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What is Irritable Bowel Syndrome (IBS)?

If you are suffering from digestive issues, your internet travels may have led you to Irritable Bowel Syndrome. So what is IBS? And, more importantly, do you have it? The answer to both questions is complicated.

In this article, I’ll describe what you need to know about Irritable Bowel Syndrome including common symptoms, diagnostic criteria, and ways IBS community members manage symptoms.

Be forewarned, you’re about to get the scoop on poop!

Understanding Irritable Bowel Syndrome

Photo Credit: YelenaYemchuk-via-iStock

What Is IBS?

Irritable Bowel Syndrome is a chronic Functional Gastrointestinal Disorder (FGID) of the large intestine (colon).  That is a lot of words, and not a lot of help, so let’s start from the beginning.

Irritable Bowel Syndrome is considered a chronic illness because, unlike a bad case of diarrhea or constipation, symptoms linger over long periods of time. While the flu may last several days, IBS symptoms last months or years. In fact, patients with IBS require a 3-month history of consistent symptoms for diagnosis.

You should also know there is currently no cure for IBS. We’ll discuss how community members manage their symptoms in a later section of this article.

As with other disorders under the FGID umbrella, IBS symptoms are caused by abnormal behaviour of the GI tract. This means there is no evidence of physical damage or chemical imbalances to explain your symptoms. Because of this, there is currently no test to confirm IBS.* As a result, your doctor will diagnose you based on the symptoms you report.

Because there’s no official test, it may be tempting to diagnose yourself. This is a bad plan! Many illnesses present with IBS-like symptoms, so it’s important you seek medical advice. A doctor can screen for warning signs of more sinister illnesses including celiac disease, chrons, ulcerative colitis, bowel cancer, etc. These illnesses damage your body and should be diagnosed as soon as possible.

It’s worth mentioning that even if your doctor does suspect IBS, they may request additional testing. These tests rule out structural causes like inflammation, obstructions (like impacted poop), or tumors, and biochemical causes like acid or hormonal imbalances. These tests are normally precautionary and are not required for an IBS diagnosis.

But, because doctors often fail to communicate they expect normal test results, Irritable Bowel Syndrome has developed a reputation as a “diagnosis of exclusion.” IBS patients often feel they receive their diagnosis because their doctor ran out of tests; not because they meet diagnostic criteria. This, combined with limited medical resources to manage patient symptoms, has created a deep sense of abandonment within the IBS community. However, contrary to popular opinion, IBS has detailed criteria required for diagnosis and is a legitimate and specific condition.

Common IBS Symptoms

One of the most frustrating aspects of Irritable Bowel Syndrome is how uniquely it sits in the body. What triggers me may not impact you, and what affects both of us may be fine for someone else. The same holds true for how we react to triggers.

Though there are many symptoms associated with Irritable Bowel Syndrome, the cornerstone of IBS is abdominal pain. This pain can appear anywhere in your abdominal cavity (from the bottom of your ribs to your hips) and may be relieved by bowel movements or remain constant.

More personal symptoms include abdominal bloating and distention, cramping, gas, constipation or diarrhea, a feeling of incomplete evacuation or urgency, and mucus in the stool. Both the severity and combination of symptoms are unique to each patient. One of the great mysteries of IBS is why asparagus gives me cramps, you diarrhea, and Bob can eat it by the bunch.

Secondary GI Symptoms

Many IBS community members experience additional GI symptoms to those listed above. For example, 25-50% of IBS patients report symptoms like heartburn, feeling overly full, or feeling nauseated. If you experience symptoms such as these, let your doctor know, as 50% of patients report co-occurring FGIDs. Because other disorders may require specific symptom management techniques, you need to know if your symptoms are IBS-related or a separate issue. I list some common co-occurring illnesses below.

Secondary Non-GI Symptoms

As if that wasn’t complicated enough, some IBS symptoms have nothing to do with your gut. The ROME IV lists fatigue, chronic pain, and poor sleep quality among the most frequently reported non-GI symptoms. Less common symptoms include generalized muscle pain, sexual dysfunction, and headaches.

Co-Occuring Functional Disorders

In case three paragraphs of possible symptoms didn’t seem frustrating enough, Irritable Bowel Syndrome has also been linked to other Functional Gastrointestinal Disorders. These include chronic spinal pain (specifically affecting the neck and lower back), fibromyalgia, chronic fatigue syndrome, chronic migraines, chronic pelvic pain (occurring in both men and women), chronic urinary symptoms (including painful bladder syndrome and interstitial cystitis), dysmenorrhea, and prostatitis.

Do I Have IBS?

So, now that we’ve established IBS is a long-term case of angry guts without a cause, do you have it? I can’t tell you one way or another, but we can discuss the specific criteria doctors are looking for.

The diagnostic criterion for IBS was developed by The ROME Foundation in 1990. This criterion is essentially a checklist used by doctors to determine if you have IBS. If you don’t meet the criteria, alternate options include Functional Diarrhea (FD), Functional Constipation (FC), Functional Abdominal Bloating/Distension (FAB/D), and Unspecified Functional Bowel Disorder (U-FBD).

The newly updated ROME IV was released in 2016 and includes updated criteria for Irritable Bowel Syndrome. According to the ROME IV, a patient with IBS must report abdominal pain at least once a week for 3 months or more. This must be combined with two or more of the following criteria:

  1. Pain related to bowel movements;

  2. Change in the frequency of stool; and

  3. Change in the appearance of stool based on the Bristol Stool Scale – This symptom must be present for 6 months to fulfill the criteria.

