Search Results

You are looking at 1 - 10 of 13 items for :

  • "transferrin receptor" x
Clear All
Restricted access

Jadwiga Malczewska, Beata Szczepańska, Romuald Stupnicki and Witold Sendecki

The transferrin receptor-ferritin index (sTfR/logFerr) was determined in 131 male and 121 female athletes in order to assess the frequency of iron deficiency (threshold value of that index taken as 1.8). Blood was drawn for determining morphological indices as well as sTfR, ferritin, iron, total iron binding capacity (TIBC), and haptoglobin. A significantly (p < .01) higher incidence of iron deficiency was observed in women (26%) than in men (11%). The iron deficiency was latent, since no subject was found to be anemic. The plasma iron was significantly lower and TIBC higher (p < .001) in both iron-deficient subgroups than in the non-deficient ones. This confirmed the latent character of iron deficiency. Some hematological indices (Hb, MCH, MCHC, MCV) were significantly lower in iron-deficient female athletes than in male athletes, which suggested a more profound iron deficiency in the former. The sTfR/logFerr index might thus be useful in detecting iron deficiency in athletes, especially in those with erythropoiesis disorders, since physical loads may affect the widely used ferritin levels.

Restricted access

Heidi L. Petersen, C. Ted Peterson, Manju B. Reddy, Kathy B. Hanson, James H. Swain, Rick L. Sharp and D. Lee Alekel

This study determined the effect of training on body composition, dietary intake, and iron status of eumenorrheic female collegiate swimmers (n = 18) and divers (n = 6) preseason and after 16 wk of training. Athletes trained on dryland (resistance, strength, fexibility) 3 d/wk, 1.5 h/d and in-water 6 d/wk, nine, 2-h sessions per week (6400 to 10,000 kJ/d). Body-mass index (kg/m2; P = 0.05), waist and hip circumferences (P ≤ 0.0001), whole body fat mass (P = 0.0002), and percentage body fat (P ≤ 0.0001) decreased, whereas lean mass increased (P = 0.028). Using dual-energy X-ray absorptiometry, we found no change in regional lean mass, but fat decreased at the waist (P = 0.0002), hip (P = 0.0002), and thigh (P = 0.002). Energy intake (10,061 ± 3617 kJ/d) did not change, but dietary quality improved with training, as refected by increased intakes of fber (P = 0.036), iron (P = 0.015), vitamin C (P = 0.029), vitamin B-6 (P = 0.032), and fruit (P = 0.003). Iron status improved as refected by slight increases in hemoglobin (P = 0.046) and hematocrit (P = 0.014) and decreases in serum transferrin receptor (P ≤ 0.0001). Studies are needed to further evaluate body composition and iron status in relation to dietary intake in female swimmers.

Restricted access

Kathleen Woolf, Megan M. St. Thomas, Nicole Hahn, Linda A. Vaughan, Amanda G. Carlson and Pamela Hinton

This study examined iron status and nutrient intake in highly active (n = 28; 20 ± 2 yr, ≥12 hr purposeful physical activity per week [PPA/wk]) and sedentary (n = 28; 24 ± 3 yr, ≤2 hr PPA/wk) women. Participants completed a 7-day weighed-food record (energy, protein, fiber, alcohol, and micronutrients), 7-day pedometer/activity log, and fasting blood draw (hemoglobin, hematocrit, red blood cell indices, C-reactive protein, serum iron, percent transferrin saturation, total iron-binding capacity, ferritin, transferrin receptor [sTfR], and sTfR index). Independent-sample t tests and the Mann–Whitney nonparametric test compared mean values between groups. Lower serum ferritin (p = .01) and mean cell hemoglobin (p < .01) concentrations were found in active than in sedentary women. Higher mean sTfR (p = .01) and sTfR index (p < .01) values were found in the active women. No significant differences were found between groups for the other blood markers. Serum ferritin concentrations (storage iron) indicated iron depletion (Stage I) in 21% of active and 18% of sedentary participants. Nonetheless, 50% of active and 18% of sedentary participants were iron depleted as evidenced by the sTfR index (ratio of functional-to-storage iron). Elevated sTfR concentrations (functional iron) were observed in 25% of active and 3% of sedentary participants. Although the active women reported greater iron (p < .01) but similar heme iron intakes, they had higher mean sTfR, higher sTfR index, and lower serum ferritin concentrations than the sedentary women. Assessment of iron status may require measures not commonly used in routine assessments.

