The top 5 SIBO Diets you need to know about_blog title

It can be a challenge to figure out the right diet for Small Intestine Bacterial Overgrowth (SIBO) with the array of conflicting advice online.  

The previous blog in this series, Understanding SIBO, reviewed the basics – common signs and symptoms, diagnosis, and treatment strategies. In this article you’ll learn about the five most popular diets for SIBO, and review the pros, cons, and available supporting evidence.

What is the role of diet in SIBO treatment?

Although poor diet can worsen bacterial overgrowth, it is unlikely the root cause. Therefore, diet alone is not typically used to “treat” SIBO, but can help manage symptoms and prevent relapse.

The common theme amongst all of these diets is elimination of specific groups of carbohydrates that are fermentable and resistant to digestion.  However each diet is unique in its overall function, which is highly dependent on the specific carbohydrates eliminated as well as overall restrictiveness.  The diets discussed in this article range from less restrictive (used for milder cases of SIBO) to highly restrictive (used for more severe cases).

When to start a SIBO-diet?

SIBO diets (with the exception of the Elemental Diet), are typically used before, during, or after the treatment regimen.  The duration and timing of the diet can vary greatly and is highly dependent on the individual and their specific treatment plan.  

Before SIBO Treatment

Sometimes a SIBO diet is recommended before the initiation of treatment, typically right after a SIBO diagnosis.  This can be helpful when the individual is experiencing extreme symptoms of gas and bloating or is highly motivated to get a jumpstart on feeling better.

During SIBO Treatment

There is still ongoing debate regarding the appropriateness of dietary restriction DURING treatment. Some practitioners recommend patients avoid certain foods to prevent “feeding” bacteria.  This may be beneficial for individuals presenting with severe symptoms.

Other practitioners take on a more liberal dietary approach during treatment, allowing intake of a small amount of fermentable carbohydrates. The idea is that bacteria may form biofilms, protective coverings that shield them from antimicrobials and reduce the overall effectiveness of treatment.  By providing a small amount of fermentable carbohydrate, the bacteria can prosper, ensuring they stay active and susceptible to the work of the antimicrobial agents. This idea is promoted by well-known SIBO researchers such as Dr. Mark Pimentel.

After SIBO Treatment

Often, a SIBO diet is continued even after completion of treatment. The goal of the diet is to prevent SIBO relapse. The diet can be transitioned over time towards a less restrictive eating style.

How long do SIBO diets last?

The duration of SIBO diets is variable and depends on the individual’s overall health, symptoms, and response to treatment.

Because these diets are restrictive in nature, following them long-term may pose certain risks.  If not planned carefully they can be devoid of important essential nutrients as well as prebiotic fiber, which is necessary for the maintenance of a healthy, diverse gut flora. The overarching goal is to use a diet to help support SIBO treatment and prevention, but eventually get back to a diverse, healthy eating style.

Review of the 5 most common SIBO diets

Here is a brief outline of the five most popular diet protocols used for SIBO.

1. Low FODMAP Diet

The Low FODMAP Diet was championed by researchers at Monash University (Australia) for the management of IBS symptoms.

The premise of the diet is to limit intake of a group of carbohydrates known as FODMAPs, short for Fermentable Oligosaccharides (fructans and oligosaccharides), Disaccharides (lactose), Monosaccharides (fructose), And Polyols (sorbitol and mannitol).

Some of these carbohydrates are resistant to digestion and when not properly broken down, can cause symptoms of gas and bloating. Additionally, some of these carbohydrates have an osmotic effect in the gut and pull in extra water, producing symptoms like loose stools, diarrhea, and abdominal cramping.

