Your Guide To Choosing The Right SIBO Diet
Written by 
Dr. Michael Ruscio, DC on
October 10, 2020
Written by
Dr. Michael Ruscio, DC on October 10, 2020
—
Reviewed by 
Heidi Turner
Comparing Low FODMAP Diets, Specific Carbohydrate Diets, and Elemental Diets.
- About SIBO|
- SIBO Causes|
- SIBO Treatment|
- SIBO Diets|
- Preventing Recurrence|
- Other SIBO Supports|
- The Bottom Line|
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What should you eat if you have SIBO? As with any digestive order, eating the right diet can lead to significant symptom improvement, even before addressing the underlying bacterial overgrowth. But it’s not always easy to decide where to start.
Let’s take a look at how to choose the right SIBO diet.
Specific Diets for SIBO
Dietary changes before, during, and after your SIBO treatment can have an important impact on your success and symptom control.
There are three main SIBO diets that research suggest may be helpful:
The GAPS diet and the Fast Tract diets are also sometimes recommended, but there is no available research to support their use yet.
Each of these SIBO diets is an elimination diet designed to remove foods that may trigger SIBO or IBS symptoms. There is no one best diet for SIBO, but one of these elimination diets is likely to help you get your symptoms under control while you work on treating your underlying bacterial overgrowth. Before we take a look at the three diet types, let’s discuss SIBO.
What Is SIBO?
SIBO stands for Small Intestinal Bacterial Overgrowth. Normally, the small intestine doesn’t harbor very much bacteria. But under the right conditions, your resident bacteria may overgrow in the small intestine or enter the small intestine from your large intestine.
SIBO is not a digestive disorder. Rather, it’s a lab finding indicating a specific type of dysbiosis that often underlies IBS [4]. It also likely contributes to a number of other conditions such as hypothyroidism [5], rheumatoid arthritis [6], restless leg syndrome [7, 8], rosacea [9], and non-responsive celiac disease [10].
Common SIBO symptoms include:
- Irritable bowel syndrome (IBS) symptoms such as diarrhea, constipation, bloating, gas, heartburn, and abdominal pain
- Brain fog
- Joint pain
- Leaky gut
- Weight loss from malabsorption
SIBO is diagnosed by a lactulose or glucose breath test. To take the test, you drink a solution that feeds bacteria and breathe into a test tube at 20 minute intervals for three hours. Your levels of hydrogen and methane gas are measured in your breath samples. A positive test indicates you have hydrogen or methane-producing bacterial overgrowth in your small intestine.
In 2020, the TrioSmart breath test was released. In addition to hydrogen and methane gases, this test measures a third type of gas (hydrogen sulfide) that may be produced by overgrown bacteria.
Note: Not everyone with a positive SIBO breath test will have symptoms. If you aren’t experiencing symptoms, you probably don’t need to treat a positive SIBO breath test.
What Causes SIBO?
There are many possible causes for SIBO, but they are largely things that affect the normal function of the digestive system.
A few commonly recognized causes of SIBO include:
- Abdominal adhesions or intestinal injury due to radiation or surgery [11]
- Slow gut motility or chronic constipation from all causes [12, 13]
- Use of proton pump inhibitors (PPIs) [14]
- Small intestinal disease, including Inflammatory Bowel Disease and celiac disease [15, 16]
There is also a close association between IBS and SIBO [17, 18]. A recent meta-analysis (highest quality research) suggests that more than one-third of IBS patients may also be positive for SIBO [19], and that IBS patients are nearly five times more likely to test positive for SIBO compared to healthy controls [20].
Additionally, it appears that people who take levothyroxine medication are more likely to have SIBO [21].
SIBO Treatment
A successful SIBO treatment plan usually requires more than quick fixes. Patients who combine a comprehensive approach including diet and antimicrobials are most successful. For patients with recurrent or stubborn SIBO, an appropriate diet and digestive support are vitally important during SIBO treatment.
A full-spectrum SIBO treatment approach includes:
- An anti-inflammatory diet that reduces food for the bacterial overgrowth [22]
- Fasting or an elemental diet [23, 24]
- Enzymes and stomach acid support to encourage good digestion [25]
- Probiotics [26]
- Antimicrobial herbs or targeted antibiotics, like rifaximin [27]
Three SIBO Diets
The low-FODMAP diet, specific carbohydrate diet (SCD), and elemental diet can each help SIBO. Let’s discuss each in turn.
Low FODMAP Diet
The low FODMAP diet is an elimination diet low in fermentable carbohydrates and starches that bacteria like to feed on. “FODMAPs” is an acronym that stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols.
Eliminating high FODMAP foods may reduce IBS and SIBO symptoms, such as bloating, gas, abdominal pain, diarrhea, and constipation [28].
There is no direct evidence that the low FODMAP diet is helpful for SIBO, but there is ample evidence from several meta-analyses [29] and numerous clinical trials to suggest the low FODMAP diet is beneficial for IBS and IBD [30, 31, 32, 33, 34]. As these conditions are associated with SIBO, we can infer that the low FODMAP diet is likely a helpful SIBO diet. My experience in the clinic mirrors this conclusion.
Some examples of high FODMAP foods include:
- Cauliflower, broccoli, and cabbage
- Lentils and beans
- Sweeteners like agave syrup, xylitol, and high fructose corn syrup
- Dairy products like milk or ice cream
- Prebiotic fiber (fiber supplements that feed beneficial bacteria)
- Dried fruit
Low FODMAP foods include things like green beans, quinoa, zucchini, tomatoes, lettuce, and cucumbers.
