Understanding Small Intestinal Bacterial Overgrowth (SIBO): Symptoms, Causes, and Treatment
Small Intestinal Bacterial Overgrowth (SIBO) is a digestive disorder that occurs when bacteria that normally reside in the large intestine move upward into the small intestine. This bacterial overgrowth can lead to a range of digestive problems, and in some cases, an overgrowth of archaea (like Methanobrevibacter) can result in excessive methane production, causing constipation and slow gut transit.
How SIBO Disrupts Digestive Function
SIBO impacts digestive health in three main ways:
Migrating Motor Complex (MMC) Dysfunction: The MMC is responsible for “cleaning” the small intestine every 90 minutes, especially between meals, by pushing bacteria and food into the large intestine. When this process malfunctions, bacteria can accumulate and overgrow.
Malabsorption: Damage to the small intestine’s microvilli reduces digestive enzyme production, leading to malabsorption of carbohydrates, proteins, and fats. The bacterial breakdown of these nutrients causes fermentation, producing gas and leading to bloating, discomfort, and altered stool patterns.
Leaky Gut (Intestinal Permeability): SIBO can also lead to leaky gut, where bacteria, endotoxins, and food particles leak into the bloodstream, triggering an immune response and inflammation, contributing to allergies, food sensitivities, or even autoimmune conditions.
Who is Affected by SIBO?
SIBO can affect anyone, but certain individuals are more susceptible, including:
People with Irritable Bowel Syndrome (IBS)—SIBO is a major cause of IBS.
Those recovering from gastroenteritis.
Individuals with symptoms that worsen after consuming xylitol, prebiotics, probiotics, or high-fibre foods.
Coeliac disease patients who continue to experience symptoms despite following a gluten-free diet.
Conditions Associated with SIBO
If you have any of the following conditions, you may be more likely to develop SIBO:
Fibromyalgia
Chronic Fatigue Syndrome (CFS)
Helicobacter pylori infection
Irritable Bowel Syndrome (IBS)
FODMAP malabsorption
Diverticulitis
Diabetes
Autoimmune diseases like Scleroderma and Lupus
Hypothyroidism
Signs and Symptoms of SIBO
The symptoms of SIBO vary but commonly include:
Bloating, belching, and flatulence
Diarrhoea or constipation
Abdominal pain and discomfort
Nutrient malabsorption (e.g., weight loss, vitamin deficiencies, iron-deficiency anaemia)
Acne rosacea or skin conditions related to nutrient deficiencies (e.g., keratosis pilaris)
Causes and Triggers of SIBO
SIBO can be triggered by a variety of factors:
Gastroenteritis: Damage to the gut wall after an infection.
Migrating Motor Complex Dysfunction: A result of frequent snacking or overconsumption of refined carbohydrates.
Medications: Proton pump inhibitors (PPIs), NSAIDs, and antibiotics disrupt gut health.
Stress: Chronic stress lowers stomach acid production, increasing bacterial load in the small intestine.
Anatomical Changes: Conditions like cholecystectomy (gallbladder removal) or ileocecal valve issues.
Dysmotility: Seen in conditions like Parkinson’s disease and diabetes.
Certain lifestyle habits, like long-term use of PPIs, opioid use, or a low-fibre, high-protein diet, can increase the risk of developing SIBO.
Diagnosing SIBO
The gold standard for diagnosing SIBO is a small bowel aspirate and culture, but due to the invasive nature of this test, it is not commonly used. Instead, a lactulose breath test is the most widely used diagnostic tool. This involves ingesting lactulose and measuring the gases (hydrogen and methane) exhaled over a period of time. If there is a significant rise in gas levels, it indicates the presence of SIBO.
However, it’s important to note that the lactulose breath test has limitations and can sometimes result in false positives. Combining it with a glucose breath test can provide more accurate results, as glucose is absorbed faster in the small intestine and can better identify upper SIBO.
Treating SIBO: Medical and Natural Solutions
Allopathic Treatment
Antibiotics are the conventional treatment for SIBO, aiming to eradicate bacterial overgrowth. Commonly prescribed antibiotics include:
Metronidazole (Flagyl): Has a 20-43% success rate in treating SIBO.
Rifaximin: A locally acting antibiotic with a 64% success rate, although some studies suggest its effectiveness may not be statistically significant.
Unfortunately, there is a high relapse rate after antibiotic treatment, with symptoms often returning within months. Additionally, antibiotics can negatively impact the large bowel microbiome, making recovery more difficult.
Natural Treatment Solutions
1. Antimicrobial Herbal Medicine:
Natural antimicrobials that have shown promise in treating SIBO include:
Pomegranate
Fresh garlic
Green tea
Oregano
Thyme
Clove
2. Prebiotics:
These non-digestible fibres fuel beneficial gut bacteria and help restore balance in the microbiome. Prebiotics such as partially hydrolyzed guar gum and galactooligosaccharides (GOS) have been found to assist in treating SIBO.
3. Diet:
Eating three meals a day with 4-6 hours between meals allows the MMC to function properly, preventing bacterial overgrowth.
Avoiding excessive fluids during meals, chewing food thoroughly, and focusing on a whole-food, plant-rich diet can improve gut health.
Therapeutic diets such as low-FODMAP, gluten-free, or low-histamine may also be beneficial for individuals with specific gut sensitivities.
4. Lifestyle Adjustments:
Ensure adequate sleep (7-8 hours per night) and regular exercise, such as yoga or walking.
Incorporate stress management strategies, including mindfulness, breathing exercises, or meditation.
Managing SIBO and Moving Forward
SIBO is a complex condition that requires a comprehensive approach to treatment. Whether through conventional antibiotics or natural treatments, addressing the root cause of bacterial overgrowth is essential for long-term gut health. Working closely with a healthcare professional to develop a personalised treatment plan will ensure the best outcomes for your recovery.
If you suspect you have SIBO or want to explore treatment options, reach out to learn more about how I can help you on your journey to better digestive health.