Acceptable Food Groups:

FOOD GROUPALLOWEDNOT ALLOWED
Meat, Poultry, Eggs, FishNon-breaded meat, poultry, fishBreaded meat, poultry, fish
DairyLow-lactose such as most cheeses and certain milk alternativesHigh-lactose dairy such as milk, ice cream, sour cream
GrainsQuinoa, millet, most gluten-free products, rice, corn flourRye, bran, barley, wheat
LegumesSmall amounts of chickpeas, edamame, lentils, extra firm tofu, etc.Most legumes like black beans, kidney beans, split peas, etc.
Nuts/SeedsMost are okay is small portionsPistachios, cashews
VegetablesBell pepper, zucchini, tomato, spinach, carrots, etc.Garlic, cauliflower, onion, asparagus, etc.
FruitsLIMITED portions of SOME fruits such as grapes, strawberries, oranges, etc.SOME fruits such as apple, watermelon, mango, etc.

** For a more comprehensive list visit the Monash University website or download their App

Research Consensus:

The Low FODMAP diet has been shown effective in improving symptoms in up to 70% of patients with IBS, especially diarrhea predominant IBS (1).  Despite a lack of studies evaluating the effectiveness of a low FODMAP diet for individuals with SIBO, there is a high prevalence of SIBO in IBS patients (2).  This strong correlation explains why a low FODMAP diet is commonly used for SIBO, especially when the individual presents with IBS-like symptoms.

Pros:

  • Shown to be effective for symptom management in IBS
  • Less restrictive than other SIBO diets
  • Wealth of information and recipes available online
  • Provides framework for reintroducing FODMAP foods

Cons:

  • Long-term adherence may increase risk for negative health outcomes if not executed properly (3)
    • Deficiency of certain nutrients
    • Potential harm to diversity of helpful gut bacteria

2. Specific Carbohydrate Diet (SCD)

The Specific Carbohydrate Diet (SCD) was developed by researcher Elaine Gottschall and Dr. Sidney Haas over 50 years ago and has been used extensively in the management of various forms of bowel disease such as Crohn’s, ulcerative colitis, celiac disease, diverticulitis, cystic fibrosis, and chronic diarrhea.

Monosaccharides (simple carbohydrates which are easily absorbed through the intestinal wall) are allowed.  Complex carbohydrates such as disaccharides and polysaccharides (which must undergo a more extensive digestive breakdown prior to absorption) are not allowed.

The premise of this diet is to limit certain carbohydrates based on their molecular structure.   

Acceptable Food Groups:

Essentially this eliminated intake of most starches and grains.

FOOD GROUPALLOWEDNOT ALLOWED
Meat, Poultry, Eggs, FishUnprocessed meat, poultry, eggs, fishProcessed, canned, or breaded meat, poultry, eggs, fish
Dairy24-hour fermented yogurt, butter, aged cheesesProcessed dairy and fresh cheeses such as feta, mozzarella, etc.
GrainsNONEALL
LegumesSOME legumes such as lentils, peas, black beans, etc.SOME legumes such as bean sprouts, garbanzo, soybeans
Nuts/SeedsMost nuts/seeds such as cashews, almonds, raw walnuts, etc.Nuts/seeds with added spices or starch/sugar coatings
VegetablesFresh or frozen non-starchy veggies such as cucumber, broccoli, garlic, etc.Canned and starchy veggies such as yams, parsnips, etc.
FruitsALL fresh, frozen, or dried fruit with no added sugarFruits with added sugar

** For a more comprehensive list visit Breaking the Vicious Cycle Legal/Illegal List

Research Consensus:

Although there has been some evidence of benefit in patients with Inflammatory Bowel Disease (IBD), the SCD has not been exclusively studied in IBS or SIBO (4).  Regardless, the SCD is often used with SIBO due to its potential to reduce intestinal inflammation, improve nutrient absorption, and bring about balance to the bacteria in the gut (5).

