SIBO (small intestinal bacterial overgrowth) might actually be at the root of your IBS & digestive issues

IBS (irritable bowel syndrome) is a label that most doctors use when they can’t find celiac disease, Crohn’s disease or other physical abnormalities in your digestive tract…. but it really doesn’t tell you anything that you didn’t already know: you have digestive problems of an unknown cause.

That’s why a diagnosis of IBS is definitely not a satisfying answer if you experience digestive problems. Use it as a starting point. Start looking for the root cause of your IBS: a parasite infection, an intolerance to gluten, dairy, fructose or FODMAPs could be responsible for your digestive issues. Or maybe you should also consider SIBO.

What is SIBO?

SIBO stands for small intestinal bacterial overgrowth. Quite self-explanatory, this term refers to an overgrowth of bacteria in your small intestines (SI). Of course, it is normal to have bacteria in your intestines. You need lots of them to have a well-functioning digestive system – 10 times more than you have human cells actually. But most of them should be in your colon, not in your SI.

The bacteria that overgrow in SIBO are not necessarily bad; they’re just not at the right place. With an intolerance to FODMAPs, bacteria located in the large intestines ferment specific types of carbohydrates, such as fructose and lactose. With a gut dysbiosis like SIBO however, the fermentation happens in your small intestines.

Signs and Symptoms

The symptoms of SIBO are the same associated with IBS:

  • constipation,
  • diarrhea,
  • abdominal pain,
  • bloating, and
  • flatulence.

As many as 84% of people with IBS actually have SIBO. (1) It can even mimic a flare-up in people with Crohn’s disease or prevent people with celiac disease or other digestive disorders from getting better. (2,3)

In addition to these obvious digestive problems, SIBO is also associated with all kinds of systemic symptoms. A bacterial overgrowth in your SI can do a lot of damage and increase your intestinal permeability.

In simple terms, SIBO often = leaky gut.

This is why you can experience all kinds of symptoms beyond digestive issues with SIBO, including

  • joint pain,
  • fibromyalgia,
  • skin problems,
  • autism and
  • other cognitive issues as well as
  • autoimmune conditions like arthritis and thyroid disorders. (4)

Over time, SIBO can also lead to nutrient deficiencies, especially

  • vitamin B12,
  • iron and
  • fat-soluble nutrients (vitamins A, D, E, K and many antioxidants),

which can also further contribute to depression, acid reflux, cognitive problems and various food sensitivities. If a gluten-free or grain-free diet like the Paleo diet doesn’t seem to be enough to improve your digestive health, you may have SIBO. Especially if the low-FODMAP approach doesn’t seem to help either. And especially if you feel like you react to almost any types of foods, especially those containing carbohydrates.


Breath testing is the most commonly used tool to diagnose SIBO. The problem is that some labs only measure hydrogen in your breath and fail to measure methane. Some use glucose and others lactulose. Some measure the gas in your breath at one point in time, for a period of 90 minutes or for up to 3 hours.

You get the picture: SIBO testing is not completely standardized…

In fact, the diagnostic accuracy of breath testing unfortunately ranges between 54 and 65%. (4) It’s worth a try but a negative result (meaning that you don’t have SIBO) doesn’t guarantee that you really don’t have it.

Treatment Options

The treatment options for SIBO all share a common goal: eliminating the chronic bacterial overgrowth.

You can accomplish this objective either by killing them directly or by starving them to death. Whatever treatment you choose, it’s important that you discuss it with a health practitioner.

Antimicrobials. SIBO usually responds well to antibiotics., although SIBO associated with constipation can be harder to treat. Specific antibiotics like Rifaximin are not absorbed in your body and mostly stay in your gut where it can eradicate most of the excess bacteria. Herbal antimicrobials such as peppermint, garlic (allicin) and oregano (ADP form) are less studied but constitute another possible option to get rid of this surplus of bugs in your SI.

Diet. You can also treat your chronic infection by depriving the surplus of bacteria of their favorite food source: carbohydrates. One option is the use of an elemental diet formula. These formulas are similar to liquid meal replacements and should replace all of your meals for a period of 3 weeks. Although elemental diet formulas are high in carbohydrates, the carbs are in the form of glucose, which is supposed to be rapidly absorbed within the first 2 feet of your SI before the excess of bacteria gets their dirty little hands on them, quickly starving them to death. Although most of these treatments are effective in the short-term, recurrence rates can be high if not accompanied with dietary changes.

Some people even choose to treat their SIBO with diet alone. Antibiotics or elemental diet formulas can speed up the process, but it is possible to obtain the same relief simply by changing your diet. The disadvantage of the dietary approach is that it can take at least 1-2 years, sometimes up to 5 years, before you can reintroduce gluten-free carbs, such as sweet potatoes and fruits, without experiencing gastrointestinal symptoms.

