I know the title looks like alphabet soup, but this is really important stuff. I’d go so far as to say that this could be the missing link for many GPers when it comes to improving symptom management. So if you feel like you’re “doing everything right” and you’re still struggling with symptoms, please read on.

What is SIBO?

SIBO stands for small intestinal bacterial overgrowth. It’s also sometimes called small bowel bacterial overgrowth or SBBO. It all means the same thing: there are bacteria in your small intestine that are not supposed to be there.

What causes SIBO?

One of the biggest risk factors for SIBO is… slow gut motility. Muscular contractions within the gut are supposed to sweep things, both food and bacteria, through the GI tract.  When it doesn’t, bacteria can take hold and multiply in places where they don’t belong. This is bad news for GPers, of course, and even worse if you’re chronically constipated, as bacteria may migrate upward from the colon to the small intestine, as well.

What’s more, it’s thought that protein pump inhibitors (PPIs), which many GPers are immediately prescribed, may encourage the growth of bacteria by limiting (or even eliminating) the anti-bacterial effects of acid in the stomach.

What symptoms does SIBO cause?

Gut bacteria has been found to play a role in everything from allergies to mood disorders to obesity, but the GI symptoms of SIBO are largely a result of the gas that bacteria produces when it “eats.” (See below for more about how what you’re eating affects bacteria.) Bloating, distention, burping, and passing gas are common symptoms.

Bowel changes, either diarrhea or constipation, as well as  malabsorption and unintentional weight loss may also result. For people with functional disorders like GP or hypersensitivity, the excess gas in the GI tract can also cause abdominal pain or cramping.

(Lots of people have asked me why GP causes so much bloating and distention. I’ve wondered this myself many, many times. I’ve never had a good answer, but I think I have one now… maybe it’s not so much the delayed emptying as the bacterial overgrowth that results from delayed emptying.) 

How is SIBO diagnosed?

The most widely available test for SIBO is a Hydrogen Breath Test. At the beginning of the test, you drink a solution that will “feed” bacteria if they are present, causing them to release gases. Your breath is measured for these gases over the course of several hours (usually 3). That’s it! The drawback is that this test is not 100% accurate and may be even less so for those delayed gastric emptying, as the test counts on the solution being in the small intestine after 3 hours.

I also recently learned that a high level of folate in your blood may indicate bacterial overgrowth. (Mine was very high; hence the breath testing today!)

Some doctors will treat SIBO empirically, meaning based on symptoms and presentation alone. If symptoms improve with treatment, it’s likely that SIBO was an issue.

How is SIBO treated?

Most of the time bacterial overgrowth is treated with antibiotics, preferably Xifaxin (rifaximin), which works only in the intestine and therefore has fewer potential side effects. There is also an herbal protocol for the treatment of SIBO, which was developed by Dr. Gerad Mullin at Johns Hopkins.

Aside from medical treatment, dietary changes are an important part of managing bacterial overgrowth. If the underlying cause of the overgrowth, slow motility, for example, isn’t resolved, then the bacteria may regrow. Eating foods that feed bacteria will make this more likely.

How do FODMAPs fit in?

FODMAPs are fermentable carbohydrates that are often malabsorbed. When we consume FODMAPs, they become fast food for bacteria exacerbating symptoms like bloating, gas, pain, etc. You may notice a reduction in your symptoms just by reducing the FODMAPs in your diet. After treatment for SIBO, a low-FODMAP diet will help to prevent a regrowth of bacteria.

Unfortunately some of the foods highest in FODMAPs are the ones that many people think of as GP-friendly staples. The things your doctor probably told you to eat when you were first diagnosed. Low-fiber wheat products (white bread, crackers, pasta, cereal, pancakes, etc.), applesauce, pears, and dairy products like skim milk, low-fat yogurt, and frozen yogurt. Many of the meal replacement drinks also contain FODMAPs in the form of FOS, inulin, or chicory root.

Is it possible to  follow a low-FODMAP GP-friendly diet? 

