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Digestive complaints are among the most common issue I hear, true of almost every client with whom I work. One of the more common complaints is, “by the end of the day, I look six months pregnant!” Bloating can of course be caused by many factors– candida, parasites, pathogenic bacteria, food intolerances– but if you find your bloating worsens over the course of the day, you experience painful bloating after every meal, or if you are bloated after meals where you think you’re even avoiding the hard-to-digest foods like gluten and dairy, your problem could be SIBO.

What is SIBO?

SIBO stands for small intestine bacterial overgrowth. We have trillions of bacteria–both good and bad–in our gut, but when the bad bacteria overtake the good, problems arise. This is known as dysbiosis. And when there is an overgrowth of bacteria in the small intestine particularly, it’s a different ballgame. The small intestine isn’t really home to much of the bacteria present in the gut, so when bacteria take root there, symptoms such as pain, bloating, belching, abdominal distention, constipation and/or diarrhea result. SIBO symptoms present similarly to candida or leaky gut, but there are a few differences.

Here are the Main Signs of SIBO

  • Gas & Bloating, especially after a meal with fiber, sugar, starch
  • Carbohydrate intolerance
  • Abdominal pain, bloating, or cramping after a meal, and you’re not sure what’s causing it
  • Feel worse after taking probiotic, which exacerbates symptoms
  • Constipation
  • Taking fiber worsens constipation
  • Chronic Diarrhea (but constipation more common)
  • B12 deficiency or low iron
  • Multiple food intolerances
  • Heartburn/reflux
  • Belching
  • Bad bout of food poisoning, and you haven’t felt quite right ever since
  • Eczema and skin rashes

Some of the key differences in symptoms that tell you it’s SIBO specifically are

  • excessive belching
  • bloating which worsens over the course of the day, looking pregnant by day’s end
  • bloating or pain with probiotics (which feed the bacteria in the small intestine, causing pain to worsen)
  • frustration because you’re not sure what’s causing your bloating or gas
  • not feeling relief after going gluten and dairy free
  • chronic constipation or alternating constipation/diarrhea.

I have many frustrated new clients that come in feeling discouraged because they’ve cut out gluten and dairy and/or they’re eating mostly paleo but still having symptoms. That’s a major bummer.

SIBO is also present in a high percent of Crohn’s, Celiac, and IBS cases and could be a cause or contributing factor to these conditions. These folks do very well on a low FODMAP diet.

So What Causes SIBO?

The most common causes are

  • slow gut motility in the small intestine: Our migrating motor complex (MMC) should clear bacteria from the small intestine, sweeping it down toward the colon, both overnight and when we’re fasting, but if the MMC is compromised in any way, bacteria remain in the small intestine. These misplaced bacteria take root in the small intestine, and they and love carbs and starches as their main food source. They eat and ferment your food (contributing to deficiencies) and multiply, contributing to the pain and bloating from gas that gets trapped in the small intestine as the bacteria are fermenting the carbohydrates/fibers you ate.
  • structural issue: partial obstruction in the small intestine that causes bacteria to back up; illeocecal valve issues
  • immunodeficiency disease (weakened immune system)
  • food poisoning (gastroenteritis): causes dysfunction in the MMC, because nerve cells can be destroyed by food poisoning
  • antibiotic use
  • steroid drugs
  • acid-blocking drugs which decrease your hydrochloric acid production
  • hypothyroidism, which slows the MMC

Slow gut motility is a main factor. There are many causes of slowed gut motility, including food poisoning, hypothyroidism, certain diseases, adhesions, and inflammation that destroys motility.

A very common pattern I see is SIBO taking hold after a bad bout of food poisoning. Interestingly, up to 80 percent of SIBO cases are caused by food poisoning. These folks will come in and say they haven’t felt the same since the food poisoning incident, yet all stool tests come back clean (SIBO isn’t detected via stool test). This is because the MMC is malfunctioning, allowing for bacteria to creep up to the small intestine.

SIBO is also common with hypothyroidism (estimated at up to 54%) because a sluggish thyroid = slowed gut motility that can allow those bacteria to migrate into the small intestine.

Who Gets SIBO?

