Fructose Malabsorption

A Possible Factor in Functional Bowel Disorders

Sheri Helms, PharmD; Fang Z. Ni, PharmD; Patricia L. Darbishire, PharmD

Disclosures

US Pharmacist 

In This Article

Pathophysiology of Fructose Malabsorption

Fructose empties more rapidly from the stomach in comparison to other sugars, utilizing an energy-dependent absorption process in the small intestines. GLUT5 and GLUT2 are transmembrane proteins primarily located in the lumen of the small intestines that are responsible for the transportation of fructose. GLUT5 transports fructose from the intestinal lumen into enterocytes by a facilitated energy-dependent process. Therefore, saturation of GLUT5 transporters with excessive fructose ingestion results in incomplete absorption, leading to GI symptoms (Table 1).[25] This transport-mediated process is limited in carrier capacity, calculated to be approximately 15 g of fructose per consumption. Fructose absorption occurs along with glucose via solvent drag and passive diffusion. Due to its osmotic effect, unabsorbed fructose combines with water and is rapidly propelled into the colonic lumen where luminal bacteria ferment fructose to carbon dioxide, hydrogen, and short-chain fatty acids. This osmotic load has a laxative effect and causes rapid gas production, leading to luminal distention, bloating, abdominal discomfort, and increased motility.[19]

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.

processing....