top of page

Small Intestinal Bacterial Overgrowth

This will explain our general approaches to SIBO, Intestinal Methane Overgrowth (IMO), Hydrogen Sulfide Overgrowth (H2s), and Small Intestinal Fungal Overgrowth (SIFO) . Below you will find a general overview as well as videos from my recent webinar.

AdobeStock_337014773.jpeg
WHAT IS INTESTINAL MICROBIAL OVERGROWTH?

 

Intestinal Microbial Overgrowth refers to an abnormal condition in which bacteria overgrow in your intestine and/or colon.  A blanket term is called dysbiosis.

​

It can be broken into three subtypes:

  1. Small Intestinal Bacterial Overgrowth of Hydrogen producing species (classic SIBO)

  2. Excessive Methane gas production causing excessive methane gas anywhere in the intestine. This production is caused by microbes from the Kingdom Archaea

  3.  Hydrogen Sulfide overgrowth anywhere in the intestine (caused by Hydrogen Sulfide producing species​​

What causes IBO?

 

IBO is associated with a number of conditions including: motility disorders of the intestine (such as irritable bowel syndrome), dysfunction of intestinal nerves or muscles (which may be caused by food borne pathogens), autoimmune diseases (diabetes or scleroderma), blind loop syndrome,
untreated celiac disease and small intestinal diverticula. Normally, the muscles in the stomach and small intestine move food through the intestine in a synchronized fashion; these series of contractions are called peristalsis. 

​

The migrating motor complex (MMC), a small intestine cleansing wave occurs only when food is not present, i.e., the fasting state or about every 90-120 minutes in patients  with normal cleansing wave function.

 

In individuals with altered intestinal motility, such as IBS, the MMC waves occur less frequently. These movements move bacteria out of the small intestine. When the action of the small intestine is disrupted, bacteria and food may remain in the small bowel leading to the potential overgrowth of microbes. 

​

A malfunctioning or surgically resected ileocecal valve (the door between your small intestine and large intestine) may allow colonic bacteria to move into your small intestine. Low stomach acid is also a potential risk factor of SIBO. Reduced stomach acid may occur normally in the aging process or secondary to acid reducing medications such as proton pump inhibitors used for acid reflux.

​

What are the symptoms of IBO?

  • Severe abdominal bloating, abdominal distention (visible protrusion of the abdomen), increased colonic gas, diarrhea and/or constipation are common symptoms of IBO. 

  • Bacteria in the small intestine can inactivate bile acids. The inactive bile acids can pull water into the colon, causing diarrhea and inhibit fat digestion. Faulty fat digestion contributes to fat in the stool. Fatty stools tend to be more malodorous, may be light in color or be difficult to flush. Free bile acids, are toxic to the intestinal lining, and can cause inflammation and release pro-inflammatory cytokines. Cytokines are proteins that serve as messengers between cells and are involved in regulating various immune responses. Cytokines can trigger inflammation in response to infections.

  • Hydrogen overgrowth is either associated with diarrhea or mixed constipation/diarrhea.

  • Methane overgrowth is more associated with constipation.

  • Hydrogen Sulfide overgrowth is more associated almost exclusively with Diarrhea.

  • Eating often (such as ad-libitum or grazing)  exacerbates symptoms of SIBO. So many people suffering with SIBO will undereat as a reaction strategy.  

  • Nutrient intake and body weight may decrease if you avoid eating in an effort to minimize intestinal distress. 

  • Poor intake may lead to nutritional deficiency and potentially impact intestinal health. Vitamin and mineral alterations, such as low iron status, elevated or reduced levels of B Vitamins and reduced fat-soluble vitamins, can occur in SIBO. This may be due to poor absorption due to low-grade inflammation, bacterial consumption of vitamins, poor nutrient intake or fat malabsorption, which can impact fat-soluble vitamin status (Vitamin A, D and E). Intestinal microbes produce fat-soluble Vitamin K; therefore, nutrient deficiency of this vitamin is uncommon in SIBO. Night blindness and metabolic bone disease due to Vitamin A and Vitamin D deficiency can occur in severe SIBO cases. 

  • Conversely, depending on the bacterial species in the intestine, blood levels of some vitamins may exceed normal values, particularly folate and/or B-vitamins, which some microbes produce.

  • The effects of IBO: Some bacteria produce endotoxins that may damage the lining of the colon and small intestine. Bacteria in the intestine ferment carbohydrates and produce short-chain fatty acids (SCFA) such as butyrate, acetate, and propionate. In the colon, short chain fatty acids are linked with speeding up colonic movements and can be beneficial for the health of the colonic cells. Excessive fermentation, however, in the colon may lead to intestinal injury and inflammation, as noted in animal studies. In the small intestine, SCFA causes a reduction in motility, perhaps contributing to bloating and distention, a common complaint of those with IBO.​

​

Conditions associated with Intestinal Microbial Overgrowth

  • Systemic disorders: Diabetes, scleroderma, hypothyroidism, immune deficiency syndrome, and chronic renal disease•    

  • Motility disorders: irritable bowel syndrome (IBS), gastroparesis, colonic inertia, untreated celiac disease•  

