What are the root causes of SIBO?
- thegutremedy
- Sep 22, 2024
- 5 min read
SIBO (Small Intestinal Bacterial Overgrowth) does not occur randomly. It's not something you simply wake up with one morning.
We naturally have ‘SIBO-proof’ bodies. There are several mechanisms that keep the small intestine's microbiome balanced, so for SIBO to develop, multiple systems in the body must first go wrong.
Why do I need to know my root cause?
You can take all the probiotics, antimicrobials, or antibiotics in the world, but if you don't address the underlying cause, the problem will likely immediately return. This is why many people experience temporary relief from SIBO treatments, only to have it relapse quickly. Conventional medicine often treats SIBO with antibiotics, but without tackling the root issue, the overgrowth often reappears very soon after treatment.
By addressing the root cause, any changes made to the microbiome will stick. In some cases, simply correcting the root cause is enough to restore the microbiome without further interventions being necessary.
It is far from impossible to heal SIBO if you don’t know your root cause. If this is the case, it is sensible to dial in on all of the key root causes first. If addressing these doesn’t bring relief, exploring other possibilities is the next step.
What are the key root causes of SIBO?
Gut-brain axis dysfunction
The gut-brain axis describes the communication between the brain and gut. When this system becomes dysregulated, gut functions are impaired. This includes reduced blood flow, poor nutrient absorption, decreased digestive secretions (such as stomach acid, enzymes, and bile), slower gut motility, impaired immunity, and increased intestinal permeability. [1] [2]
2. Sleep
Sleep deprivation can rapidly disrupt the microbiome, increase gut inflammation, and worsen insulin resistance in as little as 48 hours. It also raises cortisol levels and stops the essential growth and repair processes that the body typically performs during rest. Additionally, disrupted circadian rhythms, often seen in shift workers or people with irregular sleep patterns, have been shown to impair gut health. [3] [4] [5]
3. Low movement
Movement is essential for good gut motility, and a sedentary lifestyle can lead to a sluggish digestive system. Studies have shown that exercise increases microbiome diversity and boosts the production of short-chain fatty acids, which are beneficial for gut health. [6]
4. Antibiotic use
Frequent or prolonged use of antibiotics is one of the few direct microbiome-related causes of SIBO. Repeated antibiotic courses can reduce the diversity of gut bacteria and promote the growth of inflammatory gram-negative bacteria, which tend to flourish after antibiotic treatment. It is now well known that dysbiosis is the reason behind SIBO symptoms. [7]
5. Nutrition
Gut symptoms can often cause poor nutrition or undereating, but this can create a vicious cycle as undernourishment makes it impossible for the gut to heal. Proper nutrients fuel the brain-gut axis, support healthy sleep, provide energy for exercise, and feed the beneficial bacteria in the microbiome. [8]
What are other root causes of SIBO?
Whilst the key root causes are often the true foundations of gut health, there are other reasons you may not be seeing results from your gut healing strategies.
