Purpose of review
Fructose malabsorption is associated with gastrointestinal symptoms. This review examines new findings on the physiology, assessment and therapy of fructose malabsorption in functional gastrointestinal disorders.
Additional GLUT transport mechanisms that regulate fructose absorption might be involved in symptom adaptation to high-fructose diets. Although glucose is known to facilitate fructose absorption, erythritol promotes malabsorption. The methodologies of fructose breath testing and its clinical utility have been questioned by findings of unrealistic testing dose and poor reproducibility. Although fructose restriction appears to benefit children with functional abdominal pain, fructose restriction itself may not be the key player. In irritable bowel syndrome, fructose restriction within a diet low in other fermentable carbohydrates fermentable, oligosaccharide, disaccharide monosaccharide and polyols produced good symptom control compared with habitual diet, but such therapy resulted in significantly reduced bifidobacteria. Fructose absorption and subsequently, abdominal pain and nausea are improved by a novel enzyme therapy that converts fructose to glucose for absorption.
New insights into factors affecting fructose absorption may have therapeutic applications. Doubts surrounding clinical utility of fructose breath testing are emerging. Although restriction of fructose and other fermentable, oligosaccharide, disaccharide monosaccharide and polyols have efficacy for functional gastrointestinal symptoms, potentially negative effects on microbiota deserve attention.