean that there aren't people for whom the symptoms deliver based on getting, getting the gluten and not on the expectations. But there is clearly in some of this either something [00:34:00] about another product that people are consuming or something that is effectively a placebo expectation.

Perry: [00:34:09] Right? Remember that your brain talks to your gut like this is not just. It's all in your head. In fact, your brain can make your small intestine and colon do things. You've actually all experienced this. Like when you finally get close to a bathroom that you like and then you have to poop. That is your brain telling you like, okay, it's like something is going on here. So the fact that expectation can induce GI symptoms is totally reasonable. And it's not like a psychology problem. It's how the brain works. Yeah. Um, but it's really critical to remind people that gluten travels in the company of several other molecules that can give you some gut distress. And I think the, the big one, and there are a lot, but under the sort of, it might not be the gluten that you're sensitive to are [00:35:00] the, the fructo oligosaccharides or so-called fructans. These are essentially chains of sugar molecules that you can't digest. Like you, humans lack the enzymes to digest these things, but the bacteria in your colon are more than happy to digest them. And when they do, they those bacteria produce gas and a feeling of bloating, uh, which, you know, certainly mimics a lot of the symptoms that people with non-celiac gluten sensitivity say they have. And the main source of fructans in the Western diet is wheat. So if you cut out gluten, you're by proxy cutting out wheat, and therefore you're by proxy cutting out fructans. But so you might feel better, but it actually wasn't the gluten all along. And if you knew that it was the fructans, you might do something different than than cut out gluten.

Emily: [00:35:52] That is true.

Perry: [00:35:53] Does that make sense?

Emily: [00:35:54] You might try is what's called a Fodmap diet, which is a specific kind of diet that eliminates these oligosaccharides, [00:36:00] but.

Perry: [00:36:02] Not oligosaccharides.

Emily: [00:36:03] Does not require an elimination of all gluten.

Perry: [00:36:05] Yeah. And just to hit on the theme again, like jumping to the conclusion, I should stop eating gluten like Seth Rogen in the beginning is often incorrect. Like the the way you should do this is potentially discussing with your doctor. But more importantly, in the situation like this, talking with a dietician, because there's actually a really defined pathway of trying different foods and recording your symptoms to sort of isolate what the sensitivity is. And that's such an important piece of knowledge. If you can actually dial it in, maybe it's gluten, but if it's something else, it's so important to know that.

Emily: [00:36:40] I think there's, I mean, there's a sort of step back on this, which is to say some of what's going on here. Almost a lot of what's going on is people are saying, you know, I'm not feeling great. I'm eating food and I'm not feeling great. I feel bloated, I feel nauseous, I feel fatigued, I have brain fog, and one of the possibilities is that it is related to what I'm eating, which in the case of gastrointestinal symptoms, it seems [00:37:00] like a totally reasonable assumption. And then the question should be what is it? And yes, gluten is one of the things that you would put on the list of possibilities. But actually, for most people, there's a lot of other things that you would want to have on that list. Maybe you'd want to have these saccharides, but also you might want to say like, maybe you're not having enough fiber, maybe you're not having enough hydration, maybe you're drinking too much. Maybe you're not drinking enough. Like there's various other possibilities. And so one of the, the sort of insidious things about this gluten business for me is that I think some people are having these symptoms and just saying, oh, it's probably gluten sensitivity. Let me just cut out all this gluten, which is both making their life worse because bread is delicious, but is also actually probably not fixing the problem as much as if they took a more holistic view around the symptom pattern and ask the question, what could I do to improve my symptoms? And this a little bit. What happens in this influencer space, which is people see, [00:38:00] you know, oh, I don't feel good. And then this influencer says, you probably have a gluten allergy. You know, everybody or you probably have a gluten sensitivity and, you know, make your tortilla out of cottage cheese instead of bread and everything will get better. And that could be delicious, but it might not fix your problem.

Perry: [00:38:16] Uh, absolutely. And I think, you know, there's obviously an entire industry, a gluten free industry out there. You can buy gluten free tortillas and gluten free bread and gluten free pasta, um, and all that stuff. It's worth noting that in general, these gluten free foods are, are more processed. They're, they're more in the ultra processed food spectrum. They tend to be lower in fiber, lower in folate, generally higher in fat and sugar, and 2 to 3 times the price. So there is like a cost to be paid for switching into a non-gluten framework. There have been some studies in, uh, of rice flour. Um, I'm pulling something from the journal epidemiology from 2017, looking at the unintended consequences of a gluten [00:39:00] free diet. And one of the things they found was higher arsenic and mercury levels in the urine, because rice flour tends to be slightly more contaminated with arsenic and mercury. So yeah, don't don't jump to conclusions here. You might regret it.

Emily: [00:39:15] Yeah. And I think also we sort of see one of the things people are constantly reporting is that their gluten sensitivities are better when they are in Europe.