It takes some extra effort and attention, but it is possible to follow a GP-friendly diet that’s also low in FODMAPs. The good news is this will force you to ditch the “white stuff” that I’ve warned against before. What’s more, addressing SIBO and reducing the FODMAPs in your diet may actually reduce your overall symptoms and allow to eat a wider variety of foods.

Do all GPers have SIBO and/or need to follow a low-FODMAP diet?

No. If your comprehensive management plan is working for you and you’re feeling good, then it’s probably not something you have to worry about.  But if you feel like you’re doing everything “right” in terms of managing your GP but your symptoms remain — or continue to get worse — an overgrowth of bacteria and a diet that continues to feed them may be to blame.

Learn More

I recently recorded a Q&A with Kate Scarlata, Registered Dietitian and FODMAP expert. This will help you better understand which foods may be problematic and how to start reducing FODMAPs in your diet.

To download the FODMAP Q&A with Kate Scarlata click the button below (it’s free!).



Related Posts:


  1. 1

    Linda Fick says

    I find this very interesting too! I was recently suspected of having SIBO and they treated me for it and symptoms improved, but I found that when I ate the stuff that was my GP friendly foods (crackers, yogurt, milk products, basically carbs!) that my symptoms came back. Unfortuntely, my doctor did not tell me not to eat certain things so now I think I have it back again. I wonder how many people have this and don’t even know it. I had mine for 6 months before they finally figured it out. I think you are on to something here!

  2. 2

    Hannah says

    It was my diagnosis of SIBO by Dr. Mullin that led to the suspicion that I had gastroparesis. I recently retested for SIBO after more than a year since my last antibiotics treatment for it and the test was negative! So I think the two supplements I take to keep SIBO at bay have been working pretty well even though I still have slow motility.

  3. 3

    Kathy Bosworth says

    I have been diagnosed with SIBO and take Xifaxan which does seem to help but it is very expensive and many insurances will not pay for it. But my situation is very complicated with scleroderma, 2/3 of stomach removed including vagus nerve, gastroparesis etc. Many things work for me a little while and then stop. I know everybody is different but this med does work well to get me back on track.

  4. 4

    Susie Dilts says

    My GP has been controlled with cytotec since diagnosis 6/12. I’ve had only one episode of vomiting.
    I have started seeing various practioners at a holistic clinic due to fibromayalgic type pain and skin rashes. I felt “ganged up” upon by everyone telling me first that I was gluten intolerant [I don’t have celiac disease], then I was told to eat only vegetables, and tiny amts. of proteins and starch. This has really freaked me out. I have been gluten free for about a week and a half and right now that is a big enough adjustment for me.
    I have been lucky not to have altered my diet for GP except to eat slower and less at each meal. I think I may get the breath test done, but I fear that if positive I will have to go to a low fodmap diet. I think I would be more open to this if I were more symptomatic. Will follow your blog. Susie

  5. 5

    Hollie says

    I’m on week 2 of Xifaxin treating my SIBO. I was diagnosed with it about a year and a half ago, and the Xifaxin did the trick. After having surgery in Janurary to correct SMA syndrome, I think the prolonged slowing (of my already slow GI system) caused the SIBO to rare its ugly head again. It’s also easy to turn back to “the white stuff” when not feeling well, busy, etc. and as you said, I think it just feeds the SIBO.

    Thanks for bringing awareness to this condition!

  6. 6

    Kelly says

    This is very interesting and comes at such a perfect timing. My motility specialist is almost certain that they will find something on this breath test that i too am having in the next week. I thought he was crazy but after reading this is makes it sound more likely. I have not been able to stabalise my GP and have actually gotten worse over the last 12 months and i only eat once a day now.. Thankyou once again for valuable insight!

  7. 7

    JoAnna Gaumond says

    I’m enteral fed 24/7 Jevity 1.02. I either have bad diarrhea or bad constipation. Two months into this new way of life I had a bad case of SIBO. I was put on a strong antibiotic but a month after this treatment I was feeling just as bad. Is there anything I can do to help myself.
    I want to tell you I enjoy reading all that you have learned and are doing. I’m sending a hug for you and your baby and husband.

