This was a prospective, randomized, double-blind, placebo-controlled trial. Twenty-six healthy women (40 卤 5 y) were randomly assigned to receive either 600 mg of elemental Ca/d as CaCO3 (Ca group, n = 13) or a placebo (P group, n = 13) for 34 d. Heme Fe and non-heme Fe bioavailability were determined before and after treatment using 55Fe and 59Fe radioisotopes. A two-factor, repeated-measures analysis of variance was used to assess differences by treatment and timing.
The geometric mean (range 卤 1 SD) of heme Fe bioavailability before and after treatment was 16.5% (8.3-32.8) and 26% (15.5-43.6) for the Ca group and 21.8% (13.0-36.6) and 25.1% (16.5-38.3) for the P group. Non-heme Fe bioavailability before and after treatment was 39.5% (19.9-78.7) and 34.1% (19.1-60.6) for the Ca group, and 44.6% (24.9-79.7) and 39.3% (24.3-63.4) for the P group. There were no differences in either heme Fe or non-heme Fe bioavailability either at baseline or after treatment.
The administration of calcium supplements for 34 d does not affect iron bioavailability. This trial is registered with , number ISRCTN聽89888123.