This post is the first in a three-part series on Small Intestine Bacterial Overgrowth focusing on SIBO symptoms, root causes and testing. Make sure to read Part 2 on natural treatments and herbal supplements and Part 3 on SIBO diet plans. For a more up-to-date and thorough resource, check out my new book SIBO Made Simple.
About a year ago, I started noticing some mysterious symptoms creeping back into my life.
Having been through half a decade of digestive woes, I didn’t pay much attention to the occasional bloating and constipation. Didn’t consider how my usual diet – full of healthy foods that, in theory, supported good gut health – was starting to make me feel off after meals. Didn’t even worry that my habitual burping, and more than occasional tooting, was becoming a regular companion soundtrack to our nighttime Netflix binges.
There was so much easy rationalizing. I was drinking more homemade kombucha, which was fizzy. I was going semi-horizontal after meals, which was bad for digestion, but could eventually be corrected. And I was getting more and more comfortable in my relationship, which meant maybe it didn’t matter if I just let ‘er rip.
It wasn’t until later in the year, once my book tour downgraded to a more manageable pace, that I was able to pay attention to my daily habits and see myself more clearly. And what I saw was an inner tube in my abdomen.
If you’re familiar with my Hashimoto’s story, you’ll know that vanity was the original straw that broke the camel’s back and forced me to take my symptoms more seriously. My skin was such a raging mess I would have tried anything, even a year of intense monthly lifestyle changes, to make it better.
Once I started to put the physical pieces together—the outward with the inward–I decided to see a functional medicine doctor for a full workup. And the prognosis I received was SIBO: small intestine bacterial overgrowth.
What is SIBO?
Small intestine bacterial overgrowth is exactly what it sounds like. It’s a type of dysbiosis, which simply means an imbalance in the trillions of bacteria that dominate the gut. In the case of SIBO, however, the issue is not necessarily the imbalance between good, beneficial bacteria and bad, pathogenic bacteria (though that could be part of it). Rather, the main problem is location, not type.
Though critters colonize all sections of our alimentary canal, the majority of it is found in the large intestine (also known as the colon), where it assists in the final step of the digestive labyrinth and prepares for evacuation.
The small intestine, on the other hand, is where your food intermingles with digestive juices and nutrients are absorbed into the bloodstream. It’s not a place where bacteria belong or have a function. In fact, as is the case with SIBO, the presence of too many critters gets in the way of nutrient absorption and causes a host of other issues.
Since these are living organisms with their own palates and cravings, bacteria in your small intestines means there are other people at the dinner table competing for food and taking sustenance for themselves.
And when there’s not much nourishment to be had, they turn to the next best thing: you.
SIBO Symptoms and The IBS Connection
When unwanted bacteria begin feasting on your intestinal lining in the small intestines, the result is often leaky gut, an increased permeability of said lining. The byproduct of leaky gut disease, where larger food particles (instead of just essential nutrients) seep into the bloodstream, is often food sensitivities and autoimmunity.
Though you can have leaky gut, food sensitivities, and an autoimmune disease without SIBO, it is not unusual for it to be a root cause. For example, according to one study published in the American Journal of Gastroenterology, 66 percent of patients with celiac disease who maintained a gluten-free diet, and still had unfortunate symptoms, tested positive for small intestine bacterial overgrowth.
Some of these unfortunate symptoms that point specifically to SIBO include: bloating, gas, burping, reflux and other discomfort after meals. Constipation and diarrhea are common, though usually you only go down one of those lanes. You can find a full checklist of symptoms, root causes and risk factors in my book, SIBO Made Simple.
The reason for the distended belly is because of all the gases the bacteria release when they eat. Your small intestine was not designed to withstand the build-up, and the gases tend to get trapped, or released anyway they can through reflux and burping, or out the other end. You can also experience nausea from slowed stomach emptying due to the traffic jam.
If the miscellaneous gastro symptoms I just described sound like the usual description for IBS, you’re right. The problem with diagnoses of IBS—the most common gastro “syndrome” in the world—is that they are usually BS. It’s meant to be a diagnosis of exclusion, only reached when all other possibilities are ruled out. A collection of symptoms, not a root cause.