  8. 8

    Alexa says

    My Specialist found my folate, along with other blood markers, high and put me on the antibiotics right away, she gave me the option of doing the test, but said she was 99% sure it was SIBO. She also warned me that it could re-occur fairly easily due to the slow motility (She is an actual Gastroparesis specialist at MD Anderson). After a week it totally cleared up my bloated, gasy belly. It sure isn’t fun to deal with this on top of GP and the host of other digestive things going on! I was wondering if anyone has has Sphincter of Oddi Dysfunction? She is suspecting that for me (no gallbladder). My liver enzymes have been high for the last three blood tests and I am waiting on the last portion of blood work to come back to verify I have no other disorders, such as Hepatitis (ultrasound was good). I eat a super clean diet and run and workout every day, so this is rather frustrating.

    Good Luck today!

  9. 9

    Andrea says

    I was treated by Dr Mullin back in ’08 for the overgrowth and I chose to do his herbal regime. It worked, but took several months to irradicate since I have had it for so long. Once the overgrowth was gone I continued with his herbal protocol to keep my motility moving. Over the course of the years I noticed that my motility was slowly improving through diet change and supplements. One thing also to look out for is CANDIDA overgrowth which is what I am dealing with now. With all of the herbals for the overgrowth, my gut was wiped clean of bacteria despite repopulating with heavy doses of probiotics afterwards. I did not think to repopulate my ‘good’ yeast at the same time.

  10. 10

    Kaye says

    I have GP as well as Crohn’s and I tend to get SIBO at least once a year. My GI doc usually puts me on Xifaxan and that will do the trick. I got my annual infection last week and my doc tried another antibiotic this time…Levaquin. I was also told to hold off on my biweekly Humira injection for Crohn’s since it might make things worse. The Levaquin helped a little, but a few days after finishing the meds, I was in pain again and feeling bad. I guess we are back to Xifaxan! My diet is already very limited as it seems what I can eat for one disease I can’t with the other. But I’m very interested in learning if there is something I can do, possibly with my diet to keep these annual SIBO visits away. Thanks for touching on this subject, I’m sure if affects many of us GPers!

  11. 11

    Kathy Bosworth says

    I am enjoying reading everybody’s history with all of the digestive disorders. For so long I’ve thought I had to be the only one dealing with this. Going out to dinner can be a nightmare and people look at me like it’s my choice I eat so weird. I’ve had complete strangers come over to me and comment on how lucky I am to be so thin and they can see why because of the small amount I’m eating……….sheesh, really? Like I would choose this?
    I’m not so sure I can be of much help to anyone else since I’m struggling right now. My doctors are sending me to Yale next week and hopefully I will get more answers then. But I think it’s so helpful to have a forum to talk on with people that do “get” it. Thank you once again Crystal.

  12. 12

    Jodi Martin says

    I’m so excited you posted this! I’m currently on another round of Xifaxin. Through our last minute discussions on the program fb page, we were talking about pancakes & low FODMAP ingredients, I discovered that the list given to me by my motility spec……was INCORRECT. So much so, I was consuming the same FODMAPs over & over, daily. I could not believe that I had been eating what I shouldn’t have been eating for months on end. It took me 2 days of pure frustration & alot of anger to accept it as the past & move forward. That weekend, i emailed all my doctors, so iI could start anew on Monday. I purchased, every book & e book, that Kate Scarlata, Patsy Catsos, & Monash University have published. I now have a script for the HBT but have to wait since I’m on the antibiotic now. My instructions say two weeks. I wonder if that’s really enough time for an accurate reading? I have a scriot for a registered dietician. fasting labs scheduled for next week and follow-up 3 mth w/ PCP the week after to review labs. I’ve requested a preliminary cardiac work-up. I’ve been busy getting my dream team to work :) I’m determined to figure this out for me bc I firmly believe they are all related. so looking forward to many more discussions about this topic. I feel we are right at the surface and there is much to discover. Thank you for sharing. Between the lemons & this, I’m very inspired!!!