Autoimmunity
Autoimmunity, particularly the presence of anti-vinculin antibodies, can lead to SIBO by impairing gut motility. These antibodies attack the gut's nerves, disrupting the migrating motor complex (MMC), which normally clears bacteria from the small intestine, allowing bacterial overgrowth to occur. [9]
2. Infections/overt pathogens
Infections like Lyme disease and Epstein-Barr virus (EBV) can cause inflammation that disrupts normal gut function and weakens the immune system, leading to increased dysbiosis. This creates a higher likelihood of bacterial overgrowth and infection. [10] [11]
3. Low digestive secretions
Low stomach acid, bile, and digestive enzymes, can lead to SIBO by impairing the digestion and absorption of food, allowing undigested food to ferment in the small intestine which creates an perfect environment for SIBO. [12]
4. Liver dysfunction
Liver dysfunction can contribute to SIBO by impairing bile production and secretion, essential for fat digestion and controlling bacterial growth in the small intestine. Bile has antimicrobial properties, so reduced bile flow disrupts the gut's natural defence mechanisms and slows digestion. [13]
5. Inflammation
Gut inflammation can disrupt the normal functioning of the gut's motility and barrier, allowing bacteria to overgrow. Inflammation can also impair the digestive processes (e.g. digestive secretions and nutrient absorption) and alter the microbiome. [14]
6. Endometriosis
Endometriosis can cause adhesions, which are abnormal areas of scar tissue that form between organs and tissues. These adhesions can disrupt normal gut motility and create blockages or restrictions in the small intestine, allowing bacteria to overgrow. [15]
7. Thyroid disorders
Hypothyroidism slows down gut motility digestive processes. Reduced thyroid function affects the efficiency of the MMC, which normally clears bacteria from the small intestines. [16]
8. Medications
Proton pump inhibitors (PPIs) reduce stomach acid, which impairs digestion. Nonsteroidal anti-inflammatory drugs (NSAIDs) can cause gut inflammation and damage the intestinal lining, disrupting motility. Selective serotonin reuptake inhibitors (SSRIs) may alter gut motility and the balance of gut microbiota, creating an environment that supports SIBO development. [17] [18] [19]
10. Chronic stress/trauma
Chronic stress and trauma disrupt gut motility and increase intestinal permeability (or leaky gut), impairing the gut’s barrier and immune function. They also affect the gut-brain axis, leading to imbalances in gut microbiota and hormone levels. [20]
11. High viral load
A high viral load can impair gut motility by disrupting the normal function of the gut's nerve cells and muscles, leading to slower transit times and bacterial overgrowth. Additionally, viral infections can weaken the immune system and alter the gut microbiome. [21]
12. Heavy metals
Heavy metals can disrupt gut function by damaging the intestinal lining and impairing digestive processes. These metals can also alter the gut microbiota and interfere with the immune response. [22]
13. Mould exposure
Mould exposure causes chronic inflammation and damages the gut lining, impairing digestive function and promoting bacterial overgrowth. Mycotoxins can also disrupt the gut microbiome and compromise immune function. [23]
14. Ileocecal valve dysfunction
Ileocecal valve dysfunction can allow bacteria from the large intestine to reflux into the small intestine, leading to overgrowth. This valve malfunction disrupts the normal one-way flow of digestive contents. [24]
15. Oral dysbiosis
Oral dysbiosis can allow harmful bacteria from the mouth to enter the digestive tract, especially when other digestive processes are compromised. Poor stomach acid can fail to kill these bacteria, allowing them to reach the small intestine. [25]
16. Insulin resistance
Insulin resistance can promotes an environment that fosters bacterial overgrowth in the small intestine by increasing gut inflammation and altering gut motility. [26]
Can I have more than one root cause of SIBO?
Absolutely. In fact I had at least seven of these root causes (all of the key root causes and at least 2 further), and I don’t think this is unusual.
Where do I start?
Always start by ensuring all key root causes are addressed. These are often manageable with little to no cost and may provide significant symptomatic relief on their own.
It’s important to approach this holistically, covering multiple factors rather than focusing too narrowly on a single root cause. Only if addressing these key areas hasn’t led to improvement should you explore more complex root causes that might be contributing to your symptoms.
Treatment failure often signals an overlooked root cause. If you’ve undergone several rounds of antibiotics or tried various treatments without success, it’s a good idea to revisit this list to see if anything has been missed.
To sum up:
While understanding the root causes of SIBO is very helpful for effective treatment and long-term relief, it's not always 100% necessary for healing. SIBO doesn't happen in isolation; it results from a complex mix of factors that can disrupt gut health.
By focusing on key areas like gut motility, digestive secretions, and lifestyle choices, you can often find significant relief, even if you don't know the exact root cause. If initial efforts don’t lead to improvement, look into more complex underlying problems.
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