SIBO and Breath Testing
If you've been struggling with ongoing bloating or digestive symptoms that haven't improved with treatment, SIBO may be worth investigating. Breath testing can help us understand whether it's contributing to your symptoms.
SIBO NATUROPATH · MAROOCHYDORE, SUNSHINE COAST & ONLINE
Bloating that gets worse throughout the day, uncomfortable reactions to foods you've always eaten or digestive symptoms that keep returning can be incredibly frustrating. You may have tried changing your diet or taking supplements, only to find that the improvement doesn't last.
For some people, small intestinal bacterial overgrowth (SIBO) may be contributing. Similar symptoms can also occur with other digestive conditions, so it's important to consider the broader picture. SIBO breath testing can be useful when there's a clinical reason to investigate further.
Does This Sound Familiar?
SIBO can present differently from person to person, but some commonly reported symptoms include:
Bloating or visible abdominal distension, particularly after eating
Excessive gas, belching or abdominal discomfort
Constipation, diarrhoea or changes in bowel habits
Feeling unusually full after meals
Increased digestive symptoms after certain foods, fibres or probiotics
Symptoms that improve with treatment but keep returning
Some people find their symptoms are worse as the day goes on, while others experience discomfort shortly after eating.
These symptoms aren't specific to SIBO, but understanding when they occur and what makes them better or worse can help determine whether further investigation is worthwhile.
What Is Small Intestinal Bacterial Overgrowth (SIBO)?
SIBO occurs when there are excessive numbers of bacteria in the small intestine, where most of our digestion and nutrient absorption takes place.
When these bacteria ferment carbohydrates from the foods we eat, they produce gases that can contribute to bloating, abdominal discomfort and changes in bowel habits.
In some cases, SIBO can also interfere with nutrient absorption, leading to deficiencies or unintended weight loss.
SIBO can develop when the normal mechanisms that keep bacterial numbers under control aren't working as they should. Slower movement through the small intestine is one possible contributing factor, which we'll explore further below.
Understanding Hydrogen, Methane and Hydrogen Sulphide
SIBO breath testing measures gases produced by microorganisms in the digestive tract. The type of gas detected can help us understand what's happening and may influence treatment decisions.
H₂
Hydrogen-predominant SIBO
Hydrogen is produced when bacteria ferment carbohydrates in the gut.
Elevated hydrogen levels during breath testing may indicate SIBO, particularly when the results fit your symptoms and health history.
Hydrogen-predominant SIBO is often associated with diarrhoea, although constipation and other bowel patterns can also occur.
CH₄
Intestinal methanogen overgrowth
Methane is produced by microorganisms called archaea, which are different from bacteria. Because these organisms can be present throughout the intestinal tract, a methane-positive result is more accurately referred to as intestinal methanogen overgrowth (IMO).
Methane is closely associated with constipation and slower intestinal transit. This can include difficulty passing stools or feeling that your bowels haven't emptied completely, even if you're going every day.
H₂S
Hydrogen sulphide
Hydrogen sulphide is another gas produced by microorganisms in the gut. Higher levels have been associated with diarrhoea and abdominal discomfort.
Testing for hydrogen sulphide is less widely available, and its clinical interpretation isn't as established as hydrogen or methane testing.
These gas patterns can provide useful information, but results always need to be considered alongside your symptoms and medical history.
Why Certain Foods Can Make SIBO Symptoms Worse
If you have SIBO, you may find that foods you previously tolerated now leave you feeling bloated or uncomfortable.
This happens because bacteria in the small intestine ferment certain carbohydrates, producing gas that can contribute to digestive symptoms.
Reducing these foods may help you feel better temporarily, but it doesn't address why SIBO developed.
Several factors can contribute to bacterial overgrowth, including impaired intestinal motility, which normally helps move bacteria and food through the small intestine. Previous abdominal surgery, certain medications and underlying health conditions can also play a role.
Understanding what may be contributing is important, especially if symptoms keep returning after treatment.
Why Does SIBO Keep Coming Back?
You might have completed treatment for SIBO and felt way better, and then your symptoms gradually returned a few weeks or months later.
This can happen when the underlying factors that contributed to SIBO in the first place haven't been addressed. Slower intestinal motility, ongoing constipation or certain underlying health conditions may increase the likelihood of recurrence.
Returning symptoms don't always mean the bacterial overgrowth has returned. IBS and other digestive conditions can produce similar symptoms, even after SIBO has been successfully treated.
Before repeating antibiotics or herbal antimicrobials, I think it's important to review what improved with your previous treatment and whether the original diagnosis still fits.
Bloating Doesn't Automatically Mean SIBO
Bloating and changes in bowel habits can have several possible causes, including IBS, coeliac disease, food intolerances or problems with intestinal motility.
Some people may have more than one condition contributing to their symptoms, which can make it difficult to work out what's happening.
This is why I don't recommend SIBO testing based on bloating alone. Your symptoms and health history help determine whether breath testing is appropriate or whether something else needs investigating first.
Can SIBO Be Tested?
Yes. Hydrogen and methane breath testing is the most commonly used non-invasive method for investigating SIBO and intestinal methanogen overgrowth (IMO).
The test involves drinking a carbohydrate solution, usually lactulose or glucose, after following specific preparation instructions. Breath samples are then collected over several hours to measure the gases produced during fermentation. The results can help identify patterns consistent with SIBO or IMO.
Lactulose and glucose tests work differently. Lactulose travels through the small intestine but can be influenced by how quickly intestinal contents move. Glucose is absorbed earlier in the small intestine, so it may miss bacterial overgrowth further along. I tend to use lactulose clinically. However there are instances where glucose is more appropriate.