Perry: [00:39:22] Oh my gosh, I've had friends say that. Yes, yes. Yeah.

Emily: [00:39:24] Like in the flours different. The croissants are different. Like, well, French croissants definitely have gluten in them. Now. They may be cooked differently. The wheat is different, but there's no question that they they have. Like if you are a person with celiac disease and you eat a French croissant, you will feel like crap the same way that you will if you are an American American croissant like no difference. And so this suggests either for some fraction of these people, there's something else in the food environment that is different. Maybe there's something about the interactions with stress. Maybe there's like maybe there is something else going on, [00:40:00] and maybe there's something about the difference in the way the flour is processed. But my strong instinct is it's actually some other things.

Perry: [00:40:08] Yeah. The epidemiology of both celiac disease and non-celiac gluten and gluten sensitivity is the same in Europe and the US. So there's just as many. It's not like, oh, that no one has celiac disease over there. They they do in the same rate as we do. So yes, everything tastes better in France 100%. And we should we all feel better when we're in France. I can speak from personal experience there, but it's probably not anything magic that they're doing with their with their wheat.

Emily: [00:40:36] I just feel like if people are not. I, I have a hard time expressing this, but I feel like this has gotten in the way of people improving how they feel because it has given people an easy answer that companies are obviously delighted to take advantage of by saying, oh, you know, you can buy our gluten free crackers and, you know, you can buy our gluten free bread and gluten free this and that. And the other thing and that it has gotten [00:41:00] people into a space where they're not actually trying to figure out what's wrong, they're just defaulting to, to something which may or may not really be the solution. And that feels bad to me.

Perry: [00:41:11] Uh, yeah. And these symptoms, because they're amenable to both the placebo and nocebo effect, you might feel better by switching, even if it has nothing to do with wheat at all. Even if your symptoms are due to like, you aren't getting enough fiber. The very act of taking initiative and switching all your bread to gluten free bread that has an expectation to it that can have placebo effects as well. They tend to not last forever, and I've had plenty of friends and patients and stuff who have been gluten free for a period of time, and then things start creeping back in like symptoms start creeping back and people start to realize, you know what? Like maybe it wasn't the gluten and, and at that point in time, they actually do what is, what's real work is to figure out what you're sensitive to. It's not something that you're going to do overnight. It takes like kind of documentation of symptoms and very specific dietary changes over time. [00:42:00] But once people do that work, they're generally happy that they did.

Emily: [00:42:04] Yeah, but it is work.

Perry: [00:42:06] Um, I, as per tradition, tried to find a study that would show that avoiding gluten would improve your athletic performance so that I could get Emily to be gluten free for the next ten years. And I failed. All I found was a study appearing in the journal Medicine and Science in Sports and Exercise in 2015, which took 13 endurance cyclists and randomized them in a crossover fashion. So they went like a couple of weeks having gluten and a couple of weeks not having gluten, and then did time trials. And nope, they were just as fast and just as endurance as they, regardless of what their gluten intake was.

Emily: [00:42:45] I'm actually shocked that this did not go in the other direction. Oh, given that, I would think it would be hard to maintain the kind of carbohydrates that you need, uh, without, you know, gluten containing products. So I guess these guys probably just ate a lot of rice. [00:43:00] Uh.

Perry: [00:43:01] I think they had a dietician. I think they were, uh, calorically equivalent.

Emily: [00:43:06] Yeah, yeah, yeah. I know, uh, very few endurance athletes who don't, who are, who avoid gluten because it's just hard to get enough carbohydrates and sugars.

Perry: [00:43:17] Yeah. Um, I also checked because people ask, like, is there a difference between organic wheat and non-organic wheat? And the answer is not in terms of gluten. They both have gluten.

Emily: [00:43:28] Um, but it could be something else that's like, there could be something else between these things that are bothering, that are bothering you. Yeah, I don't know.

Perry: [00:43:36] Yeah. Talk to a dietician and work it through.

Emily: [00:43:39] Yeah. If you are having these, here's my takeaway here. And then we can smash or pass is if you are having symptoms like this, you should be tested for celiac. And if you don't have celiac, you should do something broader to try to figure out what's bothering you rather than just eating [00:44:00] some Mary's crackers, even though there. It's a very good kind of cracker.

Perry: [00:44:04] Not Ned, but but send us some Mary's crackers.

Emily: [00:44:08] All right. Perry, are you a smash or pass on gluten?

Perry: [00:44:12] I'm a smash. I'm a lover of pasta, a lover of bread. I feel for all of you who have any form of gluten intolerance, whether it's celiac disease or otherwise. And I implore those of you who might just be assuming that they have gluten intolerance to try to figure it out for 100% certain, because a life without gluten is just a lot less happy than a life with gluten. Emily. Smash or pass.

