Role of gastric acid in food iron absorption

Gastroenterology. 1981 Dec;81(6):1068-71.


Radioiron absorption tests in human volunteers demonstrated a modest but significant 28% reduction in the absorption of dietary nonheme iron from a meal that was preceded by the administration of 300 mg cimetidine. More pronounced decreases of 42% and 65% were observed with 600 and 900 mg cimetidine, respectively. Antacid caused a 52% decrease in iron absorption whereas pentagastrin had no significant effect. Since 300 mg cimetidine reduces gastric acid secretion by 60%-80% but iron absorption by only 28%, it appears that under normal conditions more gastric acid is secreted than is required for optimal iron absorption; absorption falls only when acid secretion is markedly reduced. Cimetidine in the doses currently recommended would not be expected to have a major effect on iron nutrition, although the combination of high doses of cimetidine with antacids would impair nonheme iron absorption significantly.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Absorption
  • Adolescent
  • Adult
  • Antacids / pharmacology
  • Cimetidine / administration & dosage
  • Cimetidine / pharmacology
  • Diet*
  • Female
  • Gastric Acid / metabolism
  • Gastric Acid / physiology*
  • Humans
  • Iron / metabolism*
  • Male
  • Middle Aged
  • Pentagastrin / pharmacology


  • Antacids
  • Cimetidine
  • Iron
  • Pentagastrin