Changes in iron status during competitive season in female collegiate swimmers

We examined changes in iron status in 25 female varsity collegiate swimmers over the course of a competitive season via weekly capillary blood sampling. We also studied the effectiveness of moderate iron supplementation (39 mg/day) in preventing expected changes in iron status via a double-blinded crossover design. On entry into the study, 17 of the swimmers had depleted iron stores (plasma ferritin < 12 micrograms/L) and 5 were anemic (Hb < 120 g/L). After 5 wk of placebo treatment, hemoglobin decreased (> or = 6 g/L) in 44% and increased in 12% of the subjects. After 5 wk of iron supplementation, hemoglobin decreased in 16% and increased in 24% of the subjects. Likewise, after placebo treatment, plasma ferritin decreased (> or = 5 micrograms/L) in 24% and increased in 4% of the subjects, whereas iron supplementation resulted in decreases in 4% and increases in 68% of the subjects. In the absence of iron supplementation, hemoglobin levels decreased despite mean dietary iron intakes of 16.3 mg/day. These results show that moderate iron supplementation is effective in preventing decline in the iron status of female collegiate swimmers during a competitive season, but a higher dose of iron may be necessary to reverse their iron-deficient state.