Pros:

  • Shown to be effective for patients with IBD
  • Beneficial in the case of severe inflammation or damage to the gut lining

Cons:

  • Highly restrictive with the elimination of an entire food group
  • May increase long-term risk of energy and nutrient deficiency if not executed properly

3. SIBO Specific Food Plan

The SIBO Specific Food Plan was designed by leading SIBO expert Dr. Allison Siebecker, and is one of the few diets formulated specifically for SIBO.  This diet plan essentially combines both the SCD and low FODMAP diet and therefore restricts the broadest range of carbohydrates.

Acceptable Food Groups:

FOOD GROUPALLOWEDNOT ALLOWED
Meat, Poultry, Eggs, FishUnprocessed meat, poultry, eggs, fishProcessed, canned or breaded meats, poultry, eggs, fish
Dairy24-hour fermented yogurt, butter, aged cheesesProcessed dairy and fresh cheeses such as feta, mozzarella, etc.
GrainsNONEALL
LegumesLIMITED portions of lentils (brown, green, red) and lima beansMOST legumes and beans including soy, pinto, garbanzo, split peas, etc.
Nuts/SeedsLIMITED portions of most nuts/seeds including pine nuts, pumpkin seeds, walnutsSOME nuts/seeds including chia, cashews, pistachios. Nuts/seeds with added spices or sugar/ starch coatings
VegetablesFresh/frozen non-starchy veggies such as arugula, cucumber, tomato, etc.
LIMITED portions of certain veggies such as snow peas, green beans, broccoli, etc.
ALL canned/starchy veggies such as yams, potato, corn, etc.
Larger portions of certain “acceptable” veggies
FruitsSOME fruits such as strawberry, citrus, kiwi, etc.
LIMITED portions of certain fruits such as honeydew, raspberry, pomegranate, etc.
SOME fruits such as dates, pears, avocadoLarger portions of certain “acceptable” fruits
ALL fruits with added sugar

** For a more comprehensive list see Dr. Siebecker’s SIBO Specific Diet: Food Guide

Research Consensus:

This diet has not yet been studied in clinical trials.  However, it was designed by Dr. Siebecker after years spent treating some of the more difficult cases of SIBO and incorporates principles from other well studied SIBO diets.  The rationale is that elimination of both fermentable AND complex carbohydrates will provide the benefits associated with both the SCD and low-FODMAP diet.

Pros:

  • Designed specifically for SIBO
  • Covers almost all potential trigger foods
  • May provide symptom relief for individuals who have found little success with previous, less-restrictive SIBO diets

Cons:

  • No clinical trials available proving effectiveness
  • Extremely restrictive and if not followed properly, may result in nutrient deficiencies and/or unintended weight loss in the long-term

4. Bi-Phasic Diet

The SIBO Bi-Phasic Diet designed by Dr. Nirala Jacobi is a modified version of Dr. Siebecker’s Sibo Specific Food Plan.  This treatment protocol combines diet modification with specific gut healing and antimicrobial treatments.

Her protocol utilizes a 2-phase approach:  

The first phase (4 – 6 weeks), focuses on reducing potential trigger foods, as well as repairing the gut lining and digestive function. This phase involves a very restrictive diet plan along with gut healing nutrients, digestive support, and probiotics as needed.

The second phase (4 – 6 weeks), focuses on removal of the overgrowth and restoration of gut motility.  While the emphasis is still on a low-fiber diet, it is slightly more lenient.  This phase also involves the use of antimicrobial herbs and prokinetic medications or supplements.

FOOD GROUPALLOWEDNOT ALLOWED
Meat, Poultry, Eggs, FishUnprocessed meat, poultry, eggs, fishProcessed, canned or breaded meat, poultry, eggs, fish
DairyNONE
(Some aged cheeses, homemade yogurt re-introduced in phase II)
ALL
GrainsNONE
(Some gluten-free grains re-introduced in phase II)
ALL
LegumesLIMITED portions of lentils (brown, green, red) and lima beansMOST legumes and beans including soy, pinto, garbanzo, split peas, etc.
Nuts/SeedsLIMITED portions of most nuts/seeds including pine nuts, pumpkin seeds, walnuts, etc.SOME nuts/seeds including pistachios, chia, cashews, etc. Nuts/seeds with sugar/starch coating
VegetablesSOME fresh/frozen veggies such as bok choy, carrot, kale, etc. LIMITED portions of other veggies such broccoli, snow peas, green beans, etc.SOME veggies such as garlic, mushroom, onions, etc. Canned Veggies Larger portions of certain “acceptable” veggies
FruitsLemons, limes (LIMITED portions of certain fruits re-introduced in phase II)MOST fruits

