TRUE ABSORPTION AND RETENTION OF SUPPLEMENTAL IRON IS MORE EFFICIENT WHEN IRON IS ADMINISTERED EVERY 3 DAYS RATHER THAN DAILY TO IRON-NORMAL AND IRON-DEFICIENT RATS

Absorption of daily iron supplements is inefficient. Detailed absorpti on patterns of FeSO4 supplements simulating World Health Organization- recommended doses were studied in iron-deficient and iron-normal male Sprague-Dawley rats. For 12 d after weaning, the rats were fed a preme al containing <20 (iron-deficient group) or 400 mu g Fe (iron-normal g roup) twice daily followed by iron-free AIN-76 diet for 1 h. Then, bot h groups (iron-deficient and -normal) were divided in three groups, on e continuing without change and two receiving 4000 mu g of premeal Fe either daily or every 3 d to match intestinal mucosa renewal time. Foo d intake, growth, hemoglobin concentration and periodic Fe-59-labeled iron absorption and rate of loss were determined. Iron-deficient rats became anemic, and ate and grew less. Iron absorption was stable in no rmal (34.2%), deficient (89.7%) and normal, intermittently supplemente d (9.5%) groups. Absorption decreased logarithmically in daily supplem ented rats, whereas in iron-deficient, intermittently supplemented rat s absorption decreased slowly and linearly. Rates of iron loss were si gnificantly accelerated in daily supplemented rats. Thirteen-day total iron retention in intermittently supplemented normal and deficient ra ts was 62 and 86%, respectively, of that of daily supplemented rats. I ron supplementation timed to match mucosal renewal is more efficient.