If you're struggling with persistent bloating, unpredictable bowel habits, and a general sense of digestive distress, you might be dealing with more than just a sensitive stomach. These are hallmark signs of Small Intestinal Bacterial Overgrowth, or SIBO, a condition that's increasingly recognised as a key player in many chronic gut issues, including Irritable Bowel Syndrome (IBS). While it can be a frustrating and uncomfortable experience, understanding SIBO is the first step towards finding lasting relief.
At Gut Philosophy, we take a functional medicine approach to digestive health. This means we look beyond the symptoms to uncover the root cause of your health concerns. For SIBO, this involves not just clearing the overgrowth, but also understanding why it happened in the first place. This guide will walk you through the symptoms, testing, and treatment of SIBO from a functional medicine perspective, empowering you with the knowledge to take back control of your gut health.
What is Small Intestinal Bacterial Overgrowth (SIBO)?
Your digestive tract is home to trillions of microbes, most of which reside in your large intestine, where they play a vital role in your health. The small intestine, by contrast, should have a relatively low number of bacteria. SIBO occurs when this balance is disrupted, and bacteria from the large intestine migrate and proliferate in the small intestine. It can also be caused by an overgrowth of the bacteria that normally live in the small intestine.
These misplaced or excessive bacteria then ferment the carbohydrates you eat, producing large amounts of gas. This fermentation process is what leads to the characteristic symptoms of SIBO, such as bloating, gas, and abdominal pain. It's a common underlying factor in many digestive health conditions, with studies suggesting that up to 80% of people with IBS may also have SIBO.
There are three main types of SIBO, classified by the type of gas produced by the bacteria:
Understanding the type of SIBO you have is crucial as it can influence the most effective treatment approach.
Common Symptoms of SIBO
The symptoms of SIBO can vary widely from person to person, but they primarily affect the digestive system. The most common signs include:
The most common signs of SIBO are digestive in nature. Bloating is often the most reported symptom, with the abdomen becoming visibly distended, especially after meals. This is frequently accompanied by excessive gas (belching and flatulence), abdominal pain and cramping, and altered bowel habits, which can manifest as diarrhoea, constipation, or a mix of both. Some individuals also experience reflux, heartburn, or nausea.
Because SIBO can interfere with the digestion and absorption of nutrients, it can also lead to symptoms outside of the gut, such as:
Because SIBO interferes with nutrient absorption, it can also lead to systemic symptoms such as fatigue and brain fog, new food sensitivities, skin issues like rosacea or eczema, and even joint pain. Over time, it can also lead to nutrient deficiencies, most commonly in iron and vitamin B12.
If you're experiencing a combination of these symptoms, it's worth exploring the possibility of SIBO with a qualified practitioner.
How is SIBO Diagnosed?
If your symptoms suggest SIBO, the most common and non-invasive way to test for it is with a SIBO breath test. This simple test can be done at home and involves drinking a sugar solution (either lactulose or glucose) and then collecting breath samples every 15-20 minutes for 2-3 hours.
The test measures the levels of hydrogen and methane gas in your breath. A significant rise in these gases within the first 90-120 minutes of the test indicates that bacteria in your small intestine are fermenting the sugar, which confirms a SIBO diagnosis. Some advanced tests can also measure hydrogen sulphide gas.
| Test Type | What it Measures | Best For | Considerations | | :--- | :--- | :--- | :--- | | Lactulose Breath Test | Hydrogen & Methane | Diagnosing overgrowth in the distal small intestine | Lactulose is not absorbed, so it travels the full length of the small intestine. | | Glucose Breath Test | Hydrogen & Methane | Diagnosing overgrowth in the proximal small intestine | Glucose is absorbed quickly, so it may miss overgrowth further down. | | Hydrogen Sulphide Test | Hydrogen Sulphide | Identifying H2S-dominant SIBO | A newer test, not always included as standard. |
While breath testing is the gold standard, a comprehensive stool test may also be used to provide a broader picture of your gut health, including information about inflammation, digestion, and the balance of bacteria in your large intestine. This can help to identify underlying factors contributing to SIBO.
The Root Causes of SIBO: Why Did It Happen?
A crucial part of the functional medicine approach is to understand the underlying reasons why SIBO developed. Simply treating the bacterial overgrowth without addressing the root cause often leads to relapse. Some of the most common predisposing factors include:
1. Impaired Gut Motility
Your small intestine has a natural cleansing wave, called the Migrating Motor Complex (MMC), which sweeps bacteria and undigested food down into the large intestine between meals. If the MMC isn't working properly, bacteria can accumulate in the small intestine. Factors that can impair the MMC include:
A primary cause is an impaired Migrating Motor Complex (MMC), the natural cleansing wave that sweeps debris through the small intestine. This can be damaged by the toxins from a bout of food poisoning, chronically impacted by stress, or slowed down by conditions like hypothyroidism.
