Understanding the Root Causes of IBS

Understanding Irritable Bowel Syndrome (IBS): Symptoms, triggers and root causes of IBS


What is IBS and what are the symptoms of IBS?


Irritable bowel Syndrome (IBS) is one of the most widespread digestive disorders, affecting between 7-15% of the population. Symptoms of IBS include stomach cramps, bloating, constipation, diarrhoea or alternation between the two (mixed pattern) and often causes emotional stress.


How is IBS diagnosed?


The presentation of IBS symptoms usually prompts testing to rule out conditions such as inflammatory bowel disease (for example Coeliac disease, Crohn’s disease and ulcerative colitis) and colon cancer. IBS is diagnosed if no condition or disease can be found. IBS is a diagnosis of exclusion, meaning that, it’s diagnosed when specific conditions have been ruled out. The cause of IBS often goes unexplained, even though symptoms remain. IBS is classified as a functional gastrointestinal disorder and is poorly understood.
Conventional advice for managing IBS includes: avoiding hard-to-digest food, reducing stress, exercising, keeping a food diary to monitor trigger foods and trying a probiotic. Medications such as antidepressants, laxatives and antispasmodics are often used to manage symptoms rather than address the cause. IBS-D (diarrhoea) and IBS-C (constipation) are two different types of IBS. However, they have similar risk factors, causes and triggers. The underlying causes of IBS discussed in this article apply to both IBS-D and IBS-C.


“IBS is a diagnosis of exclusion, meaning that, it’s diagnosed when specific conditions have been ruled out”


Causes and Triggers of IBS


One key aspect of managing IBS is understanding and identifying the root causes and triggers. Research has identified several root causes and triggers that can cause IBS symptoms. These often vary from person to person, but some of the most prevalent ones include chronic stress, food intolerances, inflammatory foods, microbiome imbalances (such as SIBO & Candida overgrowth) and digestion dysfunction. By recognizing and addressing these underlying causes, individuals with IBS can implement a more personalized approach towards reducing symptoms and improving their overall quality of life.


“Root causes of IBS include food intolerances, microbiome imbalances, including SIBO & Candida overgrowth, inflammatory foods and digestive dysfunction”



The Role of Gut Dysfunction in IBS


The most common gut dysfunctions will be explored in detail below, including the different mechanisms underlying these dysfunctions and what to consider to improve these different areas of gut function.


Food Intolerances & IBS

Food hypersensitivity:

Food intolerances can potentially contribute to the development of Irritable Bowel Syndrome (IBS) by triggering inflammation in the digestive system. It’s important to note that a food intolerance differs from a food allergy, as it involves a milder immune response that is delayed, prolonged, and generally less severe compared to an allergy. The most commonly encountered food intolerances are dairy, gluten, and eggs. Symptoms of food hypersensitivity can extend beyond the gut and affect the entire body, leading to issues such as headaches, muscle and joint pain, eczema, acne, fatigue, and respiratory problems. To identify specific food intolerances, one can consider trying an elimination diet, maintaining a food diary, and gradually reintroducing foods one at a time. These approaches can help pinpoint the problematic foods.


Lactose intolerance and fructose intolerance:

Lactose intolerance occurs when the body lacks the enzyme lactase, which is responsible for digesting lactose, a type of sugar found in milk. This inability to break down lactose leads to symptoms like diarrhoea and flatulence and is often overlooked as a potential cause of Irritable Bowel Syndrome (IBS). By eliminating lactose from the diet, individuals who are lactose intolerant can typically find relief from IBS-D symptoms.
Fructose, a type of simple sugar, is naturally present in small quantities in fruits and certain vegetables. However, it is found in much larger amounts in sweeteners and added sugars. When the body has difficulty absorbing fructose, it can result in abdominal pain and IBS-D, a condition known as fructose malabsorption. Managing fructose intolerance involves reducing sugar intake and focusing on improving overall gut health.


Carbohydrate malabsorption:

Carbohydrate malabsorption refers to difficulties in digesting and metabolizing foods rich in carbohydrates, particularly those that are fermentable. You may be familiar with the widely known low-FODMAP diet, often recommended for individuals with Irritable Bowel Syndrome (IBS). FODMAPs are a group of short-chain carbohydrates that are poorly absorbed in the small intestine, leading to increased gas and water in the colon for some people. This can result in IBS-D symptoms and severe bloating. Moreover, fructose and carbohydrate malabsorption have a connection to an imbalance in the gut called Small Intestinal Bacterial Overgrowth (SIBO), which we will discuss further. To address carbohydrate malabsorption caused by SIBO, it can be beneficial to try a low FODMAP diet and address any underlying SIBO issues through proper identification and treatment.



