Should you worry about gluten?
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Hello, and welcome to Zoë Shorts, the Bite Size podcast where we discuss one topic around science and nutrition. I'm Jonathan Wolff, and I'm joined by my friend, Dr. Will Bulsiewicz. And today we're talking about gluten. There's a lot of fear mongering out there about gluten. Gluten is bad, is the message we're getting. Everywhere from the supermarket to social media, and all this anxiety can make it hard to get to the truth. So Will, is gluten really as bad as everyone seems to think?

There's now a good amount of science on gluten. And also, there's a lot of myths. So I think there's a clear answer, Jonathan, and we're going to get into it. All right. I want to hear it.

We need to start, Jonathan, with what gluten actually is because there's so much misinformation. Picture a chef stretching out a ball of dough at your favorite pizza joint and they're tossing it up in the air to make that perfect pizza base. Without gluten, the dough would tear. So it turns out that gluten is a protein that's naturally found in certain plants such as wheat, rye, and barley. And cooks have loved it for millennia because it helps food keep its shape.

Gluten actually comes from the Latin word meaning glue, and humans have been using its properties for long before even the Romans, it turns out, will. So apparently the remains of flatbread baked by hunter-gatherers 14,000 years ago have been found by archaeologists in Jordan. And the gluten helped combine all the grains into a bread, which is presumably a lot easier to carry around on a hunting trip than a bunch of seeds.

Especially since you didn't have any sort of bag to carry those seeds that easily back then. But anyway, it's quite difficult to separate gluten from the wheat, barley, and the rye. So anything that contains these ingredients could potentially be problematic. And problematic because gluten is bad for you, right, Will? It causes gas and bloating and a whole host of other digestive issues. Well, no, that's not strictly true. What you're probably thinking of is celiac disease.

As I understand it, Will, celiac disease is a very serious inflammatory condition that affects the small intestine and its ability to absorb nutrients. People with the condition can't consume gluten because it's actually going to trigger their immune system. Correct. It was identified by a pediatrician during the Dutch famine of 1944 who noticed that his celiac patients improved with the strict flour rations.

Untreated celiac disease can lead to severe diarrhea, abdominal pain and bloating, malabsorption, infertility, weight loss, and even iron deficiency anemia. It causes chronic inflammation inside the intestine, so over time it could potentially lead to cancer, even though that's very rare.

So it's an incredibly serious disease. And actually, I remember my wife talked about it with patients that she's seen in the past and just sort of how serious it is. Now, this is something that you can go to the doctor and actually get a blood test. Is that right, Will? It's important for people to know, Jonathan, that the testing doesn't have to be invasive, particularly upfront. Many times, the right place to start is with a blood test. And the blood test can provide insights. And there is some additional confirmatory testing that may be required, but usually that's where we would begin.

And what's the treatment if you are diagnosed with celiac? Well, there's really only one treatment. It's very clear. And that is the strict elimination of gluten from your diet. You have to be gluten free. And it's estimated that celiac disease affects at least one in 100 people in both the UK and the US. But interestingly, only about 30% of these people are currently clinically diagnosed.

I actually find that really shocking, Will, that you're saying maybe 70% of people are not diagnosed given that it is such a serious disease and that you can change your diet to have such a profound impact on your symptoms. However, if it is only one person in 100 who has it, why do so many people think that gluten is bad for them?

Partly it's the general awareness and some of the fear that comes from the serious effects of celiac disease. There's no doubt about that. But at the same time, there were some studies done that raised concerns about gluten going back about 15 years ago, Jonathan, that concluded that gluten is inflammatory and it causes bowel damage, which of course fans the flames of the sort of gluten is bad narrative.

But the thing that people need to understand is that those studies were done in labs with rats or in test tubes. There's actually very little robust or high quality evidence showing that gluten is bad when real humans eat real food.

It's interesting because we talk often on this podcast about how you have to be very careful before you assume that a study done on animals also applies to humans. And it sounds like we need to be very careful here when we're accepting those studies about gluten as the truth for human beings. Absolutely. And here's the complicating factor. Some people do, in fact, have an adverse reaction to gluten-containing foods that's not due to celiac. And they might experience fatigue.

or bloating, abnormal bowel movements, or even a rash or neurologic symptoms. So if it's not celiac disease, why the adverse reaction? Well, there's three possibilities for a person who's having this type of adverse reaction, Jonathan. So I want to run through them if we could.

Number one, you have side effects when you eat wheat, but importantly, not when you eat rye or barley. So the first thing that you need to do in this case is to make sure that you don't have celiac disease. Any person who has a reaction to these foods should be tested for celiac.

But if there are symptoms only when eating wheat, that's more likely to be actually a wheat allergy. Got it. And I guess you do have symptoms when you consume gluten that are similar to celiac disease. So you're feeling bloated and you're getting abdominal pain, but you're not seeing the positive blood test or some other evidence for the doctor. So does this exist? Yeah, this definitely exists. These are patients that I've taken care of

thousands of times throughout my career. This is actually the most common scenario among people who have some sort of symptoms when they consume gluten containing foods. And Jonathan, what we call this is non celiac gluten sensitivity, or you could also call it gluten intolerance. And there's something really interesting about this. It turns out that this condition that we're calling gluten intolerance, it may not be the gluten at all. You see, wheat, barley and rye

these foods aren't just a big ball of gluten. They contain other nutrients. An example of this are fructans. Fructans are a type of fiber that are called a FODMAP found in gluten-containing foods. People may have heard of the low FODMAP diet. They did a recent study comparing the effects of gluten and fructans to a placebo. And what they found was that when people consumed gluten, it had no effect on their symptoms at all.

