Unraveling the Mystery of SIBO: A Gut Health Primer
This blog contains affiliate links. I may earn a commission on qualifying purchases.
What is IBS?
If you've been dealing with uncomfortable digestive symptoms like bloating, abdominal pain, and irregular bowel movements, you may have been diagnosed with IBS (Irritable Bowel Syndrome). IBS is characterized by that trio of issues - abdominal pain, altered bowel habits, and bloating.
While the causes of IBS were once largely mysterious, researchers have discovered that in many cases, an underlying condition called SIBO (Small Intestinal Bacterial Overgrowth) is the root problem. In fact, studies estimate that around 60% of IBS patients actually have SIBO.
Abdominal pain
Change in bowel movements
Bloating
What is SIBO?
SIBO is a disorder where there is an excessive growth of bacteria in the small intestine. Although it was first identified back in 1939, SIBO's connection to IBS wasn't established until the groundbreaking work of Dr. Mark Pimentel, a gastroenterologist at Cedars-Sinai, in the early 2000s. Notably, Pimentel also linked cases of IBS to previous bouts of gastroenteritis or food poisoning.
100% of patients with SIBO have bloating.
The Roots of SIBO
So, what causes this bacterial overpopulation in the small intestine? Interestingly, food poisoning from pathogens like Campylobacter, Salmonella, Shigella, and certain E. coli strains is a major trigger.
Food Poisoning's Lingering Effects
When food poisoning occurs, it can lead to the release of a toxin called CDTB that impairs the nerves in the gut lining. The body then produces anti-CDTB antibodies to fight this, fueling inflammation and GI symptoms. Anti-vinculin antibodies may also form, damaging the gut mucosa itself and potentially causing a "leaky gut" where toxins escape into the body.
This autoimmune response can manifest in wide-ranging issues beyond just typical digestive complaints, like bodily aches and pains, skin rashes, brain fog, and more.
Other Potential IBS Causes
It's important to note that while SIBO is a common underlying cause, there are other potential triggers for IBS as well, including SIFO (small intestine fungal overgrowth), Celiac disease, food intolerances, histamine sensitivities, Ehlers-Danlos syndrome, and POTS syndrome.
The Symptoms and Types of SIBO
SIBO can present differently depending on the type of bacterial overgrowth involved. The three main categories are:
Hydrogen SIBO
- Characterized by diarrhea
- Often caused by overgrowth of bacteria like E. coli or Klebsiella pneumoniae
Methane SIBO
- Often leads to constipation
- Caused by overgrowth of the archaea Methanobrevibacter smithii
Hydrogen Sulfide SIBO
- Causes excessive diarrhea
- Linked to bacteria like Fusobacterium varium or Desulfovibrio piger
Regardless of type, bloating is a universal symptom since the overgrown bacteria produce excess gas.
Diagnosing SIBO
Breath Tests
The primary way to diagnose SIBO is through a breath test that detects elevated levels of hydrogen, methane, or hydrogen sulfide gas - indicating which type is present.
Blood Tests
Blood tests checking for autoimmune antibodies like anti-CDTB and anti-vinculin can also help identify SIBO.
Endoscopy
In some cases, an endoscopy with biopsies of the small intestine may be performed.
Treating SIBO
If diagnosed with SIBO, it can be managed through a combination approach:
Antibiotics
The antibiotic rifaximin is a common first-line treatment. It may be combined with other antibiotics based on the SIBO type, such as neomycin or metronidazole for methane, or bismuth for hydrogen sulfide cases.
Dietary Adjustments
- A low-FODMAP or low-fermentation diet
- Spacing out meals further apart or intermittent fasting
- Initially reducing fiber intake, then reintroducing gradually
FODMAP foods are poorly absorbed in the small intestine. Bacteria feed and ferment on these foods, exacerbating the symptoms of SIBO.
Supplements
- Gut-healing supplements like fish oil, vitamin A, GLA
- Prokinetic aids like ginger, peppermint oil, artichoke leaf extract
- Bifido probiotics may help, but avoid lactobacillus strains
The Relapsing Nature of SIBO
Because the autoimmune process that allows SIBO to develop cannot yet be fully reversed, the condition has no permanent cure. This means that even after successful treatment, SIBO can potentially recur over time. Staying vigilant about symptoms and working closely with your doctor is important.
If you've been struggling with unexplained IBS-like symptoms, getting evaluated for SIBO is critical. By understanding this often-overlooked gut disorder, you can work with your healthcare team to find the right combination of treatments to finally get lasting relief.
Want to learn more about following a low-fermentation diet for SIBO? Check out The Gut Microbiome Connection here:
The Microbiome Connection
Ready to work with Dr. Lorenz one-on-one with a personalized functional medicine program? Book a free consultation telephone call here:
