As of 2021, about 3.8 million people globally were living with inflammatory bowel disease (IBD) — an umbrella term for conditions that cause inflammation of the digestive tract. The two main types of IBD are ulcerative colitis (UC) and Crohn’s disease.
There is currently no cure for IBD. IBD symptoms are usually managed through a combination of medications and lifestyle changes, including eliminating “trigger” foods that can cause or worsen symptoms. Types of IBD trigger foods include foods high in fat, dairy products, and foods containing gluten.
If a person with IBD reaches remission, where their symptoms are no longer apparent, they may still have lingering sensitivities to certain foods.
“Many people with IBD continue to experience food-related symptoms even when these conditions have been ruled out, and their IBD is otherwise under control,” Alberto Caminero, PhD, associate professor in the Department of Medicine at the Farncombe Family Digestive Health Research Institute at McMaster University in Canada, told Medical News Today.
“In fact, up to 70% of people with IBD report that certain foods trigger symptoms such as abdominal pain, bloating, or changes in bowel habits,” he said.
“Dairy and wheat are among the foods that IBD patients most commonly identify as triggers, but we still don’t fully understand why this happens. We don’t know exactly which components of these foods are responsible, what biological pathways are involved, or why some people develop these reactions while others don’t.”
— Alberto Caminero, PhD
Caminero is the senior author of a new study published in the journal Gastroenterology that provides an explanation as to why those in IBD remission may still experience negative reactions to certain foods. Researchers believe that gut inflammation from IBD may change a person’s microbiome, causing food sensitivities even during remission.
For this study, researchers first used a mouse model to see how gut inflammation caused by IBD might impact their food sensitivity risk.
“We used two different mouse models of intestinal inflammation,” Caminero detailed. “We found that inflammation in the gut can make animals more susceptible to developing immune responses to certain foods, including gluten and dairy.”
More specifically, Caminero said, their preclinical studies suggest that inflammation can promote the development of food-specific immunoglobulin E (IgE) responses in the gut.
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“These responses involve mast cells, which are immune cells that are also important in food allergies,” he continued. “Interestingly, in our mouse models, the response was largely confined to the gut rather than spreading throughout the body. This makes it different from a typical food allergy, where the immune response can be much more widespread and, in severe cases, lead to a life-threatening reaction called anaphylaxis.”
Caminero said their findings suggest that inflammation itself may be an important factor in why some people with IBD develop reactions to foods that they previously tolerated.
“In other words, the inflammation may change the way the immune system responds to food,” he explained. “This opens up an interesting new avenue for understanding and potentially diagnosing food-related symptoms in people with IBD.”
Researchers also recruited 148 study participants between the ages of 18 to 75 years old. Participants included a mix of Crohn’s disease and UC diagnoses, as well as non-IBD controls.
Through both the mouse model and human participants, scientists discovered that intestinal inflammation disrupts the gut microbiota, reducing some of the bacteria that normally help us break down food components such as gluten and dairy.
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“We had previously shown that these bacteria play an important role in processing food triggers, so we asked what happens during inflammation,” Caminero said. “We found that inflammation reduces these beneficial bacteria, weakening the gut’s ability to break down certain food components and potentially favoring adverse food reactions.”
“When we transferred the microbiota from inflamed mice into healthy mice, the recipient mice became more susceptible to adverse food reactions,” he continued. “We also saw similar changes in the gut microbiota of people with IBD who reported adverse reactions to certain foods.”
“While this does not prove that the same mechanism occurs in people, it provides an important clue that a similar process may be involved. Our research helps explain why some people with IBD develop food-related symptoms and could point to new ways of managing them.”
— Alberto Caminero, PhD
MNT spoke with Alyssa M. Parian, MD, gastroenterologist and medical director of the Center for Inflammatory Bowel Disease at Hackensack University Medical Center (HUMC) in New Jersey, who commented that this research is incredibly validating for patients.
“We are learning more and more about the gut microbiome and know how critical it is in IBD,” Parian, who was not involved in this study, said. “We know IBD patients have alterations in their gut microbiome that can proceed their diagnosis for several years and even despite adequate endoscopic remission, the microbiome doesn’t always seem to return to normal.”
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“For years, IBD patients who are in clinical remission have told me that foods they used to tolerate perfectly well — like dairy or gluten — suddenly trigger GI symptoms. Historically, we haven’t had a great physiological explanation for this when a patient’s endoscopy shows that their gut lining is completely healed.”
— Alyssa M. Parian, MD
“However, now understanding that the microbiome is paramount to digestion of specific foods helps us to better understand and eventually to treat these patients,” Parian said.
“Seeing concrete evidence that previous gut inflammation fundamentally alters how our microbiome breaks down food — turning those food byproducts into new immune triggers — connects a major missing piece of the puzzle,” she added.
MNT also spoke with Rudolph Bedford, MD, a board certified gastroenterologist at Providence Saint John’s Health Center in Santa Monica, CA, who likewise was not involved in this study.
Bedford agreed and said these findings provide some plausible biological mechanism for what patients have been telling gastroenterologists for years about their sensitivities to certain foods in the setting of their ongoing disease.
Could these findings help treat or eliminate food sensitivities for those with IBD?
“The question is whether or not getting the microbiome back to some state or restoring missing bacterial functions in patients, whether or not that will help in patients being able to tolerate certain foods,” Bedford answered. “It’s obviously going to require much larger human studies in order to answer that question, but it certainly is a good beginning.”
Bedford also commented that this is not just a situation seen in people with IBD.
“We also see these situations in patients after they’ve taken antibiotics — they may develop food sensitivities, what I’ll call post-infectious IBS,” he said. “So this may very well extend to other diseases also that we deal with.”
