Have you been diagnosed with irritable bowel syndrome or inflammatory bowel disease, put yourself on an IBS-friendly diet, but are still experiencing symptoms? If so, then you may be living with small intestinal bacterial overgrowth, also known as SIBO.

What exactly is SIBO?

SIBO is a digestive syndrome that is basically an overgrowth of bacteria in the small intestine.  The most common symptoms of SIBO include diarrhea and malabsorption, the latter which can present as vitamin and mineral deficiencies. Other symptoms of SIBO may include:

• Gas
• Bloating
• Abdominal pain and cramping
• Constipation, although SIBO is more commonly associated with those with IBS-D, than IBS-C.
• Food intolerances such as casein, lactose, fructose, or histamine intolerance
• Fat malabsorption, which may present as smelly, pale stool
• Skin rashes such as rosacea

What causes SIBO?

There is no single cause of SIBO, and the symptoms of this syndrome are similar to other digestive conditions. Because of this nonspecific quality of SIBO, it is often not diagnosed.  It is reported that the development of an imbalance in the gut however can be caused by a variety of factors such as gut motility issues, pH imbalance in the gut, low immunity.  Such factors can provide the opportunity for certain types of bacteria to grow in the gut and cause gas production, among other things.

Other potential risk factors for SIBO include:

• Those with a history of abdominal surgery.
• Individuals with a history of intestinal obstruction, diverticula, or fistula.
• Increased age related to likely changes in intestinal motility as a person gets older.
• Medication use such as narcotics which can affect intestinal motility.
• Conditions such as cirrhosis, celiac disease, morbid obesity, pancreatitis, or irritable bowel syndrome. A significant link has been found between those with irritable bowel syndrome and SIBO.

How do I know if I have SIBO?

Common presentation of SIBO is bloating, gas, abdominal pain, and diarrhea. Since these symptoms can be linked to many different digestive conditions, it can be hard to tell if someone has SIBO without further testing or without more symptoms to pinpoint the conditions.

Therefore, it can also be important to look at lab panels of individuals suspected to have SIBO to see if there are any vitamin or mineral deficiencies. Common nutrient deficiencies of those with SIBO include vitamins A, D, E, B12, and iron.  Other diagnostic tests may include antibiotic trials, small bowel culture or aspiration, as well as breath testing.

SIBO treatment

Once the syndrome is diagnosed, then appropriate treatment can be implemented. This can start as a change in diet such as avoiding any foods that are most likely to trigger symptoms.  SIBO patients are often placed on the low FODMAP diet as well as a specific carbohydrate diet, which is grain-free.

Other treatment options for SIBO include:

• Antibiotics such as ciprofloxacin, neomycin, rifaximin, and tetracycline.
• Elemental diet, which includes only those nutrients absorbed in the proximal small bowel. This is a medical grade powder that is mixed with liquid and consumed for 14 days. It is recommended to be done under medical supervision.
• Probiotics, which may not be effective for all individuals diagnosed with SIBO but may be an effective adjunct therapy for SIBO along with diet changes. Research has also shown that probiotics may help increase the effectiveness of antibiotic treatment. In particular, a recent study found that treatment of individuals with SIBO with the antibiotic rifaximin and a probiotic had greater reduction of symptoms than those who took an antibiotic with prebiotic consumption.
• Prokinetics, or medications that may help improve gut motility.

If you believe that you may have SIBO, contact your healthcare provider for assistance on testing and treatment options.

Written by Staci Gulbin, MS, RD a Board-certified dietitian.