Diets For SIBO Management

Benefits of the elemental diet and low-FODMAP diet

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Two common small intestinal bacterial overgrowth (SIBO) diet treatments include the elemental diet, a type of liquid diet, and the low-FODMAP diet, which focuses on limiting certain types of carbohydrates that are difficult to digest.

The goal of treating SIBO is to restore a normal balance of gut bacteria. A SIBO diet can help:

Other aspects of your SIBO treatment plan may include antibiotics such as Xifaxan (rifaximin) and management of the underlying condition (e.g., Crohn's disease or irritable bowel syndrome).

This article reviews use of the elemental diet and low-FODMAP diet for SIBO, and includes what to eat and what to avoid on a SIBO diet.

If you have SIBO, speak to your healthcare provider and/or a registered dietitian before changing your diet to ensure you are meeting your daily nutritional requirements.

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How the Elemental Diet Works for SIBO

The elemental diet is a liquid diet, or a powder mixed with water, typically used for individuals who have compromised digestive systems. The diet gets its name from the fact that nutrients are introduced into the body in as close to their elemental—or primary— form as possible.

The elemental diet is being looked at as a possible adjunct treatment to antibiotics for the following reasons:

  • Its nutrients are believed to be completely absorbed in the very first part of the small intestine, which reduces the number of food components available to bacteria.
  • It reduces the number of overall gut bacteria, which may mean a reduction in bacteria in the small intestine.
  • It's theorized to increase the amount of bile released from the gallbladder, which may strengthen the small intestine's cleansing wave and reduce bacteria levels.
  • It may impact the immune cells within the lining of the intestines, which may also serve to eradicate small intestine bacteria.

What to Eat

The elemental diet is administered either as a beverage that you drink or through a feeding tube. The amount of liquid is slowly increased over the first few days to reduce unwanted side effects, such as diarrhea or abdominal pain.

Each formulation contains nutrients in an easily digestible form. Typical formulations include:

  • Essential and non-essential amino acids
  • Glucose, an easily digested carbohydrate
  • Vitamins, fat and water-soluble
  • Minerals
  • Electrolytes
  • A small amount of fat (less than 1%)

Different commercial variations of the elemental diet can be purchased online. The powdered mixes contain only essential nutritional ingredients and provide 150 to 300 calories or more. Your healthcare provider will help you determine how much to use to get adequate nutrition.

No artificial flavors or colors are added to elemental diet mixes (which are combined with water), so the beverage has a bland taste that many people find unpalatable. Some experts suggest adding ice to give it texture, which may make it easier to consume.

Duration

The length of time that you stay on an elemental diet depends on your symptoms and on your compliance with the program.

One of the biggest challenges of the elemental diet is giving up solid food:

  • According to one published report, only about 25% of patients are willing to restrict their nutritional intake to liquid feeding for long enough to see results.
  • Several studies report that those who are compliant see results in two to three weeks.

Some people who aren't able to adopt a full elemental diet may, with their healthcare provider's okay, use a partial elemental diet that combines liquid feeding with foods that are known to be tolerable. In some cases, this approach is used for long-term maintenance.

Important Warnings

  • The elemental diet must be used only under medical supervision, as it carries some risks.
  • Do not try a homemade elemental diet formulation due to the risk of significant nutritional deficiencies that may jeopardize your health.
  • The diet is not to be used simultaneously with any antibiotic treatment for SIBO.

How the Low-FODMAP Diet Works

The low-FODMAP diet is more commonly used to treat SIBO symptoms. FODMAPs are a group of carbohydrates that include:

  • Fermentables
  • Oligosaccharides (comprised of fructans and galactans)
  • Disaccharides (milk sugar lactose)
  • Monosaccharides (fructose)
  • Polyols (sugar alcohols such as sorbitol, mannitol, xylitol, and maltitol)

On this diet, you'll avoid high-FODMAP foods during an elimination phase. At the end of this phase, you slowly introduce each FODMAP type back into your diet—one by one—to accurately pinpoint which FODMAPs cause your SIBO symptoms.

With SIBO, two FODMAP types—lactose and fructose—may be absorbed poorly due to inflammation along the lining of the small intestine. In addition, other non-absorbed FODMAPs may be fermented by the bacteria residing in the small intestine, leading to uncomfortable symptoms.

Following a diet low in FODMAPs may lead to symptom-relief in certain individuals.

Some research suggests that the low-FODMAP approach may be beneficial, but more research is needed to know for sure if the treatment is effective enough to be recommended as a standard approach.

