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Have you got SIBO or is it something else? Dietitian explains

Digestive problems can be a source of discomfort and frustration for many people. One condition that has gained attention in recent years is Small Intestinal Bacterial Overgrowth (SIBO).

However, SIBO shares symptoms with various other gastrointestinal conditions. In this blog post, we'll explore the common symptoms of SIBO, its potential causes, and how a dietitian can help you navigate the complex world of digestive health. So we can start to explore whether your symptoms are SIBO or if they may be something else!

Is your bloating and gut symptoms related to SIBO or something else?

Understanding SIBO

Small Intestinal Bacterial Overgrowth, or SIBO, is a condition characterised by an abnormal increase in bacteria in the small intestine, disrupting its delicate balance. When an overgrowth of bacteria occurs in the small intestine, it can lead to a range of digestive problems.

Common SIBO symptoms

SIBO shares symptoms with several other gastrointestinal disorders, making it challenging to diagnose. Common symptoms include:

  • Bloating

  • Abdominal pain or discomfort

  • Diarrhoea

  • Urgency

  • Gas

  • Weight loss

Potential causes of SIBO

Several factors can contribute to the development of SIBO:

  1. Impaired Motility: Conditions like irritable bowel syndrome (IBS), or nerve damage can slow down the movement of food through the small intestine, creating an environment where bacteria can thrive.

  2. Low Stomach Acid: Adequate stomach acid is essential for preventing harmful bacteria from entering the digestive system. A deficiency in stomach acid can facilitate the entry of unwanted microbes into the small intestine.

  3. Anatomical Abnormalities: Structural issues in the gastrointestinal tract, such as diverticula or strictures, can hinder the flow of digestive contents, promoting bacterial overgrowth.

  4. Medical History and Medications: Proton-pump inhibitors, opioids, gastric bypass and colostomy are some conditions and medications that may predispose an individual to SIBO.

How is SIBO diagnosed?

You should have a full assessment first to check your symptoms and what testing is right for you. If you are at risk of having SIBO you will then go onto carrying out testing.

Although not necessarily the gold standard, breath tests are the most common and non-invasive method for diagnosing SIBO. Hence you will typically be diagnosed using this method. These tests measure the gases produced by the bacteria in your small intestine.

The two primary types of breath tests used for SIBO (or other conditions associated with SIBO) diagnosis are:

  • Hydrogen Breath Test: This test involves consuming a solution that contains a specific sugar, such as lactulose or glucose. If SIBO is present, the bacteria will ferment the sugar, producing gases like hydrogen and methane, which are then measured in your breath at specific intervals.

  • Methane Breath Test: A methane breath test specifically checks for methane-producing bacteria. Similar to the hydrogen breath test, you consume a sugar solution, and the levels of methane in your breath are measured. This is what we call intestinal methanogen overgrowth (IMO)

How is SIBO treated?

Despite what you may read online antibiotics are the primary treatment for SIBO. They help to reduce the excessive bacterial population in the small intestine. Commonly prescribed antibiotics for SIBO include rifaximin. Treatment duration and specific antibiotics depend on the type of bacteria detected and the severity of symptoms. It's essential to follow your gastroenterologist's instructions regarding the antibiotics prescribed.

If you have done any of your own research into treatment for SIBO you may have read about the low FODMAP diet. A low-FODMAP diet restricts fermentable carbohydrates that can feed bacteria in the small intestine (as well as the large intestine!). This diet can help alleviate symptoms for some people with SIBO. But it is not a replacement for antibiotics. As the low FODMAP diet cannot eradicate this bacteria, it will just basically starve it. Therefore, it is not a long-term solution but may be useful for those with IBS too. It's essential to work with a registered dietitian to properly implement and manage this diet as it is very restrictive and can lead to worse health outcomes if not carried out properly.

Other tools for treatment purposes can also include certain types of prebiotic fibres and medications such as prokinetics too. This can help to improve outcomes. Your dietitian and gastroenterologist can guide you further on this.

Is it really SIBO or is it something else?

Given the overlap in symptoms between SIBO and other gastrointestinal conditions, it's crucial to consider alternative diagnoses. A dietitian and/or a gastroenterologist can play a crucial role in helping you determine the true cause of your digestive distress. Often using a method of ruling out other similar conditions. They can assist in identifying and ruling out:

  1. Food Sensitivities: Certain foods can trigger digestive symptoms that mimic SIBO. A dietitian can help you pinpoint these sensitivities and develop a tailored dietary plan.

  2. Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis share symptoms with SIBO. A dietitian can guide you in managing these conditions through diet. A dietitian can signpost you to appropriate testing with your doctor who can carry these out for you and translate your results for you.

  3. Irritable Bowel Syndrome (IBS): IBS can present with similar symptoms to SIBO, and dietary modifications can be effective in managing IBS-related discomfort.

  4. Functional Gut Disorders: You may be experiencing functional bloating and/or diarrhoea that is not related to any of the conditions above. Plenty can be done to navigate such symptoms with your dietitian.

How a dietitian can help

A registered dietitian can be your ally in finding the right path to digestive health. They can:

  1. Conduct a Detailed Dietary Assessment: A dietitian will review your diet and identify potential dietary triggers for your symptoms.

  2. Create a Personalised Nutrition Plan: Based on your symptoms and diagnosis, a dietitian can design a tailored nutrition plan to alleviate discomfort and improve your overall well-being.

  3. Provide Ongoing Support: Your dietitian can monitor your progress, make necessary adjustments to your diet plan, and offer guidance for long-term digestive health.


Digestive health concerns are not one-size-fits-all, and it's essential to consider alternative diagnoses if you suspect you have SIBO. A dietitian can be an invaluable resource in helping you determine the root cause of your digestive discomfort and guiding you toward a healthier, more comfortable life. Don't suffer in silence – seek the expertise of a dietitian to help you find answers and relief.

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