Small Intestinal Bacterial Overgrowth (SIBO) is a condition where an excessive amount of bacteria, or the wrong type of bacteria, accumulates in the small intestine. Normally, the small intestine contains relatively few bacteria compared to the large intestine. When this delicate balance is disrupted, these bacteria can interfere with normal digestion and nutrient absorption, leading to a range of digestive issues. This condition can significantly impact an individual’s well-being.
Can SIBO Resolve on Its Own?
SIBO rarely resolves completely or permanently without targeted intervention. While symptoms might fluctuate or temporarily improve, the underlying bacterial imbalance typically persists or can even worsen over time. This is because the fundamental issues allowing bacterial overgrowth often remain unaddressed.
The body’s protective mechanisms, such as stomach acid and the coordinated movement of the small intestine, prevent bacterial overgrowth. When these mechanisms are compromised, bacteria can thrive where they shouldn’t. Without addressing these dysfunctions, the small intestine continues to harbor abnormal bacteria, leading to ongoing or recurring symptoms.
Why SIBO Persists
Several underlying factors contribute to SIBO’s persistence by disrupting the small intestine’s normal functioning. Impaired gut motility, specifically the migrating motor complex (MMC), is a common cause. The MMC is a “housekeeping” wave of contractions that sweeps undigested food and bacteria from the small intestine into the large intestine between meals; if this process is slowed, bacteria can accumulate. Conditions like post-infectious irritable bowel syndrome, diabetes, hypothyroidism, or neurological disorders can affect MMC function.
Low stomach acid, also known as hypochlorhydria, is another contributor. Stomach acid acts as a primary defense, killing bacteria that enter the digestive tract. When stomach acid levels are insufficient, bacteria more easily pass into and colonize the small intestine. This can occur due to aging, H. pylori infection, or prolonged use of certain medications like proton pump inhibitors (PPIs) and antacids.
Structural abnormalities within the gut can also create environments where bacteria proliferate. These include conditions like small bowel diverticulosis, strictures, or abdominal adhesions, which impede the normal flow of contents through the small intestine. A compromised ileocecal valve, the muscular gate between the small and large intestines, can also allow bacteria from the large intestine to reflux into the small intestine. Certain medications, such as opioids and broad-spectrum antibiotics, can disrupt gut flora and slow intestinal motility, contributing to SIBO’s development.
Consequences of Untreated SIBO
If SIBO is left unaddressed, it can lead to various health complications beyond uncomfortable digestive symptoms. Chronic SIBO can result in nutritional deficiencies due to malabsorption. The overgrowing bacteria consume nutrients like fats, fat-soluble vitamins (A, D, E, K), and vitamin B12, making them unavailable for the body to absorb. This malabsorption can lead to symptoms such as unintentional weight loss, fatigue, neurological problems, or anemia due to severe B12 deficiency.
Persistent digestive symptoms, including bloating, abdominal pain, gas, diarrhea, and constipation, are common and diminish one’s quality of life. The bacterial fermentation of carbohydrates in the small intestine produces gases like hydrogen and methane, leading to these uncomfortable symptoms. Untreated SIBO can also contribute to systemic inflammation and has been linked to conditions like leaky gut syndrome, where the intestinal lining becomes more permeable.
When to Seek Professional Guidance
If you suspect SIBO based on persistent digestive symptoms, seek medical guidance. A healthcare professional, such as a gastroenterologist or a functional medicine practitioner, can diagnose the condition. Diagnosis typically involves a breath test, which measures hydrogen and methane gases produced by bacteria after consuming a sugar solution. In some cases, a small intestine aspirate and fluid culture may be performed, though this is a more invasive procedure.
Treatment approaches for SIBO are individualized and often involve a multi-faceted strategy. This includes antibiotics (pharmaceutical or herbal) to reduce bacterial overgrowth. Dietary modifications, such as a low-FODMAP diet, may also be recommended to help manage symptoms by limiting fermentable carbohydrates that feed the bacteria. Addressing underlying causes, such as improving gut motility with prokinetics or optimizing stomach acid, is also a component of treatment to prevent recurrence.