Emily: [00:44:40] I'm a smash. All my favorite foods contain gluten and I will ditto you that I think, uh, I love people to just make sure that this is what's going on with you and maybe you'll be able to have gluten. All right, that's it for gluten. Mailbag. Question of the week. After the break.

Mailbag: [00:45:01] Hi, [00:45:00] Emily and Perry. This is Ellie.

Mailbag: [00:45:04] And I'm Josh.

Mailbag: [00:45:05] And we're calling from Toronto. Our question is, is coffee really bad for kids? Does it really stunt kids growth?

Mailbag: [00:45:14] Like, would it hurt if I love it to drink a bit?

Mailbag: [00:45:19] That's our question.

Perry: [00:45:20] Emily. Do your kids drink coffee?

Emily: [00:45:22] My kids don't drink coffee because they tell me that they see how dependent I am on coffee, and they don't want that for themselves, which I think shows a level of maturity I have not achieved. Um, what about you?

Perry: [00:45:37] My 16 year old will occasionally, um, but but not too often.

Emily: [00:45:45] Coffee does not stunt kids growth. This is a myth. Uh, it's.

Perry: [00:45:50] I've 100% told my kids this, by the way. 100%. Totally not knowing. It's not true.

Emily: [00:45:56] Turn this off in front of your children. It's a myth. Um, you know, I [00:46:00] think there are reasons to not give your child coffee, which are that it you can develop a tolerance for caffeine and then you will need it. And that's not a terrible that's not a terrible thing. Uh, but you it may not be something you want to develop in a child. And particularly since many of us use caffeine to address our lack of sleep, I would urge you to make sure your children are sleeping enough so they don't need coffee. And definitely they should not have coffee at the end of the day, because it does interfere with sleep, even if it doesn't interfere with growth.

Perry: [00:46:36] So well said. Um, one note that teenagers and kids are getting most of their caffeine Not from coffee these days. They're getting them from energy drinks and sodas. And those are also not good for kids.

Emily: [00:46:50] And actually those and like that Celsius energy drink that has a lot of caffeine in it, arguably more than coffee. So people do want to be pretty careful, pretty [00:47:00] careful about those. Do you, did you I know you're probably this is not going to be for you. Did you watch if you watch saved by the Bell.

Perry: [00:47:06] I mean I remember sure I remember saved by the bell and and.

Emily: [00:47:09] Do you remember the episode? Do you remember the episode where Jessie Spano gets addicted to the caffeine pills?

Perry: [00:47:14] Yeah, yeah, yeah. They were like, we can't do real drugs, but this is going to be burned.

Emily: [00:47:20] This image of Jessie Spano, like dancing around her room because she's had too many caffeine pills. It's like burned into my mind forever. And I have in high school, even though I was tempted because I was not sleeping anywhere near enough, I would never have ever taken caffeine pills because of that. Saved by the Bell episode. Stay off drugs, kids.

Perry: [00:47:39] Oh my God, it worked, it worked. On a very special episode of saved by the Bell.

Emily: [00:47:45] Yes! Oh my God, that was so great. All right. Well, uh. Well, Josh, uh, it's probably not a good idea for you to have too much coffee, but it's not going to make you short.

Perry: [00:47:58] All right, that's it for us today. Stick [00:48:00] with us next week when we'll ask, what's the deal with fluoride? Oh, we're gonna get some emails about that one. People get upset about fluoride.

Emily: [00:48:11] Well, this actually is produced in association with iHeartMedia. Our senior producer is Tamar Avishai. Our executive producer at iHeart is Jennifer Bassett. Our theme music is by Eric Deutsch, and our content is for educational purposes only.

Perry: [00:48:25] If you like the show, help other people find us. Leave a rating and review on Apple Podcasts or your podcatcher of choice and help us spread the word about the show. You can follow us on Instagram at actually pod. And don't forget, we want to hear from you. Head over to wellness.fm and leave us a question for our mailbag, or suggest a topic for a future show.

Emily: [00:48:47] We'll let the influencers have the last word.

Jessie Spano: [00:48:49] No time. There's never any time. I don't have time to study. I'll never get into Stanford. I'll let everyone down. I'm so confused.

Zack Morris: [00:48:58] Jesse! Hey, hey, [00:49:00] just calm down. It's okay.

Jessie Spano: [00:49:02] You're right.

Zack Morris: [00:49:03] It's okay.

Jessie Spano: [00:49:03] Everything will be okay. I just need one of these pills.

Zack Morris: [00:49:07] You mean you really are taking drugs? I need them, Jesse. Give me those.

Jessie Spano: [00:49:10] I need them, Zach. I have to sing.

Zack Morris: [00:49:12] Jesse. You can't sing tonight.

Jessie Spano: [00:49:14] Yes, I can. I'm so excited. I'm so excited. I'm so scared.

Zack Morris: [00:49:25] Jesse. Jesse.