IRON-ABSORPTION AND BIOAVAILABILITY - AN UPDATED REVIEW

Regulation of iron absorption operates at the level of duodenal mucosa l cells. Despite much research, the specific biochemical pathways of i ron absorption and the regulatory mechanisms controlling it remain unk nown. This review summarizes current knowledge of and hypotheses on ea ch of the three steps of iron absorption: uptake from the intestinal l umen into mucosal cells, transit through the cell, and release from th e cells into the body. Absorption may be defined as the movement of ir on from the intestinal lumen across the epithelial cells of the digest ive tract into the circulation, while bioavailability generally refers to the proportion of iron in a given food or diet that the body can a ctually utilize. The most common technique of measuring iron absorptio n and bioavailability, extrinsic radiolabeling of a single meal, is di scussed in the context of the latest studies using this methodology. ( C) 1998 Elsevier Science Inc.