Small Intestinal Bacterial Overgrowth (SIBO)

Okay, I am about to get all science-y on you.   Are you ready?  Thinking cap on? I attended a great conference last weekend, a SIBO symposium sponsored by the National College of Natural Medicine in Portland, Oregon.  Top SIBO specialists that presented most of the information  at the symposium included: Mark Pimentel, MD, FRCPC, Allison Siebecker, ND, MSOM, LAc, Leonard Weinstock, MD, FACG and Steven Sandberg-Lewis, ND, DNANP Having had SIBO myself back in 2003 and again in 2013….and having close to 65 % of my client test positive for SIBO–I have a vested interest in this disorder! {In fact, I wrote an article for Today’s Dietitian back in 2011 that you can access if you choose to check it out.   Click here for the article. } What is SIBO? SIBO is an acronym that stands for small intestinal bacterial overgrowth. Normally, the small intestine provides a home for  few bacteria but in SIBO, bacteria that normally reside in the colon, sneak up into the small intestine and wreak havoc.  Symptoms of SIBO mimic those seen in IBS but bloating is typically the most troubling complaint. How do you get SIBO? The researchers at the conference reviewed several factors that may contribute to or predispose  someone to developing SIBO:

  • Infection (such as post-infectious IBS)
  • Decrease in pancreatic enzymes
  • Decrease in bile acids (bile acids normally emulsify in the intestine and don’t allow bacteria to grow).
  • Stress-decreases motility of the intestine so bacteria can build up in the intestine.
  • Low stomach acid

Some diseases and syndromes are associated with SIBO include some well accepted in the medical community and some ‘new kids on the block’ disorders that are linked with SIBO but more research is necessary to provide a definite link. Disorders that are well accepted as associated with developing SIBO include:

  • Scleroderma
  • Small intestinal pseudo-obstruction
  • Adhesions (scar tissue) that may cause the intestine to kink like a garden house
  • Pancreatic insufficiency
  • Small intestinal diverticulosis (small pouches that develop in the small intestinal wall)
  • Low stomach acid (achlorhydria)
  • Diabetes
  • Radiation enteritis  (inflammation of the small intestine following radiation therapy)
  • Immunodeficiency (Ig A def, T-cell deficiency)
  • J-pouch, ileo-cecal valve resection

Dr. Weinstock mentioned several other disorders that may increase risk of SIBO but more research is needed, these include:

  • Crohn’s disease
  • Celiac disease
  • IBS
  • Liver disease
  • Restless leg syndrome
  • Rosacea
  • Parkinson’s disease
  • Chronic renal failure
  • Hypothyroidism
  • Post-chemotherapy
  • Fibromyalgia
  • Rheumatoid arthritis
  • Interstitial cystitis

Wow…right!? Testing:  The consensus at this conference was to undergo a lactulose breath test to evaluate for SIBO. The test should measure BOTH  hydrogen and methane gas.  Some GI doctors are not fully on board with this the breath test for diagnosing SIBO as it is not a validated test… but for now…it is the least invasive and most likely test to be used in clinical practice. Dr. Pimentel provided info on what he deems a positive test: A positive methane test is anything >3 PPM during the testing w/ in 90 minutes. A positive hydrogen test is >20 PPM (not necessarily 20 PPM rise above baseline but rather any reading 20 PPM would be a + test) w/in 90 minutes. Interesting to note:  hydrogen sulfide producing bacteria use up 5  hydrogens to produce this gas and methane gas uses up 4  hydrogens–so it is possible to have a flat line hydrogen gas reading during the breath testing but still have SIBO.  New testing is being explored to test for hydrogen sulfide gas but is not fully developed yet. Treatment: The consensus at this conference was first line treatment was antibiotics, followed by a prokinetic (a drug that enhances your intestinal tract’s motility) for 3 months and a repeat breath test and a diet low in fermentable carbohydrates. For a + hydrogen test the recommended antibiotic therapy included:  550 mg Rifaximin three times a day for 14 days.  Caution was made to ensure to stick with this course and do not miss a pill to keep therapy as effective as possible.  Dr. Pimentel did note that higher doses would not warrant better results. For a + methane test the recommended antibiotic therapy included:  550 mg Rifaximin three times per day in combination with neomycin 500 mg twice a day for 14 days OR Rifaximin 550 milligrams three times per day with Metronidazole 250 milligrams three times per day for 14 days. Prokinetic: Dr. Pimentel mentioned erythromycin 1/4 tablet or 50 mg at night.  He reiterated the importance of taking erythromycin on an EMPTY stomach.  Probiotics: There was a difference in opinion regarding the use of probiotics for this condition.  Dr. Pimentel does not recommend them at this time but some of the other physicians do.  Probiotics mentioned included Align and Culturelle (Nature Health and Wellness w/o inulin). Probiotic studies have revealed that they enhance motility–but more research in this area is needed to provide individual recommendations. Diet:  There is no evidenced based diet to use with SIBO.  There needs to be research in this area!!  Diets that were discussed and utilized by these practitioners includes: low FODMAP, specific carbohydrate diet (SDC), a combo SDC and low FODMAP and Cedar Sinai’s Dr. Pimentel’s protocol.  Again a difference in opinion from the speakers. Dr. Siebecker likes to use a combo of the SCD and low FODMAPs diet while an individual has SIBO with a transition to low FODMAP for prevention. For those interested in learning more about this, check out Dr. Siebecker’s site here.  She mentioned that in individuals that seem to tolerate sucrose (table sugar) and grains/starch/fiber or in the underweight client low FODMAPs may be a good starting point.  Dr. Pimentel feels sucrose (table sugar) is well absorbed and is okay on the diet for those with SIBO (of course, within reason!). And lastly some key take-aways for me from this symposium:

