Iron Intake, Iron Status, Intestinal Health and Endurance Performance - Effects of Iron Supplementation in Young Female Football Players - a Pilot Study

Iron deficiency can lead to fatigue and anemia. Because iron is necessary for the formation of new blood cells (hematopoiesis), it is an extensive practice internationally among athletes to take iron supplements in the belief that this will improve endurance performance and oxygen transport capacity by increasing red blood cell production. Although iron intake in menstruating women has shown to reduce the prevalence of anemia and iron deficiency as well as increasing hemoglobin values and iron stores. However iron supplementation increases the risk of iron excess and can result in undesirable effects such as constipation and abdominal pain as well as negative impact on intestinal epithelial permeability and increase in oxidative stress. Because iron is important for the replication and survival of almost all bacteria, with few exceptions, the intake of iron also affect the composition of the intestinal bacteria. Not surprisingly, both high and low iron levels affect the composition of the microbiota in the gut.

It is not known if young menstruating Norwegian female athletes cover their need for iron via the diet or whether extra intake in the form of a low-dose supplement could be beneficial in terms of hemoglobin levels and sports performance. Because iron preparations are not prescription and are sold in pharmacies, health food stores and larger grocery stores, this can lead to uncritical intake of iron. Since the use of iron preparations has been documented to be widespread in foreign sports environments, it is important to both characterize the iron status of Norwegian athletes and at the same time examine the beneficial value of iron supplements on sports performance as well as monitoring effects on microbiota composition and intestinal health.

The aim of the study is therefore to characterize the diet and iron status of young female elite football players and examine the relationship between iron intake, iron status, hemoglobin levels, intestinal health and sports performance. In addition, the effects of low-dose iron supplements will be investigated in relation to iron stores, hemoglobin levels and sports performance and whether such supplementation affects intestinal health, microbiota composition and biomarkers for oxidative stress.