What Exactly Is SIBO: 10 Symptoms & How To Treat It, From Experts

Just because gastrointestinal (GI) symptoms like bloating, constipation, and gas, are relatively common1, doesn’t make them any easier to deal with. To start healing, many people seek a diagnosis or a root cause—and in the process, the term SIBO may come up. 

SIBO, or small intestine bacterial overgrowth, is a type of dysbiosis in the gut microbiome. 

According to board-certified internist and mbg Collective member, Vincent M. Pedre, M.D., it occurs when there is an overpopulation of bacteria in the small intestine. “This can increase fermentation of sugar in the carbohydrates you eat, and bloating often occurs from this excess gas production,” he says. 

Integrative gastroenterologist Marvin Singh, M.D., says these are the 8 most common symptoms of SIBO: 

Other symptoms might include a decrease in appetite, an increased feeling of fullness after eating, and changes in stool form.2

These are two potential causes of SIBO: 

The gut has a function called the migrating motor complex (MMC), which is meant to aid in gastric motility. In other words, it helps move undigested food through the GI tract during fasting periods (most commonly during sleep).  

“Several studies have demonstrated that abnormalities in the MMC may predispose to the development of SIBO3,” research published in the Gastroenterology and Hepatology journal states. This is because when the MMC is not working properly, bacteria that’s meant to be pushed into the large intestine might, instead, grow into the small intestine, functional medicine practitioner Will Cole, IFMCP, DNM, D.C, once wrote. 

If bacteria isn’t pushed into the small intestine by the MMC, it’s possible that the naturally occurring bacterias multiply to create SIBO. According to Singh, these are a few triggers that could lead to overgrowth: 

Carbohydrates feed bacteria in the gut microbiome. Since people with SIBO already have an overgrowth of bacteria, they often can’t tolerate carbohydrates, including starches and sugars. "Some people can't tolerate simple sugars like lactose and fructose while others have a hard time with complex starches like potatoes and rice," registered dietitian Nour Zibdeh, M.S., RDN, once wrote.

It's often recommended to work with a nutritionist or an integrative doctor to eliminate carbohydrates from the diet, then slowly add them back in to find out which might be worsening your symptoms.

"There's no one diet that works for everyone with SIBO, so it's important to identify which carbohydrates you can't digest and absorb because those are the ones that end up getting fermented by your small intestine bacteria," Zibdeh says.

"A low-FODMAP diet  helps a variety of gut conditions including Crohn's disease, celiac disease, inflammatory bowel disease, and even small intestinal bacterial overgrowth," Pedre previously told mbg. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, which are essentially easily fermentable carbohydrates.

The tricky thing about following this type of diet is that it also eliminates healthy foods, like garlic, onions, and legumes. Always work with a physician or nutritionist to make sure you're getting the proper nutrients you need while eliminating these food groups.

Intermittent fasting is a good eating strategy that may help reduce bloating, Singh says. Whether you're fasting for 12 hours or for 16, this time between meals allows the MMC to kick in and digest food properly.

Since SIBO is due to an overgrowth of bacteria, antibiotics may help manage or treat it. If antibiotics are prescribed by a doctor, it's important to follow the designated regimen, while also paying attention to diet and stress reduction. "These are often very underestimated concepts that can be very helpful when combined with herbal or prescription therapy," Singh says.

While antibiotics are the more traditional treatment, Singh says herbal supplements are a common integrative treatment. "There was a study in 2014 that compared herbal therapy to antibiotic therapy and found that the results were just as good with herbal therapy4," he says.

Adding in prokinetic agents and digestive enzymes, as well as gut-rebuilding strategies, are other useful tools he recommends to patients.