
SIBO or Small Intestinal Bacterial Overgrowth is a hot topic the holistic health world, and for good reason. It is the missed cause of many people’s GI distress and gaining popularity as people find relief from long-term GI issues. The symptoms of SIBO look like many other common GI issues and therefore can be passed off as other things. SIBO is a sleeping giant wreaking havoc on many people’s health. In addition, sometimes individual GI symptoms get addressed when SIBO is the underlying culprit. This can result in symptoms recurring or not fully resolving despite every effort toward solutions that generally work for GI related symptoms, all the while SIBO lurks in the background inhibiting digestion, absorption and motility of nutrients. If you feel like you try all the things that work for other people, but they don’t work for you, it is time to consider if SIBO is your sleeping giant. Accurately detecting SIBO is important when there is a suspicion it might be a problem. There are some GI issues that can be addressed by a good clinician using their clinical experience, common sense, and clinical knowledge, but SIBO is one issue that is best confirmed with lab testing. “If it looks like a duck and quacks like a duck…” isn’t the idiom to go by here, but many clinicians continue to make assumptions about. Test…don’t guess is a better approach.
What Is It?
SIBO happens when too much bacteria grow in the small intestines where there should be low levels of bacteria. The majority of your gut bacteria is in your colon (large intestine) and it should stay there. The small intestine is the longest section of the GI tract where food is broken down by digestive juices and nutrients are absorbed into the bloodstream. In the colon, bacteria break down the rest of food for absorption. When too much bacteria is the the small intestines it interferes with normal digestion and absorption. The bacteria can actually consume nutrients from food that should be absorbed into the bloodstream or passed on to the colon. This is where gas and bloating from SIBO can occur. SIBO can be stubborn to treat and requires patience, lifestyle changes, and in many cases, multiple treatments. SIBO is often mistaken as IBS and should be ruled out when IBS symptoms are present. Symptoms can be mild or quite severe, but generally persist until treated.
7 Signs It Could Be SIBO
- Gas
- Bloating
- Diarrhea
- Diagnosis of Irritable Bowel Syndrome or Inflammatory Bowel
- Disease
- Abdominal pain/cramping
- Multiple food intolerances and/or fat malabsorption
- Chronic illness like fibromyalgia, chronic fatigue syndrome and autoimmune diseases
Other symptoms that can occur with SIBO include acne, depression, malnutrition, weight loss and asthma.
Complications of SIBO
There are many complications of leaving SIBO untreated, the least of which is persistent, inconvenient GI distress. SIBO can damage stomach tissue and cause severe malnutrition when not addressed. When SIBO is occurring, the body cannot digest and absorb nutrients effectively regardless of how nutrient dense the diet is. SIBO can cause B12 deficiency resulting in megaloblastic anemia (loss of red blood cells) and even permanent nerve damage. Poor absorption of fat is common with SIBO and because the entire body is so reliant on fat, can have vast and lasting effects, specifically in the brain. Inadequate fat absorption can lead to neurological disorders, mood disorders, eating disorders, and hormone dysregulation. When vitamins and minerals are not adequately absorbed into the bloodstream, bones do not have what they need and osteoporosis can occur. Lastly, the damage SIBO can cause to the lining of the digestive tract contributes to leaky gut which perpetuates a host of other diseases including autoimmune diseases. For more on the other diseases associated with SIBO, see this study.
Causes and Risk Factors
Risk factors for SIBO include:
- Hypochlorhydria (low stomach acid) – a primary cause
- IBS
- Celiac disease
- Crohn’s disease
- Diabetes (type I and type II)
- Prolonged and/or frequent use of antibiotics
- Moderate and heavy alcohol consumption
- Use of oral contraceptives (birth control)
The use of oral contraceptive pills (birth control) is a risk factor for SIBO indirectly by way of the increased risk of IBS and IBD in those using birth control. Since SIBO is so closely linked to IBS and IBD, and birth control directly linked to IBS and IBD, we can comfortably say those using oral contraceptives are at higher risk for SIBO as well. It is believed that up to 80% of people with IBS have SIBO.
SIBO is caused by a variety of factors and rarely only one specific issue. The level of acidity, muscular movements, and immunoglobulins in intestinal fluid all work together to prevent gastric content to flow into the large bowel and not move back (refluxing) into the small bowel via the ileocecal valve. A combination of the effects from the risk factors listed above is believed to the be cause of gastric contents flowing back through the ileocecal valve and therefore introducing more bacteria than should be there. Structural defects in the small intestine can also allow bacteria to build up, and poor motility (movement throughout the GI tract) causes bacteria to stay in one area of the GI tract too long where bacteria can colonize and grow. .
Lab Testing for SIBO
SIBO is a condition where lab testing is crucial. It is even more crucial to have a practitioner who can interpret the results accurately. The gold standard for SIBO testing is the lactulose breath test which measures hydrogen and methane levels in the breathe. Since bacteria need to eat something to grow, they produce methane and hydrogen as byproducts of carbohydrates they consume. These byproducts can be measured in the breath. The test can also fool an untrained eye as it can produce no levels of hydrogen and methane but still have SIBO. Complications of the test are discussed here although it remains the best available method of testing to date.