What to Eat

During the elimination phase, avoid foods that are high in FODMAPs, meaning they contain one of the five types of FODMAPs:

  • Fructans: Non-digestible, fructans are found primarily in wheat, many vegetables, and some food additives, including inulin.
  • Fructose: Fructose is the sugar found in many fruits, honey, and high-fructose corn syrup.
  • Galactans: Also called galactooligosaccharides or GOS, galactans can be found in legumes, including beans, chickpeas, and lentils.
  • Lactose: Lactose is the sugar found in milk and other dairy products.
  • Polyols: These are sugar alcohols with names that typically end in "- ol." They're found naturally in some fruits (like blackberries) and vegetables (such as cauliflower and mushrooms), and are often used as artificial sweeteners.

Almost every food group contains options that are high in FODMAPs and those that are low in FODMAPs.

Low-FODMAP Foods
  • Vegetables: eggplant, green beans, cucumber, lettuce tomato, zucchini

  • Fruits: cantaloupe, grapes, kiwi, strawberries

  • Dairy: feta, camembert, hard cheeses, almond milk, soy milk

  • Protein: eggs, firm tofu, tempeh, seafood

  • Grains: corn flakes, oats, rice cakes, corn pasta, barley-free breads

  • Sweets: dark chocolate, maple syrup, table sugar

  • Nuts and seeds: peanuts, macadamia nuts, sunflower seeds

High-FODMAP Foods
  • Vegetables: asparagus, cauliflower, peas, mushrooms, onions

  • Fruits: apples, cherries, dried fruit, peaches, watermelon

  • Dairy: cow's milk, evaporated milk, ice cream, yogurt

  • Protein: most legumes, marinated meats, some processed meats

  • Grains: wheat, rye, and barley-based breads and snacks

  • Sweets: honey, high-fructose corn syrup, sugar-free treats

  • Nuts and seeds: cashews, pistachios

Duration

The elimination phase can last from two to eight weeks. During this time, you're likely to experience a decrease in symptoms.

The next phase, called the reintroduction process, is extremely important. The time needed for this phase varies widely, depending on your symptoms.

Keep in mind:

  • Not every FODMAP type is a problem for every person.
  • You may want to pick one FODMAP sub-group at a time to test the effect one on your body.
  • Plan to test each group for a week before moving onto the next group.

Most experts recommend keeping a food diary. This will help you get a better sense of the relationship between the foods that you eat and the symptoms that you experience.

This diet is not intended for long-term use. Many high-FODMAP foods are actually very good for overall health. A lot of them are considered prebiotics, meaning that they enhance a healthy balance of gut bacteria.

Recommended Timing

The timing of your meals and snacks is not a factor when following either the elimination or reintroduction phase. You can consume food according to a schedule that works best for you.

However, since re-introducing FODMAP foods may cause symptoms to occur, you may want to introduce them at a time when you are at home and can be comfortable.

SIBO Diet Considerations

Many people with SIBO have other conditions, including:

It's very common for people with these conditions and SIBO to experience malnutrition. For example, if you have SIBO, fat-soluble vitamins (vitamins A, D, E, and K) may not be properly absorbed. You may also be deficient in iron or vitamin B12.

For this reason, it is strongly advised that you work with your healthcare provider and a nutrition professional to manage SIBO and any underlying condition. Your treatment will be tailored to accommodate your specific symptoms and may include supplements.

Summary

Diet changes are likely to be part of your SIBO treatment plan. SIBO diets include the elemental diet and the low-FODMAP diet, which focuses on limiting high-FODMAP foods that are difficult for the body to process.

Both of these diets aim to restore a normal balance of gut bacteria. SIBO treatment may also involve antibiotics and management of any underlying condition.

If you have SIBO, it's essential to work with a healthcare provider and/or trained nutrition specialist before making any dietary changes to ensure you're meeting your nutritional needs.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Rao SSC, Bhagatwala J. Small Intestinal Bacterial Overgrowth: Clinical Features and Therapeutic ManagementClin Transl Gastroenterol. 2019;10(10):e00078. doi:10.14309/ctg.0000000000000078

  3. Pimentel M, Constantino T, Kong Y, Bajwa M, Rezaei A, Park S. A 14-day elemental diet is highly effective in normalizing the lactulose breath testDig Dis Sci. 2004;49(1):73-77. doi:10.1023/b:ddas.0000011605.43979.e1

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Additional Reading

By Barbara Bolen, PhD
Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.