What is SIBO? An explainer in plain English

It seems like everywhere you look on the internet these days, someone is talking about SIBO.

What the heck is it? How do you even pronounce it? Why should I care? All valid questions, all things we’ll address in this post.

Let’s start with the basics - what is SIBO?

SIBO (typically pronounced ‘see-boh’) stands for Small Intestinal Bacterial Overgrowth and put simply, it’s an accumulation of bacteria in the small intestine.

I can already hear you asking, “aren’t there supposed to be a ton of bacteria in our digestive systems?”

Yes, there definitely are, but they’re found mostly in the large intestine, with the small intestine having much fewer, comparatively. When bacteria from the large intestine (for reasons I’ll discuss below) moves up into the small intestine and overgrows, SIBO occurs.

So why does it matter?

Ok, so you’ve ended up with some extra bacteria in your small intestine - who cares? What difference does it make? Another great question. A bunch of reasons, but the most obvious ones are the symptoms.

SIBO can have many symptoms, but the most common ones are:

  • Bloating and abdominal distention (usually after eating)
  • Abdominal pain or discomfort
  • Either diarrhea or constipation (or alternating between the two)
  • Excessive gas and belching (again, very common after meals)

Sounds pretty similar to IBS, huh? Well it turns out SIBO is way more common than you’d think, and it’s estimated that up to 85% of IBS cases could actually be caused by SIBO. [Side note: Personally, I think this is great news, because so often IBS sufferers are told by their doctors that there’s nothing they can do and they’ll just have to live with it. Turns out there may be an underlying cause that can actually be addressed - woo hoo!]

After that, there can be related conditions or secondary symptoms, including:

  • Sleep issues
  • Changes in weight (gain or loss)
  • Restless legs at night
  • Joint pain
  • Mood changes
  • Multiple food sensitivities
  • Respiratory symptoms (like asthma)
  • Acne or skin rashes
  • Memory issues and/or foggy thinking
  • Iron and/or B12 deficiency

Aside from these frustrating symptoms, SIBO can damage our bodies. When a ton of bacteria are present in the small intestine, they start to interfere with the digestion and absorption of food, and in some cases can be associated with damage to the lining of the small intestine and has the potential to cause intestinal permeability (or leaky gut).

Since the lining is now damaged, larger food particles can leak through into the bloodstream, which the immune system can react to and cause a food sensitivity or even autoimmune conditions.

SIBO can also cause nutrient deficiencies because the bacteria consume some of our food before we’re able to absorb the nutrients, so conditions like low iron or B12 can be common with SIBO patients.

The bacteria can also interfere with fat absorption, which can lead to downstream issues like vitamin A, D, and K deficiencies.

Also, the bacteria can excrete acids, which in some cases can become correlated with neurological and cognitive symptoms (ranging from brain fog to autism).

So what causes SIBO?

The short answer is that SIBO is actually pretty complicated and often times there can be more than one contributing factor.

The main risk factors for developing SIBO are:

  • Celiac disease (long-standing)
  • Crohn’s disease
  • Prior bowel surgery
  • Multiple courses of antibiotics
  • Food poisoning

These risk factors and others contribute to either:

  • A damaged Migrating Motor Complex [which is a wave that sweeps through your small intestine every few hours to sweep stray bacteria out]
    • Things that damage or impair MMC function include:
    • Gastroenteritis (aka food poisoning) - this is one of the most common causes
    • Hypothyroid
    • C. difficile infection
    • Lyme disease
    • Surgery or injury to the bowel area
    • Medications like opiates or many rounds of antibiotics
  • Functional changes [where bodily function has been altered and bacteria are not killed off in the stomach or cleared out of the small intestine like they should be].
    • Things that cause this include low stomach acid (which can be caused by things like prolonged use of proton pump inhibitors, chronic stress, or h. Pylori infection), decreased bile flow, or leaky gut/intestinal permeability.
  • Structural changes [where the actual structure of the body changes and bacteria isn’t cleared as it should be and/or bacteria is allowed to move from the large intestine up into the small intestine].
    • Things that cause this include issues with the ileocecal valve (the sphincter muscle between the small and large intestine), cancer, or adhesions from abdominal surgery.

How is SIBO diagnosed?

SIBO tends to be very under-diagnosed. Why? A few reasons:

  • Many people don’t seek medical care for their symptoms (they think digestive issues are normal or don’t realize something’s actually wrong).
  • Many doctors aren’t aware of how common SIBO is.
  • The most common tests for it have fairly high rates of false negatives (meaning the test results come back negative even though you do actually have it). Also, there aren’t hard and fast agreed upon criteria for test results, so diagnosis can vary from doctor to doctor, depending on who is interpreting the test results.

Unfortunately no tests for diagnosing SIBO are perfect, but a breath test is generally agreed to be the most accurate. [Technically an aspirate of the fluid in the small intestine is the most accurate, but it’s not currently available to the general public, and it too, can sometimes miss SIBO].

The test involves drinking a sugar solution and then blowing into different tubes over the course of several hours to measure the gas in your breath. The main types of breath tests are lactulose or glucose, and they both have their pluses and minuses.

You’re more likely to find SIBO with a lactulose test, but it’s also more likely to be a false positive. You’re less likely to find it with a glucose breath test, but if you do find it, it’s much less likely to be a false positive. Either way, it’s something to discuss with your doctor so you can make an informed choice.

What the heck do you do about SIBO?

The three main ways SIBO is typically addressed are:

  • Antibiotics
    • The most common is Rifaximin (or Xifaxan) which targets the bacteria in the small intestine, while mostly leaving the bacteria in the large intestine alone, which is a good thing.
  • Antimicrobial Herbs
    • Herbs can be a good option for people trying to go the more natural route, but can take a little longer to be effective.
  • The Elemental Diet
    • The ED is a powdered drink composed of amino acids, fats, carbs, vitamins, and minerals in their most broken down or pre-digested form. You consume only this beverage for 2 to 3 weeks, with the idea being that all of the nutrients are basically pre-digested, so they get absorbed high up in the small intestine, starving any bacteria that is living further down. While it can be difficult to stick to a liquid diet for this long, it’s also one of the most effective treatments, getting rid of SIBO in up to 80% of people who complete it.

There are different diets that can be helpful in managing symptoms, but diet alone cannot cure SIBO (except the Elemental Diet). So you’d need a treatment + diet modifications to get to a good place with it.

The wrap up

SIBO can be notoriously tricky to treat and relapse is (unfortunately) quite common. Making sure you address the root cause (aka the underlying reason you got it in the first place) is imperative to making sure it doesn’t come back.

If you think you may have it, or you’ve already been diagnosed, working with a qualified practitioner who can help guide you through the process can be a huge help.

If you want more information about SIBO and how to treat it, check out this more in depth post.

And if you want help with your SIBO, feel free to schedule a time to chat.

Already treated your SIBO, but not sure what to eat? Download my free 5 Day SIBO Meal Plan + Recipe Guide here.

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