SIBO NATUROPATH · MAROOCHYDORE, SUNSHINE COAST & ONLINE
SIBO and Breath Testing
Understanding persistent bloating, food reactions and altered bowel habits, and whether breath testing may clarify what to do next
You may wake with a relatively comfortable abdomen, only to feel increasingly swollen as the day progresses.
By afternoon, your waistband feels tight. After dinner, your abdomen may look visibly distended, not merely feel a little full.
Foods that were once easy to eat now seem unpredictable. Garlic, onion, legumes, fruit, bread or even a nutritious meal can leave you uncomfortable, gassy or searching for the loosest clothes you own.
Perhaps a low FODMAP diet helped temporarily, but symptoms returned when you tried to expand your diet. Probiotics may have made you feel worse. A course of treatment may have helped, only for the bloating, constipation or food reactions to gradually return.
This is often when people begin wondering about small intestinal bacterial overgrowth, or SIBO.
These patterns can occur with SIBO, but they do not prove that SIBO is present. Constipation, IBS, coeliac disease, food intolerances, altered gut motility and other digestive conditions can produce remarkably similar symptoms.
I work with people experiencing persistent bloating, visible distension, constipation, diarrhoea and food-related digestive symptoms, including those with suspected, previously diagnosed or recurring SIBO.
Consultations are available in Maroochydore and at Kunara Marketplace in Forest Glen on the Sunshine Coast, and online throughout Australia.
RECOGNISING THE PATTERN
Does this sound familiar?
Your experience may involve:
Bloating or abdominal pressure that increases after eating
Visible distension that becomes more pronounced later in the day
Excessive wind, belching or digestive gurgling
Constipation, diarrhoea or movement between the two
Feeling uncomfortably full after an ordinary meal
Nausea, abdominal discomfort or cramping
Reactions to fermentable foods that previously seemed tolerable
Temporary improvement on a low FODMAP or restricted diet
Increased bloating after some fibres, prebiotics or probiotics
Symptoms that improve during treatment but repeatedly return
Growing anxiety around eating because reactions feel difficult to predict
Some people feel noticeably better when they have not eaten and worse as meals accumulate throughout the day. Others experience symptoms shortly after eating, several hours later or during periods of constipation.
The timing matters, but no single timing pattern diagnoses SIBO.
You may also have reached the point where eating “healthy” feels strangely difficult. Foods commonly promoted for gut health, legumes, fermented foods, resistant starch, certain vegetables or prebiotic fibres, may aggravate symptoms rather than improve them.
That does not necessarily mean those foods are inherently bad for your gut. It may mean your current digestive environment, bowel transit or sensitivity needs to be understood before more fermentable material is added.
You should not have to keep shrinking your diet without becoming any clearer about what is wrong.
UNDERSTANDING SIBO
What is small intestinal bacterial overgrowth?
The small intestine is responsible for much of the digestion and absorption of nutrients.
It normally contains microorganisms, but in considerably different numbers and conditions from the colon. SIBO describes a situation in which the amount or composition of microorganisms within the small intestine becomes abnormal and contributes to symptoms.
These microorganisms can ferment carbohydrates and produce gases. This may contribute to bloating, distension, abdominal discomfort and altered bowel habits.
In more pronounced cases, SIBO can interfere with normal digestion and nutrient absorption. Diarrhoea, fat malabsorption, weight loss or nutritional deficiencies may occur, although this is not the presentation experienced by everyone who receives a SIBO diagnosis.
SIBO is also not simply an infection caught from another person, and it is not adequately explained as having “too many bad bacteria.”
It can develop when the mechanisms that normally regulate movement and microbial numbers within the small intestine are disrupted.
GAS PATTERNS AND BOWEL HABITS
Not every positive breath test represents the same pattern
The gases identified during breath testing can provide information about the fermentation pattern, but the terminology can be confusing.
H₂
Hydrogen-predominant SIBO
Hydrogen is produced when microorganisms ferment carbohydrates.
A hydrogen rise during the small-intestinal portion of a breath test may support a diagnosis of hydrogen-predominant SIBO when it fits the person’s symptoms and clinical history.
Diarrhoea and looser bowel habits are commonly discussed with hydrogen-predominant patterns, but symptoms are not consistent enough to diagnose the gas pattern without testing.
CH₄
Intestinal methanogen overgrowth
A methane-positive result is more accurately called intestinal methanogen overgrowth, or IMO, rather than methane SIBO.
Methane is strongly associated with slowed intestinal transit and constipation. People may experience hard or infrequent stools, incomplete evacuation and bloating that continues even when they are opening their bowels most days.
