Intestinal Response to the Body's Requirement for Iron

Abstract

Dietary iron is absorbed by the mucosa of the small intestine in response to the body's requirement for iron. To a great extent, the amount of iron in the body is maintained at a constant level, not by excretion of excess iron but by the ability of the intestine to reject available, unneeded dietary iron.¹Excretion of iron is limited and, under normal conditions, apparently serves as a fine adjustment to the more important control provided by the intestinal mucosal block.¹When the requirement for iron increases as it does in iron deficiency states, the mucosal block is relaxed to permit the entry of more than the usual amount of dietary iron. When the iron deficiency has been satisfied, the mucosal block is restored to prevent the accumulation by the body of excessive amounts of storage iron. Ordinarily, the intestine absorbs only enough iron to replace the obligatory metabolic