Effects of 4 weeks iron supplementation on haematological and immunological status in elite female soccer players

Abstract

The effects of 4 weeks iron supplementation on haematological and immunological status were studied in 25 elite female soccer players aged 20-28 years. The subjects were randomized and assigned to one of the following two groups; subjects given 40 mg/day iron supplementation (S group) or those given placebo (C group). The oral iron supplementation (40 mg elemental iron) was taken in 15 ml solution once a day by the S group, and the C group took a placebo for 4 weeks. Daily energy and protein intakes met the Korean Recommended Dietary Allowances. Blood haemoglobin concentration did not change in the S group, but decreased significantly (P<0.05) in the C group over the 4-week experimental period. Haematocrit, mean cell volume, mean cell haemoglobin and total iron binding capacity decreased significantly, and mean cell haemoglobin concentration increased significantly (P<0.05) in both the S and C groups. Plasma ferritin concentration increased significantly (P<0.05) in the S group, but did not change in the C group. The change of plasma immunological parameters and erythrocyte anti-oxidative enzyme activities were almost the same between the S and C groups. These results suggest that 4 weeks of iron supplementation by elite female soccer players significantly increased body iron stores and inhibited decrease of haemoglobin concentration induced by soccer training.