  • 66% of Celiac patients (who exhibit above symptoms)
  • 15% of the elderly population
  • 90% of alcoholics
  • 53% who use antacids chronically
  • 80% of IBS patients
  • 33% with chronic diarrhea
  • hypothyroid patients (don’t have stats on this)
  • history of chronic antibiotic use (no stats on this)


How to Test for SIBO

You can test for SIBO, but it won’t show up on the conventional stool test we use to detect pathogens and parasites. There are certain stool tests that test for levels of both good and bad bacteria in the gut, and if I notice very high levels of certain bacteria, that’s a sign. But the best way to test for it is to ask your doctor for a lactulose breath test: you’ll need to drink a prepared lactulose solution, then methane and hydrogen gases are measured within 2-3 hours (SIBO feeds on the sugar and releases these gases in response).

You can order your own breath test at directlabs.com (I Use BioHealth labs), but you’ll need a practitioner to interpret the results for you.

Methane dominant SIBO is typically associated with constipation, while hydrogen dominant SIBO correlates with diarrhea.


Note on treatment: SIBO is one of the hardest gut infections to eradicate. I highly recommend working with a skilled practitioner on this, because it requires a very specific protocol and follow-up treatment. SIBO very easily recurs if there is not proper followup.

Although SIBO has no doubt been affecting humans throughout history, the research on it is fairly new and ever evolving. I also suspect SIBO is also becoming much more prevalent due to an increase in hypothyroidism, overall inflammation, antibiotic use, and poor diets.

As with candida infections, the best way to treat SIBO is to starve it and kill it off. You can use antibiotics like rifaximin and/or neomycin (from your doctor) or anti-microbial herbs. I’m beginning to see that the herbal protocols are more effective in the long run, but these protocols take longer. If you get antibiotics from your doctor, PLEASE be aware that you must follow-up the antibiotics with treatment to address poor gut motility, or the SIBO will recur. I see these cases all the time. People get quick relief with antibiotics, but there can be a very strong (I’ve heard up to 100 percent) recurrence rate after 3 weeks if you leave it at that. I believe this is true because there is no follow-up treatment to fix the MMC, which is crucial to prevent recurrence.

Diet: Many people find relief eating a low FODMAP diet. Click here to read all about FODMAP foods and how to avoid them. Most importantly, make sure you’re avoiding sugar, alcohol, refined foods, and gluten. You want to remove the starches that feed the bacteria. The exception is during the anti-microbial herb or antibiotic protocols when you actually want to encourage the bacteria to be more active (source). I recommend a paleo-type plan during the protocols, as they’re the best to reduce inflammation in the GI tract, then the low FODMAP plan for three months following treatment. For severe cases I may recommend an elemental diet. I don’t recommend a low FODMAP plan longterm because it depletes needed short chain fatty acids in the gut.

Herbs: I use an herbal combo of berberines and other bacteria-killing herbs. Garlic and oregano oil work great, too, but the ideal protocol depends on if you’re methane or hydrogen dominant. This supplement is excellent to add to a protocol for methane dominant SIBO, and I often recommend it during the 3 month follow-up to the herbs to prevent recurrence. I also use neem. Opportunistic bacteria that take over when the gut flora becomes unbalanced create strong mesh-like structures called biofilms where they reside, hide from the immune system, thrive and multiply (source). For this reason, I recommend a biofilm disrupting supplement. I use Klaire Labs Interfase Plus. You must also use a prokinetic agent after treatment to make sure your gut motility prevents bacteria from migrating back up to the small intestine. A round of herbs is about 4 weeks long.

Be aware that you may need up to 3 rounds of herbs to completely wipe out SIBO, depending on how high your gas levels are, as indicated by your breath test. A single round of herbs or antibiotics reduces gas levels by about 30ppm. 2 weeks of the elemental diet may reduce SIBO gases by up to 150ppm, so I usually recommend that for severe cases.

Follow-up: It’s really important to use the prokinetic agent for up to 3 months post treatment to prevent recurrence. AND figure out the underlying cause in the first place to prevent regrowth. I use both Iberogast and Motil-Pro for prokinetics, depending on if the person suffers with constipation or diarrhea. I’ll also recommend a soil based probiotic and leaky gut healing support, such as glutamine.

Want to Learn More about How to Get Rid of SIBO?

Check out this excellent book series. Highly recommend. Even if you’re working with a doctor, PLEASE take a look at this book. I cannot tell you how many frustrated clients come to me after several round of antibiotics prescribed by their GI docs that did NOT work for SIBO. This book + resources written by a colleague carefully lays out the treatment plan I also recommend. Click here to get it.


Other Resources

Dr Siebecker’s excellent info on SIBO
Pimentel/Kresser interview
Siebecker interview on SIBO + causes
Everything you need to know about SIBO
10 signs you have SIBO
Excellent SIBO series all about causes and treatments

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