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Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that affects approximately 11% of the global population.

It is characterised by abdominal pain, bloating, and altered bowel habits, which can significantly impact a person's quality of life.

Despite being a common condition, the exact cause of IBS is not fully understood. However, researchers have made significant strides in recent years in identifying the potential causes of IBS.

In this post, we will explore the 7 causes of IBS, based on the latest research.

1. Gut Microbiota Dysbiosis

Dysbiosis refers to an imbalance in the gut bacteria, or microbiota.

The first cause of IBS is said to be the disrupted balance of the gut microbiota which is a collection of microorganisms that reside in the human gut. Dysbiosis, or alterations in the gut microbiota, may play a role in the development of IBS.

Studies have shown that patients with IBS have a less diverse gut microbiota compared to healthy individuals.

Additionally, changes in the abundance of specific bacteria, such as increased levels of Methanobrevibacter smithii and decreased levels of Bifidobacterium, have been observed in patients with IBS (1).

2. Intestinal Inflammation

Intestinal inflammation has been identified as the second potential cause of IBS.

Studies have shown that patients with IBS have increased levels of inflammatory markers in their blood and stool samples (2).

Additionally, some patients with IBS have been found to have increased intestinal permeability, which may allow harmful substances to enter the bloodstream and trigger an immune response (2).

3. Food Intolerances

The third cause of IBS is prolonged food intolerances. Food intolerances are a common trigger for IBS symptoms.

Certain foods, such as those high in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs), can cause digestive discomfort in some individuals.

A low FODMAP diet has been shown to improve symptoms in patients with IBS (3).

4. Infection and Parasites

In some cases, IBS can be triggered by an infection or parasite in the gut. This is known as post-infectious IBS (PI-IBS). This is the fourth cause of IBS.

Studies have shown that individuals who develop PI-IBS after an infection may have changes in the gut microbiota, increased intestinal permeability, and immune activation (4).

5. Psychological Triggers

Psychological triggers, such as stress, anxiety, and depression, have been identified as potential causes of IBS.

The gut-brain axis is a bidirectional communication system between the central nervous system and the gut. It plays a crucial role in the regulation of gastrointestinal function, including motility, secretion, and immune response (5).

Psychological stress can disrupt the gut-brain axis and lead to the development of IBS symptoms.

Studies have shown that patients with IBS have higher levels of psychological distress compared to healthy individuals (5).

Chronic stress and anxiety can increase intestinal permeability, activate the immune system, and alter the gut microbiota, all of which may contribute to the development of IBS symptoms.

Additionally, depression has been found to be a risk factor for the development of IBS (5).

6. Prolonged Use of Antibiotics

Prolonged use of antibiotics has been associated with the development of IBS.

Antibiotics can alter the gut microbiota, leading to dysbiosis and potentially causing IBS symptoms.

A study found that individuals who had received more then three courses of antibiotics had a significantly increased risk of developing IBS compared to those who had received fewer courses (6).

7. Genetics

Genetics may also play a role in the development of IBS.

Studies have shown that there may be a genetic predisposition to IBS, with certain genetic variants being associated with an increased risk of developing the condition (7).

However, more research is needed to fully understand the genetic factors underlying IBS.


While the exact cause of IBS is not fully understood, researchers have made significant strides in identifying the 7 potential causes of IBS, a common gastrointestinal disorder.

Dysbiosis, intestinal inflammation, food intolerances, infection and parasites, psychological triggers, prolonged use of antibiotics, and genetics have all been identified as potential causes of IBS.

Further research is needed to fully understand the underlying mechanisms behind these potential causes and to develop more effective treatments for this condition.


What to do if you have IBS?

Download a FREE low FODMAP meal plan and get started with your symptom relief today.

Stress is a normal part of life, but chronic stress can have negative impacts on our physical and mental health. One area that is often overlooked when it comes to the effects of stress is the gut microbiome.

Stress and Gut Health - Photo by Mariana Medvedeva on Unsplash

The Gut Microbiome

The gut microbiome is the community of bacteria, viruses, and other microorganisms that live in the digestive tract. 

These microorganisms play an important role in many aspects of health, including digestion, metabolism, and immune function. 

Gut Health Balance

Research has shown that stress can disrupt the balance of the gut microbiome, leading to a range of negative effects on health.

One way that stress can impact the gut microbiome is by altering the types of bacteria that are present. 

Chronic stress has been shown to increase the prevalence of "bad" bacteria, such as Escherichia coli, and decrease the amount of "good" bacteria, such as Bifidobacteria and Lactobacilli. 

This imbalance can lead to digestive issues, such as constipation or diarrhea, as well as a weakened immune system.

Gut-Brain Axis

Stress can also affect the gut-brain axis, the communication network between the gut and the brain. 

This communication is important for maintaining gut health, but stress can disrupt this communication, leading to further imbalances in the gut microbiome.

Other Consequences of Stress

In addition to these direct effects on the gut microbiome, stress can also indirectly impact the health of the gut through behaviors that are commonly associated with stress, such as poor diet and lack of physical activity. 

These behaviors can further disrupt the balance of the gut microbiome and lead to negative health consequences.

So, What Can We Do?

Reduce daily stress

Practice stress-reducing techniques, such as meditation, deep breathing, or exercise.

Address your diet & lifestyle to support your gut health

Eliminate all the gut irritants, re-build a healthy gut and nourish it long term to improve gut health and minimise digestive discomfort. See our Gut Health Bible and Recipe Ebook which steps you through exactly how to do this yourself.

Eat a healthy, balanced diet that includes a variety of the 5 food groups, fermented foods, prebiotics and probiotics to promote the growth of good bacteria. See the Gut Health Bible & Recipe Book on how to do this.

Get plenty of rest

Get enough sleep to allow the body and the gut microbiome to rest and repair.


Stay physically active to promote good gut health, but don’t over do it!

By taking steps to reduce stress and promote a healthy gut microbiome, it is possible to improve overall health and well-being.

If you want an easy guide on how to completely re-build and nourish your gut health, see our Gut Health Bible & Gut Healthy Recipe Ebook.

We also offer a Dietitian Gut Health Program if you feel you need more accountability and support on your gut health journey.

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