Constipation is not defined by frequency alone. Stool consistency, straining and the feeling of incomplete emptying also matter.
H₂S
Hydrogen sulphide
Hydrogen sulphide is another gas produced within the intestinal environment.
It has been associated with diarrhoea and other digestive symptoms, but testing access and interpretation remain less established than for hydrogen and methane. A suspected hydrogen-sulphide pattern should not be diagnosed from stool odour or symptoms alone.
These categories can be useful, but a gas result should not replace the broader clinical picture.
Hydrogen, methane and hydrogen sulphide may each be relevant to digestive symptoms. However, they differ in how well established they are and whether they can currently be measured through commercially available testing in Australia.
WHY IT CAN DEVELOP
SIBO is not usually caused by one “bad” food
People often blame themselves for developing SIBO.
They may believe they ate too much sugar, did not eat cleanly enough or somehow damaged their microbiome.
That explanation is usually far too simplistic.
The small intestine has several mechanisms that help limit microbial accumulation. These include coordinated intestinal movement, stomach acid, digestive secretions, immune function and normal intestinal anatomy.
SIBO may become more likely when one or more of these protective mechanisms are disrupted.
Depending on the individual, relevant factors may include:
Impaired or slowed small-intestinal motility
Significant or persistent constipation
Previous gastroenteritis or another intestinal illness
Structural changes following gastrointestinal surgery
Small-intestinal diverticula, narrowing or altered anatomy
Conditions affecting the nerves or muscles of the digestive tract
Certain medications that slow intestinal movement
Medical conditions affecting digestion, absorption or immune function
Associations do not establish the cause in every person. Medication should never be stopped simply because it appears on a list of possible risk factors.
For many people, there is no single dramatic underlying cause. Several smaller influences may be interacting, and some cannot be changed completely.
The aim is to identify what is clinically plausible, not invent a “root cause” for the sake of having one.
WHY SYMPTOMS CAN RETURN
Treating the overgrowth may not address why it developed
This is where many SIBO treatment plans become too shallow.
Someone completes antibiotics or herbal antimicrobials, follows a highly restricted diet and initially feels better. A few weeks or months later, the bloating, constipation or food reactions begin returning.
They are then told they need another “kill phase.”
Sometimes retreatment is appropriate. Repeated treatment without reconsidering the diagnosis, bowel transit or predisposing factors is not a complete strategy.
Recurrence may reflect:
Persistent constipation or impaired intestinal movement
An underlying medical or structural condition
An incomplete or incorrect initial diagnosis
Treatment that reduced symptoms without addressing the main contributor
A diet that became so restricted that nutritional adequacy and reintroduction became difficult
Symptoms from IBS, visceral sensitivity or another condition being interpreted as recurrent SIBO
Not every returning symptom means the overgrowth has returned. Bloating can persist even after breath-test results improve, and symptoms can recur for reasons unrelated to SIBO.
Before automatically repeating treatment, it is worth asking:
What improved, what did not, how long did the improvement last, and does the original explanation still fit?
Bloating, abdominal discomfort, constipation, diarrhoea and food-related symptoms may also occur with:
Coeliac disease
Constipation or impaired evacuation
Lactose, fructose or other carbohydrate malabsorption
Inflammatory bowel disease
Pelvic-floor dysfunction
Gastroparesis or other motility disorders
Medication effects
Gynaecological conditions that affect abdominal comfort or bowel function
SIBO, IBS AND OTHER CONDITIONS
Bloating does not automatically mean SIBO
SIBO symptoms overlap considerably with IBS and several other gastrointestinal conditions.
This does not mean SIBO is unimportant or that symptoms are “just IBS.”
It means symptom recognition should lead to proper assessment, not an assumed diagnosis.
A SIBO label can be useful when it fits the history and meaningfully directs care.
TESTING
Can SIBO be tested?
Hydrogen and methane breath testing is the most accessible non-invasive method used to investigate suspected SIBO and IMO.
After following a preparation diet and fasting period, you drink a measured carbohydrate solution, usually glucose or lactulose. Breath samples are collected over the following hours to measure gases produced through microbial fermentation.
The timing and concentration of hydrogen and methane are then interpreted using recognised criteria. Breath testing can provide useful information, but it is not a perfect test.
Results can be influenced by:
The substrate used
Intestinal transit time
Test preparation and collection technique
Recent antibiotics, laxatives, probiotics or other treatments
The interpretation criteria applied by the laboratory or practitioner
Lactulose and glucose each have advantages and limitations. Lactulose travels through the entire small intestine but can be more difficult to distinguish from normal colonic fermentation when transit is rapid. Glucose is absorbed earlier and may miss overgrowth occurring farther along the small intestine.
