(Woodpath is an education site focused exclusively on gut health. Our articles are researched by clinical nutritionists and contain citations at the end of the page.)

SIBO (Small Intestinal Bacterial Overgrowth) occurs when bacteria that usually grows in other parts of the gut begin to grow, instead, in the small intestine.



It can lead to more serious health conditions if left untreated.

Symptoms of SIBO include abdominal pain, cramping, bloating, diarrhea, constipation, and excessive gas.

We make specific supplement recommendations at the bottom of this page. However, let's first understand the research behind SIBO, and how diet impacts your symptoms.



Under-researched

SIBO remains largely overlooked and under-researched.



According to the education and research nonprofit International Foundation for Gastrointestinal Disorders, less than 1% of digestive disease research funding is provided for functional disorders, including SIBO.



This results in many doctors and patients not realizing how common SIBO is. Plus, many SIBO symptoms overlap with those of other digestive disorders. This makes it even more difficult to distinguish SIBO from IBS or lactose intolerance. (Ducowicz et al., 2007)



The good news is that there are effective SIBO treatments that can restore gut health.

This guide breaks down the basics of this complicated condition so you can better understand how the proper diagnosis, medical care, and dietary changes will help rid you of the symptoms of this frustrating condition.

Causes

A healthy gut is essential for a strong immune system. When gut bacteria become imbalanced, it puts a person's overall health in jeopardy. Causes of this imbalance can stem from:



Poor eating habits (processed foods and added sugars)

Stress

Illness

Extended use of antibiotics

As well as other contributing factors



Combine any of these causes, and you may experience any number of digestive disorders, including SIBO.



Symptoms

The most common SIBO symptoms are:



Abdominal pain

Cramping

Bloating

Flatulence and belching

Constipation

Diarrhea



More severe symptoms can include weight loss and malnutrition resulting from nutrients not being absorbed. Left untreated for a prolonged period, SIBO can lead to more complications including:



Joint and muscle pain

Fatigue

Dehydration

Anemia

Liver disease

Osteoporosis

Kidney stones

And neuropathy

Diagnosis

Because the symptoms of SIBO overlap with those of irritable bowel syndrome, Crohn's disease, and Celiac disease, proper diagnosis is a challenge.



Some studies show that up to 80% of people with irritable bowel syndrome also have SIBO without even knowing it. (Ducowicz et al., 2007)



A standard method for diagnosing the presence of small intestinal bacterial overgrowth is with the use of a hydrogen and methane breath test using glucose and lactulose.



This breath test is an essential and non-invasive way to identify the presence of excess hydrogen or methane gas, which provides a foundation to diagnose SIBO. (Braden, 2009)



This method is not without its drawbacks. False results and misinterpretation are not uncommon, particularly between SIBO and IBS. (Simrėn & Stotzer, 2006)



Approach to Treatment

Treating SIBO requires a combination of approaches: (Ducowicz et al., 2007)



Correct the underlying cause Provide nutritional support, if necessary Treat the overgrowth itself



Diets

Several diets are used to treat the symptoms of SIBO. While there is no one best diet for every individual, these are the most prominent and effective.



Low FODMAP Diet

An acronym for "Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols," FODMAPs are carbohydrates that the small intestine doesn't digest well.



These carbs intensify IBS symptoms— as well as similar conditions affecting the gastrointestinal tract.

To combat this, researchers at the Monash University in Melbourne, Australia developed this low-FODMAP diet that has been clinically proven to improve digestive health. (Halmos et al., 2014)



Some low-FODMAP foods:



Non-starchy vegetables such as leafy greens, broccoli, bell peppers, eggplant, carrots, fresh herbs, cucumber, lettuce, tomato, zucchini, and sweet potato

Non-dried fruits including bananas, blueberries, citrus, grapes, kiwi, pineapple, and strawberry

Proteins ranging from meat, fish, turkey, and chicken to tempeh and tofu

Lactose-free dairy products and hard cheese

Grains including brown rice, quinoa and gluten-free bread made from oats, amaranth, and spelt

Brazil nuts, macadamia nuts, peanuts, pecans, pine nuts, and walnuts

Pumpkin seeds, sesame seeds, and sunflower seeds

Tea or coffee without honey or agave



You can also download the Monash University’s FODMAP app to help you identify low-FODMAP foods to add to your diet.



This diet is not intended as a lifetime requirement. It's a temporary elimination diet (typically lasting 2 to 6 weeks) intended to reduce bacterial overgrowth.



SIBO sufferers should also avoid high-FODMAP foods, including sweeteners such as high fructose corn syrup — an ingredient often found in highly processed foods.



Bottom line: It's always better to eat real whole foods than those found in a box or can.



