SIBO: What Actually IS Small Intestinal Bacterial Overgrowth?

It’s not uncommon for patients to come into our office and complain that no matter what they eat, they get bloated. Seemingly healthy foods, sometimes even water (!), they say, causes uncomfortable symptoms that are just not normal. At this point, they may have been dismissed by their doctor, or even gotten an eye-roll from your best friend—we’ve seen it all.

Gas, bloating, stomach distension… all of these are completely normal symptoms to get from time to time. But when they start becoming constant, every day, uncomfortable feelings, we begin to wonder if something might be going wrong.

When we hear these things, we start to think of digestive dysfunctions and what these symptoms could be trying to tell us. A common cause is small intestinal bacterial overgrowth or SIBO for short.

What is SIBO?

The small intestine is a piece of your digestive tract that is responsible for the majority of your absorption of your nutrition. It’s a very porous organ, and should be relatively bacteria free. When unwelcome bacteria start to take residence in your small intestine, they can ferment the foods you’re eating. That creates either methane, hydrogen or hydrogen-sulfide gases, which can become trapped, causing bloating. They can also cause leaking through the pores of your intestine, which can begin to wreak havoc internally, limiting the absorption of your vitamins and nutrients, and causing inflammation to your intestinal lining.

When all these things culminate, they can create a wide range of dysfunction.

Common Symptoms

It’s important to note that these vary for for everyone, usually by severity and accompanying imbalances. But, there are a few specific symptoms we’re looking for when we’re talking about SIBO.

  • Gut specific symptoms.
    • Excessive bloating, usually specific to the upper stomach (above the belly button in the upper 2 quadrants of the stomach), but it can be generalized.
      • This bloating can happen after you eat higher FODMAP foods, or easily digested carbs (think bread, pasta, white rice, pastries).
      • The majority of patients will say they wake up in the AM with a flat stomach, and then get bloating again with their first meal.
    • Constipation/Diarrhea. When gases start to intoxicate the nerves of the migrating motor complex (a.k.a. the nervous system of your gut), they can either speed it up or slow it way down, causing diarrhea or constipation, respectively.
    • Heartburn/Reflux
  • Worsening autoimmune disease. If you’re just having a hard time getting your autoimmunity under control and your immune system to calm down, you should look towards the gut.
  • Multiple food allergies.
  • Muscle and joint pains that are hard to get under control.
  • Brain fog that just won’t quit, even with proper thyroid treatment.
  • Acne flares and other skin rashes that aren’t going away with other treatments.
  • Headaches and migraines.

Common Causes/Risk Factors of SIBO

We are always asking WHY. So why did you get SIBO in the first place? This may not be the easiest or most straightforward question to ask, however we give it our best shot.

The easy answer is that your small intestine is located in between your stomach and your large intestine—so bacteria can only get in through the ‘top’ or the ‘bottom.’ Here is a (non-exhaustive) list of what can cause SIBO.

  • Structural reasons
    • Diverticula (pouches in the SI wall) that can collect bacteria and allow them to overgrow.
    • Past history of abdominal surgery that would leave your abdomen wall with adhesions. These adhesions can ‘pull’ the organs around or pull open the sphincter between the large and small intestine and allow bacteria to get in. (Think c-sections, gall bladder surgeries, appendix surgery, stomach shrinking weight loss surgeries—these are the most common.)
  • Medications
  • Other Diseases
    • Diabetes, both type 1 and 2.
    • Systemic autoimmune diseases such as Lupus and Scleroderma.
    • Celiac disease.
    • Non-alcoholic fatty liver disease.
    • Low stomach acid.
    • Crohn’s disease.
    • Fibromyalgia, although this may be difficult to determine what about fibromyalgia would cause SIBO, the need for management medications, or the actual dysfunction that causes the fibromyalgia.


SIBO Correlations with Other Pathology

Not every case of SIBO is as easy as checking the boxes. Sometimes we bring SIBO up when we’re trying to identify what could be exacerbating or making the condition we’re treating worse.

Some examples:

  • Hashimoto’s Thyroiditis: This the autoimmune condition that attacks your thyroid gland, and one piece to fighting this is figuring out what is adding fire to your immune system. With the bacteria layering the most porous pieces of your digestive tract, your immune system can identify those invaders front and center. With Hashimoto’s patients, we often ask about the digestive tract and if a SIBO picture fits their case.
  • Irritable Bowel Syndrome (IBS): We’re at a point where culturally, we’re acknowledging that IBS is just a catch all diagnosis for ‘we don’t know what’s wrong with your stomach.’ You have to ask the right questions to differentiate between lower intestine dysbiosis, candida, parasites, and small intestinal dysbiosis—but when you figure it out you can successfully reverse IBS.
  • Brain Fog, Memory and Chronic Fatigue: We measure these bacteria and identify them based on the gases they produce, but bacteria innately create ammonia as a byproduct. Humans also create ammonia, which our liver is apt to deal with (if there’s isn’t liver disease going on). However, when you have a lot of things going on that your liver is dealing with (medications, birth control, high estrogens, your nightly glass of wine, environmental toxins…), adding in one more thing could set it over the edge. When it’s set over the edge, you can get other symptoms that may not be related to your endocrine system, but SIBO. Think brain fog, difficulty with attention and focus, excessive fatigue, muscle weakness and lethargy.
  • Multiple Food Intolerances: We’re believers in the fact that certain foods can cause a reaction and symptoms in your body. However, if there are several (think 7 or more) foods that cause a systemic reaction in your body, it may not be the foods. It may be that SIBO is heightening your immune system, making it over-reactive to the foods you’re eating (not to mention the inflammation to the gut lining makes your body over-reactive). When you eradicate the SIBO and heal the gut lining, you can successfully reintroduce foods that once caused reactions.

In all honesty, it’s hard to narrow down what else could be caused by SIBO, because your ENTIRE body is interconnected. There are limitless things that an inflamed gut, a heightened immune system, malabsorption of your vitamins and minerals, and foreign gases can cause—but these are some of the common things that I’ve seen can be correlated with SIBO.

So You Think You Have SIBO: What Now?

The least invasive, and cheapest way to diagnose SIBO is by breath test ordered by your doctor. I can’t say it’s a fun test, but it can be done in the comfort of your own home, watching an episode of Grey’s Anatomy (McDreamy can get you through anything).

Patients drink a provoking drink of either lactulose or glucose to wake the bacteria up. They then exhale into tubes that collect the breath sample. Easy as that. You send the sample away and you’ll receive a graph indicating the levels of both methane and hydrogen in your small intestine.

I’m Positive for SIBO: What’s Next?

Come back next week to learn about our treatments for SIBO—what we’ve seen work, what we know doesn’t work and what expectations you can have for recovery.

If you’re ready to start your healing journey today, you can find more information about our office here.