Commonwealth labs has the most common and reliable lactulose breath test. The Organix Dysbiosis test is also used by some to detect SIBO through interpretation of the byproducts of bacteria and yeast found in urine. A skilled practitioner will know when to suspect SIBO and use testing to confirm their suspicion. In the event SIBO is suspected, other related issues ruled out, and lab tests are inconclusive, the practitioner may choose to treat anyway.
Functional Medicine Treatment for SIBO
Functional medicine practitioners will often have different ways of addressing a similar issue and SIBO is no different. You will hear people who advocate for use of antibiotics for SIBO, those who don’t and those who do in specific situations. Two things almost all practitioner will agree on: 1. SIBO can be stubborn and often needs repeat or ongoing treatment. 2. Diet changes are imperative in adequately treating SIBO. In general, SIBO needs something to kill the bacteria (antibiotics or antimicrobial herbals), diet changes to restrict the bacteria’s food source, decrease inflammation and heal the gut, and aids to address constipation, diarrhea or gut motility issues. Here is some more information on key aspects of treatment, but to fully elaborate on each area requires more than can be accomplished in this post, so stay tuned for more indepth SIBO resources from us in the future!
Antibiotics: Rifaximin and Neomycin are prescription antibiotics used for SIBO. Rifaximin is more widely used because it affects only the small intestines therefore does not affect good bacteria in the colon. It also does a good job of eradicating the problematic bacteria in the small intestines. It can be quite costly for some therefore is not always an option.
Herbal Antimicrobials: Herbal sources of antibiotics are also useful such a Allicin (garlic), Berberine, and Neem.
Studies show different rates of effectiveness of antimicrobials vs. antibiotics so the jury is still out since some research shows Rifaximin being more effective and other studies show antimicrobials being more effective. It is not uncommon to need multiple rounds of antibiotic treatment regardless of type (pharmaceutical or herbal).
Supplemental support: Other types of supplements may also be included in your individualized healing plan such as prokinetics to keep things moving through the GI tract rather than staying in the small intestines too long and growing bacteria. Products to break down biofilm like Interfase by Klaire Labs may also be used to expose the bacteria. Bacteria like to protect themselves just like any other organism and will become encased in a mucus type layer preventing antibiotics from reaching them. Supplements that break down biofilm break down this protective layer around the bacteria allowing antibiotic treatment to be more effective. Most of the time, you will not see high amounts of broad-spectrum probiotics used, during SIBO treatment, but rather smaller doses of more targeted strains during treatment with a more specific replenishment of good bacteria after SIBO is resolved. Probiotics when used too aggressively during SIBO treatment can be too irritating.
Diet– There are a variety of food approaches for SIBO that can be utilized. Some people even require bowel rest in the form of an elemental diet. For most people, following a low carbohydrate, very low sugar and low FODMAP diet is enough during treatment and then a transition back into a Plant Dominant Paleo eating plan works well. For others a more aggressive approach is temporarily needed such as GAPS or SCD. In extreme cases, an elemental diet is used. The most effective is a homemade version like this one. If already underweight, or experiencing weight loss from SIBO symptoms, an elemental diet is likely not going to be an option. Although an elemental diet for 14-21 days is not convenient, and tastes very bad, the success rate of an elemental diet can be as high as 85% in treating SIBO.
There is a school of thought that carbohydrates should not be restricted during SIBO treatment in order to keep the bacteria active and thriving so the antibiotics/antimicrobials can kill the most bacteria possible. This is a newer approach to the SIBO diet trends and more common is to restrict sugar and carbohydrate intake in order to stop feeding the bacteria while also eradicating them. This is an offensive and defensive approach where not restricting carbohydrate sources is more of an offensive option. Both have shown effectiveness and need more research and anecdotal evidence to determine if one approach is truly better than the other. Regardless of approach, carbohydrate levels do not need to be severely low to treat SIBO
At the end of the day, there are a variety of diets and combinations of GAPS, SCD, Low FODMAP, and Paleo are generally used. Diet protocol needs to be personalized by a dietitian trained to treat this condition to take into account your specific history, current issues, and needs.
Final Thoughts
SIBO is affecting many more people than we think and is often the unknown source of a variety of GI disorders. When it is not addressed, it not only further impairs gut health, but can trigger other chronic and autoimmune diseases. There are many people trying to address SIBO on their own with the vast number of SIBO resources and protocols on the internet. While we are the first to advocate taking a proactive and informed approach to your health, SIBO is an area we recommend working with a practitioner. It has many nuances that trained functional medicine practitioners can address quicker and more effectively than doing it yourself. One such nuance is methane vs hydrogen dominate SIBO. There are different treatment options/protocols and methane dominate SIBO can be more difficult to eradicate. Trying to treat SIBO without the correct testing and a skilled practitioner can delay healing and prolong nutrient deficiencies. SIBO is very treatable and the quality of life that is restored when adequately treated is exceptional. People dealing with SIBO have generally felt poor for years, even if they didn’t realize the extent to which they were feeling badly. When their health is restored, it is a joy to see them come alive again mentally, physically, emotionally and spiritually.
If you experience persistent problematic GI symptoms, fatigue, skin issues, low or anxious mood, persistent weight or bloating, or a mood disorder, you can feel better. You can get the health you need for the life you want. We are here to help!
in2GREAT Integrative Health is your solution to getting to the root cause of your condition. Our functional medicine practitioners focus on inflammation causing triggers that lead to chronic degenerative disease. See our Overland Park providers for your digestive needs.

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