Dietary Approach

Although SIBO is a new term, this bacterial overgrowth problem has been known for over 100 years. The SCD (specific carbohydrate diet) diet was based on the dietary approach developed by Dr. Haas in the first part of the 20th century to help people with all kind of digestive issues, including IBS, celiac disease, Crohn’s disease and ulcerative colitis. It is a shame that all of Dr. Haas’ work went completely forgotten when the gluten protein was discovered and doctors started using a medication-based approach to control their patient’s symptoms.

The GAPS (gut and psychology syndrome) diet is Dr. Nathasha Campbell-McBride’s upgraded version of the SCD diet, with an emphasis on healing and sealing the gut and correcting gut dysbiosis to address associated psychological conditions. The SCD and the GAPS diets are similar to the Paleo diet in many ways because they both eliminate grains, sugars and processed foods. The GAPS diet is also dairy-free, at least in the first 6 weeks. The goal, like with the elemental formula liquid diet, is to starve the excess bacteria by depriving them of their preferred source of energy: sugar, starches and fermentable carbohydrates. More precisely, monosaccharides (carbohydrates made of a single molecule) are allowed, while di- and poly-saccharides (carbohydrates made of 2 or more sugar molecules) are not. This eliminates all grains, potatoes and most sugars, but allows carbohydrates from almost all vegetables, squashes and fruits, according to your individual tolerance. These dietary approaches are both based on animal protein and traditional fats. Bone broths, fermented foods and digestive enzymes are emphasized on the GAPS diet to heal and seal the gut.

For many of my clients, combining principles of the GAPS nutritional protocol with the low-FODMAP approach (as explained in my book DHwRF) and adjusted to your individual tolerance to quickly get your symptoms under control.

Basically, it’s a form of elimination diet. You start with the most healing, nutrient-dense, anti-inflammatory and less irritant foods that are not likely to feed your gut dysbiosis (imbalance in the gut flora) for the first few weeks and then cautiously proceed to the reintroduction phase when you can gradually add more variety to your diet while keeping your symptoms and SIBO in check.

My SIBO. That’s exactly the approach I personally took when I was diagnosed with SIBO in 2011 after suffering from a parasite infection and post-infectious IBS. I could only tolerate 4 foods back then. And now I still need to stay gluten-free but can now tolerate a wide variety of vegetables, fruits, tubers and chocolate as well as occasional indulgences like gluten-free grains (mostly organic corn and white rice) and even good-quality dairy. 😉

Over time, as your gut flora re-balances itself and your intestines are no longer leaky, your food tolerance should improve. Your IBS is not all in your head and you can get better and control SIBO by tweaking your diet.

Bottom Line

If you want the best health, you should expect your poop to be perfect because it is the best indicator of how your digestion is going. Abnormal digestion is a sign that your health is not optimal. Health starts in the gut, so make sure you get your digestion in order if you want to achieve optimal health.

If you need extra help to get there:

* Article originally published in Paleo Magazine.

Want to learn more? Watch my SIBO webinar here.

Want to learn more? Watch my SIBO webinar here.

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References (1)      Pimentel M, Chow EJ and Lin HC. Normalization of Lactulose Breath Testing Correlates With Symptom Improvement in Irritable Bowel Syndrome. A Double-Blind, Randomized, Placebo-Controlled Study. American Journal of Gastroenterology. 2003 Feb;98(2):412-9. (2)      Klaus J, et al. Small intestinal bacterial overgrowth mimicking acute flare as a pitfall in patients with Crohn’s disease. BMC Gastroenterology. 2009. 9: 61. (3)      Tursi A, Brandimarte G and Giorgetti G. High prevalence of small intestinal bacterial overgrowth in celiac patients with persistence of gastrointestinal symptoms after gluten withdrawal. American Journal of Gastroenterology. 2003. 98(4): 839-843. (4)      Siebecker A. Small Intestine Bacterial Overgrowth: Clinical Strategies. Siboinfo.com. 2011. [recorded webinar: http://www.siboinfo.com/learning-more.html] (5)      Gottschall EG. Breaking the Vicious Cycle: Intestinal Health Through Diet. 1994. (6)      Campbell-McBride, N. Gut and Psychology Syndrome: Natural Treatment Of Autism, ADHD, Dyslexia, Dyspraxia, Depression and Schizophrenia. 2004. (7)      Siebecker A. SIBO-Small Intestine Bacterial Overgrowth. [accessed online: http://www.siboinfo.com/index.html