Symptoms

There are several common symptoms of SIBO, including:

• Abdominal pain.
• Bloating.
• Diarrhea.
• Constipation.

In some cases, there is also nutrient malabsorption. Non gut-related symptoms like fatigue, joint pain, and headaches can also be present.

Causes

Typically, the body has defenses that prevent the overgrowth of bacteria in the small intestine, such as stomach acid, bile, digestive enzymes, gut motility, and immune factors. When these defences fail, bacteria can multiply in the small intestine, leading to SIBO.

Treatment

There are three types of SIBO:

• Methane SIBO
• Hydrogen-dominant SIBO
• Hydrogen sulfide-dominant SIBO

Completing specialized testing to determine your SIBO type is vital to developing an appropriate treatment plan. 

There are two main tests for SIBO: a breath test to measure the amount of different gases you exhale and a test where a small fluid sample is collected from the small intestine to test for the presence of bacteria.

SIBO treatment typically includes antibiotics to eradicate bacterial overgrowth. It’s also important to treat any nutritional deficiencies. 

Rifaximin is the most commonly used antibiotic to treat hydrogen-dominant SIBO. Methane SIBO typically requires treatment with two antibiotics: rifaximin and neomycin. Antibiotics are typically taken for two weeks.

Fermentable Carbohydrates Can Feed the Bacteria

Fermentable carbohydrates, such as high-FODMAP foods, can worsen SIBO symptoms. FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. These foods provide fuel for the bacteria in your small intestine. When these carbohydrates are fermented, it can increase gas production, bloating, and abdominal discomfort. 

Limiting high FODMAP foods may help reduce symptoms of SIBO. However, simply eating low-FODMAP foods may not be enough to eradicate SIBO, which typically requires antibiotics.

Foods to Avoid with SIBO

The American Journal of Gastroenterology recommends reducing or eliminating high-fiber foods, sugar alcohols, fermentable sweeteners (such as sucralose), and prebiotic foods like inulin (which feeds the bacteria) to treat SIBO.

In addition, you may want to avoid foods high in FODMAPs. Since these foods are fermented by bacteria, reducing your intake may relieve some of the gas and bloating associated with FODMAP fermentation.

Some high FODMAP foods to avoid include:

• Onions.
• Garlic.
• Beans.
• Brussels sprouts.
• Honey.
• High fructose corn syrup.
• Peaches.
• Pears.
• Apples.
• Milk and dairy products.
• Wheat.

You may feel better after cutting these foods out. It’s best to work with a dietitian if you plan on cutting foods out of your diet, as eliminating foods can lead to nutrient deficiencies. A dietitian can help you plan a diet that provides necessary nutrients while relieving SIBO symptoms.

Foods to Eat with SIBO

There are many foods you can continue to eat if you have SIBO. The University of West Virginia Digestive Health Center recommends the following safe foods:

• Proteins, such as chicken, turkey, fish, shellfish, eggs, milk, beef, and pork.
• Plant proteins, such as tofu, tempeh, unsweetened nut or seed butter, nuts, and seeds (one ounce or less per serving).
• Grain products, such as bread, pasta, unsweetened breakfast cereals, unsweetened hot cereals, and crackers.
• Fruits, up to one small piece of fresh fruit or half a cup of applesauce daily. It’s best to speak with your dietitian about whether you should eliminate fruit completely when starting this diet.
• Starchy vegetables, such as white potatoes and butternut squash (no more than half a cup per meal).
• Non-starchy vegetables, such as green beans, carrots, greens, and tomatoes (no more than half a cup per meal).
• Dairy products, such as plain milk, plain yogurt, plain kefir, and cheese.
• Beverages, such as water, herbal tea, and unsweetened tea.
• Condiments, such as oil, vinegar, mayonnaise, and dressings free from fermentable sweeteners.
• Sweeteners, such as Equal, Sweet N Low, and Stevia.

Can a Dietitian Make Me a Meal Plan for SIBO?

As part of your SIBO treatment plan, a dietitian can create a customized meal plan to help starve the overgrowing bacteria and treat nutrient deficiencies. They may also recommend herbal supplements that can kill harmful bacteria.

When creating your SIBO meal plan, your dietitian will consider nutritional balance, personal preferences, and any other underlying health issues to create a plan custom to you and designed to be sustainable and straightforward to follow.

What’s the Best Diet for SIBO?

While there’s no specific SIBO diet, eating foods low in fermentable carbohydrates may help with symptom management. However, eating low-FODMAP foods typically doesn’t eliminate bacterial overgrowth. If you have SIBO, you’ll likely still need antibiotics to treat and eradicate the overgrowing bacteria.

An exception is if antibiotics have failed to get rid of bacterial overgrowth. In these cases, a short-term elemental diet may be considered. An elemental diet consists of broken-down nutrients in an oral formula. It’s thought that an elemental diet starves the bacteria. However, this diet should only be followed with close supervision by a physician and dietitian.