  13. 13

    Sarah says

    Thanks for another great article. I, too, have been treated for SIBO over the past about two years. In addition to GP, I have Chrons and Celiac’s. The Celiac’s diagnosis was in 2002, so I have been gf for years and basically avoiding all of the “white foods”. The SIBO, Chrons and GP diagnosis have all been within the past few years. I have read about the FODMAP diet but, honestly, with all the other foods my other GI conditions eliminated, I have not followed a FODMAP diet. However, I have found that I needed to eliminate gf bread and rice noodles as those seemed to quickly feed the bacteria. Xifaxan has worked the best for me, and if I really watch what I eat, I have managed to stretch out more than 6 months between rounds of antibiotics! What we eat definitely affects SIBO! Best of luck!

  14. 14

    Kelleigh says

    I remember doing the breath test and being diagnosed with something like this. It must have been SIBO. I did the antibiotics but it was so long ago that I don’t remember if it actually helped. I remember it upsetting my stomach mostly. I thought the antibiotics were a one time thing. What is the herbal protocol? Are there any supplements to help keep the bacteria from coming back? After reading this, I believe SIBO must be my main problem.

  15. 15

    Claudia Schmidt says

    Alexa I had the Sphincter of Oddi! It was difficult because my liver enzymes got so high it was poisoning my body! I had to be rushed two hours away to repair it. No pain medication could ease what I felt. Goodluck with your test and I will pray they figure it out soon!

  16. 16

    Donna Chase says

    Thank you this information came right before my appointment with my GI. Much like Kelly my GP has been barely manageable for 12 months and my IBS/C has been worse! I discussed this with my doc and am now on Xifaxan. Thankfully my insurance covers it. I am now reading all I can on how to avoid SIBO in the future and tailoring my diet yet again.

  17. 17

    Melissa C-Black says

    I was diagnosed last month with SIBO as the result of biopsies and aspirations taken during an EGD by Dr Wo at the IU Motility Clinic. He prescribed 10days on Xifaxin which Anthem BCBS would not cover. Luckily, my regular GI doc had samples. I’m not sure it was successful or not. I still have the same symptoms.

  18. 19

    Kathy says

    I would like to check for SIBO. I knowingly have gp. GERD and acalasia. Anyone else have this combination? My body feels like a three ring circus every night. The direct pains and referred pains are debilitating.
    How do you best work with these? Any procedures, meds., surgeries, etc. found to be helpful?

  19. 20

    Deb Jackson says

    Hi Crystal,
    Just curious if the test was helpful for you and if you got any results regarding the SIBO. I know the breath test can be inaccurate at times, so wondering if you felt it was helpful.

    One last question, I know you had mentioned when they do an endoscopy, they can test for SIBO. Do you know if they automatically check for this during the scope, or if a person has to request it?

  20. 21

    Kathy Bosworth says

    I was diagnosed with SIBO with a small bowel GI test. They followed the barium I drank (t least I think it was barium) going through the lower intestines. That is also how they diagnosed rapid transit. I’ve never had the breath test. I did have an endoscopy and they couldn’t tell from that or the colonoscopy.

  21. 22

    Deb Jackson says

    I am curious how they detected SIBO from a barium swallow study? My daughter had one of these done a couple years ago, and interestingly enough, several days before the test she became really backed up even on her regular dose of mirilix and then increased dosages to try to break her loose before the test. But, it wasn’t working. Well, when they did the barium swallow, and they had her roll to her side and lifted her legs up, the barium went swoosh, all the way back up to her throat. There was no place for it to go but up, because she was so backed up. I couldn’t figure out what brought on her constipation back then, was looking at the foods she had, etc. Now that I know she has fructose malabsorption, I remembered that she had several of the Kellog’s brand of rice crispy bars and upon looking at the labels, it is filled with a ton of HFCS and other sweeteners. Amazing to me that malabsorption issues can and do cause a person’s stomach/bowels to shut down like that from trapped gas, and but it does. I’ve never been told she has SIBO, but when we do the full elimination diet this summer, I have to take her off all sugars for 2 weeks to reset her bowels. I’m assuming this is to starve out the bad bacteria. It is not going to be a fun 2 week period for a 7 year old and her momma!

