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Gluten-free diets: In celiac disease absence, a source of confusion, uncertainty

Benjamin Lebwohl

The phrase “gluten-free” has become ubiquitous in American diet culture, and is a fixture in grocery store aisles, cookbooks and restaurant menus. Regardless of whether consumers truly understand the objectives of this diet or the specific population it is designed to serve, “gluten-free” seems to have become a catch-all synonym for “healthy.” Gluten-free weight loss diets are widely promoted and adopted, and diets eliminating wheat have been suggested as a means of reversing medical conditions from high blood sugar to minor rashes.

This surge in popularity is borne out by recent data. For example, in 2016, an analysis of the National Health and Nutrition Examination Survey found that gluten restriction in the absence of celiac disease has tripled between 2009 and 2014. The study additionally found that the number of adherents to gluten-free diets (2.7 million) is significantly higher than the number of patients with celiac disease (1.76 million).

“That is very recent data, though — the only way we had to estimate gluten avoidance before that came from a mix of anecdote and Google search data, which seem to suggest that things really started to change in the mid-2000s,” Benjamin Lebwohl, MD, director of clinical research at the Celiac Disease Center at Columbia University, told Healio Internal Medicine. “In that first decade, Googling ‘gluten-free diet’ and ‘gluten-free food’ really started to increase.”

Lebwohl spoke with Healio about the reasons for this increase, the potential harm of undertaking a gluten-free diet in the absence of celiac disease, and a lesser-known diagnosis called ‘non-celiac gluten sensitivity,’ which may be mistaken for celiac disease.

Question: What do you think prompted so many people to adopt a diet that is meant for a specific disease?

Answer: I don’t think it’s a coincidence that the rise in interest in gluten happened around the same time we realized that celiac disease was more common than previously thought. Celiac disease used to be considered a very rare condition, affecting less than one in 1,000 individuals in the United States. But in 2003, a study was published that showed that actually close to 1% of all individuals in America have celiac disease. Not only that, but it also became clear that the majority of patients with celiac disease were undiagnosed and that celiac disease can produce many different symptoms. That led to efforts to increase awareness of all the ways celiac disease can affect the body. This really is a multi-system disorder.
I do think some of that rubbed off on the general population in a good way in that people got tested for celiac disease. However, it also might have encouraged people to try out the gluten-free diet, even in the absence of celiac disease, which really complicates matters.

Q: In what way does it complicate things?

A: Once the gluten-free diet is begun, the clock starts ticking because celiac disease patients will have a normalization of tests after starting a gluten-free diet. In blood work, for example, the antibodies used to detect celiac disease start to normalize after the gluten-free diet has begun. It typically takes 6 to 12 months for antibodies to become normal, but it can be very variable. Some people normalize much more quickly. The same goes for a biopsy of the small intestine. The abnormalities that are seen with celiac disease will usually disappear within a couple of years after going gluten-free.

The upshot is that, if an individual tries a gluten-free diet and feels better on it, and then a few years later wants to figure out if he or she has celiac disease, it can be tricky, because all of the tests for celiac disease will look normal.

Q: If a person who has undiagnosed celiac disease decides to go off the gluten-free diet, will the symptoms return?

A: The relationship between internal damage and symptoms is very shaky. Celiac patients can run the whole gamut in terms of symptoms — from people who get very ill whenever they eat gluten to people who get minimally ill or have no symptoms whatsoever. Non-celiac gluten sensitivity is a condition that we still don’t have a handle on in terms of what causes it, how to test for it, and whether it’s more than one condition.

Non-celiac gluten sensitivity is the term we use in cases where someone for sure does not have celiac disease, and yet they get ill when they eat gluten. It’s a bit controversial because some studies suggest that, at least in a subset of patients, it’s not gluten that’s making them sick. Something else that correlates with a gluten-free diet is driving their symptoms. For example, a gluten-free diet shares a lot in common with a low FODMAP [fermentable oligosaccharides disaccharides, monosaccharides and polyols] diet. A low FODMAP diet is often effective in treating irritable bowel syndrome. In some people, FODMAPs are the trigger, not gluten. In still others, there might be a component of the placebo effect. Then, in others, it may very well be gluten itself that is causing the problems, even if we don’t have a good way to monitor or detect it beyond listening to the patient.

Q: Is research being done to better understand what other causes there are for gluten sensitivity?

A: Absolutely. We and others have been studying this fairly intensively because so many patients who don’t have celiac disease want to know why gluten seems to be causing them symptoms. Our group recently published a paper that found that patients with non-celiac gluten sensitivity have increased markers of inflammation in their blood relating to the activation of the immune system and gut permeability or leakiness.

