As I detailed in my last post, bacteria is associated with endometriosis pathogenesis, progression, symptoms, and more. This is more than causing symptoms, it’s contributing to disease. But “bacteria” can mean many things, indeed we have more bacterial cells in our body than human ones! So today I want to talk about a very specific bacterial issue called SIBO (Small Intestinal Bacterial Overgrowth).

You may not be surprised to learn that many of us with endo suffer from this, so let’s chat about how it happens, how it’s associated with endo, and how to fix it.

Endometriosis and SIBO: Super Impressive Bloating Omg

SIBO occurs when the small intestine becomes colonized with too many bacteria. Some of it may typically live in the small intestine, but it’s now overgrowing; or it may not usually live in them small intestine but has invaded from the colon. Either way, your delicate small intestinal ecology is majorly messed up now…

The small intestine should house very limited amounts of bacteria with very specific roles—namely, to help facilitate the final breakdown of carbohydrates and fats to be absorbed. That is the primary job of the small intestine: nutrient absorption.

The large intestine is really where the vast majority of your bacteria should be residing since this is where the fermentation magic happens! How much more bacteria? While the upper small intestine houses 10(3) bacteria, your colon holds 10(12), which is the difference of 1,000 bacteria versus 1,000,000,000,000. See the difference in quantity?

But your large intestine is made for this. It’s BIG, wide, massive in comparison to your small intestine, and ready to expand as it’s filled with extra gas and water (which happens from healthy fermentation). It also has a double mucosal layer to prevent all those E. coli and other gram-negative bacteria (that naturally cohabitate in your colon) from causing damage to your intestinal cells. With thick mucous protecting your intestinal lining, your fermenting bacteria and gram-negative frenemies can live in peace and harmony in your body.

How does SIBO happen?

Alas, little shifts in the internal landscape of our body can so easily knock our health off-kilter (in my book, I refer to this as “body ecology”). This is especially apparent in the intestinal tract, where, in SIBO, bacteria that should flourish in the large intestine are found flourishing in the small intestine. Or, bacteria that do normally live in small amounts in the small intestine overgrow and dominate. This shouldn’t happen! So why does it? Here are 3 potential root causes:

• Poor digestion: Your small intestine should be so much more acidic than your large intestine thanks to stomach acid and bile, part of what makes this environment totally different from your large intestine. If you have low stomach acid or poor bile flow, this may contribute to a less acidic environment (what colonic bacteria love to live in because it resembles the colon!). I write about digestive insufficiency in depth here.

• Ileocecal valve (ICV) issues: Touch this spot right here, is it tender? This is your ICV, a delicate little flap that acts like a door between your small and large intestine. Don’t negate the importance of its job! It’s like keeping Mordor away from the Shire (sorry, nerdy Lord of the Rings reference there). If the ICV is inflamed or damaged (or you lost it to surgery) there is no door, and Mordor colonic bacteria can easily leak into your small intestine. Learn more about that here.

• Motility issues: Your entire intestinal tract is ruled by the enteric nervous system (ENS), an entire nervous system dedicated to your gut! The ENS signals to your 17-foot-long intestinal tract when and how to propel food forward so that you can eat and poop without thinking about shuffling that food along. This is called the Migrating Motor Complex, or MMC, and if there’s dysregulation within this system, you can have a hiccup in propelling. MMC dysfunction is often a root driver of SIBO since “food goo” will sit around too long in the small intestinal tract, feeding the wrong kinds of bacteria. It also turns out one study found 100% of us with endo and digestive issues to have motility issues. [1]

If you have any/all of these issues, your intestinal ecology can go awry. This invites the wrong type of bacteria to the small intestinal party… and hellooOOOoooo SIBO.

What does SIBO do to my body?

Certain varieties of bacteria are great at producing excessive levels of gas, and others are incredible producers of endotoxins (highly inflammatory particles that drive inflammation in endometriosis). This can cause any/all of pain, bloating, swelling, diarrhea, or constipation since this process is happening in the delicate small intestinal tract, and it’s totally not prepared for this type of activity!

Think drawing water in (bloat), producing gasses (bloat more), and creating a terrible slew of inflammation since LPS and gram-negative bacteria may easily damage the intestinal wall (bloat bloat bloat).

Or… you can also have SIBO and not have overt gastro symptoms. This is called “silent SIBO,” and I wouldn’t have believed it had I myself not suffered from it. Instead, you may have a lot of other symptoms of intestinal damage and inflammation: low zinc, iron, or B vitamins, autoimmune/inflammation, headaches, histamine intolerance, allergies, eczema or psoriasis, etc. Yeah, sounds a lot like the symptoms associated with endo. Maybe it’s not so “silent” after all.

