What to Eat When You Have SIBO

Small intestinal bacterial overgrowth (SIBO) is a condition in which excessive gut bacteria are present in the small intestine.

The goal of treating SIBO is not to entirely eliminate gut bacteria, but rather restore a normal balance of it. Antibiotics, such as Xifaxan (rifaximin), are usually the cornerstone of SIBO treatment.

SIBO is common in people with other gastrointestinal disorders such as Crohn's disease and irritable bowel syndrome (IBS). Both of these conditions can encourage bacterial overgrowth in the small intestine and make symptoms worse, so treating them is important.

A special SIBO diet can play a role in treatment by:

• Hindering multiplication of gut bacteria
• Reducing inflammation
• Addressing nutritional deficiencies

SIBO Diets

Different SIBO diets are used to help reduce related symptoms and complications, which include:

• Abdominal bloating
• Cramping
• Diarrhea
• Nutritional deficiencies
• Weight loss

Though nutritional strategies may be part of a comprehensive treatment plan, there's limited evidence to support any single SIBO diet.

Two common SIBO diet treatments include the elemental diet and the low-FODMAP diet. Which one works for you may depend on the severity of your symptoms.

Research: Elemental Diet

An elemental diet is a liquid diet typically used for patients who have compromised digestive systems. However, the diet is getting some new attention as a possible treatment for SIBO.

Although it remains somewhat controversial, some research has indicated that an overgrowth of bacteria within the small intestine is responsible for IBS symptoms in some individuals.

The elemental diet is being looked at as a possible adjunct 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 so it's theorized that it may help reduce 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.

One trial evaluated the diet's effect on IBS symptoms plus the level of lactulose in the breath —which is believed to indicate excessive amounts of bacteria in the small intestine.

In the study, 93 participants with IBS who had abnormal results on the lactulose breath test (LBT) went on an elemental diet formulation for two weeks.

After the two weeks, 80% of participants had normal LBT tests. Those who still had abnormal LBT results were advised to continue the diet for an additional week. After that third week, another 5% had normal LBT results, bringing the total to 85%.

Researchers reported that the people with normal LBTs, regardless of IBS sub-type, had more improvement in IBS symptoms than those whose results continued to be elevated.

Other studies have investigated the use of the elemental diet for Crohn's disease, another condition that often accompanies SIBO. Evidence supporting its use is mixed.

Research shows that compliance with the diet is a barrier. Many patients find the diet to be unpalatable and others find it unsustainable to adhere to a liquid diet for long enough for the diet to be effective.

If you're motivated and willing to stick with it, though, you may be able to reduce your symptoms.

Research: Low-FODMAP Diet

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)

FODMAPs are poorly absorbed by the small intestine and are known to aggravate symptoms of irritable bowel syndrome. Researchers have found that when people with IBS follow a diet low in FODMAPs, many experience significant symptom relief.

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 inappropriately in the small intestine, leading to bloating and other digestive symptoms.

The low-FODMAP diet may be helpful for SIBO because the reduction in carbohydrate consumption might "starve" the bacteria in the small intestine.

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.

In 2018, authors of a study published in Gastroenterology Clinics of North America stated that the role of dietary changes in the management of SIBO is still poorly understood. 

There's some speculation that the low-FODMAP diet may reduce the effectiveness of antibiotics used to manage SIBO. It's generally recommended that you eat a normal diet while on the antibiotic and switch to the low-FODMAP diet once you've completed the full course.

How It Works: Elemental Diet

The elemental diet involves complete dietary restriction to a specific liquid formulation. 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.

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. However, 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 doctor's okay, use a partial elemental diet that combines liquid feeding with foods that are known to be tolerable.

A partial elemental diet is sometimes also used for long-term maintenance, but working closely with your healthcare professional is essential to maintain proper nutrition.

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 flavor or color is 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 so it is easier to consume.

Because the elemental diet can be inconvenient and unappetizing, it is generally used as a last resort. However, if SIBO symptoms are severe enough, an elemental diet might be worth it to you.

How It Works: Low-FODMAP Diet

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 SIBO symptoms.

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.

Not every FODMAP type is a problem for every person. It is recommended that you pick one FODMAP sub-group at a time to test the effect of each group on your body. Plan to test each group for a week before moving onto the next group.

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.

Thus, the reintroduction phase and continued re-testing of foods is extremely important to ensure you're eating a varied diet without re-experiencing symptoms.

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 (fruits, vegetables, grains, etc.) contains foods that are high in FODMAPs and foods that are low in FODMAPs.

When following this diet, it is smart to work with a registered dietitian who specializes in SIBO diets to help you choose the best compliant foods for you.

Remember that during the elimination phase, you can eat any food that is low in FODMAPs. The list above is just a sample of the foods that are available to you based on information developed by Monash University in Australia, a leader in research on this topic.

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.

Modifications

Many people with SIBO have other conditions, including:

• Celiac disease
• Chronic pancreatitis
• Cirrhosis of the liver
• Crohn's disease
• Diabetes
• Other disorders

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.

Considerations

When following the FODMAP diet, most experts recommend keeping a food diary. A simple diary will help you get a better sense of the relationship between the foods that you eat and the symptoms that you experience.

You will also want to gather resources so that you can evaluate the FODMAP content of each food that you choose.

The low-FODMAP smartphone app from the researchers at Monash University is a must-have. It can also be helpful to purchase some low-FODMAP cookbooks and find low-FODMAP recipes online.

Lastly, remember the low-FODMAP diet is not designed to be a permanent eating plan. Many high FODMAPs foods are healthy. Keep re-introducing them at regular intervals to see if your sensitivities have changed. Your food diary will help to guide you through this process.

A Word From Verywell

SIBO is becoming more widely recognized so that proper treatment is easier to find. Work closely with your healthcare team to get personalized advice.

Once your nutritional needs are met, you're likely to regain energy and feel more comfortable. Keep in mind that SIBO can fluctuate over time, so you may be able to take a break from treatment for months, or even years, at a time.

Be sure to discuss recurring symptoms with your doctor so that flare-ups can be treated promptly.