UNDERSTANDING SIBO: Causes, Symptoms, and Management

 

 

Small Intestinal Bacterial Overgrowth (SIBO) is a condition that affects the small intestine, where excessive bacteria proliferate, leading to a range of gastrointestinal symptoms. Unlike the large intestine, where a high concentration of bacteria is normal (this is where our gut microbiome resides), the small intestine typically harbours relatively few bacteria.

When this balance is disrupted, and higher number of bacteria start to take hold, it can result in various health problems. Rosacea, IBS, MS, Restless Leg Syndrome and Rheumatoid Arthritis are some of the conditions linked to SIBO (this does not mean that SIBO causes these conditions, but it might play a role in their progression).

 

What is SIBO?

SIBO occurs when the small intestine becomes overrun with bacteria that are usually found in the colon. These bacteria can interfere with the digestion and absorption of nutrients, leading to malnutrition and a range of gastrointestinal symptoms.

The condition is often diagnosed through breath tests that measure hydrogen and methane produced by bacteria in the small intestine.

 

Causes of SIBO

Several factors can contribute to the development of SIBO, including:

1. Poor Motility: Conditions like irritable bowel syndrome (IBS) and diabetes can affect the normal movement of the small intestine, allowing bacteria to accumulate.
2. Structural Abnormalities: Surgeries or diverticula in the small intestine can create a favourable environment for bacterial overgrowth.
3. Immune System Dysfunction: A weakened immune system can fail to control bacterial populations in the gut.
4. Low Stomach Acid: Conditions or medications that reduce stomach acid (such as PPis) can lead to an increase in bacteria, as stomach acid typically helps to kill bacteria before they reach the small intestine.

 

Common Symptoms of SIBO

The symptoms of SIBO can vary widely, but they often mimic those of other gastrointestinal disorders. Common symptoms include:

1. Bloating and Gas: One of the most prevalent symptoms, bloating can be severe and persistent, often worsening after meals.

   Why It Happens:

   • In a healthy digestive system, food moves efficiently through the small intestine, and bacteria are primarily located in the large intestine. However, in SIBO, bacteria ferment food too early in the digestive process, producing excessive gas (hydrogen, methane, or hydrogen sulfide).
   • This gas leads to bloating and abdominal distension, often worsening throughout the day or after meals, especially those high in fermentable carbohydrates (like bread, pasta, fruits, and dairy).
2. Diarrhoea, Constipation or both: Some individuals may experience constipation, which can alternate with diarrhoea.Frequent, loose stools are a common symptom due to the malabsorption of nutrients.

   Why It Happens:

   • Bacterial fermentation creates byproducts that affect gut motility (the movement of food through the digestive tract).
   • Hydrogen-dominant SIBO often accelerates motility, leading to diarrhea.
   • Methane-dominant SIBO slows motility, resulting in constipation.
   • Some individuals experience a mix of both, where gut function is unstable and swings between diarrhea and constipation.
3. Abdominal Pain: Cramping or discomfort in the abdomen is often reported by individuals with SIBO.

   Why It Happens:

   • The trapped gas and fermentation process stretch the intestinal walls, leading to pain and discomfort.
   • Bacteria can also irritate the gut lining, causing inflammation and heightened sensitivity (a condition known as visceral hypersensitivity).
   • If food moves too slowly or too quickly due to altered motility, it can trigger spasms and cramping.
4. Excessive gas (both belching and flatulence):This is often a predomint issue with SIBO.

   Why It Happens:

   • The fermentation of undigested carbohydrates by overgrown bacteria produces gases such as hydrogen and methane.
   • Hydrogen-producing bacteria can cause excessive belching, while methane-producing bacteria can contribute to excessive flatulence.
   • The type of gas produced may also influence stool patterns—hydrogen-dominant SIBO is often linked to diarrhea, while methane-dominant SIBO is more commonly associated with constipation.
5. Malnutrition: Due to poor absorption of nutrients, individuals with SIBO may experience weight loss, fatigue, and deficiencies in vitamins and minerals.

