[Listen to this interview on the Earth Eats podcast]

Intro

Alex Chambers:So Kayte, you eat gluten?

Kayte Young: Uh, yeah.

AC: And I know this partly because you make incredible pies.

KY: Yeah, Pie.

AC: And also you may emember we taught a bread class together?

KY: Yeah, you can't make bread without gluten!

AC: No, you can't. Do you know a lot of people who are avoiding gluten?

KY: Yes. a lot.

AC: It's crazy to me how many people I know who are avoiding it. My mom, my brother. I was in New York a couple of weeks ago, visiting a couple of childhood friends and both of them are avoiding it. One of them said to me, you remember how I used to be lactose intolerant? And I said yeah, I actually do remember that. And he said, "It turns out, I got tests a while back and I'm actually gluten intolerant, not lactose intolerant."

KY: Oh, wow. Well it can be hard, when you're a baker and your friends and family don't eat gluten

Alex: It's a real bummer!

KY: Yeah.

AC: Although it's probably more of a bummer for the people who can't eat it.

KY: Yeah, and I do wonder what's going on with that...the increase?

AC: Yeah, I know, it's really interesting, I've been wanting to figure it out, too. So I talked with Andrea Wiley, who's been on the show before, and Christa Voirol, who's been collaborating with her to try to answer that question.

KY: Great! What'd they find out?

AC: It's complicated.

KY: I figured.

AC: So, there's Celiac disease, which is an immune reaction to gluten, affects about 1% of the general population. But you don't have to have celiac to have a problem with wheat, and so many people are feeling better without wheat that sales of gluten-free products almost quadrupled between 2011 and 2015.

So many people are avoiding the stuff that some doctors are warning their patients against a gluten-free diet if they don't have celiac disease since it usually means replacing whole grains with more highly refined starches from potatoes, tapioca, and rice.

KY: yeah, I could see that.

But other people feel like those doctors are discounting their own experience of feeling better by avoiding wheat. That's what I was trying to understand when I invited Christa and Andrea into the studio.

Interview

Alex Chambers: So, if you could each just start out by introducing yourselves?

Christa Voirol: My name is Christa Voirol, and I'm a senior at IU and a Cox research scholar, and I've been working with Dr. Wiley now this will be my fourth year, on our gluten project.

Andrea Wiley: Oh yeah, so I'm Andrea Wiley, I'm professor of anthropology here at IU. I am a biological anthropologist, so I'm interested in human evolution and human biological variation. My particular interests are in the role that diet has played in shaping human evolution and human variation.

AC (voiceover): Andrea Wiley's been on Earth Eats before, talking about her research on milk. But whereas the main problem with milk is lactose intolerance, it seems to be more complicated with wheat.

AW: there's a spectrum of wheat intolerances, and there are 3 major categories. There's celiac disease, which is like an autoimmune disease. So when you consume gluten your immune system essential starts to attack the cells of your small intestine and eventually it destroys them. So that is one end of the spectrum. There's wheat allergy as well, which is also immunologically driven, but it is driven, it's mediated by a different part of the immune system, the IGE system, and the mechanism is similar to any kind of food allergy. And that's not particularly common. It's more common among kids, as are most food allergies. And then there's this other category that is called non-celiac gluten sensitivity.

CV: Yes. Some researchers have also considered adapting the name to non-celiac wheat sensitivity, but you can also kind of run into problems there because wheat is not the only gluten-containing grain. Also popular gluten-containing grains are barley and rye. So, there's also a naming issue as well as kind of an identification issue.

AC: So, we've seen that that celiac itself has actually increased, and it's not just due to better diagnosis. There was that study of the, where they took the blood samples...

AW: The army recruits!

AC: ...from, they were taken in what the 50s? And saw that the rates of celiac in their blood samples, or the indicators for celiac was way lower than what we're finding in similar populations now. So celiac is on the rise.

CV: When you look at celiac on its own and, for example in that study of army recruits, it can seem really alarming. But when you look at it within the context of other autoimmune diseases, other autoimmune diseases are also on the rise at the same or similar rates as celiac disease.

AW: Or at least it's part of the package right? So the question becomes why are autoimmune diseases in general on the rise. And there are a number of hypotheses for that. I would say, thinking about more of the cultural stuff I think it has to be put in the context of interest in low-carb diets, for one thing, that began in the ‘80s and ‘90s, with Atkins at the start, where you're really eliminating things like bread from your diet, and people had, some people report great success in removing carbohydrates from their diet, and now that has transformed into the Keto Diet, and of course there's the Paleo Diet, and all these diets would eschew wheat or grains of most kinds, so I think that's a strand, and there's probably some conflation in people's minds about gluten and carbohydrates, right, that 'oh well, bread has is carbohydrates and oh I've also heard it's got gluten in it' and so collectively those become things that you can eliminate from your diet if you're trying to achieve weight loss for example.