SIBO and Endometriosis: Kissing Cousins (eww)

There may be a deep connection between SIBO and endometriosis. Not only do their symptoms line up somewhat perfectly, but treating SIBO also appears to help reduce endometriosis symptoms. The problem is, there are limited studies connecting the dots. This is not to say there’s not a BIG correlation—just few studies ever done.

But one study is pretty powerful! It tested 50 women with both severe GI complaints and endo for hydrogen-based SIBO, and a whopping 80% tested positive. However, they didn’t test for methane-dominant SIBO, and sincethe remaining 20% all had constipation (the primary symptom of methane-dominant SIBO, or IMO), it’s possible all 100% were actually positive.[1]

If 80% (or potentially 100%) had SIBO, that’s a pretty significant number. What other studies are around? Not much. To fish for other information, I did a lot of number crunching in comparing SIBO and endo. Consider this:

• Motility issues: Small intestinal motility issues predispose patients to develop SIBO in the first place, and one study showed 100% of us (OMG!!!!) had small intestinal motility issues. This specifically was called an ampulla of Vater–duodenal wall spasm. If your small intestine isn’t propelling food forward properly it can stagnate and breed bacteria. [1]

• Allergies: You’re about 2.5x more likely to suffer from environmental allergies, dairy allergies, or asthma if you have endo or SIBO. Yup, exactly the same. [2]

• Diet:  In the endo population, a LowFODMAP diet reduced both gastrointestinal and endometriosis symptoms simultaneously. We know a low FODMAP diet is the best way (short term) to manage SIBO symptoms, leading me to suspect SIBO in many of these patients. [3]

• Microorganisms: The most prevalent strains of bacteria in endometriosis include  Proteobacteria, Enterobacteriaceae, Streptococcus spp. and Escherichia coli across various microbiome sites. These are almost identical to the strains most commonly associated with SIBO. [4,5]

• IBS: IBS is often a co-diagnosis for those with endo, some research estimates up to 84% of people with IBS actually have SIBO. So yah, SIBO may actually be the root driver here for many of us. [5]

• SIBO is not rare!: Up to 20% of the general population may have SIBO, so it’s not uncommon. It’s especially associated with those who have a chronic disease, like, um, us. [6]

Do I Have SIBO? How To Test

Stool tests will tell you the types of bacteria in your gut, not the place they live. So to find the place these little critters are existing (like, in your small intestine or large?), you need to measure their fermentation through your breath! It’s a cool hack.

The basic premise of SIBO testing is this: You first cut out supplements/probiotics for a week. The day before the test, you follow a strict and boring diet that is basically meat, salt, and white rice—nothing that bacteria can ferment. Then you fast for a solid 12 hours the night before the test. Altogether, this gives you a low fermentation baseline, so you don’t get any false positives.

On the morning of the test, you drink a sugar solution (which is fun after not eating sweets for a whole day, not going to lie), then breathe into bags every 15 min to capture the gases being released. If your microbes eat the sugar solution and ferment gases rapidly before they make it to the large intestine (usually before 90 min, the average time to get to the large intestine where you would see a spike), then you have fermenters in the small intestine. This would indicate SIBO.

Ordering a lab test is currently considered the “gold standard” for SIBO testing. If you want details on that, read this. But today, I’m going to talk about something a little different for all the gals out there who want easy access to a test (yes!), to save money, and get real-time results… how to finagle a test with an at-home breathe device called the Food Marble Aire (I write all about it here).

Informally Testing for SIBO With the Aire

The Food Marble Aire is the same price as a SIBO lab test, except you can use the Food Marble a million more times. Talk about bang for your buck. So even if $250 seems pricey off the bat, think about how much money you can save on follow-up tests!

To test for SIBO with the Food Marble you’ll need the device (duh) plus a sugar test solution. The 2 leading test solutions recommended are lactulose or glucose. Unfortunately, you can’t get lactulose in the U.S. without a prescription, and I’m not a massive fan of glucose testing (it’s okay, but there are a lot of false negatives associated with it). Instead, what you could consider testing with a non-absorbable sugar called inulin.

Inulin is a complex sugar almost entirely fermented by the bacteria in the large intestine. Research shows it’s an ideal substrate for breath testing because it doesn’t mess up your transit time (leading to false positives). It’s also easy to get at the local health food store or online, like this one.

