Your Persistent Upset Stomach Might Not Be the Result of IBS—You Could Have SIBO

SIBO shares many symptomatic overlaps with IBS, which is more common, but its cause—bacterial overgrowth in your gut—is much different.

If you're suffering from bloat, abdominal discomfort, diarrhea, and loss of appetite, there are countless medical conditions that might pop up in your Google search. One of the lesser known culprits is something known as SIBO, or Small Intestine Bacterial Overgrowth. This happens when the bacteria that lives in your small intestines reaches an abnormally high count; this can also include a certain type of bacteria that is usually found in other parts of the colon, explains Lauren W. Powell, M.D., a family medicine physician and culinary medicine specialist in Atlanta, Georgia. "While this condition was initially thought to affect a very small number of people, with an improvement in diagnostic testing, we are finding an increase in prevalence," she says. "Though the exact prevalence is unclear, we do know that the incidence increases with age."

Ahead, everything you need to know about SIBO, including how it differs from other common gut ailments.

woman with stomach pain touching stomach
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IBS is the most common disease diagnosed by gastroenterologists, affecting an estimated 10 to 15 percent of the U.S. population, according to the American College of Gastroenterology. As such, many people associate SIBO with IBS, especially considering the fact that they share many of the same symptoms, such as bloating, gas, diarrhea, and abdominal pain. The biggest difference, according to Dr. Benjamin Hyatt, M.D., a gastroenterologist at Middlesex Digestive Health and Endoscopy Center in Acton, Massachusetts, is that SIBO causes symptoms due to an overgrowth of bacteria in the intestines, whereas IBS symptoms stem from abnormal muscle contractions and nerve hypersensitivity in the gut.

Predisposing Conditions

Dr. Powell explains that we all have natural defenses that are responsible for maintaining the right amount and type of bacteria in our small intestines. However, there are certain conditions that can compromise those defenses and increase a person's risk of SIBO. Those who suffer from hypochlorhydria, or low gastric acid, are particularly susceptible: "Gastric acid suppresses the growth of certain bacteria, so when there is a decrease in gastric acid production, either as a result of age, autoimmune etiology, or long term use of an antacid like H2 blockers or PPI (proton pump inhibitors), this can be a predisposing factor," says Dr. Powell.

Motility disorders are also to blame; there is a complex process behind the factors responsible for moving material through the gastrointestinal tract. Certain conditions and drugs affect this motility—or the ability of things to move through the GI tract—including IBS, diabetes, and narcotic use, notes Dr. Powell. This can lead to a buildup of bacteria and cause SIBO, as can structural or anatomical abnormalities. Adhesions or structures in the intestines can predispose someone to SIBO, notes Dr. Powell. "This includes GI tract surgeries that create a blind loop or anastomosis predispose those to overgrowth due to abnormal motility," she adds.

Immunity Matters

One of the best ways to prevent bacterial overgrowth in your body? Keep your immune system in tip-top shape. You can do this by consuming a healthy diet rich in vegetables, fruits and whole grains, and maintaining an active lifestyle, say our experts.

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