Complementary and Alternative Therapies for Functional Gastrointestinal Diseases

Functional gastrointestinal diseases (FGID) are common in the world and account for more than 40% of clinical visits to gastroenterology clinics. Common FGID include gastroesophageal reflux disease (GERD), functional dysphagia, functional dyspepsia, gastroparesis, irritable bowel syndrome (IBS), functional constipation, diarrhea, and fecal incontinence. While pathogeneses of FGID are not completely understood, major pathophysiological factors include impaired gastrointestinal motility, visceral hypersensitivity, and psychological issues as well as disruption of the gut microbiota [1]. Gastrointestinal dysmotility is most common in FGID. For example, impaired lower esophageal sphincter function may lead to dysphagia in case of impaired relaxation during swallowing or GERD in case of reduced pressure or increased transient relaxation. In the stomach, reduced gastric relaxation during food intake may lead to impaired gastric accommodation, causing symptoms of early satiety and bloating; impaired antral peristalsis may lead to delayed gastric emptying, causing symptoms of nausea and vomiting. In the lower gut, impaired colon motility slows down transit, resulting in constipation, whereas a weak anal sphincter may lead to fecal incontinence. Visceral hypersensitivity is one of the major causes of pain and discomfort. It is commonly reported in patients with noncardiac chest pain, functional dyspepsia, and IBS. Depression and anxiety are commonly present in patients with FGID. Recently disruption of the gut microbiota has also been reported in patients with FGID.