It remains unclear whether iron supplementation is beneficial for athletes with ID but not anemia, or for those with normal iron status. While there is some evidence that iron supplementation may improve fatigue in iron-deficient athletes and non-athletes,[1] and intensive training is a potential cause of iron depletion,[2] only a few studies have investigated the benefits of iron supplementation in athletes with adequate iron levels to replenish iron loss due to training.
In one study involving iron-sufficient soccer players during training, iron supplementation was found to maintain ferritin and iron store levels, and these levels decreased once the supplementation was interrupted.[3] However, this study did not observe any significant difference in transferrin levels, which provide information on the iron levels required for erythropoiesis (red blood cell production), and it lacked a control group.
In another study, swimmers between the ages of 12 and 17 were either given an iron supplement (47 mg iron daily) or instructed to consume an iron-rich diet. Both interventions failed to significantly alter either the participants’ iron status (measured as iron, ferritin, and transferrin levels) or their athletic performance.[4]