  22. 23

    Jessy says

    Hi, Crystal! I was diagnosed about a year ago with GP and have had so many of the same struggles as you. I have been feeling pretty bad (worse then the usual) for the last couple of weeks and after reading your post, am wondering the same as everyone else: Do I have this? How did your test turn out? Should I be tested? I hope you are doing well and look forward to your updates!

  23. 24

    Kathy Bosworth says

    My doctors assume I have gastroparesis by the symptoms I have had since gastric surgery 7 years ago due to a blocked pyloric outlet due to many years of undiagnosed ulcers which caused scar tissue to build up. However, I’m doing a test next week at Yale since I’ve lost 8 more pounds in the last 6 months. It might be a narrowing of the pyloric outlet since the surgery or a narrowing somewhere along the digestive route. I have to eat a sandwich with radio active stuff in there and they will follow it as it goes through my system. If it’s not a narrowing or blockage in the pyloric outlet due to scar tissue buildup, then it’s gastroparesis. They told me they have meds for it but I’ve tried so many already and none have been effective. More tests……….more waiting. sigh. Crystal’s book has helped me so much just knowing what foods to stay away from. Acupuncture has also helped.

  24. 25

    Nikki says

    Hi all,

    In case any of you are not aware of this – Monash University Department of Gastroenterology (where the research into FODMAPs was done) has released an app that makes following the Low FODMAP diet easy:

    The good thing about using the app is that the list of FODMAPs in it is up-to-date – as Jodi found, lots of professionals have out-of-date lists of FODMAPs so people end up avoiding the wrong things and thinking that the Low FODMAP diet isn’t working for them. Same goes for books – because research into FODMAPs is being conducted all the time.

  25. 26

    Crystal says

    Yes, great suggestion, Nikki! I”ve been using this app recently and find it really helpful. Thanks for sharing!

  26. 27

    Kelly says

    Hi Crystal, I had my results back from my previous comments and I don’t have SIBO. I have seen a new dietrician and he has placed me on a low salicylate diet and I have become so much better. It turns out i have GP and I am intolerant to foods high and very high in salicylates. I am wondering if any oher GPers have this also.

  27. 28

    Mary Ward says

    I have GP. Have gotten most all of the books on GP and read all the blogs I could
    find. I just cannot figure out what to eat. Is there someplace I can go on the internet
    or a book that has Lowfoodmat diet?? I am at a lost and eat mostly cheese, chicken,
    eggs, saltines, your roasted veggies and oven fries. Most all white.
    Just need to find out where the diet is written. I don’t have a fancy phone and am not
    computer type person. HELP!
    I am on reglan and it has helped a lot!
    thank you for letting me talk,

  28. 29

    Crystal says

    Hi, Mary. There are a few books on the low FODMAP diet. One that I like is Kate Scarlata’s Complete Idiot’s Guide to Eating Well for IBS. There’s also a book called IBS- Free At Last by Patsy Catsos, which is based on the low FODMAP approach. Hope that helps!!

  29. 30

    Mary Ward says

    Hi Crystal,
    Thank you so much for the name of the books. Will check in to them tom.
    Last year I had my gall blander removed – still not recovered.
    Also, last Oct. I got Shingles. They were right next to spine and nerves, etc that
    went around and hit my digestive system. After 10 months, still have nerve
    damage. Please encourage people to have the shingles shot.
    l have been following you since Feb. when diagnosed with gastroparesis
    My doctor in Atlanta highly recommended your books and web site.
    Again, thank you .

  30. 31

    Beth says

    For those of you that took Dr. Mullins herbal protocol, can you share it. He doesn’t give out the details in his Fast Tract book.

  31. 32

    Kevin says

    I have GP and have constant nausea and no appetite. As a result, I find it extremely difficult to get solid foods down — but liquids are much easier for me.

    Does anyone know if there is a low FODMAP liquid full meal replacement that gives you everything (or most everything) you need in liquid form?