Iron considerations for the athlete: a narrative review

Abstract

Iron plays a significant role in the body, and is specifically important to athletes, since it is a dominant feature in processes such as oxygen transport and energy metabolism. Despite its importance, athlete populations, especially females and endurance athletes, are commonly diagnosed with iron deficiency, suggesting an association between sport performance and iron regulation. Although iron deficiency is most common in female athletes (~15-35% athlete cohorts deficient), approximately 5-11% of male athlete cohorts also present with this issue. Furthermore, interest has grown in the mechanisms that influence iron absorption in athletes over the last decade, with the link between iron regulation and exercise becoming a research focus. Specifically, exercise-induced increases in the master iron regulatory hormone, hepcidin, has been highlighted as a contributing factor towards altered iron metabolism in athletes. To date, a plethora of research has been conducted, including investigation into the impact that sex hormones, diet (e.g. macronutrient manipulation), training and environmental stress (e.g. hypoxia due to altitude training) have on an athlete's iron status, with numerous recommendations proposed for consideration. This review summarises the current state of research with respect to the aforementioned factors, drawing conclusions and recommendations for future work.

UEFA expert group statement on nutrition in elite football. Current evidence to inform practical recommendations and guide future research

“…[123][124][125] Due to regular blood loss during menstrual bleeding (and possibly due to a diet less rich in meat), postpubertal female players are at the highest risk of iron deficiency. 126 127 While iron deficiency in athletes is common, with a prevalence of about 15%-35% in female athletes and 5%-11% in male athletes, 128 data on professional football players at various stages of the season are limited. Iron deficiencies may present as lethargy and reduced performance and can be identified through blood screening.…”

“…The tolerable upper intake level (UL) is 45 mg/ day; high-dose iron supplements of >45 mg/day elemental iron should not be taken unless iron deficiency is present, as there is a real danger of harmful iron toxicity. For further information on iron considerations, readers are directed to a review by Sim et al 128…”

Dietary Intake, Body Composition and Iron Status in Experienced and Elite Climbers

“…Sim et al (32) suggested that reducing energy intake may result in proportionally lower dietary iron consumption. The current findings are in agreement, with medium strength correlations found between iron intake and daily energy intake.…”

Recent advances in clinical probiotic research for sport

“…A further area of recent interest in regards to probiotics and nutrient absorption is within the field of inorganic iron supplementation. Iron is crucial for oxygen transport, mitochondrial energy production, and cellular immune responses and has been shown to negatively affect physical performance and adaptation to training when low [ 21 ]. Increasing the absorption of iron could be a strategy for improving iron status and avoid the use of traditional high-dose iron supplements and thereby adverse side effects.…”