There are a lot of strong opinions surrounding gluten free diets. Some view them as a fad diet, popularized by media and celebrities. Others report real improvements in their GI symptoms when going gluten free. And of course there are those with Celiac Disease, for whom a gluten free diet is a life changing therapy. Throughout my time as an undergrad studying dietetics, I have learned about the gluten free diet from all angles. I think a lot of the confusion surrounding the gluten free diet in IBD comes from two sources. First, there appears to be a difference between what patients report and what the limited research has shown. Second, this limited research and lack of conclusive evidence has created a difference of opinions among healthcare professionals themselves. It is a difficult situation where providers using their clinical judgement can recommend for or against IBD patients going on a gluten free diet, and both recommendations would be completely justifiable.
In this article, I plan to give some background on the gluten free diet, and the current evidence for and against its use for patients with IBD. Then, I will summarize the wonderful study I learned about during DDW 2021 presented by Dr. Maria Moomal Dahar titled: Positive Gluten Sensitivity Seriologies and the Impact of Gluten Free Diet in Patients with IBD.
What is a Gluten Free Diet?
Gluten free diets are designed to eliminate the protein gluten from one's diet. Gluten is a storage protein found in some grains, including wheat, barley, and rye. Gluten is an important protein for baked goods, as it forms a sticky network that gives dough its characteristic stretch and elasticity. I don’t want to go too much in depth, as there is already an amazing article on the CCYAN website written by Leah Clark that describes the gluten free diet. If you desire to learn more about the specifics, her article can be found here.
The Gluten Free Diet and IBD
The main reasons to follow a gluten free diet are Celiac Disease, non celiac gluten sensitivity, and wheat allergy.
Previously, there had been conflicting data regarding whether IBD patients are at a higher risk of developing Celiac Disease than healthy people. Some older, smaller studies have found increased risk, while others have found no increased risk or even decreased likelihood of having Celiac Disease.1 A recent, larger study has shown that IBD patients have an increased risk of having celiac disease.
Non celiac gluten sensitivity is characterized by abdominal pain, discomfort, bloating, changes in bowel habits, fatigue, or depression after consuming gluten. The prevalence of non-celiac gluten sensitivity in IBD patients surveyed is reported to be between 5-28%.1 Those IBD patients who reported non-celiac gluten sensitivity were more likely to be following a gluten free diet. One thing I found interesting was that IBD patients were more likely to report gluten sensitivity if they also had a flare in the past 60 days. This points to the possibility that gluten sensitivity might be worsened in patients who are currently flaring or who have recently had a flare up of their IBD.
Most research on the gluten free diet in IBD patients has been done through survey based studies. Unfortunately, these types of studies can only provide weak evidence at best. The surveys did find that of IBD patients who had tried a gluten free diet, about 2/3 reported an improvement in one of abdominal pain, bloating, diarrhea, nausea, or fatigue. About 40% of patients following a gluten free diet reported less severe or less frequent flares. Contrary to those positive results, a different survey study found that there were no significant differences in disease activity, hospitalization, or rate of surgery in IBD patients following a gluten free diet versus those who were not.
A few different organizations and guidelines have weighed in on the gluten free diet and IBD:
The International Organization for Inflammatory Bowel Diseases currently states that in IBD “there is insufficient evidence to recommend restriction of wheat and gluten.”
The Crohns and Colitis Foundation states that “some IBD patients have found that a gluten-free diet reduces their symptoms, but researchers have not proven that it reduces IBD inflammation.”
The Asain Working Group guidelines on diet and inflammatory bowel disease state that “a gluten-free diet is not of a proven value in patients with inflammatory bowel disease.”
There are also some confounding factors when discussing gluten free diets. Gluten is often paired with fructans in foods, which are a type of fermentable carbohydrate that is associated with gastrointestinal symptoms. One study showed that 80% of patients with suspected non-celiac gluten sensitivity couldn’t be diagnosed after a gluten challenge.2 This points to the possibility that something found alongside gluten might be the culprit. Fructans offer a convincing alternative cause for why some might experience GI symptoms while eating gluten containing foods. Indeed, research has shown that in patients with suspected non-celiac gluten sensitivity, eating fructans was associated with more gastrointestinal symptoms when compared to eating gluten.3
Positive Gluten Sensitivity Seriologies and the Impact of Gluten Free Diet in Patients with IBD
When I first noticed this study as a part of DDW I was excited. I think that the study design is well thought out. The term “Celiac serologies” means that antibodies to proteins associated with consuming gluten were found in patients’ blood. These patients have immune systems that have already falsely identified these specific proteins as foreign invaders. By studying patients with positive celiac serology, the researchers were able to look at the effect of a gluten free diet in the patients that were likely to experience the greatest benefit from going gluten free.
The goal of this study presented by Dr. Maria Moomal Dahar was to determine if there were any differences in clinical outcomes between IBD patients with positive celiac serologies following a gluten free diet compared to those who were not following a gluten free diet. Out of the 1537 patients IBD patients looked at, only 89 had positive celiac serologies. Of these 89 patients, 29 reported adhering to a gluten free diet.
One interesting finding was that of the 89 patients with positive celiac serologies, those who were not on a gluten free diet were more likely to have a high ESR (measure of inflammation) and eosinophilia (associated with inflammation and infection).
Based on this study, the authors recommend testing for celiac serologies in patients with IBD. They also suggest a trial of a gluten free diet in IBD patients with confirmed celiac serologies.
My Closing Thoughts
It is so important that research is being done to evaluate the gluten free diet in IBD. Any time where a large majority of patients report improvement following a dietary trend, that should at least warrant some investigation into whether or not those improvements can be replicated in a randomized controlled trial. I am thankful for researchers like Dr. Dahar and her colleagues who are making efforts to further our knowledge in regards to the gluten free diet and its use in IBD.
One thing I also want to note is that the majority of therapeutic diets studied in IBD (IBD-AID, CDED, EEN, and SCD) all exclude gluten containing grains. Some of these diets show real promise in treating inflammation or alleviating symptoms of patients with IBD, and it is a trend worth noting. On the contrary, the mediterranean diet has also shown similar promising results, and includes gluten containing grains.
In my opinion, current literature is frustratingly inconclusive. Like many nutrition topics, there isn’t enough evidence to be able to make any strong recommendations one way or another. In light of that, I think that the best approach is the same one I echo all the time: Find out what works for you individually. You know your own body better than any study, scientist, or doctor ever will. So if you notice feeling better on a gluten free diet, maybe that is something you decide you want to continue even if the evidence isn’t quite there yet to show benefit in IBD patients.