Vitamin D may influence iron metabolism and erythropoiesis, whereas iron is essential for vitamin D synthesis. We examined whether vitamin D deficiencies (VDD) are associated with reduced iron status and whether progressive iron deficiency (ID) is accompanied by inferior vitamin D status. The study included 219 healthy female (14–34 years old) athletes. VDD was defined as a 25(OH)D concentration < 75 nmol/L. ID was classified based on ferritin, soluble transferrin receptor (sTfR), total iron binding capacity (TIBC) and blood morphology indices. The percentage of ID subjects was higher (32%) in the VDD group than in the 25(OH)D sufficient group (11%) (χ2 = 10.6; p = 0.001). The percentage of VDD subjects was higher (75%) in the ID than in the normal iron status group (48%) (χ2 = 15.6; p = 0.001). The odds ratios (ORs) for VDD increased from 1.75 (95% CI 1.02–2.99; p = 0.040) to 4.6 (95% CI 1.81–11.65; p = 0.001) with progressing iron deficiency. ID was dependent on VDD in both VDD groups (25(OH)D < 75 and < 50 nmol/L). The ID group had a lower 25(OH)D concentration (p = 0.000). The VDD group had lower ferritin (p = 0.043) and iron (p = 0.004) concentrations and higher values of TIBC (p = 0.016) and sTfR (p = 0.001). The current results confirm the association between vitamin D and iron status in female athletes, although it is difficult to assess exactly which of these nutrients exerts a stronger influence over the other.

IntroductionHaemoglobin is a key determinant of maximal oxygen uptake. This study's objective was to assess total haemoglobin mass (tHb-mass), as well as blood volume and morphological indices in athletes training different sports disciplines.Material and methodsThis study was conducted on 176 endurance and non-endurance athletes (males and females). tHb-mass, blood volume (BV), plasma volume (PV), and red cell volume (RCV) were determined by optimized carbon monoxide rebreathing method. Haemoglobin concentration (Hb), haematocrit (Hct), red blood count (RBC) were also determined.ResultsIn endurance sports, gender regardless, no significant differences in relative mean values of tHb-mass (12.8–13.1 g/kg – males; 10.4–10.6 g/kg – females), BV (90.8–94.0 ml/kg – males; 82.7–86.9 ml/kg – females), RCV (36.6–38.0 ml/kg – males; 31.1–31.5 ml/kg – females) or of PV in males (54.2–56.4 ml/kg) were observed. The above indices’ relative values, gender regardless, were significantly lower in judo (11.2 ±0.7 g/kg, 81.8 ±5.9 ml/kg, 48.6 ±4.5 ml/kg and 33.1 ±2.0 ml/kg – males; 9.3 ±0.7 g/kg, 74.3 ±5.6 ml/kg, 46.4 ±4.0 ml/kg and 27.9 ±2.1 ml/kg – females) compared to endurance sports (p < 0.001). No substantial differences were observed in morphological blood indices in males, whereas this differentiation was found between certain sports in female athletes.ConclusionsThe lack of differences in tHb-mass, BV, PV and RCV in endurance sports and presence of this differentiation between various sports shows that the types of training might affect levels of mentioned indices. Measurements of tHb-mass and BV parameters prove Hb, Hct and RBC to have limited value for haematological status evaluations.

The aim of the study was to examine the possible relationship between I/D polymorphism of ACE gene and selected indices of aerobic capacity among male and female athletes practising winter endurance sports. Sixty-six well-trained athletes (female n = 26, male n = 40), aged 18.4 ± 2.8 years, representing winter endurance sports (cross-country skiing, n = 48; biathlon, n = 8; Nordic combined, n = 10) participated in the study. Genotyping for ACE I/D polymorphism was performed using polymerase chain reaction. Maximal oxygen consumption (VO2max), maximal running velocity (Vmax) and running velocity at anaerobic threshold (VAT4) were determined in an incremental test to volitional exhaustion on a motorized treadmill. The ACE genotype had no significant effect on absolute VO2max, relative VO2max (divided by body mass or fat free body mass), VAT4 or Vmax. No interaction effect of gender x ACE genotype was found for each of the examined aerobic capacity indices. ACE gene variation was not found to be a determinant of aerobic capacity in either female or male Polish, well-trained endurance athletes participating in winter sports.

These results suggest that the ACTN3 gene may play a significant role in determining muscle phenotypes. However, this gene is only one of many factors which could contribute to athletes' performance and muscle phenotypes.

Malczewska-Lenczowska, J, Orysiak, J, Majorczyk, E, Zdanowicz, R, Szczepańska, B, Starczewski, M, Kaczmarski, J, Dybek, T, Pokrywka, A, Ahmetov, II, and Sitkowski, D. Total hemoglobin mass, aerobic capacity, and the HBB gene in polish road cyclists. J Strength Cond Res 30(12): 3512-3519, 2016-The relationship between genes, amount of hemoglobin, and physical performance are still not clearly defined. The aim of this study was to examine the association between-551C/T and intron 2, +16 C/G polymorphisms in the beta hemoglobin (HBB) gene and total hemoglobin mass (tHbmass) and aerobic capacity in endurance athletes. Total hemoglobin mass and aerobic capacity indices, i.e.,V[Combining Dot Above]O2max, oxygen uptake at anaerobic threshold (V[Combining Dot Above]O2AT), maximal power output (Pmax), and power at anaerobic threshold (PAT) were determined in 89 young road cyclists, female (n = 39) and male (n = 50), who were genotyped for 2 polymorphisms in the HBB gene. The relative values of aerobic capacity indices differed significantly among intron 2, +16 C/G polymorphisms of the HBB gene only in female cyclists; athletes with GG genotype had significantly higher values of V[Combining Dot Above]O2max (p = 0.003), V[Combining Dot Above]O2AT (p = 0.007), PAT (p = 0.015), and Pmax (p = 0.004) than C carriers. No relationships were found between the C-carrier model (CC + CG vs. GG in the case of intron 2, +16 C/G and CC + CT vs. TT for -551 C/T polymorphisms of the HBB gene) and relative values of tHbmass. Our results demonstrated that the HBB gene could be related to aerobic capacity, but it seems that it does not result from an increase in the amount of hemoglobin in the blood.