Healing SIBO

1. SIBO: Microbial Imbalance, Not Just Infection

SIBO stands for small intestine bacterial overgrowth. It is a kind of microbial dysbiosis, or an imbalance in the small intestine. It is often confused with an infection, but it is not, as the overgrown bacteria aren’t pathogenic.

Location matters. SIBO isn't about harmful bacteria invading your gut; it's about having too many bacteria in the wrong place – the small intestine. Normally, the small intestine should have very few bacteria, with the majority residing in the large intestine. When bacteria overgrow in the small intestine, they ferment carbohydrates, leading to gas, bloating, and other digestive issues.

Understanding digestion. To grasp SIBO, it's essential to understand the digestive process. Food travels from the esophagus to the stomach, where it's broken down by stomach acid. This partially digested food, called chyme, then moves into the small intestine, where nutrients are absorbed. Finally, the remaining material reaches the large intestine, where most bacteria reside.

SIBO vs. IBS vs. IBD. SIBO is often the underlying cause of Irritable Bowel Syndrome (IBS), with studies suggesting that up to 78% of IBS cases are linked to SIBO. It's crucial to differentiate SIBO from Inflammatory Bowel Disease (IBD), which includes conditions like ulcerative colitis and Crohn's disease. While SIBO can cause IBS, IBD can also lead to SIBO due to structural changes in the gut.

2. Food Poisoning: A Major Culprit Behind SIBO

By far the most common cause of SIBO is food poisoning.

The aftermath of food poisoning. Food poisoning, caused by bacteria like E. coli and salmonella, can trigger SIBO. These bacteria produce a toxin called cytolethal distending toxin B (Cdt-B). While most people recover, about 10% develop post-infectious IBS, which is often caused by SIBO.

Autoimmune response. The body produces antibodies to fight Cdt-B, but these antibodies can mistakenly attack vinculin, a protein crucial for nerve cell connections. This autoimmune response damages the nerves responsible for the migrating motor complex (MMC), which sweeps bacteria out of the small intestine.

Compromised MMC. When the MMC is compromised, bacteria remain in the small intestine, overgrow, and ferment undigested food, leading to SIBO symptoms. Even a mild case of food poisoning can trigger IBS, and the onset of SIBO can be delayed for up to three months, making it difficult to connect the dots.

3. Structural Issues and Medications: Hidden SIBO Triggers

It’s unfortunate but true that the very medications you take to save your life can also have unintended life-altering side effects, one of which might be developing SIBO.

Adhesions and obstructions. Adhesions, internal scars made of collagen fibers, can obstruct the normal flow of the small intestine, preventing bacteria from moving through properly. Endometriosis, a condition where endometrial tissue grows outside the uterus, can also cause adhesions and, therefore, SIBO.

Medication-induced SIBO. Certain medications, such as antibiotics, opioids, and proton-pump inhibitors (PPIs), can increase the risk of developing SIBO. Antibiotics can disrupt the gut microbiome, while opioids and PPIs can slow intestinal motility, creating an environment conducive to bacterial overgrowth.

Other triggers. Radiation therapy, particularly pelvic radiation, can damage the small intestine and lead to SIBO. Thyroid issues, both hyper- and hypothyroidism, can also be an underlying cause, as thyroid hormones impact motility directly.

4. The SIBO Breath Test: Your Key to Diagnosis

The best way to determine if you have SIBO is to take the SIBO breath test.

Why a breath test? The SIBO breath test is the most effective way to diagnose SIBO because the bacterial overgrowth doesn't show up on imaging tests like MRIs or CT scans. Stool tests and urine organic acid tests are not reliable for diagnosing SIBO, as they reflect what's in the large intestine or indicate bacterial overgrowth somewhere in the gut, but not specifically in the small intestine.

How the test works. The breath test involves drinking a sugar solution (lactulose or glucose) that feeds the bacteria, encouraging them to produce gas. The presence and quantity of bacteria are determined by the amount of gas produced, as humans don't normally produce these gases. You then blow into a tube every twenty minutes over the course of three hours to capture the gas.

Lactulose vs. glucose. Lactulose, available only with a prescription in the United States, is more likely to provide an accurate result because it tests all the way down to the bottom of the small intestine. Glucose, available without a prescription, only tests for SIBO bacteria in the first few feet of the small intestine.

5. Methane, Weight, and the Gut-Brain Connection

Methane, in effect, slows down the large and small intestine so that once the bacteria break down the foods you eat, you’ll have a longer time to absorb the calories that are there.

Methane and weight gain. Methane-producing bacteria, particularly Methanobrevibacter smithii, are efficient at breaking down food and turning it into calories. An overgrowth of these bacteria can lead to increased calorie absorption and weight gain. Studies have shown a positive association between methane and being overweight.

SIBO and malnutrition. SIBO can also lead to weight loss and malnutrition. Bacteria may steal nutrients, diarrhea can cause rapid food transit, and nausea and belly pain can reduce appetite. It's important to address these issues to prevent unhealthy habits and ensure proper nutrient absorption.