But on the flip side, when they consumed the fructans, it actually triggered their symptoms. We usually attribute these symptoms to gluten, but we probably should be attributing them to the fructans instead.

That's really interesting because what that means is there might be lots of people listening to this right now who think that they have this intolerance to gluten, but actually they're intolerant to something else. And in which case, switching to gluten-free food is a horrible mistake because it's just going to eat lots more sort of ultra processed food for no benefit. Exactly. And if you have symptoms eating bread, I have sort of an interesting way that you could approach this to test at home.

And the way that you do this is by eating sourdough bread, because it turns out that sourdough bread is low in fructans. So like the fermentation process will reduce the fructan content, but the sourdough bread still contains gluten. So if you consume sourdough bread and you have no side effects, then you may have an inversion to fructans rather than gluten, which means that the good news, here's the bright side, you get to enjoy lots of yummy sourdough bread.

Brilliant. So that was the first and second category. What's the third category, Will? The third category actually manifests outside of the digestive system. And it could be things like neurologic symptoms, like poor muscle control or difficulty with balance. We actually have a term for this. It's called gluten ataxia. Or it could be a rash with itchy, fluid-filled spots that are occurring on your forearms, on your knees, potentially your scalp or your bottom.

We call this dermatitis herpetiformis. Now, these things, just to be upfront, they sound scary. It's important for people to know they are extremely rare. These are far less common than celiac disease. And in fact, actually, in the vast majority of these people, if you test them, you will find that they do actually have celiac disease. It's not just happening without the celiac. So either way, the solution is a gluten-free diet. They both resolve on a gluten-free diet.

All right, then, Will. So what have we learned from all of this? Is gluten really as bad as we've all heard? From what you've told me, it seems like gluten for most people is not necessarily bad, despite the huge numbers of people who've been cutting out of their diets over the last decade. Yeah, there's actually, believe it or not, evidence that would suggest that gluten-containing foods should be a part of a healthful diet.

There's a 2017 study, Jonathan, of over 100,000 participants. And now it's important to point out that these people did not have celiac disease. And when they took a look, they found that there was no association between consuming gluten and the risk of heart disease. You would assume if the gluten was truly an inflammatory food, it would increase our risk of these conditions. But in fact, in the study, those people who avoided gluten, they actually increased the risk of heart disease.

Most likely what's happening here is that they're reducing their whole grain consumption when they go gluten-free. This is problematic because whole grains contain many nutrients. They could contain gluten, but they also contain many nutrients like fiber or B vitamins, magnesium, and iron. So believe it or not, even the fructans that you and I were just speaking about a moment ago and saying, yes, these fructans can cause your symptoms. The fructans actually are a form of fiber. They're prebiotic and they feed our good gut bugs.

And I think one of the things that is now clear to me that wasn't at all before is that if you are self-diagnosing yourself as needing to eat gluten-free food and that isn't required, that basically you start to switch to all of these things that you can now buy in the store that say that they're gluten-free. Most of these foods are incredibly processed. So like ultra processed, as we would say. And so you are swapping out

foods that might be whole grain that have all of this fiber for these things where we now know that not only are you potentially losing some of these nutrients, but actually these ultra-processed foods can be very bad for you with these emulsifiers and sweeteners that can affect your microbiome. You're trying to do something really good for your health, right? You understand this thing is bad. Your

actively making these positive choices to buy this food that says it's gluten-free and actually you're taking something which is going to turn out for most people to be worse for them than if they hadn't made this swap. And am I catastrophizing here or do you think that's fair? Yeah, I think that striving towards a diet of abundance where we really prioritize getting a wide variety of different foods, particularly plant foods into the diet, that's a central thing

philosophy with zoe i think one of the other things with zoe is quality quality is important and even whether we're talking about gluten-containing foods or gluten-free foods either way one of the central messages that should be taken away from our podcast today is that the quality is important so if you're opting for gluten-containing foods you want the high quality gluten-containing foods you want that whole grain sourdough bread you want that rye bread you want that barley

And if you're opting for gluten-free foods, this is where, once again, you just need to be cautious not to be opting for those ultra-processed choices. That's right. And you're probably not wild on gluten having been separated by the food manufacturing process in order to stick into a bunch of other foods as a glue, right? Like, I don't think at all. I mean, one of my takeaways is there's nothing you're saying here to say like gluten is a magically good property of a food. Is that right, Will? It's more that there's no reason to think that it's harmful for most people. Yeah.

I think it's looking at the entirety of the food, Jonathan, and understanding that this food is more than just gluten containing. And so that food matrix contains so many other factors that we've touched on that include fiber and vitamins and polyphenols. And this is why let's not focus so much on the gluten and lose sight of the big picture, which is like what happens when you eat a piece of sourdough bread? Does it nourish your body? Does it feed your gut microbes? The answer is yes. So let's enjoy that.

Wonderful. In my case, not too often, but absolutely. Well, I think the myths about gluten are really pervasive. I think that a lot of people will have, like me, learned a lot from this episode. So it's been great to really get into the science and I look forward to exploring more of this in the future.

If you've been listening to this episode and you'd like to try Zoe's personalized nutrition program to understand your own biology and understand what to eat to improve your health, you can get 10% off by going to joinzoe.com slash podcast. I'm Jonathan Wolfe. And I'm Will Balshawitz. Join us next week for another Zoe podcast.