  • Partial or intermittent small intestinal obstruction (might be caused from scar tissue from previous intestinal surgery) preventing movement of bacteria and food out of small intestine•    Small intestinal diverticula (pockets in the intestinal walls that can fill with bacteria and food, more commonly found in the colon or large intestine)•   

  • Surgical alterations of the GI tract including: removal of ileocecal valve, small bowel resection, gastric bypass or resection

  • Ehlers Danlos syndrome (EDS), a genetic connective tissue disorder

  • Chronic pancreatitis

  • Crohn’s disease

  • Parkinson disease

  • Restless leg syndrome

  •  Fibromyalgia

  •  Rosacea

  • Other findings on lab tests sometime associated with IBO:

    • RBC folate >20 may indicate overgrowth

    • Total serum bile acid level may elevate

    • B12 may be reduced or potentially very high (in the absence of B vitamin supplementation)

  • Stool tests

    • ​Stool elastase may be reduced

    • Stool fat may be elevated​​​

Treatment Strategies
  •  

  •  

  •  

  • TREATMENT OPTIONS:Health care providers often prescribe antibiotics (traditional or herbal) to treat the overgrowth of bacteria in the small intestine. But the treatment is largely driven by your gas production>Treatment regimens may vary depending on whether there are elevations of hydrogen (H2), Hydrogen Sulfide (H2S) or methane (CH4) gas.Current antibiotic SIBO treatment recommendations:� 550 milligrams rifaximin three times per day in H2 positive SIBO for 14days.� 550 milligrams rifaximin three times per day with 500 mg neomycintwice per day with Methane overgrowth or 10-14 days.� Herbal remedies shown in one study to be effective for SIBOtreatment include: Biotics Research Labs: Dysbiocide and FC CidalOR Metagenics, Inc.: Candibactin AR and Candibactin BRTreatments vary from 4 weeks to 2 months of these herbal mixtures.Dr. Rinde uses combinations related to these formulas in practice.* Herbal and natural remedies for Methane Overgrowth include Allicin, Neem , Quebracho, Red Yeast Rice, and Lactobacillus reuteri ,* Herbal and Natural remedies for Hydrogen Sulfide overgrowth often include Codonopsis root, Butyrate, Prebiotics, and Serum Bovine Immunoglobulins.After SIBO antibiotic treatment: Small intestinal bacterial overgrowth should be considered a symptom of an underlying problem rather than a final diagnosis. Identifying and treating the underlying abnormality should be the goal, if possible. Bacterial overgrowth in the small intestine should be eradicated with proper antibiotic (pharmaceutical or herbal) therapy and nutritional deficiencies should be corrected. Implementing a prokinetic drug such as low dose erythromycin (50 milligrams) at night, Iberogast, an herbal prokinetic supplement, or resolor post antibiotic therapy may reduce incidence of rapid relapse of the bacterial overgrowth by encouraging adequate cleansing of the small intestine, although more research is needed in this area.Diet therapies:There is no evidenced based diet therapy for SIBO treatment or prevention. Online nutrition misinformation is rampant. Dietary therapies showing promise in clinical practice include: the low FODMAP diet or utilizing an elemental formula (a pre-digested, easy to absorb nutritional supplemental drink consumed over 2 weeks). Emphasis on eating a nutritionally balanced diet should be prioritized to replenish nutritionaldeficiencies, to nourish the intestine and aid the healing process.Other diet therapies that have been suggested for Hydrogen overgrowth prevention and treatment include: the Specific Carbohydrate Diet (SCD) or a combination SCD and low FODMAP diet or GAPs diet. The SCD diet does not take into consideration the potential role of fructose malabsorption in SIBO and is very restrictive. The combination low FODMAP/SCD approach is highly restrictive and therefore, should not be a first line diet therapy. The Gaps diet, a 6-phase high protein, low carbohydrate diet, which encourages large quantities of bone broth, has little research to support is use or its nutritional adequacy. A severely low carbohydrate diet may lower the production of digestive enzymes in the small intestine that aid carbohydrate digestion as noted in this case report and may be detrimental to the gut flora in the long term. During antibiotic therapy, patients are sometimes to include fermentable foods such as those of high FODMAP composition to enhance effectiveness of the antibiotic therapy. This theory, however, has limited substantiation in the literature.Dietary approaches for Methane Overgrowth are poorly understood at this time.Dietary approaches for Hydrogen Sulfide overgrowth include the reduction of Taurine, Methionine, and Choline rich foods as well as monitoring sulfur rich foods. This approach amounts to a Vegan Mediterranean style diet without Soy. This should only be done temporarily unless the patient finds long term benefit on this plan. Meal spacing is encouraged for patients with SIBO to allow the migrating motor complex (MMC) to initiate a cleansing wave. Allowing 3-4 hours between meals and snack times may allow for more small intestinal cleansing waves, keeping the small intestine clean of food and microbes! The role of viruses and fungi may play a role in symptom exacerbation in SIBO, an area of science that hopefully will soon be further explored.There are other aspects that may be considered in your treatment on a case by case bases such as1. biofilm treatment2. digestive enzyme replenishment3. intestinal lining repair4. liver and renal detoxification support.Dr. Rinde will discuss your unique plan with you.

bottom of page