Small-bowel aspirate and culture is sometimes described as the diagnostic reference standard, but it is invasive and also has important sampling and interpretation limitations.
There is currently no flawless standalone test for SIBO.
This is why a result should be interpreted alongside symptoms, bowel pattern, relevant risk factors and previous treatment.
Comprehensive stool testing does not diagnose SIBO. It examines stool, which primarily represents the large-intestinal environment.
When might breath testing be worthwhile?
Testing may be reasonable when:
Symptoms and history make SIBO or IMO clinically plausible
Bloating, distension or altered bowel habits remain persistent despite appropriate first-line care
Constipation and slow transit suggest a possible methane-associated pattern
Symptoms began following a relevant gastrointestinal illness, surgery or change in motility
Previous treatment helped temporarily, but the original diagnosis was never adequately established
The result would meaningfully change the treatment plan
Testing may be less useful when significant constipation has not yet been addressed, preparation cannot be completed accurately or another medical condition needs to be investigated first.
01 — Initial consultation
Your symptoms, bowel pattern, medical history, medication, previous investigations and treatment response are reviewed before testing is recommended.
This determines whether SIBO or IMO is plausible and whether medical assessment should take priority.
The SIBO testing pathway
02 — Test preparation and collection
If testing is appropriate, you receive instructions for the preparation period, fasting requirements and breath-sample collection.
Following the preparation instructions matters because poor preparation can make the result difficult to interpret.
03 — Interpretation and treatment planning
The result is considered alongside your symptoms and clinical history.
A positive result does not automatically determine one standard treatment. A negative result also does not mean the symptoms are unimportant or that nothing is wrong.
The findings should clarify the next decision, which may involve medical treatment, nutritional care, bowel support, herbal medicine, further investigation or a different explanation altogether.
TREATMENT
SIBO treatment is more than a “kill phase”
Online SIBO protocols often follow the same sequence: restrict fermentable foods, take antimicrobial products, add a biofilm supplement and repeat until symptoms disappear.
That can sound decisive. It is not automatically good clinical care.
Treatment should reflect:
Whether SIBO or IMO has been reasonably established
The dominant gas and bowel pattern
Symptom severity and nutritional status
Relevant medical conditions and medication
Previous treatment and tolerance
Factors that may be contributing to recurrence
Very specific antibiotics may be used medically to treat symptomatic SIBO. The choice of treatment must be made by an appropriately qualified prescriber.
Practitioner-prescribed herbal medicine can also be considered in naturopathic care, or the use of an elemental diet. The three options will be discussed with you during your results consultation.
Treatment may also include support for constipation or bowel transit, correction of nutritional deficiencies, meal-pattern adjustments and gradual dietary expansion.
The objective is not to sterilise the intestine. It is to improve the clinical problem while avoiding unnecessary treatment and long-term restriction.
DIET AND FOOD REACTIONS
A low FODMAP diet may reduce symptoms, but it is not a SIBO cure
Reducing fermentable carbohydrates can decrease bloating, wind and discomfort for some people because it changes the amount of material available for fermentation. That can be useful for symptom management.
It does not prove SIBO is present, eradicate an overgrowth or correct impaired intestinal motility.
A restrictive diet may be used temporarily and strategically, but it should have a defined purpose and a plan for review. Removing more foods every time symptoms occur can leave the diet unnecessarily narrow and make reintroduction increasingly intimidating.
Some people do not need a formal low FODMAP diet. They may benefit from adjusting portions, meal combinations, fibre type or the foods causing the greatest difficulty while maintaining as much variety as possible.
The goal is not to achieve a symptom-free life by eating six “safe” foods.
It is to improve digestive tolerance while maintaining nutritional adequacy and a workable relationship with food.
MY APPROACH
SIBO should be investigated carefully, not assumed from symptoms
SIBO is frequently overdiagnosed from bloating alone and undertreated as a recurring “bacterial problem.”
Neither approach is adequate.
My role is to determine whether SIBO is a convincing explanation, whether testing is likely to help and what else may need attention for treatment to be effective.
01 — Clarify the pattern
We organise when the symptoms began, how they change through the day, the predominant bowel pattern, current food restriction, medication, previous illness, testing and treatment.
I am particularly interested in what happened before the symptoms began, and what changed during any period of improvement.
02 — Choose the most useful starting point
The first step may involve breath testing, medical investigation, improving bowel regularity, adjusting fermentable foods, correcting nutritional inadequacy or beginning treatment for an established result.
Not everyone needs every intervention at once.
03 — Measure what changes
Progress may be assessed through abdominal distension, post-meal discomfort, bowel frequency and completeness, food tolerance, dietary variety and the effect of symptoms on daily life.
