Small Intestinal Bacterial
Overgrowth (SIBO)​

Small intestinal bacterial overgrowth (SIBO) refers to an abnormal increase in the number of bacteria present in the small intestine. Rather than being caused by a single type of bacteria, SIBO involves an overgrowth of various bacterial species that are typically found in the colon, but their migration to the small bowel can lead to a range of digestive issues.

This bacterial overgrowth can significantly disrupt the digestion of food and absorption of nutrients by damaging the mucosal lining of the small intestine, leading to a condition known as leaky gut. This, in turn, can result in decreased nutrient absorption and inflammation.

Furthermore, the byproducts resulting from the bacterial breakdown of food can trigger episodes of loose stools, as well as other symptoms, highlighting the intricate relationship between gut health and overall well-being.


SIBO Risk Factors

SIBO Symptoms

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Common SIBO Symptoms

SIBO Breath Testing

The diagnostic criterion considered for detecting Small Intestinal Bacterial Overgrowth (SIBO) is the Breath Test. This test involves administering a substrate after the patient has followed a non-fermentable diet for 24 hours. Breath samples are collected every 20 minutes for a total of 3 hours after the substrate has been administered, and the concentration of hydrogen and methane gases is measured in each sample. If there is a significant increase or an overall elevated level of either of these gases, it indicates bacterial fermentation of the sugar, leading to a positive diagnosis of SIBO.

While other tests, such as stool analysis, may provide supplementary markers for SIBO, they are not considered true diagnostic tests for this condition. The Breath Test remains the primary diagnostic tool for accurately detecting Small Intestinal Bacterial Overgrowth.

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SIBO (Small Intestinal Bacterial Overgrowth) Treatment

Resolving Small Intestinal Bacterial Overgrowth (SIBO) typically requires a multifaceted approach involving a series of steps. Initially, the digestive tract environment must be reset using either natural or pharmaceutical antimicrobial agents, in conjunction with dietary and nutraceutical therapies to restore gut health and minimize the risk of future recurrence.

While various diets, such as the low FODMAP diet, have been found to be incredibly effective in managing SIBO symptoms, it is crucial to remember that the root cause of the problem lies in the interaction between the gut ecosystem and food. Consequently, any dietary intervention should be considered a short-term solution. Relying solely on a diet as a long-term strategy fails to address the underlying issue, which is why many patients continue to experience recurring symptoms.

What sets The Edinburgh Centre for Functional Medicine apart in treating SIBO is our holistic focus on the entire gut microbiome, rather than solely concentrating on the small intestine. While eradicating the bacterial overgrowth is paramount, we also prioritize the restoration of beneficial flora that produce beneficial molecules, such as short-chain fatty acids, which confer multiple benefits to the host.

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Why Choose the Edinburgh Centre for Functional Medicine?


Each individual is distinct and has a unique set of circumstances. Your symptoms, lifestyle, diet, genetics, and ability to heal are all different and therefore require a personalized approach that is tailored specifically to you


Once you begin the process with us, our collaborative approach with a practitioner will guide you through every step. We will collect the necessary information through detailed intake forms tailor our support to motivate and assist you throughout the process.


Our functional medicine practitioners have years of experience focusing on the route cause of disease that address any imbalances rather than just treating symptonms.

SIBO Symptoms
Small Intestinal Bacterial Overgrowth, or SIBO for short, is a gastrointestinal condition that occurs when bacteria which is typically found in the large intestine proliferates into the small intestine. This proliferation can disrupt the intricate balance of the digestive system and affect the normal function of the small intestine as these bacteria, along with other single-celled organisms known as archaea, ferment sugars, leading to the production of gases. The accumulation of these gases, predominantly hydrogen and methane, manifests in a spectrum of symptoms, with the following six being particularly common:
Abdominal Pain
Associated with bloating and stomach distention, abdominal pain can occur when the gases produced by bacterial fermentation distend the walls of the small intestine. This distension can induce varying degrees of intestinal pain and discomfort, ranging from mild to incapacitating, severely impacting an individual's quality of life and ability to engage in everyday activities.
The hallmark symptom of SIBO is bloating. This manifests as a pervasive sensation of fullness and abdominal discomfort. This can cause stomach distention, which is most pronounced around one to two hours following the consumption of meals rich in carbohydrates, which serve as substrates for bacterial fermentation.
Reflux and belching is a consequence of the accumulation of gases within the small intestine. While belching is a natural physiological process, it can be a distressing symptom for individuals with SIBO as the magnitude and frequency of belching is often excessive. This can cause significant discomfort and social embarrassment. Furthermore, excessive belching in individuals with SIBO can result in the regurgitation of acidic gastric contents into the oesophagus, mimicking the symptoms of gastro-oesophageal reflux disease (GERD) and manifesting as heartburn.
Just like belching, flatulence is very normal! However individuals with SIBO often experience heightened levels of intestinal gas production, characterised by increased frequency and potency of flatulence. This pervasive flatulence can cause significant bowel pain and discomfort, let alone embarrassment and avoidance of social activities and exercise. It can severely impact interpersonal interactions and self-esteem.
The excess bacteria in your small intestine breaks down bile salts, which are normally needed to digest fats. This can lead to poor digestion of fats, which can subsequently result in malabsorption of vitamins as your body can’t fully absorb fat-soluble vitamins like Vitamin A, D, E and K. Bacterial overgrowth can also lead to a Vitamin B-12 deficiency. This malabsorption can cause fatigue, weakness, brain fog and chronic tiredness.
A common symptom of Irritable Bowel Syndrome (IBS), diarrhoea and/or constipation is also a hallmark feature of SIBO. Diarrhoea is often caused by a malabsorption of fats, which can cause loose bowels. Both loose bowels and constipation can be extremely uncomfortable and embarrassing for both Irritable Bowel Syndrome and SIBO sufferers, but it’s important to understand why you are experiencing the symptoms and what the causes are, to be able to create an effective treatment plan.
SIBO Symptoms
These multifaceted symptoms collectively underscore the profound impact of SIBO on intestinal health and overall well-being, necessitating comprehensive evaluation and tailored therapeutic interventions to alleviate symptoms and restore optimal gastrointestinal function.