Dr. Stefano Guandalini on the rise of celiac disease
To the general public, celiac disease and gluten sensitivity came out of nowhere in the past few years. Few people had ever heard of gluten, then suddenly grocery stores were filled with gluten free products and restaurants everywhere were touting gluten free dishes and separate menus. But to Stefano Guandalini, MD, founder and medical director of the University of Chicago Celiac Disease Center, celiac disease is nothing new. He has spent the past 40+ years studying the disease, now estimated to affect 1 percent of Americans, and working toward what he believes will be a cure within the next decade.
We spoke to Dr. Guandalini recently about the seemingly sudden rise in celiac disease, what might be causing it, and what he sees in store for treatment
Let's start with the basics. People with celiac disease can't tolerate gluten, but what exactly is gluten?
Gluten itself is a protein that has been in wheat since it was cultivated about 10-12,000 years ago, when the agricultural revolution began and men began to become stable and raise their crops. It is the main protein component of three cereals: wheat, rye and barley. It comes in three slightly different varieties, but more or less these three grains contain what we define as gluten.
Human beings simply do not have the enzymes necessary to fully break down this protein, so as a result, some of these peptides, or pieces of the protein, remains undigested in our gut. If you're healthy, this is not a big deal. They're just eliminated and that's it, end of story. But if you have celiac disease, these peptides are actually dangerous because some of them may cross the intestinal barrier and get in touch with the immune system, and then this starts a series of events which leads to the damage.
Celiac disease and gluten sensitivity have been on the rise recently. Why is this happening? Is there more gluten in the wheat produced today?
They are more frequent than they used to be, and it's a common belief that modern wheat contains more gluten than wheat that was available 100 years ago, for instance, and because of this we are exposed to higher content of gluten if they eat the same amount of wheat. Well, let me tell you this is false. It's simply not true. At the 15th International Celiac Disease Symposium last fall in Chicago, Don Kasarda, who is a scientist working for the USDA in California, presented data comparing wheat cultivars from the early 1900s with modern wheat cultivars, and he was able to show that the average gluten content was in exactly the same range, roughly between 10 and 15 percent. So 10 or 15 percent of the whole wheat is represented by gluten, and this has not changed with time.
Another common rumor is that people believe that the wheat we now consume is not the same wheat as 100 years ago because is has been genetically modified. Well let me make the record straight: There is no genetically modified wheat commercially available in any country of the world as we speak today. True, through breeding and cross-breeding-which farmers have been doing of course for centuries-different varieties have been generated, but the gluten content has not changed in quality or in quantity. So this is also a rumor which is not founded.
A third myth is that people think that we are eating more wheat in this country in general, that maybe the gluten hasn't changed but we are eating way more bread than we did 100 years ago. Once again, Dr. Kasarda was able to produce data showing clearly that the amount of wheat consumed per capita in the year 2000 was actually half of the wheat consumed per person in 1910. He estimated there was about one loaf of bread on the average consumed per day by every American in 1900, and we now are down to 0.6 loaves of bread. So there is no increase in wheat or gluten in the wheat. We have to search elsewhere to find an answer to what is actually causing this widespread increase in the prevalence in celiac disease.
Do you have a theory as to why there is such an increase in celiac and gluten sensitivity?
I actually endorse one of the prevailing theories that goes back to the so-called hygiene hypothesis that because of the cleanliness of the society in which we live, that between birth and the first 18 months or so of life, our babies are not exposed to the same amount of antigenic load that mother nature expected, so not enough dirt, in other words. Everything is kept clean and has to be sterilized. We make sure our babies are not in touch with any dirt or put something dirty in their mouth.
Now the good about that is of course we have almost eliminated a number of infectious conditions that might've otherwise been predominant. But the bad news about this habit is that our gut immune system, which develops and directs the development of the whole immune system of the body, not being exposed to that kind of antigenic load by bacteria and other compounds that were supposed to be there, has developed in a way in which its response is skewed towards developing autoimmune and allergic diseases.
Celiac is an autoimmune condition, and it is not the only autoimmune condition that is increasing in prevalence. For instance, type 1 diabetes is following the same trend too. So I think this theory has some reason to be believed, and there are some data and epidemiological support for it. For instance, in developing countries where socioeconomic conditions don't allow for this extreme cleanliness, they almost don't know the existence of autoimmune or allergic conditions. And when the same country develops, for instance like in northern India where this has been documented, then this disease is there to strike.
How many Americans do you think have celiac, either diagnosed or undiagnosed?
The current estimate is a number close to 1 percent. Therefore out of 300 million Americans, you can roughly expect about 3 million of us have celiac disease. The problem is that only about 15 to 17 percent or so of the expected celiac cases are actually known, so roughly 85 percent of those that have celiac disease in this country are not diagnosed, and this is a problem. We are lagging behind the rate of diagnosis in other countries. For instance, in the Scandinavian countries, the rate of diagnosed patients is around 40 percent. Even there, though, the majority of those that have celiac disease remain undiagnosed.
Why are so many people undiagnosed?
One reason in this country is lack of awareness by physicians and the general public, although this is increasing, I must say. But the other is that with time we have come to learn that celiac disease can present itself with minimal, and sometimes even no symptoms. So you may have full-blown celiac disease, like your intestine being damaged, and yet have no symptoms. We call this silent celiac disease. It's a well-known presentation, and we have come to learn about it by screening patients that were at risk for celiac-for instance, first degree relatives of celiac patients-or patients that have other conditions that are known to be often associated with celiac, like type 1 diabetes or down syndrome. And if you have no symptoms you don't go to the doctor and ask to be screened.
Do you think one percent of the population with celiac is more, less or the same as 50 to 100 years ago?
Looking back, studies have shown that the prevalence was actually only 0.2 percent in the early 1950s. So there is an increase, a doubling about every 20 years in prevalence. This is exactly the same rate of increasing prevalence that has been found in some European countries, so this is a general phenomenon that we have seen everywhere. Whether it will continue to increase at this pace, so in 20 years we'll have 2 percent instead of 1 percent, I can't tell you. I don't have a crystal ball here. But it's reasonable, unless we understand fully what are the factors that cause this increase.
What worries me more than increased prevalence is the fact that 85 percent of Americans remain undiagnosed. I think we all can do a better job in thinking of celiac disease every time there is a condition-and there are many-that will suggest it. We need to do a better job in screening for celiac disease.
Why do you think diagnosis is so difficult for celiac?
Diagnosis of the disease is both difficult and easy. It's easy if you have in your mind a high degree of suspicion for this condition, because celiac disease can present itself with a variety of symptoms. We used to call typical or classic presentation the gastrointestinal symptoms, mostly chronic diarrhea, abdominal pain, weight loss, or in children "failure to thrive." This still of course remains the way in which celiac disease can manifest itself, but we have learned that there are so many other ways that celiac can present itself, and many individuals are not mindful of that. Colleagues should be paying more attention to the many different ways in which celiac can present itself. For instance, joint pain: Six percent of children that have arthralgia or even arthritis, obvious objective inflammation of their joints don't have juvenile rheumatoid arthritis, they have celiac disease that is responsible for that. In diabetic children, 10 percent of them have celiac disease. If we don't screen these individuals, we will never know if they have celiac disease. It requires a high degree of suspicion and knowledge of the fact that celiac can present in many different ways, and listening to the parents when they tell you.
Stefano Guandalini, MD
Stefano Guandalini, MD, is the founder and medical director of the University of Chicago Celiac Disease Center, and Section Chief of Pediatric Gastroenterology, Hepatology, and Nutrition at the University of Chicago Medicine.See Dr. Guandalini's bio