Iron Deficiency in sports – definition, influence on performance and therapy

Abstract

Iron deficiency is frequent among athletes. All types of iron deficiency may affect physical performance and should be treated. The main mechanisms by which sport leads to iron deficiency are an increased iron demand, an elevated iron loss and a blockage of iron absorption due to hepcidin bursts. As a baseline set of blood tests, haemoglobin, haematocrit, mean cellular volume (MCV), mean cellular haemoglobin (MCH) and serum ferritin levels are the important parameters to monitor iron deficiency. In healthy male and female athletes >15 years, ferritin values <15µg/l are equivalent to empty, values from 15 to 30µg/l to low iron stores. Therefore a cut-off of 30µg/l is appropriate. For children aged from 6–12 years and younger adolescents from 12–15 years, cut-offs of 15 and 20µg/l, respectively are recommended. As an exception in adult elite sports, a ferritin value of 50µg/l should be attained in athletes prior to altitude training, as iron demands in these situations are increased. Treatment of iron deficiency consists of nutritional counselling and oral iron supplementation or, in specific cases, by intravenous injection. Athletes with repeatedly low ferritin values benefit from an intermittent oral substitution. It is important to follow up the athletes on an individual basis with the baseline blood tests listed above twice a year. A long-term daily oral iron intake or iv-supplementation in the presence of normal or even high ferritin values does not make sense and may be harmful.