The gut-brain axis. SIBO affects hormones, influencing both mental and gastrointestinal functions. Stress, anxiety, and depression can elevate cortisol levels, shutting down the digestive system. Serotonin, a mood-influencing neurotransmitter, is primarily made and stored in the gut, and abnormal levels can affect both mood and gastrointestinal function.

6. SIBO Symptom Relief: Your Home Medicine Cabinet

In this chapter, I’ll cover many of the over-the-counter herbs, supplements, and medications you can find in drugstores or health food stores or online, and other strategies you can use at home when you are experiencing a flare-up or just not feeling great.

Bloating busters. Activated charcoal absorbs gas and toxins, providing relief from bloating. Atrantil, containing polyphenols, can help reduce bloating caused by methane. Gas-X breaks up gas bubbles, while Iberogast, a liquid herbal formulation, stimulates motility and alleviates gas, pain, nausea, constipation, and diarrhea.

Pain relievers. Kava kava and black cohosh are herbs that work as muscle relaxants, alleviating pain caused by muscle cramps or contractions. Peppermint oil or peppermint tea can also relax smooth muscles and has antibacterial qualities.

Constipation solutions. Osmotic laxatives, such as magnesium oxide, draw water into the large intestine, softening the stool. Insoluble fiber can help some people, while others may find it aggravates symptoms. Iberogast can also help with motility, and probiotics can regulate bowel movements.

7. Dietary Changes: The Cornerstone of SIBO Management

Changing your diet is the fastest way to start feeling relief from your SIBO symptoms.

Limit fermentable carbs. The general rule is to limit your intake of carbohydrates, which are fermentable foods that feed SIBO bacteria. This doesn't mean cutting out carbs completely, but rather reducing your intake of fermentable carbs to a quantity you can tolerate without exacerbating your symptoms.

Low FODMAPs. Focus on foods that are low in FODMAPs (fermentable oligo-, di-, mono-saccharides and polyols), which are forms of sugar found in carbohydrates that feed the bacteria in your small intestine. This includes limiting high FODMAP foods like apples, pears, some legumes, and wheat products.

Individualized approach. Every person and every case of SIBO is different, so no two people will follow the diet exactly the same way. Experimentation with your diet will be key, and as you get better, you will want to try reintroducing more foods. The more diverse foods you are eventually able to eat, the more diverse your gut microbiome, which is important for overall health.

8. The SIBO Specific Food Guide: A Flexible 21-Day Plan

The nutrition plan I outline in this chapter is based on the SIBO Specific Food Guide (SSFG) (also called the SIBO Diet or SIBO Specific Diet).

The SIBO Specific Food Guide (SSFG). This food guide, developed by Dr. Allison Siebecker, combines the recommendations of the Specific Carbohydrate Diet and the low FODMAP diet and is low fermentable. It's a flexible plan that allows for individual tailoring and reintroduction of foods.

Other dietary approaches. Other nutrition plans for SIBO include the low FODMAP diet, the Cedars-Sinai Low Fermentation Diet (CSD), the Specific Carbohydrate Diet (SCD), the GAPS (gut and psychology syndrome) diet, and the SIBO Bi-Phasic Diet. All of these diets work by reducing the amount of fermentable carbohydrates you're eating.

The 21-day plan. The plan involves a structured approach to dietary changes over three weeks, starting with a restrictive phase to control symptoms and gradually reintroducing foods. Preparation, meal planning, and symptom tracking are key to success.

9. Eradicating SIBO: Antibiotics, Herbs, and the Elemental Diet

There are three kinds of treatment you can use to do that: pharmaceutical antibiotics, herbal antibiotics, and the elemental diet.

Pharmaceutical antibiotics. Rifaximin (Xifaxan) is a special antibiotic that is not absorbed into the bloodstream, minimizing side effects. Neomycin and metronidazole are also used, but they are typical antibiotics that can cause unpleasant side effects and impact the microbiome.

Herbal antibiotics. Herbal antibiotics, such as neem, berberine, oregano, and allicin extract, are a natural treatment option that can be as effective as pharmaceuticals. They generally take longer to work, about a month, and are often used in combination.

The elemental diet. The elemental diet is a liquid medical food diet that consists of predigested nutrients, starving the bacteria in the small intestine. It's a difficult treatment method to follow, but it is also the fastest and can decrease severe gas levels in a single two-week course.

10. Retesting and Relapse Prevention: Staying on Track

Missing once is an accident. Missing twice is the start of a new habit.

Retesting is crucial. After completing treatment, it's essential to retest to see whether or not the SIBO is gone. This should be done within two weeks of completing treatment because two-thirds of the people who have SIBO will relapse, many will relapse within two weeks, and the point of retesting is to see how effective your treatment was before you relapsed.

Prokinetics for relapse prevention. If you're feeling 90 percent better, start a prokinetic right away to keep the MMC sweeping and prevent bacteria from coming back. Meal spacing, with three to four hours between meals, is another way to support a healthy MMC.

Addressing underlying causes. If you're not feeling 90 percent better, it may be because you have some other, associated condition that needs to be checked out and dealt with. It's essential to determine the underlying cause of your SIBO to prevent relapse.

Last updated: February 25, 2025