Microbiome Imbalances & IBS

Our gut harbours a diverse array of microorganisms, including bacteria, viruses, parasites, and fungi. These microorganisms serve crucial roles in our immune system, metabolism, detoxification processes, and the regulation of inflammation. The majority of these bacteria reside in the large intestine, while the small intestine contains a significantly smaller population.



IBS & SIBO: SIBO stands for Small intestinal bacterial overgrowth (SIBO):

This condition refers to the abnormal growth of bacteria in the small intestine. Patients with Small Intestinal Bacterial Overgrowth (SIBO) commonly experience symptoms such as nausea, abdominal cramping, bloating, flatulence, and diarrhoea, which are similar to those seen in IBS-D. The prevalence of SIBO in individuals with IBS ranges between 19-37%. It is worth noting that constipation may also be associated with SIBO, albeit with the overgrowth of different bacteria compared to the dominant form in diarrhoea-predominant SIBO. Typically, methane-producing bacteria are involved, and the overgrowth tends to occur more in the large intestine rather than the small intestine.

Several risk factors contribute to the development of SIBO, including impaired digestion, immunodeficiency, physical abnormalities resulting from abdominal surgery, medication usage, and poor gut motility. The initial step in diagnosing SIBO is usually a SIBO breath test. If the test yields a positive result for SIBO (either hydrogen or methane), a treatment protocol is recommended, involving either antibiotics or antimicrobial herbs to address the overgrowth. Following SIBO treatment, it is typically advisable to undergo a gut restoration protocol aimed at supporting a healthy gut microbiome, promoting gut motility, and optimizing digestive function to prevent relapse.
The prevalence of SIBO in IBS patients is between 19-37%. SIBO is a common cause of IBS in many cases.



Parasite infection:

A Blastocystis infection may be overlooked as a cause of IBS symptoms in some individuals. There is a high rate of Blastocystis in IBS patients. Blastocystis can cause inflammation in the gut and intestinal hyper-permeability. Specific antibiotics or antimicrobial herbs can be used to target this infection.


Gut dysbiosis:

An imbalance between beneficial and pathogenic bacteria in the gut can trigger an immune response, leading to heightened gut inflammation, intestinal hyperpermeability, and heightened sensitivity to gut pain. Individuals with IBS often exhibit low levels of the beneficial bacterium Bifidobacterium. To restore a healthy balance of gut bacteria, a diet abundant in probiotic and prebiotic foods, coupled with probiotic supplements, can be beneficial.
Candida overgrowth may cause increased intestinal permeability (leaky gut), allowing toxins and undigested food particles to enter the bloodstream and trigger an immune response.



Candida overgrowth:

In certain cases of IBS, an imbalance in the gut microbiota, specifically an overgrowth of Candida, can occur. This overgrowth disrupts the delicate equilibrium of the gut ecosystem, resulting in digestive symptoms commonly associated with IBS, including bloating, gas, and irregular bowel movements. Moreover, candida overgrowth can contribute to increased intestinal permeability, also known as leaky gut, allowing toxins and undigested food particles to enter the bloodstream and trigger an immune response. To address this issue, an anticandida protocol is recommended, which typically involves incorporating antifungal herbs, probiotics, detox support, and gut-healing nutrients.


“Leaky gut can be caused by food intolerances, infections and chronic stress and is another common cause of IBS symptoms”



Leaky gut:

Intestinal hyperpermeability, also known as “leaky gut,” refers to a condition where the lining of the intestines, which is naturally selective in allowing specific substances like nutrients and immune messengers to pass through while preventing others like food particles from entering the bloodstream, becomes compromised. This compromised intestinal lining can lead to inflammation. Leaky gut can be triggered by factors such as food intolerances, infections, and chronic stress. It contributes to chronic low-grade intestinal inflammation and heightened sensitivity to pain, which are key characteristics of IBS. Several factors can influence intestinal hyperpermeability, including viral and bacterial infections, dietary factors, and exposure to environmental toxins. It is recommended to address the underlying causes of leaky gut, such as food intolerances, inflammatory bowel disease (IBD), and microbiome imbalances while implementing a gut healing protocol to promote healing and restoration of the intestinal lining.


