Modern medicine has identified several conditions that encompass the symptoms described by the concepts of food stagnation and dampness-phlegm in the Donguibogam, and one of them is small intestinal bacterial overgrowth (SIBO). Countless microorganisms inhabit our gut, but most reside in the large intestine to break down food waste. The small intestine is supposed to remain clean with a low bacterial count to absorb nutrients efficiently. However, when bacteria that belong in the large intestine excessively migrate into the small intestine and proliferate for various reasons, SIBO occurs.
These bacteria consume the carbohydrates or sugars that our body has not yet digested in the small intestine and ferment them excessively. During this process, they release large amounts of various gases, such as hydrogen and methane, which are the main causes of abdominal distension and gas buildup. Beyond merely causing gas, these bacteria induce inflammation in the intestinal mucosa and interfere with nutrient absorption, which can lead to anemia, vitamin deficiencies, and, in severe cases, weight loss. In addition, toxins produced by these bacteria damage the intestinal barrier, causing leaky gut syndrome; once these toxins are absorbed into the bloodstream, they can lead to systemic inflammation or abnormal immune responses. Because the brain and gut are connected via the vagus nerve to form the gut-brain axis, SIBO can also influence neuropsychiatric symptoms such as anxiety, depression, and chronic fatigue.
The causes of SIBO are diverse. Decreased gastric acid secretion, pancreatic enzyme deficiency, intestinal hypoperistalsis (migrating motor complex, or MMC dysfunction), a history of bowel surgery, stress, and certain medications can act in combination. In particular, when intestinal motility slows down, bacteria linger longer in the small intestine, creating an environment ripe for proliferation. Symptoms are diverse and non-specific—such as abdominal distension, frequent belching and flatulence, diarrhea, constipation, and abdominal pain—making it easy to confuse with irritable bowel syndrome (IBS). While an accurate diagnosis is made through a breath test or intestinal fluid culture, what matters most is listening to your body and making an effort to identify and improve lifestyle habits that trigger symptoms. Modern medicine continues to conduct research to unravel this complex gut mystery.