Specific Carbohydrate Diet

Also called the SCD diet, this eating plan is free from grains, and low in sugar and lactose. It was developed in the 1920s by pediatrician Dr. Sidney Haas as a treatment for celiac disease.



Similar to the Low FODMAP diet, the SCD diet is also an elimination diet that focuses on avoiding certain foods. The SCD diet may be used for both IBS and IBD.



Prohibited Foods on the SCD:



Sugar, molasses, maple syrup, sucrose, and processed fructose including high-fructose corn syrup or any processed sugar

All grain including corn, wheat, wheat germ, barley, oats, rice, and others. This includes bread, pasta, and baked goods made with grain-based flour

Canned vegetables with added ingredients

Some legumes

Seaweed and seaweed byproducts.

Starchy tubers such as potatoes, sweet potatoes, and turnips

Canned and most processed meats

Canola oil and commercial mayonnaise (because of the additives)

All milk and milk products high in lactose such as mild cheddar, commercial yogurt, cream, sour cream, and ice cream.

Candy, chocolate, and products that contain FOS (fructooligosaccharides)



Allowed Foods on the SCD:



Meats without additives, poultry, fish shellfish, and eggs

Certain legumes, including dried navy beans, lentils, peas, split peas, un-roasted cashews and peanuts in a shell, all-natural peanut butter, and lima beans

Dairy limited to cheeses such as cheddar, Colby, Swiss, dry curd cottage cheese, and homemade yogurt fermented for at least 24 hours

Most fresh, frozen, raw or cooked vegetables and string beans

Fresh, raw or cooked, frozen or dried fruits with no added sugar

Most nuts and nut flours

Most oils, teas, coffee, mustard, cider or white vinegar and juices with no additives or sugars

Honey as a sweetener



While more scientific research is needed, some clinical studies published in the Journal of the Academy of Nutrition and Dietetics show that the SCD diet is effective for reducing IBD symptoms and achieving remission. (Kakodkar et al., 2015)



GAPS Diet

An acronym for Gut and Psychology Syndrome, the GAPS diet was created as a modification to the SCD diet. It has a focus on the connection between the gut and the brain.



The theory is that many conditions affecting the brain are caused by a leaky gut, which allows chemicals and bad bacteria from your food to enter the bloodstream when they normally wouldn't.

However, this is a highly controversial theory and more research is needed to prove or disprove its legitimacy. (Quigley, 2016)



There are two parts to the GAPS diet: The Introduction Diet and the Full GAPS Diet.



People with severe digestive issues and severe food sensitivities are recommended to start with the Introduction Diet. Details of the Introduction Diet for GAPS can be found here.

Those suffering from constipation and mild symptoms should start with the Full GAPS Diet. Details about the Full GAPS Diet can be found here.



Fast Tract Diet



The Fast Tract Diet was developed by Norm Robillard, Ph.D. It uses a points-based system to help people manage their symptoms by tracking their intake of fermentable carbohydrates, which have been scored according to fermentation potential.

It is similar to the low FODMAP diet, but also includes some additional foods that may cause symptoms. It is often successful for people who failed a low FODMAP diet.



Antibiotics

Just as an overgrowth of bacteria can lead to compromised gut health, so too can a deficiency of good bacteria.

Given that antibiotics destroy good bacteria along with harmful bacteria, antibiotic treatment is not an ideal long-term solution.



On the other hand, closely monitored antibiotic treatment can help, since diet alone will not cure SIBO.

Targeting not just the bacterial overgrowth — but the types of bacteria colonizing the small intestine — is essential. Fortunately, prescription antibiotics given by a medical doctor can be a viable option.



Studies show the success rate of herbal antibiotics as equivalent to the results of using pharmaceutical antibiotics. (Chedid et al., 2014)



Probiotic Supplements

Taking probiotic supplements is another strategic tool for treating SIBO. One study showed that adding a lactol probiotic helped maintain bacterial overgrowth in the small intestines. (Khalighi et al., 2014)



Specific strains of probiotics may help to promote motility, reduce intestinal permeability and reduce methane gas. Although the idea of using probiotics for SIBO seems counterintuitive, they are part of a successful treatment strategy when carefully selected.



But it’s important to take the right probiotic strains based on your specific symptoms. Probiotics, for example, may exacerbate your issues, if an incorrect strain is used.



If you decide supplements are right for you, we recommend these high-quality products:

Path to Gut Health

If you're suffering from SIBO, it can be a difficult road getting your body back on track, especially when SIBO is so often misdiagnosed and often under-diagnosed.



The good news is that it's manageable. While the solution to SIBO is likely not found in one approach, knowing the different options can provide a holistic view of how to treat this condition effectively.

