Written by Clinical Nutritionist, Sofie Beker.
What is SIBO, and why does it happen?
Small Intestinal Bacterial Overgrowth (SIBO) occurs when bacteria that normally live in the large intestine start proliferating in the small intestine. The small intestine isn’t designed to house large amounts of bacteria, so when it does, fermentation happens too early in the digestive process. The result is a cascade of symptoms that can significantly affect quality of life.
SIBO can be triggered by:
- Poor gut motility
- Low stomach acid
- Chronic stress
- Previous gut infections or antibiotic use
The key point: SIBO isn’t simply “too much bacteria.” It’s bacteria in the wrong place — and that distinction matters enormously for how it’s treated.
Common SIBO Symptoms
SIBO symptoms can vary considerably between individuals, but the most consistent sign is bloating that begins shortly after eating — and often worsens as the day goes on.
Other common symptoms include:
- Excess gas, particularly after carbohydrate-rich meals
- Abdominal pain or distension
- Diarrhoea, constipation, or a pattern that alternates between both
- Food intolerances, especially to FODMAPs
- Fatigue or brain fog
Some people also experience:
- Nutrient deficiencies, particularly B12 and iron
- Skin conditions such as acne or rosacea
My personal tip: If your bloating is worst in the morning and builds throughout the day — especially after meals — that pattern is always a flag for me. It’s one of the first things I look at when a client comes in with persistent, unexplained bloating.
What actually causes SIBO?
A common misconception is that SIBO is caused by eating the “wrong” foods. The root cause is almost always a dysfunction in how the gut is working, not the diet itself. Common underlying drivers include impaired gut motility, low stomach acid, ileocecal valve dysfunction, chronic stress, and previous gut infections or food poisoning.
This is why restrictive diets alone don’t resolve SIBO. A low-FODMAP diet may reduce symptoms by starving bacteria of fuel, but it doesn’t fix the underlying dysfunction that allowed SIBO to develop.
My personal tip: I see so many clients who have been on low-FODMAP diets for years and are still struggling. Removing foods can quiet symptoms, but it doesn’t address why SIBO developed. That’s always where we need to start.
How to treat SIBO effectively
Treating SIBO requires a structured, multi-step approach — there’s no single supplement or diet that resolves it. Attempting to self-treat without understanding the root cause is also one of the main reasons SIBO keeps coming back. A thorough protocol works through five stages – not always in this order, either, which is why expert guidance is key to long-term resolution!
1. Support digestion
Improving stomach acid levels helps ensure the digestive environment isn’t creating conditions for bacterial overgrowth to return.
2. Restore gut motility
Supporting the migrating motor complex (MMC) – the “cleaning wave” that sweeps bacteria through the gut between meals – is critical to preventing recurrence. Practically, this means spacing meals 4–5 hours apart, avoiding snacking where possible, and using motility-supporting herbs like ginger or supplements like 5-HTP where indicated.
3. Repair the gut lining
Bacterial overgrowth often damages the intestinal barrier, contributing to increased intestinal permeability. Targeted nutrients used therapeutically help restore the gut lining and reduce systemic inflammation in the process.
4. Reduce bacterial overgrowth
The approach depends on the type of SIBO present and suspected underlying drivers, as well as what else is going on in the gut as a larger picture. This is why testing matters before starting any protocol. Treatment without knowing your type is essentially guesswork.
5. Rebalance the microbiome
Probiotics can be a valuable part of recovery, but timing matters enormously. Introducing them too early — before the overgrowth has been adequately cleared — can worsen symptoms. Strain selection is also important; not all probiotics are appropriate for SIBO. This step is best done with clinical guidance.
My personal tip: Step two – motility support – is the one most people skip, and it’s often why SIBO comes back. The MMC is your gut’s built-in cleaning mechanism. If it’s not working properly, you’re treating the overgrowth without fixing what allowed it to develop.
Final thoughts
SIBO can feel relentless, particularly when symptoms keep returning despite your best efforts. But with the right approach — one that looks at the full picture rather than just the bacteria — it is absolutely manageable. If you’re dealing with persistent bloating, food intolerances, or digestive symptoms that don’t respond to dietary changes alone, our team at Perth Health Collective can help you investigate the root cause and build a personalised plan.
SIBO FAQs
How do I know if I have SIBO?
The most reliable way to diagnose SIBO is through a hydrogen and methane breath test. However, we often recommend a functional stool test over the breath test, as we can get far more information about the gut’s overall environment and function, which allows us to treat more effectively.
Can I treat SIBO with diet alone?
Diet can help manage symptoms, but it doesn’t clear the overgrowth or address the underlying drivers. Long-term restrictive eating can also deplete beneficial bacteria over time, which compounds the problem.
Are probiotics helpful for SIBO?
It depends on timing. During active overgrowth, certain probiotics can worsen symptoms. In the later stages of recovery, carefully selected strains can support microbiome rebalancing. Timing and strain selection matter — this is one to work through with a practitioner rather than self-prescribing.
Want to know more?
If you’re ready to get to the bottom of your gut symptoms for good, our clinical nutritionist Sofie is here to help! Sofie provides evidence-based strategies tailored to your goals.
Contact us or book a consultation today to get started.
