Quick answer: SIBO, or small intestinal bacterial overgrowth, happens when too many bacteria grow in the small intestine, where they ferment food too early and produce hydrogen, methane or hydrogen sulfide gas. Common symptoms are bloating, gas, abdominal pain, diarrhea or constipation, and nutrient malabsorption. Care usually involves reducing the overgrowth, restoring healthy gut movement, supporting the lining and preventing relapse.
Key takeaways
SIBO happens when too many bacteria settle in the small intestine and ferment food early, producing hydrogen, methane or hydrogen sulfide gas.
Slowed gut movement, especially of the cleaning wave between meals, is one of the most common reasons it develops.
A breath test is the usual way to look for it, and the article also discusses how meal spacing relates to the gut’s cleaning wave.
Common SIBO symptoms
Common SIBO symptoms include bloating that worsens through the day or after meals, gas, belching and abdominal discomfort, and diarrhea, constipation or both. Feeling full quickly is common too, along with fatigue, brain fog or nutrient deficiencies (such as B12 or iron).
What causes SIBO?
SIBO can follow slowed gut movement, especially of the migrating motor complex (MMC), the “cleaning wave” between meals, or low stomach acid, including from long-term PPI use. Previous food poisoning or gut infections and abdominal surgery or adhesions can also set the stage.
Conditions such as diabetes, hypothyroidism or celiac disease are other contributors, as are opioid medications.
How SIBO is tested
SIBO is commonly assessed with a lactulose or glucose breath test that measures hydrogen and methane (and sometimes hydrogen sulfide). Results are interpreted with your symptoms. Related: IBS: bloating, pain and irregular bowels.
Natural strategies
Herbal antimicrobials such as berberine, oregano oil, allicin (garlic extract) and neem are used for a defined period with guidance. On the diet side, that may mean a temporary low-FODMAP approach, or a supervised elemental diet in some cases. Prokinetics such as ginger and certain herbal blends support the MMC.
Gut-lining support may include glutamine and zinc carnosine, and targeted probiotics and fibers, such as spore-based probiotics or partially hydrolyzed guar gum (PHGG), are introduced carefully.
Herbs and medications both have a role. Antibiotics such as rifaximin are a standard medical option and can be discussed with your doctor. Amounts and duration should be individualized. If you work with me, products I commonly use are in my Fullscript dispensary.
Preventing relapse
Space meals a few hours apart so the MMC can work, and eat slowly and chew thoroughly. Daily movement and diaphragmatic breathing help, and it is worth reviewing long-term PPIs or opioids with your prescriber. Above all, address the underlying cause, such as motility or thyroid issues.
SIBO and healthy aging
Overgrowth keeps the immune system activated and can interfere with absorbing nutrients, both of which add to chronic inflammation and strain on cellular energy. An unbalanced microbiome (dysbiosis) is itself one of the processes that drives aging. Restoring healthy digestion supports both comfort now and long-term health. Related: supporting the gut lining.
When to see a naturopathic doctor
It may be time to see a naturopathic doctor if bloating, gas or irregular bowels keep coming back, or if your symptoms returned after previous SIBO treatment. The same is true if you have low B12 or iron along with gut symptoms, or if you want a plan that addresses why SIBO developed.
See a medical provider promptly for blood in the stool, unintended weight loss, persistent vomiting, severe abdominal pain, fever, or trouble swallowing.
Bloating that keeps coming back? Let us figure out why.
A free 15-minute consultation with Dr. Kneessi. No cost, no obligation. In-office in Odenton, MD or by telehealth.
Questions to bring to your clinician
These questions can help you get the most out of your next visit.
Would a breath test add useful information about my bloating and gas?
Which labs or assessments would help us understand SIBO in my case?
Which daily habits are most likely to make a difference for SIBO for me?
How long would it be reasonable to try these steps for SIBO before we review them together?
Practitioner-grade options in my Fullscript catalog: if you and your clinician decide a supplement makes sense, my supplement guide by health goal links to the practitioner-grade products I trust.
Frequently asked questions
What does SIBO feel like?
Most people describe bloating that builds through the day, gas, abdominal discomfort and changes in bowel habits.
Can SIBO come back?
Yes, relapse is common when the underlying cause, such as slowed motility, is not addressed. Prevention is part of the plan.
Are herbs as effective as antibiotics for SIBO?
Some studies suggest certain herbal antimicrobials can help, but research is limited. Both options can be discussed with your provider.
Should I take probiotics if I have SIBO?
Some probiotics can help and others may worsen bloating. Choice and timing should be individualized.
Sources
- Rezaie A, et al. Hydrogen and methane-based breath testing in gastrointestinal disorders: the North American Consensus. Am J Gastroenterol 2017. PMID: 28323273. https://pmc.ncbi.nlm.nih.gov/articles/PMC5418558/
- Chedid V, et al. Herbal therapy is equivalent to rifaximin for the treatment of small intestinal bacterial overgrowth. Glob Adv Health Med 2014. PMID: 24891990. https://pmc.ncbi.nlm.nih.gov/articles/PMC4030608/
- Lo WK, Chan WW. Proton pump inhibitor use and the risk of small intestinal bacterial overgrowth: a meta-analysis. Clin Gastroenterol Hepatol 2013. PMID: 23270866. https://pubmed.ncbi.nlm.nih.gov/23270866/
- MedlinePlus Medical Encyclopedia: Small Bowel Bacterial Overgrowth
- NCCIH: Probiotics: Usefulness and Safety
This article is for educational purposes only and is not medical advice. It does not replace an individual evaluation. Talk with your healthcare provider before starting supplements or changing medications, especially if you are pregnant, nursing, or managing a health condition.