** For a more comprehensive list see Dr. Jacobi’s SIBO Bi-Phasic Food Guide

Research Consensus:

Like the SIBO Specific Food Plan, there are no clinical trials to support the effectiveness of this protocol. Support for the SIBO Bi-Phasic Diet comes from patient testimonials and backing from well-known SIBO experts such as Dr. Jacobi.

Pros:

  • Consists of a diet within a treatment protocol and was designed specifically for SIBO
  • Covers all potential trigger foods with the addition of certain food allergies
  • May provide symptom relief for individuals who have found little success with previous, less-restrictive SIBO diets

Cons:

  • No clinical trials available showing effectiveness
  • Highly complex, requires guidance of knowledgeable health care provider
  • Extremely restrictive and if not followed properly may result in nutrient deficiencies and/or unintended weight loss in the long-term

5. Elemental Diet

The Elemental Diet is by far the most restrictive, and is the only diet considered to be a primary treatment strategy for SIBO.

The diet requires exclusive consumption of a medical food beverage for 2 – 3 weeks.  The goal is to provide all nutrients necessary for survival in their most basic, predigested form.  

The benefit of this is two-fold.  First, because the gut isn’t being taxed with the job of breaking down large food particles, it has the opportunity to rest and repair. Second, because all carbohydrates are absorbed almost immediately, the overgrowth of bacteria is starved of its primary food source and will begin to die off.

FOOD GROUPALLOWEDNOT ALLOWED
Meat, Poultry, Eggs, FishNONEALL
DairyNONEALL
GrainsNONEALL
LegumesNONEALL
Nuts/SeedsNONEALL
VegetablesNONEALL
FruitsNONEALL

** Visit Dr. Siebecker’s website for a more detailed overview of what constitutes an Elemental Diet.

Research Consensus:

The Elemental Diet has been shown effective in both symptom management, as well as treatment of SIBO.  One study looking at the effectiveness of a 14-day elemental diet in individuals with IBS, found that up to 84% of patients went from displaying abnormal to normalized breath tests by the end of treatment (6).

Pros:

  • Highly effective in treating SIBO
  • Short in duration (2 – 3 weeks)
  • Fairly straightforward and requires very little decision making
  • Advantageous for individuals who are highly motivated or have found little success with past treatment strategies

Cons:

  • Extremely restrictive, adherence can be difficult
    • Social situations involving food can be emotionally taxing
    • May result in feelings of deprivation and constant hunger due to lack of chewing
  • Risk for insufficient nutrient and calorie intake
    • Liquid formula can taste bad
  • Can be expensive – most insurance companies don’t cover over the counter medical food beverages
  • Should be used with caution in the following populations:
    • Diabetes
    • Underweight individuals
    • Fungal Overgrowth

Which SIBO diet is best for me?

Choosing the most appropriate SIBO diet depends on your current lifestyle, eating habits, motivation level, and SIBO history.

Some diets are more mild and may be appropriate for those experiencing their first round of SIBO treatment.  Other diets are much more aggressive and geared towards individuals with severe cases of SIBO or a history of multiple failed treatment attempts or relapse.

There are many important considerations but at the end of the day, there is no perfect diet for SIBO and relapse prevention!  The best strategy is to stay informed on the available options and to work closely with a knowledgeable health care professional to find a treatment plan that works best for you.

Guest Contributor May Rees, MSN