ABSTRACT
The absorption of dietary minerals is determined by nutritional needs of the organism, by the amount present in the diet, and by factors in uencing the bioavailability and utilization of the mineral. Whereas nutritional needs tend to modulate homeostatic mechanisms of absorption, the bioavailability of minerals is principally in uenced by exogenous factors. Factors in uencing mineral bioavailability can be grouped as to the site at which they occur and include luminal, mucosal, and postabsorptive events (Rosenberg and Solomons, 1984). Luminal events refer to the dissociation of the mineral from the chemical matrix with which it was associated in the food and possible interactions with factors that may enhance or reduce its solubility. Mucosal actions include uptake of minerals at the mucosal membrane, which may or may not include receptors. Postabsorptive transport of minerals away from the intestinal epithelium to body tissues and organs involves the participation of binding or transport proteins. Each of these factors or processes depends on nutrients and chemical compounds in the diet that directly or indirectly affect absorption and utilization of minerals. Other factors, such as enteral recycling and hormonal in uences, may also play a role.
