Effect of lactulose on carbohydrate metabolism and diabetes mellitus

Scand J Gastroenterol Suppl. 1997;222:62-4. doi: 10.1080/00365521.1997.11720721.


Background: Unabsorbable disaccharides, by reducing transit time and possibly glucose absorption, are expected to affect carbohydrate metabolism.

Aim: To test the effects of a preparation containing fibre and lactulose in the form of biscuits on glucose and insulin levels in obesity.

Methods: In 10 obese patients glucose and insulin were measured in the fasting state and in response to a meal during two consecutive days on a strictly controlled diet; on one day a total of 11 biscuits (10 g dietary fibre, 2 g raw fibre +8.2 g lactulose) were randomly substituted for an equicaloric part of a diet.

Results: Glucose and insulin in response to breakfast and to lunch were blunted by dietary fibre and lactulose, without any trend towards post-meal hypoglycaemia. Average day-time glucose decreased by 0.53 +/- SD 0.28 mmol/L, and insulin by 74.6 +/- 45.2 pmol/L. Plasma amino acids were higher during supplementation, ruling out malabsorption as a cause of glucose flattening.

Conclusion: Because of the rationale of the preparation, good compliance of patients, and significant results in short-term experiments, the association of fibre and lactulose deserves more careful evaluation in long-term clinical studies.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Blood Glucose / metabolism
  • Cross-Over Studies
  • Diabetes Mellitus / diet therapy*
  • Dietary Carbohydrates / metabolism*
  • Dietary Fiber / pharmacology*
  • Gastrointestinal Agents / pharmacology*
  • Humans
  • Insulin / metabolism
  • Lactulose / pharmacology*
  • Obesity / diet therapy*


  • Blood Glucose
  • Dietary Carbohydrates
  • Dietary Fiber
  • Gastrointestinal Agents
  • Insulin
  • Lactulose