Post-Infectious IBS diet – Low FODMAP Is NOT a long-term solution

Post-Infectious IBS diets should take into account the principal characteristic of this type of IBS, which is heightened visceral hypersensitivity. And while low-FODMAP diets are helpful, they are not a long term solution
Article Highlights
Personalized dietary plans crucial for managing IBS symptoms due to unique microbiome signatures in each subtype
Post-infectious IBS (PI-IBS) is characterized by enhanced visceral hypersensitivity, making tailored diet interventions essential
Low-residue diet (3-5 weeks) beneficial for PI-IBS patients by alleviating visceral hypersensitivity
Low-FODMAP diet not a long-term solution, can reduce gut microbiome diversity and inhibit probiotic strains
Identifying the initial infection trigger helps design precise dietary interventions to address specific biochemical alterations
Table of Contents

Post-Infectious IBS Case Study

Each subtype of IBS, including post-infectious IBS (PI-IBS), has unique microbiome signatures and structural and biochemical alterations, which can influence symptoms and treatment options. That’s why generic diet plans do not cover the specific needs of each patient and most of the time lead to symptom-rebound upon reintroduction of eliminated foods. Besides, the majority of the patients that come to my office have already tried 2-3 general diets that have read online or were suggested to them by a dietitian. Most of the time it didn’t work. Developing a personalized dietary plan is crucial for effectively managing IBS symptoms and addressing the unique characteristics of each subtype.

Irritable bowel syndrome subtypes based on the initial trigger


Every IBS is unique

Besides the common IBS subtyping based on the major bowel movement pattern (IBS-D Diarrhea, IBS-C Constipation, IBS-M Mixed), subtyping based on the initial symptom-trigger is very useful. For example, post-cholecystectomy IBS (after gallbladder removal) or PPI-IBS (after proton-pump inhibitors abuse). Distinguishing IBS subtypes based on their initial trigger allows for the identification of unique biochemical and microbiological alterations, leading to more precise dietary interventions. There are at least 30 different subtypes of IBS, most of which are analyzed in detail in the book IBSYNCRASY.
Graphic with some of the subtypes of IBS based on the initial trigger. Gallbladder removal, proteus infestation, gastroenteritis or food poisoning and proton pump inhibitors abuse

Characteristics of some IBS subtypes

Post-cholecystectomy IBS
Trigger: Gallbladder removal
Unique trait: Intestinal pH alkalinization

Post-cholecystectomy IBS occurs after the removal of the gallbladder, which can lead to altered bile acid metabolism and intestinal pH alkalinization. This change in pH has a huge impact on the gut microbial ecology and contributes to the development of IBS symptoms.

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Trigger: PPI abuse
Unique trait: Transient hypochlorhydria

PPI-IBS is triggered by the overuse of Proton Pump Inhibitors, which can cause hypochlorrhydria or reduced stomach acid production. Hypochlorrhydria impairs digestion and absorption of nutrients, altering the microbial balance

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Proteus IBS
Trigger: Proteus colonization
Unique trait: Swarming ability

Proteus-predominant IBS is triggered by the colonization of Proteus bacteria in the gut, which have a unique swarming ability in the presence of excess glutamine. This disruption leads to several biochemical alterations in susceptible patients that will eventually develop PI-IBS

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Post-Infectious IBS
Trigger: Gastroenteritis or food poisoning
Unique trait: Enhanced visceral hypersensitivity

PI-IBS, caused by bacteria like Salmonella or Campylobacter, or viruses like Norovirus is characterized by increased sensitivity of the gastrointestinal tract to various stimuli, leading to abdominal pain and discomfort. This hypersensitivity may result from altered gut motility and sensation, as well as imbalances in the gut microbiome.

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Diet interventions tailored to post infectious IBS

Post-Infectious IBS Recovery Time: 7 Tips for Faster Healing
Understanding the molecular mechanisms, enteric nervous system involvement and visceral hypersensitivity affecting post-infectious IBS (PI-IBS) is crucial for designing an appropriate diet. This, of course, does not mean that diet should not be designed from scratch for every patient as the risk factors vary in each case. In my practice, I have seen that patients suffering from the same subtype of IBS sometimes respond differently to the same diet. But, knowing the initial trigger is extremely helpful to be as precise as possible. In PI-IBS, heightened pain sensitivity can be triggered by various factors such as gas, digestive residues, and substances that enhance motility. A low-residue diet (3-5 weeks) is extremely beneficial in desensitizing the gastrointestinal tract and managing PI-IBS symptoms, especially if combined with other behavioral and lifestyle interventions.

