Effect of gastric juice on iron absorption in patients with gastric atrophy.

The influence of gastric juice on iron absorption has been studied extensively in recent years. The absorption of haemoglobin iron is unaffected by achlorhydria (Biggs, Bannerman, and Callender, 1962) but inorganic iron is better absorbed in the presence of normal gastric juice (Goldberg, Lochhead, and Dagg, 1963; Cook, Brown, and Valberg, 1964). It has been shown that the administration of hydrochloric acid to patients with achlorhydria will increase iron absorption (Jacobs, Bothwell, and Charlton, 1964) but it has also been suggested that other gastric juice constituents also play a part. Koepke and Stewart (1964) and Murray and Stein (1967) have produced evidence from experiments in dogs and rats that the stomach secretes an absorptionpromoting factor which is increased in some conditions associated with high iron absorption. Davis, Luke, and Deller (1966), on the other hand, demonstrated an iron-binding protein in normal gastric juice which was absent in patients with high iron absorption. They suggested that this substance, which they call gastroferrin, inhibits inorganic iron absorption and that variations in its secretion provide a physiological mechanism for regulating the uptake of iron from the body. The object of the present study was to see whether normal human gastric juice influences the absorption of inorganic iron in human subjects with gastric atrophy when given together with a standard meal under conditions in which gastric pH is maintained at neutrality. Clear evidence was produced that gastric juice promotes iron absorption even when the local effect of acid is eliminated. No inhibitory effect was observed.