We compared sorbitol given alone and as part of a mixed meal to nine insulin-dependent diabetics (IDD's) during continuous subcutaneous insulin infusion (CSII). Blood glucose, sorbitol and breath hydrogen + methane were measured following six test meals: Pure glucose, sorbitol and lactulose, a mixed meal alone, and sweetened with sorbitol and sucrose. Blood glucose increase was very small after lactulose and sorbitol, significantly larger after glucose. A considerable increase in breath hydrogen + methane appeared after sorbitol and lactulose, but not after glucose. No differences in blood glucose responses were found after the mixed meal alone or sweetened with sorbitol and sucrose. A sustained low level increase in breath hydrogen + methane occurred after all solid meals. Sorbitol was not detected in serum after any meal.
Conclusion: Sorbitol ingested by IDD's during CSII in watery solution is not absorbed in the small intestine and causes osmotic diarrhoea. Ingested in a composite meal it does not affect blood glucose and does not cause osmotic diarrhoea.