Desensitization through dietary choices

The heightened pain sensitivity in PI-IBS is linked to an overactive enteric nervous system and increased responsiveness of pain receptors in the gut. Foods that stimulate pain receptors or promote gas production can exacerbate this sensitivity. Therefore, dietary choices should focus on minimizing these triggers. For example, avoiding gas-producing foods such as beans, cabbage, and carbonated beverages can help alleviate discomfort. This is not a healing process, but symptomatic relief until the treatment gives results. 

Low-residue diet for PI-IBS

A low-residue diet (LRD) can be particularly useful for PI-IBS patients. This diet limits the intake of fibrous and indigestible food components, reducing the amount of undigested material that reaches the colon. By decreasing the volume of digestive residues, the LRD reduces the pressure and distension within the large intestine, which in turn can alleviate the visceral hypersensitivity experienced by PI-IBS patients.

Foods recommended in an LRD include refined grains, lean meats, and well-cooked vegetables without skin or seeds. On the other hand, high-fiber foods, raw vegetables, and fruits with skin should be avoided, as they can contribute to increased residue in the colon.

Low-FODMAP diet: A common but temporary solution

The Low-FODMAP diet is often regarded as the holy grail for IBS and, according to some practitioners, for several inflammatory bowel diseases. Despite its popularity, the low-FODMAP diet is not a long-term solution. This is due various reasons, including its impact on the gut microbiome and potential risks for individuals with eating disorders.

Limitations and risks of low-FODMAP diet

  1. Reduction of bifidobacteria: Low-FODMAP diets (LFD) limit the intake of fermentable carbohydrates, which leads to a reduction in bifidobacteria, essential for maintaining a healthy GI tract.

  2. Symptomatic reduction due to histamine reduction: While the diet may alleviate symptoms through the reduction of histamine levels, it does not address the root cause of the symptoms.

  3. Inhibition of probiotic strains: Some beneficial bacterial strains may not thrive in an LFD environment, potentially compromising gut health.

  4. Fear of FODMAPs: Individuals may become apprehensive about reintroducing important FODMAP-containing foods, which can lead to nutrient deficiencies.

  5. Reduced microbiome diversity: Prolonged adherence to LFD may reduce gut microbiota diversity, increasing the risk of developing other health issues.

  6. Worsening eating disorders: A highly restrictive diet like the LFD may exacerbate existing eating disorders.

List of the risks of long-term low-fodmap diet as part of post-infectious IBS diet


Are there different types of IBS?

Yes, there are different types of IBS. They can be categorized based on bowel movement patterns, such as constipation (IBS-C), diarrhea (IBS-D), and mixed (IBS-M). Additionally, IBS subtypes can be identified based on the initial trigger, such as post-infectious IBS (PI-IBS), PPI-IBS, Proteus-predominant IBS, and post-cholecystectomy IBS (following gallbladder removal).

Is there a specific diet for IBS?

There is no one-size-fits-all diet for post-infectious IBS (PI-IBS) as each subtype presents unique biochemical, microbiological, and structural signatures that require personalized approaches. To effectively manage symptoms, individuals with IBS should work with a healthcare professional to develop a tailored dietary plan that addresses their specific needs and considers the unique characteristics of their IBS subtype. This ensures optimal symptom relief and long-term management of the condition.

Theodoros Prevedoros
With extensive experience evaluating over 3000 cases in various specialties, including gastroenterology, pediatrics, and endocrinology, Theodoros has collaborated with more than 25 doctors from Greece and Cyprus and over 10 laboratories worldwide.

With a background in Chemistry and Biochemistry from the National and Kapodistrian University of Athens, Theodoros brings a wealth of knowledge in functional medicine and advanced treatments to his role. He possesses exceptional skills in analysis, pattern recognition, diagnostic translation, and storytelling. He is also FMU certified in Functional Medicine and has received training in advanced treatments from the Saisei Mirai Clinic in Japan.
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