Screenshot 2023-02-02 at 13.28.19
Screenshot 2023-02-02 at 13.28.19

How Do I Know If I Have IBS?


Irritable Bowel Syndrome (IBS) is a chronic condition that affects the large intestine and can cause a variety of symptoms such as abdominal pain, bloating, constipation, and diarrhoea. 

The exact cause of IBS is unknown, but several factors that may contribute to its development, include:

  • Abnormalities in gut muscle contractions
  • Abnormalities in an individual’s gut bacteria
  • Increased sensitivity to pain in the gut
  • Psychological stress
  • Food intolerances or sensitivities
  • Hormonal changes in women
  • A previous gastrointestinal infection
  • Dysbiosis – an imbalance of bacteria in the gut – common post antibiotic/certain medication use 
  • Family history of IBS
  • SIBO – small intestinal bacterial overgrowth



To know if you have IBS, your doctor may use the Rome criteria, which are a set of guidelines used for diagnosing Irritable Bowel Syndrome (IBS). It was developed by the Rome Foundation, an international medical organisation dedicated to improving the understanding and management of functional gastrointestinal disorders. 

The Rome criteria are based on symptoms, and require the presence of abdominal pain or discomfort associated with changes in bowel habits over a minimum of 6 months.(1) The criteria are widely used by doctors as a diagnostic tool for IBS:

  1. Recurrent abdominal pain or discomfort at least 3 days per month in the last 3 months, associated with two or more of the following:
    • improvement with defecation
    • onset associated with a change in frequency of stool
    • onset associated with a change in form (appearance) of stool.
  2. Your doctor will also rule out other conditions such as inflammatory bowel disease (IBD), celiac disease, lactose intolerance, and colorectal cancer.

It is important to note that even if you meet the Rome criteria, it does not necessarily mean you have IBS, it’s just one of the tools that doctors use to identify potential cases of IBS. Your doctor will also consider your symptoms, medical history and may conduct some testing to rule out other conditions.

It is important to see a doctor if you think you have IBS to rule out other conditions and provide an accurate diagnosis.



An IBS diagnosis can be complicated for several reasons:

  1. Symptoms vary: IBS symptoms can vary greatly from person to person, and can also change over time. This makes it difficult for practitioners to diagnose based on symptoms alone.
  2. No specific test: There is no specific test for IBS, and diagnostic tests such as blood tests or imaging studies are typically normal in people with IBS.
  3. Overlapping symptoms: IBS symptoms can overlap with other conditions such as inflammatory bowel disease (IBD), hormonal conditions such as endometriosis, celiac disease, and certain infections. These conditions need to be ruled out before making a diagnosis of IBS.
  4. Multifactorial: IBS is a multifactorial disorder, meaning that a combination of factors such as genetics, gut bacteria, stress and diet may contribute to the development of symptoms.

Due to these complexities, a doctor’s diagnosis of IBS can sometimes take time and may involve a process of elimination to rule out other potential causes of symptoms.



Whilst doctors have a good understanding of the symptoms and potential triggers of IBS, the underlying mechanisms that could be triggering the IBS may not be explored, making it challenging for doctors to determine the best course of treatment for each individual patient. 

Medications are often given to clients, such as antispasmodics, laxatives, antidiarrheals, and low-dose antidepressants. 

These medications are not effective for some individuals and can also have negative side effects such as constipation, diarrhoea, bloating or abdominal pain. 

Due to IBS being an extremely complex condition with numerous potential causes, no one-size-fits-all when it comes to treatment. Patients are often given medication and told to live with the symptoms, which puts a plaster over their health concerns, rather than get to the underlying root cause.


A nutritional therapist who specialises in gut health can provide individualised dietary recommendations and support for managing IBS symptoms. They can help identify food triggers, rule out other conditions, provide guidance on eating patterns, and suggest supplements to help alleviate symptoms. 

They may also use functional testing to address underlying imbalances that may contribute to IBS. 

Functional testing that is often used in the Clarissa Lenherr clinic includes:

  1. Stool analysis: To get a deeper look into the gut microbiome and detect any imbalances, infections or inflammation.
  2. Breath tests: To assess small intestine bacterial overgrowth (SIBO), a common underlying issue in IBS.
  3. Organic acid testing: Helps to measure the levels of organic acids in urine, which can provide information about gut bacteria and metabolic function.
  4. Mould/ mycotoxin testing: Mycotoxins can be the cause of digestive issues such as abdominal pain, bloating, and diarrhoea. Additionally, mycotoxins can damage the gut lining and disrupt the delicate balance of the gut microbiome.
  5. Blood tests: To check for nutrient deficiencies and markers of inflammation
  6. Salivary hormone tests: To assess hormone imbalances, such as cortisol and serotonin, which can impact gut function and contribute to IBS symptoms.

It is important to note that not all functional tests are appropriate for every individual with IBS, and the choice of testing will depend on the specific symptoms and individual needs of the person.

A doctor may also provide information on dietary changes, but may focus more on medical treatment options to rule out any more serious conditions. Consulting both a doctor to rule out other conditions and a nutritional therapist for the management and reduction of symptoms can be beneficial for comprehensive management of IBS. 


If you want to read more about how a nutritional therapist can help in the management of your symptoms, read the below article and further explore the difference between a nutritional therapist, a nutritionist and a dietician: 


If you need support with your gut health and IBS, email my team for more information at  




References: (1)

Please note, Clarissa Lenherr Nutrition Limited uses affiliate links. If you buy something using these links, we may earn an affiliate commission, at no additional cost to you.

Leave a Comment

Hi there

London Nutritionist Clarissa Lenherr

I’m Clarissa, a registered nutritionist (mBANT) and workplace wellness expert. In my practice, I have helped hundreds of clients reach optimal health through creating sustainable, effective habits and dietary adjustments. My aim is to empower people with the skills, tools and knowledge to take their health into their own hands and feel the happiest, healthiest versions of themselves. Featured in The Daily Mail, Women’s Health, The Telegraph, and more.




Sign up for my exclusive 'Happy Gut Health' Ebook with recipes, expert advice and latest news.