Sex-specific relationships among iron status biomarkers, athletic performance, maturity, and dietary intakes in pre-adolescent and adolescent athletes

Abstract

Background The purpose of this study was to examine relationships among biomarkers of iron status, athletic performance, growth and development, and dietary intakes in pre-adolescent and adolescent male and female athletes. Methods Two-hundred and forty-nine male (n = 179) (mean ± standard deviation for age = 12.0 ± 2.1 years, height = 156.3 ± 13.9 cm, and weight = 49.1 ± 16.5 kg) and female (n = 70) (12.0 ± 2.2 years, 152.4 ± 12.3 cm, 45.3 ± 14.5 kg) athletes volunteered for capillary blood sample, anthropometric, athletic performance, and dietary intake assessments. Outcomes included maturity offset from peak height velocity, percent body fat, estimated muscle cross-sectional areas, vertical jump height (VJ), broad jump distance (BJ), pro-agility time (PA), L-cone time, 20-yard dash time (20YD), power push up (PPU) force, dietary intakes, and ferritin, soluble transferrin receptor (sTfR), and hemoglobin (Hb) concentrations. Results Athletic performance was consistently correlated with Hb in males (r = .237–.375, p < 0.001–0.05) and with sTfR (r = .521–.649, p < 0.001–0.004) and iron intake (r = .397–.568, p = 0.001–0.027) in females. There were no relationships between dietary intakes and ferritin, sTfR, or Hb (p > 0.05). After partialing out age and height, VJ, PA, LC, and 20YD remained correlated with Hb in males (|rHb,y.Age| = .208–.322, p = 0.001–0.041; |rHb,y.Height| = .211–.321, p = 0.001–0.038). After partialing out iron intake, PA and LC remained correlated with sTfR in females (|rsTfR,y.ironintake| = .516–.569, p = 0.014–0.028). Conclusions Iron status biomarkers demonstrated sex-specific relationships with anaerobic exercise performance in youth athletes, which may be more dependent on maturity status and dietary intake than age. Moderate relationships between sTfR and athletic performance in adolescent female athletes emphasizes the importance of iron intake in this demographic.

Evaluation of Nutrition and Performance Parameters in Division 1 Collegiate Athletes

“…Additionally, approximately 28.6% of the studies reviewed in a systematic review of indoor team sport athletes met recommendations for protein while 50% did not; however, there was no delineation of differences for sex or sport [ 2 ]. Low protein intake is common in female athletes [ 13 , 45 ], which was also confirmed in this study ( Table 2 ). While not as important as a fuel source for performance, adequate protein is essential for muscle protein synthesis to tissue adaptations to training, recovery, and body composition changes, such as increased muscle mass [ 4 , 45 ].…”

“…Several micronutrients have been highlighted as micronutrients of key interest for athletes, including iron, calcium, vitamin D, and antioxidants (including vitamins C, E, and beta-carotene) [ 4 ]. In general, all athletes had low intakes for these micronutrients, as well as many other vitamins and minerals analyzed in this study, with a specific concern for very low intakes of vitamin D and magnesium for all athletes, and iron and calcium in female athletes, which is an unfortunate common theme for female athletes [ 12 , 13 , 48 , 49 ].…”

“…Protein intake is necessary to support training adaptations, repair and rebuild tissue, and support protein turnover [ 10 , 11 ]. Additionally, many micronutrients such as vitamin D, calcium, and iron are all important for musculoskeletal health and performance [ 12 , 13 , 14 , 15 , 16 ]. Iron has a key role in red blood cell production, oxygen delivery, and electron transport during oxidative phosphorylation [ 17 , 18 , 19 ].…”

Youth Athlete Development and Nutrition

“…In terms of performance, even mild tissue decrements in iron have the potential to adversely affect endurance capacity and aerobic adaptation to training [ 60 ]. Indeed, a recent study involving over 70 adolescent female athletes indicated a moderate relationship between athletic performance, the concentration of soluble transferrin receptors, and dietary iron intake, emphasizing the importance of iron intake for aspiring adolescent female athletes [ 61 ].…”

Influences of Vitamin D and Iron Status on Skeletal Muscle Health: A Narrative Review

“…In addition, Tsai et al reported that mildly anemic males enlisted within the Taiwan Military were likely to be the worst 10% performers during a standard 3000 m run test but were likely to be the best 10% performers during an anaerobic test such as the 2 min push-up test [170]. Shoemaker et al also indicated within youth athletic population that performance during aerobic fitness tests such as vertical jump, broad jump, agility drill times, 20-yard dash time, power push up force, were related to Hb status in males and with sTfR and iron intake in females [171]. Together these studies further support the notion that iron plays a role in aerobic metabolism and cardiorespiratory fitness; however, the role on iron status and anaerobic fitness tests require further investigation.…”