AC (voiceover): The number of people avoiding gluten has turned out to be a big market opportunity. I mentioned to Andrea and Christa that by 2020, the sales of gluten-free products are projected to be almost 24 billion dollars.

AW: That seems an incomprehensible number. So clearly-

CV: Someone's buying them, even if maybe the numbers seem low, or maybe someone isn't willing to say that they're adopting a gluten-free diet, or maybe not entirely, to the point that they would want to answer that on the survey, but people are buying gluten-free products.

AW: Whether they are self-diagnosed or otherwise diagnosed as gluten sensitive, perhaps there is a larger sense that 'mhm, maybe gluten is something to be avoided. And hence, given a choice between two products, one that doesn't have the gluten-free label and one that does, I choose the gluten-free one, because it carries some kind of health halo. And so it must be, I didn't know that gluten was bad but if it doesn't have it, then that seems good.' It's not an uncommon marketing ploy when it comes to food labeling.

AC: Yeah, I mean that health halo goes beyond food. I get this shampoo that I use, it's sort of an eco-friendly shampoo, and it's gluten-free also, apparently.

AW: [laughter] Yeah, so it's, clearly gluten has some cultural currency right now, and some real currency. You know, one of the things the wheat industry says is that, and I, this is true in my limited experience, is that gluten-free products are more expensive, and so we want to be careful, you know there are probably lots of people out there consuming gluten-free foods who don't need to be, and so they're essentially wasting their money. Again, that's the wheat industry's line in this. Obviously they have an interest in minimizing this, and eager to see this trend go away.

AC (voiceover): But while the popularity of gluten-free diets suggests it's the latest fad diet, a lot of people are experiencing discomfort, and researchers are trying to figure out why. One of those questions is whether the problem is the gluten, or something else.

AW: So there are other components of wheat that people seem to be sensitive to as well. There are enzymes in wheat that seem to trigger intolerant symptoms, there are also...

CV: Carbohydrates as well.

AW: Yeah, there's this whole category of, what would you call them, food constituents called FODMAPS which you may or may not be familiar with, which are sugar molecules of varying sizes and complexity

AC (voiceover): FODMAP, by the way, stands for "fermentable oligosaccharides, disaccharides, monosaccharides, and polyols," in case you were wondering. Okay, back to Andrea.

AW: And wheat has a number of those as well. And FODMAPS have been shown to have some of the same symptomatology as gluten intolerance, and there are a number of studies where if you take people who say they're gluten intolerant and reduce their FODMAP consumption they actually get better, even when you reintroduce gluten, so there is some confusion about whether gluten is-it surely is, but is it the only constituent of wheat that is bothersome.

AC: And another reason it's hard to figure out whether it's gluten, or FODMAPs, or something else, is that the only way to figure out whether someone has non-celiac gluten sensitivity is by how they report their symptoms.

AW: Right now there is no biomarker either for nonceliac gluten sensitivity. So, that is one of the key problems in the field right now. So it's really all done by well, if you take gluten out of someone's diet, do they report feeling better. Do they report a reduction in their symptomatology, and then it becomes very important to run a double blind placebo study, so that people aren't simply reporting 'well, yeah, I removed gluten and I'm feeling great.' And those studies that have kind of looked at FODMAPS vs gluten in a blinded way have found in some cases that the FODMAPs are the problem and that when people are eating gluten and not knowing it they're actually doing okay. For some studies. Other studies show the opposite. And so there's no biomarker, and there's no – the evidence isn't all converging, at this point, which makes for a very messy science right now.

AW: A strand of this too is kind of this trust in science and skepticism of science, and I think we're at a particular moment in our history where that is really kind of coming to a head, and I always find it kind of interesting, you know in a political sense, I have many colleagues who will defend science and its benefits against the current skepticism, but have their own kind of, again we are our own experiments, and so in my, I have this particular experience, it doesn't match up with the science, and so I, what am I trying to say here, I privilege my own experience over the science. And that's fair, in some respects, science only tells you about probabilities of things, they don't tell you about experiments of one, and I think gluten is a good example where, you know, skepticism and science kind of ride, skepticism of the science, skepticism of this as a real phenomenon, are present with science trying to figure out what this is.

AC (voiceover): In other words, it's really hard to tease out the cultural aspects of this from the biological ones. Are we thinking we're feeling better because we've been hearing for decades that carbs are bad for us? Is there something about our immune systems that are having more trouble dealing with wheat than we used to? Or is there something different about the wheat itself? There's good evidence for all of these things, even though they seem like they would cancel each other out. What's to be done? Well, one thing I would say is, don't pay too much attention to individual studies. As Andrea pointed out, they're pretty quick to contradict each other. When you can, eat whole grains. There's consensus on that. As for wheat, and gluten, and FODMAPs, do what works for you. The research is probably going to converge eventually. The scientists-and the anthropologists-are on it.