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How Do I Know If I Have IBS?

By 10th October 2022February 7th, 2023IBS
IBS Diagnosis

What is IBS?

IBS stands for irritable bowel syndrome which describes a set of symptoms relating to the digestive tract. IBS affects between 9-16% of the general population with higher levels seen in females.

The exact cause of IBS is unknown and likely varies between individuals depending on a range of factors. These include genetics, diet, environmental factors as well as alterations in the immune response in the gut.

The symptoms of IBS are abdominal pain and an associated change in stool frequency and/or form. For a diagnosis of IBS, there also needs to be the absence of a diagnosed gut condition such as coeliac disease, Crohn’s disease or bowel cancer.

Once IBS is diagnosed, it can then be classified into 1 of 4 different types of IBS.

These are:

  1. IBS-C – IBS with constipation
  2. IBS-D – IBS with diarrhoea
  3. IBS-M – IBS with bowel patterns that alternate between constipation and diarrhoea
  4. IBS (unclassified) [Source: Pubmed]

As with the diagnosis of IBS, the referral to the subtype further describes the types of symptoms being experienced. However, it does not explain the reason for the symptoms being present.

Considering the term ‘IBS’ as an umbrella term means that further understanding is needed to identify the underlying issue or issues that lead to the symptoms. [Source: MDPI]

What causes IBS?

The factors that lead to the symptoms of IBS can vary from patient to patient. However, they commonly fall into 3 groups. While not relevant to each person with IBS, a combination of these factors may be present and have a contributory impact leading to the symptoms of IBS.

  1. Lifestyle and Environmental Factors
  2. Nutritional Factors
  3. Functional Imbalances

Each of these categories can be expanded further.

Lifestyle and Environmental Factors

  • Stress
  • Circadian disruption
  • Physical inactivity

Nutritional Factors

  • Carbohydrate intolerance
  • Lactose intolerance
  • Food hypersensitivity
  • Non-coeliac gluten sensitivity
  • Nickel-related intestinal mucositis
  • Vitamin D deficiency

Functional Imbalances

  • Exocrine pancreatic insufficiency
  • Low-grade inflammation
  • Intestinal permeability
  • Bile acid diarrhoea
  • Chronic constipation
  • Dysbiosis
  • SIBO (small intestinal bacterial overgrowth)
  • Parasitic infection [Source: MDPI]

Also Read: IBS and Stomach Noises

Woman With IBS

How do I know if I have IBS?

IBS will be diagnosed by a doctor or gastroenterologist. Commonly this is once other conditions have been tested for and ruled out.

These conditions that are considered and ruled out for a diagnosis of IBS can include:

  • Coeliac disease
  • Inflammatory bowel disease (Crohn’s disease or ulcerative colitis)
  • Bowel cancer
  • Diverticular disease
  • Gallstones
  • Microscopic colitis
  • Bile acid malabsorption
  • Anti-biotic associated diarrhoea
  • Hyperthyroidism [Source: Pubmed]

Once these conditions have been considered, there are a set of criteria that need to be met for an official diagnosis of IBS. These are part of the Rome IV criteria which state for a diagnosis of IBS there needs to be:

“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” [Source: Pubmed]

This means that if specific conditions have been ruled out and the symptoms are still present a diagnosis of IBS is likely given.

Also Read: How To Cure IBS Permanently

Gut Health and IBS

An alteration in the balance of the gut microbiome is a key area that contributes to the development of IBS symptoms. This alteration in the gut organisms is understood to result in changes in the immune response in the digestive tract. This can then lead to the alterations in gut function commonly seen in IBS [Source: Pubmed].

There is not a single type of imbalance that is seen in the gut bacteria of all of those with IBS. However, imbalances in key microbial species can often be seen in IBS patients. For example, the Bifidobacteria species of gut bacteria tend to be lower in IBS patients when compared to those without IBS.  The reduction in this species correlates with increased severity of IBS symptoms such as abdominal pain [Source: Frontiers]

Research into prebiotic supplements such as GOS and PHGG (which can support the growth of Bifidobacteria species) have been reported to reduce IBS symptoms. [Source: Pubmed]

As will be discussed in more detail, long-term dietary patterns are associated both with the development and the ongoing nature of symptoms in IBS.

Also Read: How Long Does IBS Last?

Worst foods for IBS

There are certain foods that can trigger symptoms of IBS. These are considered a ‘first-line’ approach to managing IBS symptoms.

The most common triggers for people with IBS symptoms are commonly:

  • Alcohol
  • Caffeine
  • Spicy foods
  • Fats [Source: Pubmed]

Research has indicated that restricting these groups may be as effective as a more restrictive diet such as the Low FODMAP diet [Source: Pubmed]. It is also important to note that meal timing can contribute to IBS symptoms with a regular eating pattern being beneficial for gut health [Source: MDPI].

Certain foods may trigger symptoms of IBS within several hours after they’ve been consumed therefore limiting these foods may help to manage symptoms. However, overall dietary patterns are important when considering the development and worsening of IBS symptoms.

Also Read: What To Eat With an IBS Attack

In particular, the higher intake of sugar and refined carbohydrates (found in sweets, cakes, and refined wheat products) may contribute. This is due to the ability of the gut microbiome in the small intestine to digest these sugars very rapidly.

