Gastrointestinal Diseases and Sarcopenia.

Sarcopenia is a progressive systemic condition characterized by a reduced skeletal muscle mass, strength, and physical function. In gastrointestinal diseases, it is increasingly recognized as a clinically relevant factor associated with symptom burden, treatment tolerance, postoperative complications, quality of life, and survival. Its development reflects not only aging but also disease-related malnutrition, anorexia, malabsorption, chronic inflammation, cachexia, altered gut motility, defecatory dysfunction, dysbiosis, and reduced physical activity levels. Conversely, sarcopenia can impair swallowing, mastication, abdominal pressure generation, pelvic floor function, mobility, bowel function, and nutritional status, creating a bidirectional vicious cycle. This review summarizes the shared pathophysiology linking gastrointestinal diseases and sarcopenia, disease-specific clinical implications in esophageal, gastric, colorectal, inflammatory bowel, constipation-related, and functional gastrointestinal disorders, and practical approaches to assessment and multidisciplinary intervention in older patients in gastroenterology practice.