For a complete FODMAP food list, read How To Use the Low FODMAP Diet to Improve IBS Symptoms.
Specific Carbohydrate Diet (SCD)
The Specific Carbohydrate Diet is a more restrictive low carbohydrate diet. It removes grains and all complex carbohydrates to help reduce IBS and SIBO symptoms for those who don’t respond completely to a low FODMAP diet. This diet removes foods such as starchy vegetables, grains, and all sugars. Only simple sugars, fruits, and vegetables with simple sugars are allowed [35].
SCD was developed by Dr. Sidney Haas in 1951 as a therapeutic diet for patients with celiac disease. It was later shown to be helpful for patients with celiac disease and inflammatory bowel diseases (including Crohn’s Disease) [36, 37, 38, 39].
Because the SCD diet is even more restrictive than the low FODMAP diet, I don’t often recommend it. However, it is a potential SIBO diet that may help patients who still experience symptoms on the Low FODMAP diet.
Elemental Diet
When a patient’s symptoms are not improved by dietary changes, research suggests that the elemental diet may be a useful dietary approach.
An elemental diet is a complete-nutrition liquid meal replacement. By removing all fiber and normal food, you give your digestive system a complete break from the hard work of digestion and reduce exposure to irritants. This starves out the bad gut bacteria that contribute to your SIBO symptoms and calms down gut inflammation.
An elemental diet can either be used as a short reset at the beginning of your dietary change or used as a 2-3 week course of treatment. You can also use the elemental diet as a long-term, gut-friendly meal replacement for one meal per day [40].
We don’t yet have a lot of specific research into elemental diets and SIBO, but one study showed lactulose breath tests normalize in 80% of SIBO patients after a two-week elemental diet [41]. Sixty-five percent of patients in the same study experienced an improvement in their IBS symptoms.
What About the Gut and Psychology Syndrome (GAPS) and FastTract Diet?
The GAPS Diet is a gut-healing diet designed to repair the gut lining. It involves a nutrient-dense diet and targeted supplements.
The FastTract diet is a special elimination diet to remove all types of fermentable carbohydrates, including simple and complex sugars, starches, and fiber.
Though people have undoubtedly experienced positive results from using these diets, there is as of yet no specific evidence to recommend their use as a SIBO diet, or for other digestive disorders. However, we do have evidence for the low FODMAP diet and the elemental diet as well as some limited research supporting the use of the SCD diet.
Recommending unvalidated treatments isn’t always a valuable treatment strategy [42]. It’s best to stick to treatments that have documented evidence to back them up.
A Note on How to Use SIBO Diets
Overly restrictive diets are not healthy in the long term. I have seen too many patients become paralyzed with fear around eating, which can interfere with their healing process. This is very common with SIBO diets.
Therapeutic diets are designed to be short-term elimination diets to help you calm down inflammation and symptoms. After the initial elimination phase, you will reintroduce foods and watch for obvious symptoms. If you don’t notice any reaction, you can safely add that food back into your diet. If you have reactions, you can continue to avoid that food.
The purpose of this process is to help you identify your worst triggers. The longer-term goal is to expand your diet as much as possible while avoiding eating foods that are problematic for you.
Preventing SIBO Recurrence
According to SIBO expert Allison Siebecker, SIBO recurs at some point for about 60% of patients, but this doesn’t mean it’s a given. Several practices can reduce the likelihood of relapse.
One of the most important steps you can take is to improve your gut motility. This means encouraging your food to move through your digestive tract in a timely manner.
Some ways to improve your gut motility include:
- Intermittent fasting
- Fasting for a minimum of four hours between meals
- Prokinetic supplements or prescription medications, like Motil Pro, Iberogast, low dose naltrexone, low dose neomycin, or prucalopride
- Physical exercise
- Manual manipulation or visceral massage
- Reducing stress
- Continuing to avoid the foods that cause your worst symptoms to flare
The good news is that for most people, supporting gut motility can reduce the frequency of SIBO relapse. Including prokinetic strategies can even help repair the autoimmune nerve damage that happens after some cases of post-infectious IBS and SIBO [43].
Other SIBO Supports to Include
A few additional digestive supports to remember as you improve your diet during SIBO treatment are probiotics, digestive enzymes, and stomach acid support.
It’s a commonly held opinion that probiotics should not be used during SIBO treatment. This opinion does not stand up to scientific scrutiny. A meta-analysis, which includes results from multiple studies, concluded that probiotics improve outcomes for SIBO patients [44]. Specifically probiotics reduce bacterial overgrowths and hydrogen concentrations and improve symptoms such as abdominal pain.
Digestive enzymes may reduce SIBO symptoms because many SIBO symptoms are due to difficulty digesting certain carbohydrates and sugar. Encouraging their complete digestion with enzymes may help [45].
Low stomach acid and the use of proton-pump inhibitors are associated with SIBO [46, 47, 48]. Stomach acid support may help prevent SIBO.
The Bottom Line
There is promising evidence for using the low FODMAP diet and the elemental diet as SIBO diets, and there’s limited evidence for the Specific Carbohydrate Diet (SCD). Identifying your dietary triggers is one of the most important and accessible steps you can take to improve SIBO. Choose one of these SIBO diets, and adapt it to your body’s individual needs.
Dr. Michael Ruscio is a DC, natural health provider, researcher, and clinician. He serves as an Adjunct Professor at the University of Bridgeport and has published numerous papers in scientific journals as well as the book Healthy Gut, Healthy You. He also founded the Ruscio Institute of Functional Health, where he helps patients with a wide range of GI conditions and serves as the Head of Research.➕ References
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