Test preparation is important. Recent antibiotics, certain medications and how the samples are collected can all affect the results. For this reason, I interpret breath test findings alongside your symptoms and medical history.
It's also worth knowing that comprehensive stool testing cannot diagnose SIBO, as it primarily reflects what's happening in the large intestine. Sometimes, however, certain overgrowths may give me a clue to what could be happening in the small intestine.
When is SIBO testing be worthwhile?
Breath testing may be worth considering if you've been experiencing ongoing bloating, abdominal discomfort or changes in bowel habits. It may also be useful if you've previously been treated for SIBO and your symptoms have returned.
Testing isn't always necessary for everyone with digestive symptoms. I consider your health history and previous investigations. If testing is appropriate, we can discuss the available options and what the results may tell us.
The SIBO testing pathway
01 — Initial consultation
We'll discuss your symptoms, health history and any previous testing to work out whether SIBO breath testing is appropriate for you.
02 — Test preparation and collection
If testing is recommended, I'll organise a home testing kit with instructions on how to prepare and collect your breath samples.
03 — Interpretation and treatment planning
Once your results are available, we'll review them together and discuss what they mean for your treatment. If further investigation is needed, we'll also discuss the options.
The results will help us decide what happens next, whether that's treatment, further investigation or looking at other possible causes for your symptoms.
How Is SIBO Treated?
Treatment depends on the type of overgrowth identified and why it developed in the first place.
Antibiotics are commonly used to treat SIBO, while herbal antimicrobials or an elemental diet may also be considered. These approaches have different considerations such as length, cost and suitability, and treatment needs to be chosen carefully.
Addressing factors such as impaired intestinal motility or ongoing constipation may also be important, especially when SIBO has returned after previous treatment.
In my practice, I look your test results alongside your symptoms and previous treatment experiences before recommending an approach.
Reducing bacterial overgrowth is only one part of your treatment. I also want to understand and address what may be contributing to the problem so we're not repeatedly treating recurring SIBO.
Can a Low FODMAP Diet Help With SIBO?
A low FODMAP diet can help reduce bloating and digestive discomfort by limiting certain carbohydrates that bacteria ferment in the gut.
For some people, this provides welcome relief. However, reducing symptoms doesn't necessarily mean the bacterial overgrowth has been treated.
I prefer to use dietary restrictions only when there's a clear reason, and for as long as they're needed. The longer foods are unnecessarily excluded, the harder it can become to maintain a varied diet.
Sometimes, adjusting portions or identifying particular food triggers is enough without following a strict low FODMAP diet.
When Your Digestive Symptoms Just Keep Coming Back
After years of dealing with digestive symptoms you've probably tried changing your diet or following different treatment protocols. The onslaught of information can be exhausting.
I know it’s so frustrating when something seems to help initially, only for the symptoms to return.
I particularly enjoy working with people who've reached this point. Sometimes it means revisiting previous investigations or questioning whether SIBO is actually responsible for the symptoms.
You shouldn't have to keep trying different treatments without understanding why they're being recommended.
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SIBO can cause bloating, excessive gas and changes in bowel habits, but these symptoms can also occur with other digestive conditions.
A breath test can help investigate whether SIBO is present, but it needs to be considered along with your health history and symptoms.
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Sometimes, but the timing of bloating alone doesn't tell us whether SIBO is present.
Bloating shortly after eating can also be related to constipation, increased sensitivity in the gut or how your digestive system responds to a meal.
I want to know when your symptoms occur alongside your overall digestive history before deciding whether SIBO testing would be useful.
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Yes, although constipation is more strongly associated with intestinal methanogen overgrowth (IMO), often called methane SIBO.
Methane-producing microorganisms can slow intestinal transit, contributing to constipation, bloating and difficulty fully emptying the bowels.
You can also have elevated methane levels without severe constipation, so bowel habits alone aren't enough to identify IMO.
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Yes. Diarrhoea can occur with SIBO and is more commonly associated with hydrogen-predominant overgrowth.
However, ongoing diarrhoea can have several causes, so it's important to investigate rather than assume SIBO is responsible.
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SIBO can make certain foods harder to tolerate, especially carbohydrates that are easily fermented by bacteria.
You might notice more bloating or discomfort after eating foods that previously caused no problems.
This doesn't necessarily mean you've developed a true food intolerance. Food tolerance often improves with treatment.
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Some people with SIBO experience increased bloating or gas when taking probiotics, while others tolerate them well.
The response can depend on the strains used and the individual's digestive symptoms. Probiotics aren't automatically helpful or harmful in SIBO, so I prefer to consider whether there's an obvious reason to use them rather than recommend them routinely.
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A prokinetic is intended to support gastrointestinal movement. Prescription or complementary options can be considered when impaired motility appears relevant.
They aren’t automatically required after every SIBO treatment. The choice depends on bowel pattern, contributing conditions, medication and safety considerations.
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SIBO can return when underlying factors, such as impaired intestinal motility or ongoing constipation, haven't been addressed.
However, returning symptoms don't always mean SIBO has returned. It's important to reassess what's happening before repeating treatment.
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I arrange SIBO breath testing following an initial consultation so we can first determine whether it's appropriate for your symptoms.
This also gives us an opportunity to review any previous investigations and make sure the test is likely to provide useful information.
If testing is recommended, I'll organise the kit and arrange a follow-up to discuss your results.
Frequently asked questions
Looking for Help With SIBO?
If you've been struggling with ongoing digestive symptoms or have already been treated for SIBO without lasting improvement, I'd be happy to help.
We can review what's been happening and work out whether further investigation or treatment is appropriate for you.