Nutritional consequences of small intestinal bacterial overgrowth

Small intestinal bacterial overgrowth (SIBO) is an increasingly recognized cause of malabsorption and is likely an under-recognized cause of a variety of nonspecific gastrointestinal symptoms. Disturbances in small bowel motility and gastric acid secretion are the principal predisposing factors providing a clue to patient groups at risk of this condition. The accurate diagnosis of SIBO remains problematic. Although simple, non-invasive breath tests are commonly used to diagnose SIBO, the gold standard test remains the culture of a small intestinal aspirate, which can be readily collected at the time of endoscopy. As reversal of the underlying condition predisposing to SIBO is unlikely, correction of any associated nutritional deficiencies is advised. Treatment with a broad-spectrum antibiotic is generally effective in relieving symptoms; however, repeated courses are often needed.