Irritable Bowel Syndrome (IBS): The Ultimate Guide

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What Is Irritable Bowel Syndrome (IBS)?

Functional gastrointestinal disorders (FGIDs) account for at least 40% of all referrals to gastroenterologists. Of the 33 recognized adult FGIDs, irritable bowel syndrome (IBS) is the most prevalent, with a worldwide prevalence estimated at 12%.

The diagnosis of IBS can be made by performing a careful review of the patient’s symptoms, taking a thoughtful history (e.g., diet, medication, medical, surgical, and psychological history), evaluating the patient for the presence of warning signs (e.g., “red flags” of anemia, hematochezia, unintentional weight loss, or a family history of colorectal cancer or inflammatory bowel disease), performing a guided physical examination, and using the Rome IV criteria. The Rome criteria were developed by a panel of international experts in the field of functional gastrointestinal disorders.

Recurrent abdominal pain on average at least 1 day/week in the last 3 months, associated with two or more of the following criteria:

  1. Related to defecation
  2. Associated with a change in the frequency of stool
  3. Associated with a change in the form (appearance) of stool

What Are The Symptoms Of IBS?

Cosstipation, diarrhoea, bloating, abdominal cramping, abdominal pain, a feeling of not fully evacuating the bowel after a movement,

The Bristol Stool Chart And IBS

The Bristol stool form scale (BSFS) was developed in the 1990s in the Bristol Royal Infirmary in England [12]. The authors described seven types of stool, which are noted below:

Type 1: Separate hard lumps, like nuts (hard to pass)

Type 2: Sausage-shaped, but lumpy

Type 3: Like a sausage but with cracks on its surface

Type 4: Like a sausage or snake, smooth and soft

Type 5: Soft blobs with clear cut edges (passed easily)

Type 6: Fluffy pieces with ragged edges, a mushy stool

Type 7: Watery, no solid pieces, entirely liquid

The authors classified stool types 1 and 2 as being associated with constipation, while stool types 6 and 7 were associated with diarrhea (and stool type 5 to some degree). Stool types 3 and 4 were considered normal stools. The BSFS is a convenient way for patients to describe their bowel habits, and is routinely used in clinical trials.

How To Test For IBS?

The diagnostic testing for IBS patients include routine blood tests, stool tests, celiac disease serology, abdominal sonography, breath testing to rule out carbohydrate (lactose, fructose, etc.) intolerance and small intestinal bacterial overgrowth. Colonoscopy is recommended if alarming symptoms are present or to obtain colonic biopsies especially in patients with diarrhoea predominant IBS.


A paper entitled IBS and IBD – Separate Entities or on a Spectrum? states: “The acute phase of IBD with inflamed gut and often ulcerated mucosa is clearly different from the apparently normal mucosa characteristic of IBS. However, more detailed assessment has detected immune activation, increased gut permeability, increased mucosal serotonin availability, abnormalities of enteric nerve structure and function, and dysbiosis in gut microbiota in IBS – all features seen in IBD. Furthermore, as treatments for inflammation in IBD have become more effective it is now apparent that 1 in 3 patients with IBD in remission from inflammation still have persistent abnormalities of sensation, motility and gut microbiota, which might cause IBS-like symptoms.”

What Causes Irritable Bowel Syndrome (IBS)?

Because IBS is a label – it doesn’t actually inform us what is causing symptoms – it is hard to answer the question. However imbalances that we often see in these suffering on going IBS, both in lifestyle or/and in the body, include:

  • Chronic stress
  • An imbalanced diet
  • Antibiotics and other medications
  • SIBO
  • Mycotoxins and high toxic burden
  • Thyroid dysfunction and other hormone imbalances
  • Food poisoning
  • A traumatic brain injury
  • Abdominal surgery

The Best Diet For Irritable Bowel Syndrome (IBS)

There is debate on the role food plays in IBS but it is clear, being a clinician at the forefront of supporting clients with the condition, that food can play a major role in exacerbating symptoms. There are lots of diets out there ranging from low FODMAP, to the paleo diet, the autoimmune-paleo diet, GAPS, SCD diet, the bi-phasic diet, the SIBO diet.

The good news is they all have one thing in common: a reduction in fermentable carbohydrates. Without knowing details of a person we could argue that it’s about picking one to begin with! Without additional context of the individual we might not be able to go any further. And do we need to when we consider the role that yoga and somatic therapy, sleep, physical activity, emotions and many other variables play in modulating our gut health.

Sleep And IBS

A systematic review concluded that “the prevalence of sleep disorder was higher in IBS compared to healthy controls and may be associated with the pathogenesis of IBS.”

Difficulty in falling asleep, shorter sleep time, frequent arousal and awakenings, or non-restorative sleep are the most common manifestations

Stress And IBS

Exposure to stress results in alterations of the brain-gut interactions (“brain-gut axis”) ultimately leading to the development of a broad array of gastrointestinal disorders including:

  • Inflammatory bowel disease (IBD)
  • Irritable bowel syndrome (IBS) and other functional gastrointestinal diseases
  • Food antigen-related adverse responses
  • Peptic ulcer and gastroesophageal reflux disease (GERD)

The major effects of stress on gut physiology include:

  1. Alterations in gastrointestinal motility
  2. Increase in visceral perception
  3. Changes in gastrointestinal secretion
  4. Increase in intestinal permeability
  5. Negative effects on regenerative capacity of gastrointestinal mucosa and mucosal blood flow
  6. Negative effects on intestinal microbiota

Yoga And IBS

Preliminary data supports yoga as beneficial in this population

A systematic review concluded that:

The findings of this systematic review suggest that yoga might be a feasible and safe adjunctive treatment for people with IBS

However the authors did state that “no recommendation can be made regarding yoga as a routine intervention for patients with IBS because of major flaws in study methods” and that “more research is needed”.

Probiotics For Irritable Bowel Syndrome (IBS)

Probiotics may profoundly affect the brain-gut interactions (“microbiome-gut-brain axis”) and attenuate the development of stress-induced disorders in both the upper and lower gastrointestinal tract

Supplements For Irritable Bowel Syndrome (IBS)

It’s important that we investigate the underlying imbalances that might be contributing to the diagnosis of IBS. However considerations that have been shown to be helpful in the research include:

  • Prebiotics
  • Probiotics
  • Fibres
  • Antimicrobials such as oregano oil

When we understand what imbalances are present we can become more specific with our recommendations.

Additional Comments

In a very interesting paper entitled New Insights in IBS-like Disorders: Pandora’s Box Has Been Opened; A Review the authors also discuss celiac disease, non-celiac gluten sensitivity, fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), lactose intolerance, small intestinal bacterial overgrowth (SIBO), α-amylase/trypsin inhibitor (ATIs), nickel allergic contact mucositi

IBS Resources

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