The morning of the test, take a baseline reading on the Aire to make sure your hydrogen levels are low (in the green), demonstrating you followed the prep diet perfectly. If your hydrogen levels are medium to high, sorry, you must re-do the prep day and be more boring with your diet — no cheating this time! If your methane levels are higher, it’s ok, although indicative of methane SIBO.

Once you have the baseline reading, drink 10g of inulin powder (about 3 rounded teaspoons) mixed into 8 oz water. Set a timer and take a reading every 15 min…for 2.3-3 hours (longer if you deal with constipation, shorter if you don’t).

Yes, that’s a long time to sit around and do that but, hey, think of it like a journey of discovery as you follow that inulin through your digestive tract :) Read a good book. I recommend Heal Endo ;)

What were your results? If you always have fast transit time (diarrhea), look to see if there was a rise in hydrogen gases over 4 (this is how the Aire measures gas, not part per million, ppm) before 90 min. If you have average or slower transit time, follow the fermentation for 2 hours. If hydrogen rises above 4 during that time, it’s indicative of SIBO.

For methane, you’re looking for something similar, a medium level or higher. The difference here is that you’re looking for a medium to high level at any time through the 3-hours since, with IMO (Intestinal Methanogen Overgrowth), you can have an overgrowth anywhere in the intestinal tract causing symptoms.

Treating The Problem versus the (lowercase) problem

When we test positive for SIBO, most of us become obsessed with KILLING. Killing bacteria, that is. The whole focus of the SIBO novice is usually how many antimicrobials one can swallow at one time to get rid of the invaders (been there, done that). Alas, this is but one small piece of the puzzle. It’s not the whole problem.

Think about it, most SIBO bacteria are totally normal and healthy microorganisms that belong in the gut! But for some reason, they’re living in a totally bizarre place, or living in huge populations when they should be negligible. This is weird, so something had to happen in the first place to allow that bacteria to overgrow and/or migrate.

If we just eradicate the bacteria and don’t address the other “why’s,” it’s possible the SIBO will come right back…as it does in 60% of SIBO cases.

To change our SIBO destiny, we have to change the body ecology. I can’t wait to chat about this in my next post! Stay tuned.

1. Mathias, J. R., Franklin, R., Quast, D. C., Fraga, N., Loftin, C. A., Yates, L., & Harrison, V. (1998). Relation of endometriosis and neuromuscular disease of the gastrointestinal tract: New insights. Fertility and Sterility, 70(1), 81–88. https://doi.org/10.1016/s0015-0282(98)00096-x

2. Peña-Vélez, R., Toro-Monjaraz, E., Avelar-Rodríguez, D., Ignorosa-Arellano, K., Zárate-Mondragón, F., Cervantes-Bustamante, R., Montijo-Barrios, E., Cadena-León, J., & Ramírez-Mayans, J. (2019). Small intestinal bacterial overgrowth: could it be associated with chronic abdominal pain in children with allergic diseases?. Revista espanola de enfermedades digestivas, 111(12), 927–930. https://doi.org/10.17235/reed.2019.6321/2019

3. Moore, J. S., Gibson, P. R., Perry, R. E., & Burgell, R. E. (2017). Endometriosis in patients with irritable bowel syndrome: Specific symptomatic and demographic profile, and response to the low FODMAP diet. The Australian & New Zealand Journal of Obstetrics & Gynaecology, 57(2), 201–205. https://doi.org/10.1111/ajo.12594

4. Leonardi, M., Hicks, C., El-Assaad, F., El-Omar, E., & Condous, G. (2020). Endometriosis and the microbiome: a systematic review. BJOG : an international journal of obstetrics and gynaecology, 127(2), 239–249. https://doi.org/10.1111/1471-0528.15916

5. Moore, J. S., Gibson, P. R., Perry, R. E., & Burgell, R. E. (2017). Endometriosis in patients with irritable bowel syndrome: Specific symptomatic and demographic profile, and response to the low FODMAP diet. The Australian & New Zealand journal of obstetrics & gynaecology, 57(2), 201–205. https://doi.org/10.1111/ajo.12594

6. Dukowicz, A. C., Lacy, B. E., & Levine, G. M. (2007). Small intestinal bacterial overgrowth: a comprehensive review. Gastroenterology & hepatology, 3(2), 112–122.

7. Pyleris, E., Giamarellos-Bourboulis, E. J., Tzivras, D., Koussoulas, V., Barbatzas, C., & Pimentel, M. (2012). The prevalence of overgrowth by aerobic bacteria in the small intestine by small bowel culture: relationship with irritable bowel syndrome. Digestive diseases and sciences, 57(5), 1321–1329. https://doi.org/10.1007/s10620-012-2033-7