   Why It Happens:

   • SIBO interferes with the absorption of key nutrients:
     • Vitamin B12 Deficiency: Certain bacteria consume B12 before the body can absorb it, leading to fatigue, weakness, brain fog, and even nerve issues.
     • Iron Deficiency: Poor absorption of iron can result in anemia, fatigue, dizziness, and brittle hair or nails.
     • Fat-Soluble Vitamin Deficiencies (A, D, E, K): If SIBO disrupts bile production, fat digestion suffers, leading to deficiencies that impact immune function, bone health, and skin integrity.
6. Fatigue and brain fog: Chronic tiredness can result from nutrient deficiencies and the body’s ongoing battle with bacterial overgrowth. Many people with SIBO report struggling with poor concentration, difficulty recalling information, and mental sluggishness.

   Why It Happens:

   • Nutrient deficiencies, particularly in B vitamins and iron, contribute to low energy levels and mental fogginess.
   • The toxins and byproducts of bacterial overgrowth may also trigger inflammation, affecting neurotransmitter function and cognitive performance.
7. Food Intolerances: People with SIBO may develop intolerances to certain foods, particularly those high in fermentable carbohydrates (FODMAPs).

   Why It Happens:

   • SIBO damages the gut lining, making it more permeable (“leaky gut”), which can trigger immune responses to certain foods.
   • Common trigger foods include gluten, dairy, and high-FODMAP foods (fermentable carbohydrates like onions, garlic, beans, and certain fruits).
   • Some individuals develop histamine intolerance due to SIBO, leading to symptoms like headaches, flushing, and congestion after eating histamine-rich foods.
8. Skin issues (acne, rosacea, eczema and skin rashes): Not many practitioners think about SIBO with skin conditions, but the gut-skin connection is a hot topic in scientific research.

   Why It Happens:

   • The gut-skin connection is strong, and SIBO-related inflammation can manifest as skin issues like acne, rosacea, eczema, and unexplained rashes.
   • Research suggests a high correlation between rosacea and SIBO, with many individuals experiencing skin improvement after treating bacterial overgrowth.
   • Malabsorption of essential nutrients (like zinc, omega-3 fatty acids, and vitamin A) can also contribute to poor skin health.

 

Diagnosis

Diagnosing SIBO typically involves breath tests that measure hydrogen and methane production. These gases are produced by bacteria in the small intestine and can be detected in the breath after consuming a sugar solution. Elevated levels of one or both gases indicate bacterial overgrowth.

At the time of writing, very few hospitals and doctors in the UK are knowledgeable about SIBO and are offering testing options, this is why many people will have to consider private healthcare.

 

Management of SIBO often includes:

1. Antibiotics or Antimicrobial Herbs: Specific antibiotics or antimicrobial herbs can dramatically reduce bacterial overgrowth, providing relief from symptoms. Antibiotics works very quickly but kill indiscriminately good and bad bacteria, while herbs are slower, giving the chance to work on repopulating the good bacteria while killing the bad ones.
2. Dietary Changes: A low-FODMAP diet can help reduce symptoms by limiting fermentable carbohydrates that feed bacteria. This is not a long-term solution, but it can be implemented to improve symptoms while tackling the root cause.
3. Probiotics and Prebiotics: These can help rebalance the intestinal microbiome, although their use in SIBO should be tailored to the individual.
4. Addressing Underlying Conditions: Treating underlying conditions, such as poor motility or immune deficiencies, is crucial for long-term management, otherwise the SIBO can reoccur in few months.
5. Nutritional Support: Supplements may be necessary short term to address nutrient deficiencies caused by malabsorption.

 

Conclusion

SIBO is a complex condition that requires a multifaceted approach to diagnosis and management. Understanding its symptoms and potential causes is crucial for effective treatment. If you suspect you have SIBO, it’s essential to consult with a healthcare professional who can guide you through appropriate testing and treatment options. With the right approach, many people with SIBO can find relief from their symptoms and improve their quality of life.