When treating SIBO, diet is an important intervention to include. Generally, the food we eat is one of the reasons SIBO has developed, by creating inflammation and providing a fuel for bacteria to multiply. When we eat a diet of mostly carbohydrates such as bread, pasta, sugary drinks, and rice, bacteria consume the carbohydrates and proliferate, leading to overgrowth (1).
There are many dietary treatment options when treating SIBO, all of which aim to starve the bacteria by removing their fuel source. Each of these dietary protocols can be effective at reducing symptoms and preventing relapse if followed correctly for a sufficient period of time, and combined with alternative treatment options such as herbal or prescription antibiotics, stress management, and other considerations (SIBO: Beyond Diet – Part 1). Even in the absence of further treatment modalities, many patients find symptomatic relief from dietary changes as long as they remain on the diet. However, for permanent resolution of SIBO, a treatment plan that includes dietary intervention, as well as other interventions that address the etiology of SIBO is ideal.
Why do we address the diet when treating SIBO?
Bacteria feed on carbohydrates, leading to a proliferation of bacteria, gas production and other symptoms caused by SIBO. Improvement in symptoms is a result of starving the bacteria of their fuel source in order to decrease the amounts of bacteria within the small intestine, as well as elimination of highly inflammatory foods. Dietary changes can also help to determine which carbohydrates are specifically problematic, as carbohydrate sensitivity tends to be individual. Any of the diets listed below are helpful starting points in determining individual sensitivities and eradicating SIBO.
FODMAP refers to the four classes of fermentable sugars and sugar alcohols: fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Initially developed as a treatment for IBS, this diet aims to remove foods that contribute to intestinal fermentation (2). This diet has shown to be helpful in some cases of IBS and IBD; however, very little research has been completed to test the efficacy of this diet in cases of SIBO (3). The low FODMAP diet still allows for many sources of carbohydrate such as grains and starchy vegetables that are generally not tolerated in cases of SIBO. For these reasons, it is not considered a first-line dietary intervention for SIBO.
Created by Dr. Natasha Campbell-McBride, this diet is based on the idea that all disease starts in the gut. The Gut and Psychology/Physiology Syndrome plan, aka GAPS, includes seven phases, beginning with a strict diet of only animal stock, homemade soup, fermented foods, and small amounts of cooked vegetables. With each phase, the allowed food options increase; however, sugars, potatoes, rice, flour, and grains are not allowed at any point (4). Due to the highly restrictive nature of this diet and emphasis on fermented foods, it can reduce inflammation while encouraging gut healing and improvements in the gut microbiome. Additionally, due to the slow reintroduction of foods outlined in each phase, it is a helpful template to discover individual reactions to certain foods. While there is no formal research on the use of the GAPS
diet for the treatment of SIBO, we have found it to be a beneficial treatment method if followed correctly and modified as needed. The full protocol is outlined in the book written by Dr. Campbell-Mcbride (5).
Specific Carbohydrate Diet
Also known as SCD, the Specific Carbohydrate Diet limits complex carbohydrates (disaccharides and polysaccharides), lactose, sucrose, and many processed foods. This diet was originally developed to treat Celiac Disease; however, due to its removal of foods that are generally harmful to our digestive tract, promote bacteria and yeast overgrowth, and lead to inflammation, it can be helpful in a variety of conditions. Similarly to GAPS, SCD begins with a highly restrictive introduction phase, slowly reintroducing foods as the intestines heal. This diet is outlined in much more detail in Breaking the Vicious Cycle by Elain Gottschall (6).
SIBO Specific Food Guide
More of a guide than a diet, this template combines the SCD and the low FODMAP diet, based on recommendations from Dr. Siebecker, a leading expert in the treatment of SIBO. It is more restrictive than each individual diet but is considerably more focused on SIBO. Due to its highly restrictive nature, patients may want to try a low FODMAP or SCD diet initially before progressing to the SIBO specific plan. Dr. Siebecker has outlined this guide; however, it contains minimal dietary instructions regarding phases or reintroduction (7).
SIBO Bi-Phasic Diet
Developed by Dr Nirala Jacobi, the SIBO Bi-Phasic Diet builds on the SIBO Specific Food Guide, turning it into a diet plan, complete with phases (8). It combines the guidelines of low-FODMAP, SCD, and the GAPS diet, and is therefore quite restrictive. However, it is not as lengthy as the GAPS diet as it contains only two phases rather than seven. It also has two options for the initial phase, depending on the severity of symptoms.
The elemental diet consists of only meal replacement drinks and is generally considered the strictest treatment diet, due to the lack of solid food. Only a highly digestible powdered meal replacement is consumed for 2-3 weeks. A variety of companies produce elemental diet powders, or it can be made at home. Typically, this type of diet provides 1800-2000 calories a day. This diet starves bacteria and has an 80-85% cure rate (9). However, it can be quite pricey and challenging to adhere to.
Additionally, there is a concern for yeast overgrowth during this diet so it is advisable to combine it with anti-yeast supplementation. Because of these concerns, many doctors consider the elemental diet only if patients have not responded sufficiently to diet and herbal or prescription antibiotics.
While the diets listed above focus on treating SIBO, the Cedars-Sinai diet is aimed at prevention. Developed by Dr. Mark Pimental, this diet isn’t as strict as the others but follows similar principles in an effort to ensure SIBO does not develop. Pimental recommends avoiding certain sweeteners, dairy, and experimenting with carbohydrates to see which ones you tolerate. However, he does not limit gluten. Due to the high incidence of gluten sensitivity, this diet may need to be modified to eliminate gluten-containing grains. He also includes lifestyle recommendations in addition to dietary restrictions, such as drinking 8 cups of water per day and avoiding eating between meals and before bed (10). This diet is outlined in more detailed in his book, A New IBS Solution (11).
Regardless of which diet is implemented, many patients benefit from taking steps to improve digestibility of their meals such as cooking fruits and vegetables rather than eating them raw, consuming soups, stews, and broths, and being cautious with highly fibrous/dry foods such as nuts, seeds, nut flours. Patients may be inclined to begin to restore their microbiome with fermented foods but these are generally poorly tolerated until the bacterial overgrowth is reduced.
Some healthcare practitioners are recommending to continue a relatively normal diet during the ‘kill phase’, when herbal or prescription antibiotics are utilized, in an effort to keep the bacteria active in the digestive tract, enabling complete eradication (12). However, certain patients do not tolerate this approach due to the intense symptoms that result. Resolution from SIBO has been seen when the kill phase is completed prior to dietary changes, as well as when they occur concomitantly.
No matter which diet is used, the goal is to eventually expand the diet to the widest variety possible without the return of symptoms. Diet alone can manage symptoms of SIBO but is not truly treating the cause; once the diet is deviated from, symptoms tend to return. Treatment is typically a long-term process that addresses both the SIBO and the root cause. By and large, it involves dietary changes, herbal or prescription antibiotics, as well as lifestyle changes. (SIBO: Beyond Diet – Part 1)
Interested in learning more about the dietary treatment of SIBO? Our holistic nutritionist, Keyrsten McEwan, is well-versed in treating SIBO and can help guide you through a complete dietary protocol.