That said, as I mentioned, there are other studies that suggest at least a subset of such patients with symptoms are, in fact, triggered by FODMAPs and not by gluten.

There is a great deal of uncertainty around this topic, and we’re working on that. Right now, we’re recruiting patients to the Celiac Disease Center at Columbia University who don’t have celiac disease, but who feel ill when they eat gluten. We’re testing to see if gluten is affecting their intestinal microbiome. We are collecting stool samples before, during and after a gluten challenge in which they eat two slices of bread a day for 2 weeks. It’s an area that is ripe for investigation.

Although most investigators in the celiac community believe non-celiac gluten sensitivity is a condition, it’s also acknowledged that there are no proven biomarkers and no tests that can determine if someone has a non-celiac gluten sensitivity. Despite the absence of proven tests, many companies are taking advantage and preying on unsuspecting patients, selling them tests for non-celiac gluten sensitivity.
If you Google “gluten sensitivity test,” you can find a lab where you can send away your blood, saliva or stool and pay them to test it for gluten sensitivity. None of that is proven. It’s an unfortunate aspect of contemporary medicine.

Q: It seems that gluten-free weight loss diets gained popularity not long after the low-carb diet craze. Were people more receptive to gluten-free diets due to a prevailing “bread is bad” mindset?

A: Well, I should point out that, parallel to the rise in interest in celiac disease and gluten in the absence of celiac disease, there were a number of bestselling books that vilified gluten, including “Wheat Belly” and “Grain Brain.” These books cited some of the science coming from celiac disease, and then implied that perhaps the general population, or many people in the population, became ill in various subtle ways from gluten. This is based on extremely speculative notions, and is generally not regarded as mainstream science. But these bestsellers seem to have had an impact, because with their publication came even more interest in avoiding gluten.

While it certainly appears to be the case that gluten makes some people ill, even in the absence of celiac disease, that is very different from saying that gluten is generally bad for you. Just like the interest in the Atkins Diet that implied carbs are generally bad, so too these books implied that gluten may be bad for everyone. There is no compelling data to support that, yet it became almost a given in the lay public that gluten-free means healthy, even though that’s not necessarily the case.

Q: Is there any potential harm to someone who has no sensitivity to gluten whatsoever, but simply chooses to avoid it?

A: It’s possible to have a healthy gluten-free diet, but that doesn’t automatically happen. Often, if someone starts a gluten-free diet, particularly if it’s without the guidance of an expert dietitian, fiber intake plummets. A low-fiber diet can have bad effects on bowel regularity. If a low-gluten or gluten-free diet results in low consumption of whole grains, there may be bad downstream effects. A gluten-free diet shouldn’t be seen as intrinsically healthy or unhealthy. There’s more than one kind of gluten-free diet.

Additionally, the most common or relevant downside of being strictly gluten-free is the difficulty, both in terms of cost and convenience, especially when traveling or eating out. If someone feels well and wants to have a healthy diet but does not have celiac disease, there is no reason to put oneself through that additional hardship of avoiding gluten, which is in so many foods. It’s also possible that, if it's not done carefully, it could result in a decreased intake of fiber and whole grains. We found a low-gluten diet, if deficient in whole grains, can increase the risk of coronary heart disease. That can have the exact opposite effect of what the person is looking for, which is to have a healthy diet.

Q: What advice would you give to physicians when evaluating a patient who comes in and reports having gluten sensitivity?

A: One thing I tell doctors is, when a patent says, “I have a gluten sensitivity,” you should follow-up. You can say, “What do you mean by that? Do you have celiac disease? Yes, no or unsure?” That can really be a conversation starter. Gluten sensitivity can mean many different things to different people. It’s important that we share with patients what we know about celiac disease, what we don’t know about non-celiac gluten sensitivity, and that we listen. We should try to unpack that term when patients refer to gluten sensitivity.

When patients say they avoid gluten, it’s always helpful to ask why. Maybe they are having symptoms that are alleviated by the gluten-free diet, and sometimes those symptoms might be a sign of something else that should be investigated further. We shouldn’t assume when someone is gluten-free that it’s the end of the story. That should be a conversation starter, not a conversation stopper. – by Jennifer Byrne

Reference:

Ahlawat SK, et al. JAMA Intern Med. 2016;doi:10.1001/jamainternmed.2016.5254.

Laszkowska, et al. Clinical Gastroenterol Hepatol. 2017;doi:10.1016/j.cgh.2017.07.042.

Lebwohl, et al. BMJ. 2017;doi:10.1136/bmj.j1892.

For more information:

Benjamin Lebwohl, MD, can be reached at 622 W. 168th St., New York, NY 10032; email: bl114@cumc.columbia.edu.

Disclosure:  Lebwohl reports no relevant financial disclosures.