  • SIBO is not a diagnostic term–it is a condition that arises due to something else.  Work with your doctor to determine WHY you developed SIBO.  If you don’t determine the cause, it will likely just come back.  Dr. Pimentel feels the decrease in MMC (migrating motor complex or ‘cleansing waves’) is the primary cause of SIBO in seen in IBS.  Remember in order for the MMC to initiate a cleansing wave you must be in the FASTING state–so avoid grazing and try to space/snacks meals 3-4 hours apart. You can include water or coffee in between meals.
  • Methane + constipation is harder to treat and should be treated with rifaximin and neomycin together.  This combo drug therapy may be better than neomycin on its own in terms of minimizing risk of neomycin drug resistance.
  • Methane bugs tend to come back sooner.
  • Methane gas appears to come primarily from Methonobrevibacter smithii which is actually not a bacteria but rather a microorganism from the Archaea kingdom. These microorganisms do not have a cell nucleus. Methane bacteria are linked with higher body weight (>BMI)
  • Dr. Pimentel said he would like to frame IBS patients as non-methane IBS or methane + IBS vs. IBS-C and IBS-D: treatments differ for the two based on gases.
  • Use a prokinetic drug and diet to help minimize risk of re-occurance.
  • If you have a SIBO  relapse within 1 month, it is likely in 50% of individuals that another disease is causing it.  If no relapse, pull back on erythromycin or prokinetic after 3 months.
  • Diet for SIBO should be customized–work with a dietitian or health care practitioner with SIBO knowledge!
  • Dr. Pimentel’s theory in regard to diet during antibiotic treatment is to NOT be on a low fermentable carb diet while using antibiotics as the microbes go in a hibernation phase and are less likely to be eradicated….I  tell my clients that fermentable carbs are somewhat like cheese to a mouse–let those microbes come out to eat so you can get ’em with the antibiotic!!

Why rifaximin might not work for some?

  1. SIBO too severe for symptom relief in one course
  2. Methane bacteria benefit from dual treatment: rifaximin + neomycin
  3. Bacteria may not be sensitive to rifaximin
  •  NOTE: Rifaximin has two forms: the alpha form has the anti-microbial while the beta form is not anti-microbial  (some forms found outside US such as India may have a combo of beta and alpha which would be LESS effective).

Herbal therapies such as herbal antibiotics that may be helpful: berberine herbs, allicin for methane producers, oregano & neem were all mentioned.  Of course, if you choose to try herbal therapies do so with a knowledgable practitioner.  Just because a product is an herb doesn’t mean that it will not have side effects! Personally, I find a low FODMAP diet keeps my SIBO at bay with meal spacing a key component! I have worked with some clients that have needed a bit more of a strict diet including removal of some grains and leanings toward the SCD diet but I have found that has been more of an exception than a rule.  Prokinetic drugs to add a longer duration of therapeutic benefit for many but not all of my clients have tolerated them.  Trying alternatives to erythromycin might offer benefit such as trying prucalopride or cisapride. Congratulations if you made it this far with my ramblings! Is your brain full from this post? Ha! More to come in this exciting area of digestive health! Stay tuned!