EFFECT OF MAGNESIUM-HYDROXIDE ON IRON-ABSORPTION FOLLOWING SIMULATED MILD IRON OVERDOSE IN HUMAN-SUBJECTS

Objective: To determine the effect of oral magnesium hydroxide [Mg(OH) ,] on iron absorption after simulated iron overdose in human subjects. Methods: A randomized, controlled crossover study was conducted in he althy adult male human volunteers taking no medications. Subjects rece ived an average of 5.0 mg/kg elemental iron orally followed 1 hour lat er by either oral administration of 4.5 g of Mg(OH), per g ingested el emental iron or no treatment. Serial serum specimens were obtained ove r the 12 hours following iron ingestion and stored at -60 degrees C un til standard serum iron assay was performed. After a 2-week washout pe riod, the subjects were enrolled in the alternative trial arm. Individ ual baseline diurnal variation in serum iron levels was determined ove r a 12-hour period on the day prior to each trial. Area under time-con centration curves (AUCs) were calculated, and the AUC due to experimen tal iron ingestion (Delta AUC) was determined by subtracting the basel ine diurnal AUC from the experimental AUC for each subject. Results: T hirteen healthy adult male subjects were enrolled. Mean +/- SEM for De lta AUC due to experimental iron ingestion followed by treatment with Mg(OH)(2), 78 +/- 23 mu mol(hr)/L, was significantly less than that fo llowed by no treatment, 144 +/- 33 mu mol(hr)/L (p = 0.03 by signed ra nk test). Conclusions: Magnesium hydroxide, administered 1 hour post-i ron ingestion at an oral dose of 4.5 g per g elemental iron ingested, significantly reduced iron absorption during a 12-hour period followin g simulated mild iron overdose in healthy adult human volunteers.