Diet and the irritable bowel syndrome

The ingestion of food is a major triggering factor in the induction of gastrointestinal symptoms in the irritable bowel syndrome (IBS). A retrospective dietary history and a prospective analysis of food intake may uncover nutrients that trigger or perpetuate esophageal, gastric, small bowel, or colonic symptoms. Lactose, sorbitol, fructose, and sorbitol-fructose combinations are several food items that may aggravate pre-existing hypersensitive smooth-muscle function. Incompletely absorbed carbohydrates acted on by colonic fermentative bacteria may induce excessive gas production, thereby evoking postprandial bloating, increased flatus production, and abdominal discomfort. Elimination of beans, cabbage, lentils, brussels sprouts, and legumes from the diet may reduce such symptoms. Fatty foods, acting neurohormonally, may delay gastric emptying, alter small bowel motor function, and trigger ileocolonic motor dysfunction in IBS patients. Soluble and insoluble fiber have differing physiologic effects in the hollow tract. Selective use of these agents may ameliorate some IBS symptoms.