The majority of these sufferers are actually experiencing SIBO in disguise (or, staring right at you, so long as you know what to look for)–60 percent of all IBS cases are caused by SIBO!
Other symptoms to look for are a result of the absorption issue: being underweight and anemic. As a consequence of all the shared meals with your bacteria, nutrient deficiencies are common, especially with vitamin B12, decreased ferritin and increased folic acid.
Lastly, brain fog, depression and anxiety can occur as a result of the damaged cell wall affecting the brain. It’s not personality or stress alone. It’s a symptom of the gut’s circumstance.
Here’s a symptom cheat sheet:
- Abdominal bloating
- Gas: belching and flatulence
- Abdominal pain and cramps
- Constipation, Diarrhea, or both
- Acid Reflux
- Food Sensitivities
- Joint Pain
- Eczema, rosacea or rashes
- Anxiety and depression
- Malabsorption / nutrient deficiency
- Anemia (Iron or B12)
- Weight Loss
What Causes SIBO?
So if SIBO is an underlying cause of IBS, leaky gut, and autoimmune disease, what is the underlying cause of this bacterial overgrowth?
Diet certainly affects the balance of bacteria in our bodies. But one of our internal functions must go haywire in order for our bacteria to enter the small intestines and become stuck there.
Contrary to what some may think, the migration of bacteria from the colon doesn’t just happen. The small intestine is its own organ with a front and back door–completely separate chambers from the large intestine. Which means (unless their is an issue with said backdoor, the ileocecal valve) the problem must occur earlier on in the digestive process.
On the front end, the main culprit to explore is low stomach acid, usually a result of popping one too many Peptos, Prevacids or other Proton Pump Inhibitors in one’s lifetime.
Though certain drug companies have tried to convince you otherwise, your stomach acid is very necessary for maintaining gut health, preventing food poisoning, and generally, making sure that outside bacteria get killed before making their way into the small intestine.
But even if some unwanted bacteria get through that initial hurdle, our migrating motor complex (MMC) should ensure that it gets pushed down and out. This internal function also protects against back flow from the large intestine.
Which is why Dr. Allison Siebecker, who’s arguably one of the world’s leading experts on SIBO, believes that the root cause of SIBO centers around the malfunction of the MMC. The question, as she puts it, is why aren’t the bacteria being removed, not why are they there.
The Root Cause of the Root Cause: Why the MMC Goes Haywire
The Migrating Motor Complex only activates during a fasting state, between meals and overnight, and relies on nerve cells to kick it into gear.
The most common cause of low MMC function is food poisoning, also known as post-infectious IBS. When harmful bacteria enter the small intestine (often as a result of low stomach acid) they release a toxin that damages the nerve cells that trigger your MMC.
Often times you’ll feel better from food poisoning a day or two later. The deeper symptoms related to the MMC may take months to arise, which is why doctors don’t always link it to SIBO.
The second cause is structural—a kinking of the intestines (blind loop syndrome), an impasse or strictures from abdominal surgeries (hernia, C-section, appendectomy, endometriosis, etc.), or other organs pressing on it. Here are some strategies for overcoming this type of root cause.
Finally, another important cause: hypothyroidism can slow the migrating motor complex (!!). There’s still a little ambiguity regarding the connection, but several studies have chronicled the link between sibo and hypothyroidism. And the most common GI complaint among low functioning thyroid sufferers is constipation, a result of slowed motility.
It’s worth noting that most people experience constipation when the MMC is not functioning properly, but you can have poor motility in the small intestine and still experience diarrhea if there’s fast motility in the large intestine.
The good news is that SIBO only becomes chronic when the underlying cause is not addressed. The bad news is there is a high probability of relapse, especially when the underlying cause is not fixable. I will get into how to address some of these issues during part two of this series that focuses on treatment. There is also an entire chapter in my book (30 pages!) on designing the treatment plan that’s right for you, including a handy chart on everything in my medicine cabinet arsenal.
How Do You Test For SIBO?
