What Is the Main Idea?

This blog post is about irritable bowel syndrome (IBS). It is inspired by the recent open access paper “Improvement in Food Intolerance Symptoms after Pretreatment with Antibiotics Followed by Faecal Microbiota Transplantation: A Case Report” in the journal Case Reports in Clinical Nutrition, which looks at a technique called fecal microbiota transplantation that has considerable potential in the treatment of IBS.

What Else Can You Learn?

Learn about the differences between food allergies, which involve immune system reactions and can be life-threatening, and food intolerances, which have major impact on quality of life, but do not provoke anaphylactic reactions.

What Is Irritable Bowel Syndrome?

Irritable bowel syndrome (IBS) affects around 12% of the world’s population. It is a lifelong condition with symptoms including abdominal pain, cramping, constipation, diarrhea, and bloating. Patients may have periods with no symptoms followed by days, weeks or even months of symptoms that impact quality of life.

Despite considerable research, the cause of IBS is unknown and there is still no cure. Evidence suggests that multiple factors may contribute to IBS, with current thinking focused on interactions between the gut microbiome (i.e., the microorganisms that live in the gut), the gut endocrine cells (which produce and secrete hormones), the central nervous system, and the diet. Food certainly plays a part, and anyone with IBS will have identified various foods they believe to trigger reactions. However, the biological mechanisms underlying these food reactions require more research.

Because the cause is unknown, treatments for IBS can only focus on the symptoms. Patients are often asked to keep diaries of what they eat to see what might trigger problems, with fatty and spicy foods, excessive amounts of fruit, and alcohol being commonly identified culprits. Probiotics are often prescribed. Regular meals, relaxation and exercise are also recommended. However, since stress is a trigger and food triggers can be unpredictable, management of IBS proves difficult for many patients.

What’s the Difference between a Food Allergy and a Food Intolerance?

A food allergy is an adverse food reaction that involves the immune system: for example, peanut allergies and shellfish allergies. They can affect multiple organs, usually have a rapid onset, within seconds or minutes, and may include skin reactions (rashes, hives, itching); swelling of facial and throat tissues that can result in difficulty swallowing or breathing; or digestive responses such as vomiting, cramps or diarrhea. They are triggered by even the smallest amounts of the food.

Anaphylaxis is the most severe type of allergic reaction, and it can be caused by a food allergy. The immune system releases a high amount of chemicals that can send the body into life-threatening shock, with symptoms including a sudden drop in blood pressure, changes in heart rate, narrowing of airways and vomiting. An immediate medical response is essential: an epinephrine injection (e.g., an EpiPen) followed by an emergency room visit.

Celiac disease has many features of food allergies: The immune system is involved, and it affects multiple organs, with responses including gastrointestinal issues, headaches, and joint pain. However, anaphylaxis is not a feature of celiac disease. Some sources classify it as a food allergy, others as a food intolerance.

A food intolerance is also called a non-immune mediated food reaction. The immune system is not involved, the impact is not always immediate, and it may even be possible for the sufferer to eat small amounts of the food. The reactions can be caused by the lack of an enzyme that is needed to digest the food (e.g., lactose intolerance is due to a lack of lactase); sensitivity to particular chemicals in food, such as sulfites, fermentable carbohydrates, or biogenic amines; and even psychological responses, such as recurring stress related to particular foods. Food intolerances affect around 20% of the general population and are commonly seen in patients with IBS.

What Is Fecal Microbiota Transplantation?

Fecal microbiota transplantation (FMT) is emerging as a potentially effective treatment for IBS. The patient receives an infusion of a homogenized and filtered stool from a healthy donor who has gone through an intensive screening process. This transplantation of healthy gut bacteria can help with a number of diseases, such as Clostridioides difficile infection, ulcerative colitis, and Crohn’s disease.

The case study “Improvement in Food Intolerance Symptoms after Pretreatment with Antibiotics Followed by Faecal Microbiota Transplantation: A Case Report” describes how a 35-year old cisgender female patient with IBS was helped by FMT and indicates that the gut microbiome plays a role in the pathogenesis of food intolerances.

What Does the Case Involve?

The patient had been suffering from nausea, abdominal pain, and alternating loose stools or constipation for 18 months. She had identified severe food intolerances to dairy, gluten, egg and soy, and moderate intolerances to onion, garlic, raw vegetables and high-fructose fruit.

After an intensive examination to rule out other pathologies, the diagnosis of IBS with suspected gut microbiota dysbiosis (a medically significant reduction in microbial diversity) was given. She was treated with antibiotics followed by FMT enemas over a 12-month period.

Twelve weeks after the start of the FMT treatment, the patient reported an 80–90% improvement in her symptoms, with less pain and nausea, better bowel movements, and improved energy levels. After the year, she was able to include gluten and dairy in her diet with no symptoms.

What Does This Case Mean?

As mentioned, the linked paper is a case study, so its conclusions are preliminary and cannot be considered thoroughly clinically tested. In addition, it is unknown how long the improvements will last. However, it certainly shows that FMT has promise and could be the way forward for treating some people’s IBS and food intolerances.

Should I Go Gluten-Free If I Have IBS?

As mentioned in Dr. George Marx’s post “How Useful Is a Gluten-Free Diet?”, a gluten-free diet is not harmful provided your nutrition is balanced. Unfortunately, it can be difficult to create a balanced gluten-free diet, so you should always seek support from a doctor or dietician before taking such a decision.


Note: One of the authors of the paper declared that they have a pecuniary interest in the Centre for Digestive Diseases, is a medical advisor to Finch therapeutics, and holds patents for FMT treatment. It is normal for authors to declare this in case it might be perceived as a conflict of interest. For more detail, see the Conflict of Interest Statement at the end of the paper.

Related Posts

The authors of the open-access research article “Perspective: Food and Nutrition Insecurity in Europe: Challenges and Opportunities for Dietitians”, published...
Gastroesophageal reflux disease affects 10–30% of the Western population. Patients may dismiss it as “permanent indigestion” and try to cope...
Clostridioides difficile (C. difficile) is a bacteria that can lead to mild and serious bowel problems. The authors of the...


Share your opinion with us and leave a comment below!