2. Low Stomach Acid
Stomach acid is a crucial first line of defence against ingested bacteria. If stomach acid is low (a condition called hypochlorhydria), more bacteria can survive the journey into the small intestine. Common causes of low stomach acid include:
Furthermore, low stomach acid (hypochlorhydria) reduces your first line of defence against ingested microbes. This can be caused by the long-term use of acid-blocking medications (PPIs), chronic stress, or an *H. pylori* infection.
3. Structural Issues
Anatomical abnormalities or changes in the gut can create an environment where bacteria can thrive. These include:
Finally, structural issues can play a role. A dysfunctional ileocecal valve, the gateway between the small and large intestines, can allow bacteria to flow backwards. Similarly, abdominal adhesions or scar tissue, often from past surgeries, can create blockages that trap bacteria.
A Functional Medicine Approach to SIBO Treatment
Our approach to treating SIBO at Gut Philosophy is multi-faceted. We aim to not only eradicate the bacterial overgrowth but also to address the underlying causes and restore a healthy gut environment to prevent recurrence. This typically involves a combination of the following strategies, tailored to your individual needs through our functional medicine services.
1. Eradicate the Overgrowth
The first step is to reduce the bacterial load in the small intestine. This can be achieved through:
The first step is to reduce the bacterial load. This can be achieved with herbal antimicrobials like oregano, berberine, and neem, which studies have shown to be as effective as prescription antibiotics. For more severe or resistant cases, an elemental diet—a liquid formula of pre-digested nutrients—can be highly effective at starving the bacteria while nourishing the patient. In some situations, a targeted course of prescription antibiotics like Rifaximin is the most appropriate choice.
2. Support Digestion
To ensure you're properly breaking down and absorbing your food, and to reduce the fuel available for the overgrown bacteria, we may recommend:
To reduce the fuel available for bacteria and ensure proper nutrient absorption, we may use digestive enzymes to aid the breakdown of food and stomach acid support (such as betaine HCl) to restore optimal acidity.
3. Restore Gut Motility
To restore the cleansing action of the MMC, we use prokinetic agents. These can be natural compounds like ginger or pharmaceutical options, and they are crucial for preventing a relapse.
4. Dietary Management
While we're treating the overgrowth, a temporary change in diet is often necessary to manage symptoms. The most common dietary approach for SIBO is the Low-FODMAP diet. FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) are a group of short-chain carbohydrates that are poorly absorbed and readily fermented by gut bacteria, leading to gas and bloating. Reducing them for a period of 4-8 weeks can provide significant symptom relief.
It's important to remember that the Low-FODMAP diet is not a long-term solution. The goal is to reintroduce foods systematically once the SIBO has been treated, to ensure a diverse and resilient gut microbiome in the long run. If you're struggling with bloating and gut health, this dietary approach can be a game-changer.
Frequently Asked Questions about SIBO
What is the best diet for SIBO?
While a Low-FODMAP diet is often recommended during treatment to manage symptoms, it is not a long-term solution. The best diet is one that is tailored to your individual needs and tolerances, and that can be expanded over time to include a wide variety of plant fibres to support a healthy gut microbiome. Working with a practitioner can help you navigate this process.
How long does it take to treat SIBO?
The duration of SIBO treatment can vary depending on the severity of the overgrowth, the underlying causes, and the chosen treatment protocol. A course of antimicrobials typically lasts for 4-6 weeks, but it may take several months to fully address the root causes and restore gut health.
Can SIBO come back after treatment?
Yes, SIBO has a high rate of recurrence if the underlying causes are not addressed. This is why a functional medicine approach that focuses on restoring normal gut function is so important for long-term success.
Is a SIBO breath test available on the NHS?
While some gastroenterology departments in the UK may offer SIBO breath testing, it is not widely available on the NHS. Many people choose to work with a private functional medicine practitioner to access testing and a comprehensive treatment plan.
Take the Next Step Towards a Healthier Gut
Navigating the complexities of SIBO can be challenging, but you don't have to do it alone. A functional medicine approach offers a path to not just manage your symptoms, but to understand and address the root cause of your digestive issues, leading to lasting relief and improved overall health.
If you suspect you may have SIBO or are struggling with chronic digestive symptoms, we are here to help. At Gut Philosophy, Elena Rolt and her team are dedicated to providing personalised, evidence-based care to help you restore your gut health and reclaim your vitality. Contact us today to learn more about our services and to book a consultation.