The main SIBO test involves drinking a synthetic sugar solution and breathing into a tube at various intervals thereafter. It is fairly time consuming, but not unpleasant in the grand scheme of gastrointestinal tests!
The test measures the levels of hydrogen and methane in your breath as the sugar solution makes its way through various parts of your intestines.
Carbs are your bacteria’s number one food source, and symptoms of bloating are caused by the gases they produce as they eat our food. Hydrogen and methane can only be produced by bacteria so their presence in your breath is a dead giveaway. The timing is what indicates whether it is in your small or large intestine. It usually takes two hours to progress to the latter.
The tests only vary in the type of sugar solution used: glucose or lactulose. There are pro’s and con’s to each, and some doctors after receiving a negative result, will try the other.
Glucose can only test the first two to three feet of the intestines, because after that it’s absorbed into the body. But you tend to get a better, clearer reaction from it, so long as the bacteria is actually in that area of the intestines. Lactulose is the safer bet if you want to test for bacteria beyond that point, where it is more likely to hang out.
One thing to note is that doctors and labs still lack a definitive consensus on what levels constitute a positive result. If you come up negative and doubt that diagnosis, it may be worth trying the other sugar (lactulose or glucose) or taking your results to another specialist for a second opinion.
If you treat your SIBO and still have symptoms but come up negative on the SIBO test, there’s likely another diagnosis at play. Most of the time we have more than one digestive problem. And if the connection between SIBO and other conditions is any indication, that is usually true of our whole health picture.
Today, it’s fairly easy to order an at-home SIBO test. I did the 2 hour and 15 minute, 10-tube lactulose breath test from Commonwealth Diagnostics. You can order here or by phone. Just note that if you don’t have a doctor prescribe it, you will likely have to pay out of pocket ($250). Here are some other labs that offer the breath tests as well.
The most important thing to note about breath tests is you MUST prepare properly before you take it. This includes stopping certain medications the week before. My book has a very helpful checklist for everything you need to do to get an accurate result.
What Are My SIBO Treatment Options?
There are many options for treating SIBO, both through antibiotics, herbal supplementation and diet, or a combination of all three. It often varies for the individual case, and can take a few tries to hit on the right recipe.
The next post in this series will cover the many options out there for SIBO treatment, and the final installment will do a deep dive on how diet factors into getting rid of this pesky bacterial overgrowth and healing the gut.
OTHER SIBO RESOURCES
- The SIBO Made Simple book (now on shelves everywhere!) takes all the learnings from 50+ interviews with practitioners and distills the advice into a 350 page practical roadmap with 90+ recipes.
- The SIBO Made Simple Podcast covers each puzzle piece of SIBO and breaks it down into easily digestible terms. Here are some topics we cover:
- SIBO Breath Testing
- The Elemental Diet
- Post-Infectious IBS & Food Poisoning
- Methane & Hydrogen Sulfide SIBO
- Candida & Yeast Overgrowths
- Leaky Gut & Autoimmune Disease
- SIBO & Hypothyroidism
- SIBO & Celiac Disease
- Mast Cell Activation Syndrome
- Heavy Metals, Mold & Other Toxins
- CBD Oil & SIBO
- The Low FODMAP Diet
- The Bi-Phasic Diet
- SIBO & Intermittent Fasting
- Skin Issues and SIBO
- Probiotics and Prebiotics for SIBO Treatment
- Healing Structural Issues
- Fertility & SIBO
- Histamine Intolerance & SIBO
- How SIBO Effects Depression and Anxiety
- Acupuncture for SIBO Healing
- Busting Biofilms
- Dr Allison Siebecker’s site is hub of amazing information, SIBOinfo.com
- SIBO 2.0: How to Find the SIBO Treatment That’s Right For You
- SIBO 3.0: The Best Diets and Lifestyle Changes to Treat, Heal and Prevent SIBO From Recurring
- My FREE Low FODMAP Weeknight Meal E-Book
Get more SIBO info right in your ear…
Disclaimer: this website offers health, wellness, and nutritional information for educational purposes only. Information provided is not intended as a substitute for the advice provided by your physician or other healthcare professional. Always speak with your physician before trying any new treatment.