Colonic conservation of malabsorbed carbohydrate

Area of Science:

• Gastroenterology
• Nutritional Science
• Microbiology

Background:

• Jejunoileal bypass surgery can lead to significant carbohydrate malabsorption.
• The role of the colon in processing unabsorbed carbohydrates post-bypass is not fully understood.

Purpose of the Study:

• To investigate the absorption of [14C]sucrose in the small bowel and colon after jejunoileal bypass.
• To determine the colon's contribution to mitigating carbohydrate malabsorption and its osmotic effects.

Main Methods:

• Utilized an ileal perfusion technique to differentiate small bowel from colonic absorption of radiolabeled sucrose ([14C]sucrose).
• Quantified the amount and form of [14C]sucrose and its metabolites in the small bowel, feces, and dialyzable fractions.

Main Results:

• Healthy controls absorbed most sucrose, with minimal unabsorbed [14C] in feces.
• Jejunoileal bypass patients exhibited significant small bowel malabsorption (29-84%) of [14C]sucrose.
• The colon salvaged a substantial portion of malabsorbed carbohydrate, converting it to less osmotically active forms, primarily through bacterial metabolism.

Conclusions:

• The colon plays a critical role in salvaging unabsorbed carbohydrates and reducing osmotic load following jejunoileal bypass.
• Individual variations in diarrhea and weight loss may be linked to differences in colonic bacterial flora and their carbohydrate metabolism.
• Understanding colonic function is essential for managing carbohydrate malabsorption after intestinal surgery.