If you feel you meet the criteria above, you may have IBS. However, a diagnosis should always be provided by a medical professional.

IBS Subcategories

If you’ve joined an IBS community as part of your research or to find support for your symptoms, you may have noticed members identifying themselves as IBS-C, IBS-D or IBS-M/A. If you feel like you’re missing something, don’t fret.

In addition to meeting basic IBS diagnostic criteria, patients are subdivided into one of 4 groups: IBS-C, IBS-D, IBS-M (A), or IBS-U. Each subcategory has another specific set of criteria required for diagnosis. These are based on the percentage of abnormal bowel movements that fall within a specific range on the Bristol Stool Scale.

What this means is, when you add up your problematic bowel movements at the end of the month, how many of them were constipation or diarrhea according to the Bristol Scale. The technical breakdown for each subcategory is outlined below.

IBS-C: These patients suffer from constipation. To be assigned to this group, at least 1/4 (25%) of a patient’s bowel movements must fall clearly between 1 and 2 on the Bristol Scale.

IBS-D: These patients suffer from diarrhea. To be assigned to this group, at least 1/4 (25%) of a patient’s bowel movements must fall clearly between 6 and 7 on the Bristol Scale.

IBS-M: Patients in this category experience both constipation and diarrhea. They are described as “mixed” (M). However, within the IBS community, they are often called “alternating” (A). Either one is generally acceptable.

Patients assigned to this group require at least 1/4 (25%) of their bowel movements to fall between 1 and 2 (C) and an additional 1/4 (25%) or more to fall between 6 and 7 (D) on the Bristol Scale.

IBS-U: Patients who don’t fit clearly into the IBS-C, -D, or -M categories are considered “unspecified.” They are normally referred to simply as patients with IBS. This isn’t based on the severity of symptoms, but rather, on the percentage of problematic bowel movements that fall clearly within the C or D range.

Managing Irritable Bowel Syndrome

Because there is no known cure for IBS, patients must find ways to manage their symptoms. In order to effectively manage your IBS, you will need to know how your symptoms are triggered.

Some IBS patients are triggered by stress. These community members often benefit from stress management techniques (like meditation, physical activity, setting healthy boundaries, etc.), personal therapy, behavioural modification techniques like Cognitive Behaviour Therapy (CBT) or Dialectical Behaviour Therapy (DBT), some have also reported success with techniques like hypnosis.

Other patients are triggered primarily by diet. These community members benefit from removing specific trigger foods through dietary programs like the Low FODMAP Diet, taking probiotics, and/or restricting resistant starches and other common gut irritants.

Many patients benefit from a combination of stress reduction and diet changes. Others require the use of medications like antispasmodics and laxatives in combination with varying symptom management techniques.

If you are diagnosed with IBS, the symptom management tools in your toolbox will be specific to you. Remember that while IBS support communities can be helpful, every IBS patient is different. What works for someone else may not be right for you and vise versa. When someone insists there is one treatment method for IBS, remember Bob and his asparagus.


If you came here to understand IBS, this is what I want you to take away:

IBS is a chronic disorder of the large intestines (colon). It has no signs to look for, no tests to confirm your diagnosis, and currently, no cure. However, it does have a specific set of criteria and is a legitimate and recognized disorder. With this in mind, if you are experiencing frequent abdominal pain combined with problematic bowel movements it’s time to speak to your doctor.

Finally, I want you to take away hope that there are more avenues to explore, possibilities to consider, and most importantly, that you are not alone.

* There is currently a blood test for post-infectious IBS-D called IBScheck. I cannot confirm the accuracy of this test as there is not enough research to determine its reliability at this time.



This article was edited by Dr. Anne Agur B.Sc.O.T; M.Sc; Ph.D.

  1. Drossman, D. A., & Chang, L. (2016). Rome IV multidimensional clinical profile (MDCP) for functional gastrointestinal disorders. Raleigh: Rome Foundation.

  2. Dugum, M., MD, Barco, K., RD, LS, CNSC, & Garg, S., MD. (2016). Managing irritable bowel syndrome: The low-FODMAP diet. Cleveland Clinic Journal of Medicine, 83(9), 655-662. Retrieved from hhttp://www.mdedge.com/ccjm/article/111918/gastroenterology/managing-irritable-bowel-syndrome-low-fodmap-diet
  3. Heidelbaugh, J., & Hungin, P. (2016). Rome IV Functional Gastrointestinal Disorders for Primary Care and Non-Gi Clinicians (First ed.). Raleigh, NC: Rome Foundation.
  4. Mayo Clinic Staff. (2014, July 31). Irritable Bowel Syndrome (IBS) Fact Sheet. Retrieved April 22, 2017, from http://www.mayoclinic.org/diseases-conditions/irritable-bowel-syndrome/basics/definition/con-20024578
  5. The Monash University low FODMAP diet: reducing poorly absorbed sugars to control gastrointestinal symptoms. (2013). Clayton, Vic.: Monash University.
  6. Womens Health.Org (2012, July 16). Irritable Bowel Syndrome (IBS) Fact Sheet. Retrieved April 22, 2017, from https://www.womenshealth.gov/publications/our-publications/fact-sheet/irritable-bowel-syndrome.html#a

If you liked this article, you may also like one of these:

What is a FODMAP?

What is the Low FODMAP Diet?

3 Reasons to Keep A Food Journal


© 2017 Amy Agur – The FODMAP Formula




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