This then has the potential to lead to an imbalance in the small intestinal microbiome, a factor that is understood to contribute to IBS. While these sugars and refined carbohydrates may not trigger symptoms, a high intake may lead to imbalances in the gut microbiome which can perpetuate IBS symptoms [Source: Pubmed]

Low FODMAP diet for IBS

The Low FODMAP diet has been designed as a diet to manage symptoms in those with IBS. It works by restricting the intake of highly fermentable carbohydrates that are consumed.

These carbohydrates are found in a wide range of foods which include garlic, onions, beans, lentils, apples and wheat.

While these foods are generally considered healthy, if there are imbalances in the gut these foods can trigger symptoms such as pain, bloating, distention, and alterations in bowel function. [Source: Pubmed]

The Low FODMAP diet for IBS is considered a short-term approach to help identify triggers and manage IBS symptoms. It does not address the underlying imbalance in the digestive tract.

It is also worth noting the potential downside to a Low FODMAP diet. Long-term adherence to a Low FODMAP diet may lead to further imbalances in the gut microbiome. This is due to low levels of the beneficial gut fibre which reduced the presence of key gut species such as Bifidobacteria [Source: Pubmed].

Also Read: What Is a FODMAP Diet?


Small intestinal bacteria overgrowth (SIBO) is where there is an abnormally high number of bacteria in the small intestine. This overgrowth is typically in certain groups of bacteria that ferment carbohydrates. This fermentation in the small intestine can lead to many of the symptoms commonly seen in IBS and SIBO.  These include:

  • Bloating
  • Flatulence
  • Abdominal discomfort/pain
  • Alterations in stool form (diarrhoea or constipation) [Source: Pubmed]

There are links between long-term dietary patterns and the development of SIBO. This is where there is a higher intake of refined carbohydrates and sugars alongside a lower intake of dietary fibre. This pattern is often referred to as the Western Diet [Source: Pubmed]

Since these carbohydrates and sugars are quickly fermented in the small intestine, they may contribute to the bacteria overgrowth seen in SIBO [Source: Pubmed]

Working to address this bacterial overgrowth can be a key aspect of an IBS program.

Can stress and anxiety cause IBS?

Anxiety, as well as depression, are both frequently seen in those with IBS. In as many as 65% of cases, these symptoms may be the result of gastrointestinal disturbances. This can mean that for many, these symptoms are the result, not the cause of the IBS. [Source: Pubmed]

However, long-term stress (described as chronic life stress) is a factor that can predict the intensity of symptoms in those with diagnosed IBS. It has also been seen that the absence of stress from someone’s life can result in a better improvement of symptoms. [Source: Pubmed]

Additionally, poor ability to cope with stress has also been found to predict the severity of the IBS symptoms experienced. [Source: Pubmed]

Bad Sleep and IBS

The sleep-wake cycle is described as the circadian rhythm. A regular and consistent circadian rhythm regulates a wide range of biological processes. From a gut perspective, it influences factors such as:

  • Gut motility (bowel movements)
  • Visceral sensitivity (the sensitivity of the nerves in the gut)
  • The gut immune system
  • Gut integrity of the gut lining (how resilient the gut lining is) [Source: Pubmed]

When studied, those with IBS and sleep disruption are more likely to experience gut more intense symptoms of IBS. These symptoms include more pain, increased distress and a reduction in quality of life. [Source: Pubmed]

This is not solely related to sleep quality. It has been seen that those who work shifts (eg night shift workers) have a higher level of severity of IBS symptoms, regardless of the quality of their sleep. [Source: Pubmed]

Supplements for IBS

A wide range of supplements can support the gut in IBS. Some of the most commonly use are peppermint oil, probiotics and prebiotics.

Peppermint oil has been well-researched for addressing a wide range of IBS symptoms. It contains certain compounds that can help to relax the muscles in the gut making it helpful for reducing cramps and spasms. Additionally, it has antimicrobial, anti-inflammatory and pain-reducing properties, all of which are relevant in many cases IBS [Source: Pubmed]

Probiotics can be used to support the gut microbiome and address IBS. When selecting probiotics, the exact type of bacteria in the product is an important consideration to make. Selecting the strain of bacteria with the appropriate research can lead to better outcomes. For example, the L Rhamnous GG probiotic may be most appropriate for those with the IBS-D or IBS-M subtypes of IBS [Source: Pubmed]. While the Lactobacillus Plantarum 299v strain may be most appropriate for bloating and abdominal pain [Source: Pubmed]

Prebiotics are types of fibres that support the growth of key beneficial bacteria. As with the use of probiotics, the selection of prebiotics can be made based on symptoms and the specific gut bacteria that may need support. The prebiotic PHGG has been shown to reduce bloating and help to normalise bowel patterns. This means that it can help in both IBS-D and IBS-C [Source: Pubmed, Pubmed, Pubmed].


It can be reassuring once the more concerning gut conditions (such as IBD and cancer) have been ruled out. However, this can commonly mean that a diagnosis of IBS is given. While not life-threatening it does commonly lead to a reduction in the quality of life of the patient. Patients are also commonly told that they need to self-manage the condition.

While all cases of IBS there is an underlying issue or combination of issues. These factors can vary from person to person which means a personalised approach is required.

At The IBS & Gut Health Clinic, we work to identify and address these issues and restore gut health. Contact us for an initial 15-minute assessment.