Do You Have SIBO? What Bacterial Overgrowth Actually Is and What To Do About It
By Kylie Sartori | Kylie Sartori Naturopathy, Spotswood, Melbourne
Bloating that will not budge no matter what you eat. Cramping after meals. A growing list of foods your body seems to react to. Brain fog that makes it hard to get through the day. Constipation, exhaustion, low mood, and nutrient deficiencies that keep showing up in blood tests even when you are eating well.
These are the kinds of symptoms that clients frequently mention when they first come to see me, and they are also among the most common signs of a condition called SIBO.
What Is SIBO?
SIBO stands for small intestinal bacterial overgrowth. In a healthy gut, the majority of your bacteria live in the large intestine, where they break down food, produce vitamins, and support waste elimination. When bacteria that belong in the large intestine migrate upward into the small intestine, where they do not belong, SIBO occurs.
The small intestine is where most of your nutrient absorption happens. When bacteria set up residence there, they interfere with that process in a significant way. They ferment food before it can be properly absorbed, damage the gut lining, drive intestinal permeability (sometimes called leaky gut), and place a considerable load on the liver and immune system. Over time, this affects far more than just digestion.
What Are the Symptoms?
SIBO presents differently from person to person, which is one of the reasons it is so frequently missed or misattributed to IBS. The most common symptoms include bloating and gas, often severe and worsening across the day, cramping and abdominal discomfort, constipation or unpredictable bowel habits, and difficulty tolerating carbohydrates and FODMAP foods like onion, garlic, legumes, and wheat.
Beyond the gut, SIBO can show up as exhaustion that does not improve with rest, brain fog and difficulty concentrating, low mood, depression, and anxiety, recurring vitamin and mineral deficiencies including iron and B12, food intolerances to gluten, lactose, fructose, and histamine, skin conditions like rosacea, joint pain, and in some cases contributes to the picture in conditions like fibromyalgia and autoimmune disease.
The breadth of that symptom list reflects the fact that when your small intestine cannot absorb nutrients properly, the effects ripple outward into every system in the body.
What Causes It?
SIBO rarely appears out of nowhere. The most common drivers I see in clinic include a history of antibiotic use, even a single course can be enough to disrupt the microbial balance significantly, long-term use of the oral contraceptive pill, regular use of anti-inflammatory medications like ibuprofen, a diet high in sugar, alcohol, and processed foods, and high or chronic stress, which affects gut motility and changes the environment bacteria live in.
Understanding what caused SIBO in the first place matters, because without addressing those drivers, it has a strong tendency to return.
How Is It Diagnosed?
SIBO is diagnosed either through a breath test, which measures the hydrogen and methane gas produced by bacteria when they ferment a sugar solution, or through a comprehensive stool analysis. Both have their place depending on the clinical picture. I use functional testing to determine which approach gives us the most useful information for each individual client.
Can SIBO Be Treated?
Yes, and thoroughly. With the right protocol, SIBO can be cleared and the gut can be restored. The key is treating it in the right order and addressing the full picture rather than just targeting the bacteria in isolation.
A comprehensive SIBO protocol typically works in phases. The first is removing the conditions that allow the bacteria to thrive, which means pulling back on sugar, alcohol, and the fermentable carbohydrates that feed the overgrowth. The second is using targeted antimicrobial herbal medicine to reduce the bacterial load in the small intestine. The third is restoring and rebalancing the microbiome with the right strains of beneficial bacteria, introduced in the right sequence. Alongside that, we support the organs that have been under pressure throughout, particularly the adrenals, thyroid, and liver, and work on the lifestyle and stress factors that contributed to the environment in the first place.
This is not a quick fix, but it is a very solvable problem when it is approached properly.
If you would like to understand more about how I work and what a treatment plan looks like, you can read more on my conditions treated page or explore the functional testing I use to investigate what is happening in the gut.
Working Together
If the symptoms in this post sound familiar, and particularly if you have been managing bloating, food intolerances, or digestive discomfort for a long time without a clear answer, we can work together to get to the bottom of it.
I see clients in person at my clinic in Spotswood, Melbourne, and via telehealth for those across Australia.
Frequently Asked Questions About SIBO
How do I know if I have SIBO or IBS? Many people diagnosed with IBS actually have SIBO sitting underneath it. IBS is a description of symptoms rather than a cause, so if you have been given that diagnosis but have not had your gut microbiome or breath tested, it is worth investigating further. The symptom overlap is significant, but the treatment approach is quite different.
Can SIBO cause anxiety and depression? It can contribute to both. The gut produces a large proportion of the body's serotonin, and when the small intestine is damaged and inflamed, that production is affected. Nutrient deficiencies resulting from poor absorption, particularly B12, iron, and magnesium, also have a direct impact on mood and energy. Clients frequently mention that their mental health improves alongside their gut as treatment progresses.
Does SIBO come back after treatment? It can, particularly if the underlying causes are not addressed as part of the protocol. This is why understanding what drove the overgrowth in the first place matters as much as clearing it. A well-structured treatment plan accounts for prevention as part of the process.
What is the difference between SIBO and dysbiosis? Dysbiosis refers broadly to an imbalance in the gut microbiome, where beneficial bacteria are low and less helpful species are overgrowing. SIBO is a specific type of dysbiosis where bacteria have migrated into the small intestine. The two can coexist, and both are assessed through functional gut testing.
Kylie Sartori is a degree-qualified naturopath based in Spotswood, Melbourne, specialising in gut health, microbiome restoration, hormonal health, and family wellbeing. She offers in-person consultations at her Spotswood clinic and telehealth appointments for clients across Australia.
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