If treatment does not produce meaningful improvement, the diagnosis and strategy should be reconsidered rather than endlessly expanded.
What treatment may look like
The first stage depends on what is already known.
For someone who is significantly constipated, improving bowel movement may need to begin before or alongside targeted SIBO treatment.
For someone with diarrhoea, weight loss or possible malabsorption, medical investigation and nutritional assessment may take priority.
For someone with a convincing previous diagnosis but repeated relapse, the focus may be less about finding another antimicrobial and more about reconsidering motility, contributing conditions and whether the recurring symptoms still represent SIBO.
Recommendations may involve:
Nutrition and meal-pattern changes
Constipation and motility support
Practitioner-prescribed herbal medicine or nutritional supplements
Collaboration with your GP or gastroenterologist
Correction of identified nutritional deficiencies
A structured plan for food reintroduction
Repeat testing when the result would genuinely affect management
Each recommendation should have a purpose, timeframe and review point.
You should understand what we are targeting, what improvement we expect to see and what the next decision will be if that improvement does not occur.
When you have already tried everything for your gut
Many people reach a SIBO consultation after years of trying to solve the problem themselves.
You may have completed several elimination diets, bought expensive probiotics, used oregano or other antimicrobials, followed advice from podcasts and become increasingly afraid of triggering symptoms.
You may also have been told that SIBO explains everything, only to find that treatment did not provide the lasting change you expected.
Your response to previous diets, fibres, probiotics, laxatives, antibiotics and herbal products can help show which explanations remain plausible and which need to be questioned.
You do not necessarily need a more aggressive protocol.
You need a clearer understanding of what has already been tried, what genuinely changed and which next step is most likely to provide useful information.
You need more than a list of foods to avoid
Persistent bloating can gradually reshape the way you eat, dress, socialise and plan your day.
You may know which foods seem risky but still not understand why your digestion has changed, or why treatments only seem to help temporarily.
Your initial consultation can be used to organise the history, assess whether SIBO or IMO is plausible and determine whether the next step should involve breath testing, medical investigation, bowel support, nutritional treatment or a different clinical direction.
Consultations are available in Maroochydore and at Kunara Marketplace in Forest Glen on the Sunshine Coast, and online throughout Australia.
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Symptoms alone cannot confirm SIBO.
Bloating, distension, gas, constipation, diarrhoea and food reactions can occur with SIBO, but they also occur with IBS and other digestive conditions.
Your history can help determine whether SIBO is plausible. Breath testing may then be considered when the result is likely to influence treatment.
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It can occur in people with SIBO, but it is not diagnostic.
Immediate bloating may also be influenced by meal volume, swallowed air, the gastrocolic response, constipation, visceral sensitivity or impaired accommodation of the stomach and abdomen.
The timing should be considered within the broader pattern rather than used as a standalone test.
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Methane detected during breath testing is associated with slowed intestinal transit and constipation.
This is more accurately called intestinal methanogen overgrowth, or IMO, because methane-producing archaea may be present in the small or large intestine.
People with constipation should not assume they have IMO, but methane testing may be relevant when the broader presentation fits.
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Yes, diarrhoea can occur with SIBO, particularly in more significant cases involving disrupted digestion or absorption.
However, persistent diarrhoea has many possible causes and warrants appropriate medical assessment rather than being treated empirically as SIBO.
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SIBO may reduce tolerance to certain fermentable carbohydrates and contribute to food-related symptoms.
This does not necessarily represent a permanent intolerance or allergy to each food.
Food reactions can also occur through other mechanisms, so progressively removing foods without clarifying the pattern may create more restriction than understanding.
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Some people experience increased gas or bloating after taking certain probiotics. Others tolerate them well or find them helpful.
The effect depends on the strain, dose, product and individual presentation. Feeling worse after a probiotic does not prove SIBO, and probiotics should not be prescribed or avoided automatically.
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A prokinetic is intended to support gastrointestinal movement. Prescription or complementary options may be considered when impaired motility appears relevant.
They are not automatically required after every SIBO treatment. The choice depends on bowel pattern, contributing conditions, medication and safety considerations.
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Symptoms may return when impaired motility, constipation, altered anatomy or another predisposing factor remains.
They may also return because the symptoms were not entirely caused by SIBO in the first place.
A recurrence should prompt reassessment rather than an automatic repeat of the same protocol.
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I require an initial consultation before ordering a SIBO breath test.
This allows me to assess whether the test is appropriate, identify anything requiring medical investigation and make sure the result is likely to influence your treatment.
The test should not be purchased simply because bloating is present.