Malabsorption of vitamin B12 and intrinsic factor secretion during biguanide therapy

Diabetologia. 1983 Jan;24(1):16-8. doi: 10.1007/BF00275941.


In a survey of 46 randomly selected diabetic patients on biguanide therapy, 30% had malabsorption of vitamin B12. Withdrawal of the drug resulted in normal absorption in only half of those with malabsorption. In most patients with persistent malabsorption, the results of absorption tests with exogenous intrinsic factor suggested the diagnosis of coincidental intrinsic factor deficiency. Further considerations, however, led to the concept that biguanides can induce malabsorption by two different mechanisms. One of these is temporary and unrelated to intrinsic factor secretion and the other is permanent and mediated by depression of intrinsic factor secretion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Biguanides / adverse effects*
  • Biguanides / therapeutic use
  • Diabetes Mellitus / drug therapy*
  • Female
  • Humans
  • Intrinsic Factor / deficiency
  • Intrinsic Factor / metabolism*
  • Malabsorption Syndromes / etiology*
  • Male
  • Metformin / adverse effects
  • Middle Aged
  • Phenformin / adverse effects
  • Vitamin B 12 / metabolism*


  • Biguanides
  • Intrinsic Factor
  • Metformin
  • Phenformin
  • Vitamin B 12