Small Intestinal Bacterial Overgrowth
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.
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.
Risk factors
SIBO risk factors
- Ulcerative colitis
- Crohn’s disease
- Coeliac disease
- Irritable bowel syndrome
- Diabetes
- Cirrhosis / pancreatitis
- Medications
- Oral health
- Sinus infection
- Low stomach acid
Symptoms we see
SIBO symptoms
SIBO can produce both digestive and wider, systemic symptoms — many of which seem unrelated to the gut.
- Constipation
- Distended gut
- Headaches
- Brain fog
- Fatigue
- Loose stools
- Joint pain
- GERD
- Anxiety / depression
- Excessive gas
- Weight gain
- Thyroid issues
- Sleep dysregulation
- Skin issues (psoriasis, rosacea)
Diagnosis
SIBO breath testing
The diagnostic criterion considered for detecting SIBO is the breath test. This involves administering a substrate after the patient has followed a non-fermentable diet for 24 hours. Breath samples are collected every 20 minutes over three hours, and the concentration of hydrogen and methane gases is measured in each sample. A significant increase, or an overall elevated level of either gas, indicates bacterial fermentation of the sugar and leads to a positive diagnosis.
While other tests, such as stool analysis, may provide supplementary markers, they are not considered true diagnostic tests for SIBO. The breath test remains the primary diagnostic tool for accurately detecting small intestinal bacterial overgrowth.
In detail
Six common SIBO symptoms
As bacteria and archaea ferment sugars, they produce gases — predominantly hydrogen and methane — that drive a spectrum of symptoms.
Abdominal pain
Gases produced by bacterial fermentation distend the walls of the small intestine, inducing intestinal pain and discomfort ranging from mild to incapacitating.
Bloating
The hallmark symptom of SIBO — a pervasive sensation of fullness, most pronounced one to two hours after meals rich in carbohydrates.
Reflux
Accumulated gas can cause excessive belching and regurgitation of acidic contents into the oesophagus, mimicking GERD and heartburn.
Flatulence
Heightened gas production means increased frequency and potency of flatulence, which can cause bowel pain, discomfort and social avoidance.
Fatigue
Excess bacteria break down bile salts needed to digest fats, impairing absorption of fat-soluble vitamins A, D, E and K and vitamin B12 — leading to fatigue and brain fog.
Diarrhoea / constipation
A hallmark feature shared with IBS. Understanding why you experience these symptoms, and what is driving them, is essential to an effective treatment plan.
Treatment approach
Our objective is to aid you in achieving optimal health and wellbeing
Resolving 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 minimise the risk of future recurrence.
While diets such as the low FODMAP diet can be incredibly effective at managing symptoms, the root of the problem lies in the interaction between the gut ecosystem and food. Any dietary intervention should be considered a short-term solution — relying on diet alone as a long-term strategy fails to address the underlying issue, which is why many patients experience recurring symptoms.
What sets the Edinburgh Centre for Functional Medicine apart is our holistic focus on the entire gut microbiome, rather than solely the small intestine. While eradicating the overgrowth is paramount, we also prioritise restoring the beneficial flora that produce molecules such as short-chain fatty acids, which confer multiple benefits to the host.
Why choose us
Care built around understanding why
Our mission
We provide a supportive environment paired with cutting-edge expertise in nutrition and functional medicine.
Our mission is to help you uncover the root causes of your health concerns and guide you through them with personalised nutrition and lifestyle strategies.
Our values
We practise root-cause medicine — because true healing starts with understanding why symptoms arise.
Our goal is to uncover the underlying drivers of your health concerns and empower you with the tools to make lasting, sustainable changes.
Support
Once you begin with us, our collaborative approach guides you through every step. We collect the information we need through detailed intake forms and tailor our support to motivate and assist you throughout the process.
Success stories
What our clients say
★★★★★Working with Rob was a truly transformative experience. His guidance not only helped me navigate a wide range of symptoms but also gave me the knowledge and tools to build lasting, healthy habits. I feel more empowered and informed about my health than ever before. Edinburgh CFM is setting a new standard for how healthcare should be delivered — I can’t recommend Rob highly enough.
Alex
★★★★★Edinburgh CFM has been life-changing for me. Living with eczema was overwhelming — it felt like it was taking over every part of my life. I joined the 6-month programme hoping for some guidance, and what I got was so much more. With Rob’s support I now understand the specific foods and lifestyle triggers that were making things worse. For the first time my eczema is under control without relying on steroids — and I finally feel empowered in my own skin.
Rebecca
★★★★★My daughter was having health challenges and someone recommended the centre. She received a diagnosis of gut issues and found out she had SIBO. With the help of our practitioner we were able to get her back to school so she could continue her studies for her exams. Highly recommended.
Joan
★★★★★I came to the centre with a diagnosis of Hashimoto’s. I hadn’t been able to find a clinic that would provide understanding and a way to approach the disease without just suppressing symptoms. I feel like I matter and so do my symptoms. Progress has been far greater than through any other treatment option, and at each appointment I can share where I am and look at the next steps. I would highly recommend this clinic.
Marcus
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