Stress & IBS


Stress plays a significant role in both triggering and intensifying symptoms of irritable bowel syndrome (IBS). The relationship between stress and IBS is intricate and operates in both directions. When we encounter stress, whether it originates from emotional factors, work demands, or life circumstances, our body’s stress response is activated. This response can impact the functionality of the digestive system, leading to alterations in gut motility, heightened pain sensitivity, and changes in intestinal permeability. For individuals with IBS, these physiological changes can provoke symptom flare-ups, including abdominal pain, bloating, diarrhoea, or constipation. On the flip side, the unpredictability of IBS symptoms can also generate significant stress and anxiety, establishing a vicious cycle.



Digestion and IBS


Pancreatic insufficiency:

Pancreatic insufficiency refers to the insufficient production of digestive enzymes by the pancreas, which is essential for breaking down proteins, carbohydrates, and fats in the gut, allowing for proper nutrient absorption from food. When pancreatic insufficiency occurs, digestion and nutrient absorption become compromised, leading to inflammation, malabsorption, intestinal hyperpermeability, and disrupted gut microbiota balance (dysbiosis). These factors collectively contribute to the manifestation of IBS symptoms. The assessment of pancreatic insufficiency typically involves stool testing, which can measure levels of pancreatic elastase. In cases of pancreatic insufficiency, digestive enzyme supplements can be taken to support digestion and compensate for inadequate enzyme production.


Low stomach acid (hypochlorhydria):

Low stomach acid, medically referred to as hypochlorhydria, can contribute to the development or worsening of irritable bowel syndrome (IBS). Stomach acid plays a vital role in the digestion process, including breaking down food, neutralizing harmful bacteria, and aiding nutrient absorption. Insufficient levels of stomach acid can hinder proper food digestion and breakdown. Consequently, undigested food particles may pass into the intestines, leading to fermentation and the production of gas. This can give rise to IBS symptoms such as bloating, abdominal discomfort, and altered bowel habits. Additionally, low stomach acid can disrupt the balance of gut bacteria, impede nutrient absorption, and compromise the overall integrity of the digestive system. Addressing low stomach acid through dietary and lifestyle adjustments, coupled with guidance from a holistic nutritionist, can potentially alleviate IBS symptoms and enhance overall digestive health.
When bile acids are not properly absorbed, they can accumulate in the colon and act as irritants, triggering symptoms such as diarrhoea, abdominal pain, and urgency, which are characteristic of both IBS and BAM.


Bile acid malabsorption (BAM):

Irritable bowel syndrome (IBS) and bile acid malabsorption (BAM) are two gastrointestinal conditions that often intersect with each other. Bile acids, produced by the liver and stored in the gallbladder, play a vital role in fat digestion. In certain cases, individuals with IBS may experience an imbalance or dysfunction in the regulation and absorption of bile acids in the intestines, leading to BAM. When bile acids are not properly absorbed, they can accumulate in the colon and act as irritants, triggering symptoms such as diarrhoea, abdominal pain, and urgency, which are common to both IBS and BAM. The connection between IBS and BAM underscores the intricate nature of digestive disorders and emphasizes the importance of accurate diagnosis and tailored treatment approaches to address the underlying causes and manage symptoms effectively. BAM is closely associated with factors like small intestinal bacterial overgrowth (SIBO) and gut inflammation, which present as specific areas we can target for symptom improvement.



Thank you for reading through all of the technical information. If you’re feeling overwhelmed and unsure about how to determine the underlying root cause of your condition, don’t worry! Many of these factors are interconnected and can be addressed simultaneously through dietary and lifestyle adjustments, along with targeted nutritional supplements to address your specific gut imbalance and triggers. You may find this post on Natural Remedies For IBS helpful. Working with a registered holistic nutritionist who specializes in IBS and gut health can be beneficial in identifying the specific root cause of IBS and addressing your individual gut health needs. If you have any questions, please don’t hesitate to reach out.



Brown, B.I., 2019. Does Irritable Bowel Syndrome Exist ? Identifiable and Treatable Causes of Associated Symptoms Suggest It May Not. (3), pp.314–340.

1 Comment

  1. Annmarie

    What a fantastic blog on the symptoms of ibs. Sadly too many medical drs blame so many digestive issues as ibs. But they have no real idea how to treat those suffering from it. Thank goodness we have claire and her knowledge to help seek out the root causes from digestive problems.