Restricted access

Laura E. Murray-Kolb, John L. Beard, Lyndon J. Joseph, Stephanie L. Davey, William J. Evans and Wayne W. Campbell

Objective:

To examine the effects of resistance training on hematological and selected indices of iron status in 17 women aged 54–71 years and 18 men aged 56–69 years.

Design:

Tests and evaluations were done before and after all subjects participated in a resistance training program twice weekly for 12 weeks.

Results:

The resistance training was effective as evidenced by increases in skeletal muscle strength of 20 ± 9% and 23 ± 13% for the men and women, respectively. Hematological parameters and serum iron concentrations were within normal clinical ranges and were unchanged by resistance training for both the men and the women. Total iron binding capacity (TIBC) and transferrin saturation were also unaffected by resistance training in the women but were significantly affected in the men. The men showed a decreased TIBC (p < .0001) and an increased transferrin saturation (p = .050). Serum ferritin concentrations decreased significantly in the women (p = .041) but were unchanged in the men. Transferrin receptor concentrations were unaffected by resistance training in the women but increased significantly in the men (p = .030).

Conclusions:

With resistance training, iron status of older men and women changes in a sex specific way.

Restricted access

Irena Auersperger, Bojan Knap, Ales Jerin, Rok Blagus, Mitja Lainscak, Milan Skitek and Branko Skof

Exercise-associated iron deficiency is a common disorder in endurance athletes. The authors investigated the effects of long-term endurance exercise on hepcidin concentrations, inflammatory parameters, and iron status in moderately trained female long-distance runners. Eighteen runners were assigned to either an interval- or a continuous-training exercise group. The physical training consisted of two 3-week progressive overload periods, each followed by a week’s recovery, and concluded with a 10- or 21-km competitive run. Samples were taken 6 times during the 8-wk training program, first at baseline (BPre), then after the first and second 3-wk training loads (TPost1, TPost2), after each recovery week (Recovery1 and Recovery2), and poststudy (BPost). Soluble transferrin receptor (sTfR) concentrations were increased in Recovery2 and BPost compared with BPre (p = .02), hemoglobin decreased in TPost1 and TPost2 (p < .001), and red blood cells decreased in TPost2 (p = .01). Hepcidin decreased with time in TPost1 and in BPost compared with BPre (p < .001) and increased in TPost2 compared with TPost1 (p < .001). No differences over time were found for high-sensitivity C-reactive protein. The main findings of the current study indicate that serum hepcidin and sTfR were affected after 8 weeks of endurance running in women. No positive relation was found with inflammation.

Restricted access

Thaiz Mattos Sureira, Olga Silverio Amancio and Josefina Aparecida Pellegrini Braga

This study evaluates the relationship between body iron losses and gains in artistic gymnastics female athletes. It shows that despite the low iron intake and exercise-induced hemolysis, iron deficiency or iron-deficiency anemia does not occur, but partial changes in the hematological profile do. The hypothesis that gymnasts’ nutritional behavior contributes to anemia, which may be aggravated by exercise-induced hemolysis, led to this cross-sectional study, conducted with 43 female artistic gymnasts 6–16 yr old. The control group was formed by 40 nontraining girls, paired by age. Hemogram, serum iron, ferritin, soluble transferrin receptor, haptoglobin, total and fractional bilirubin, Type I urine, and parasitologic and occult fecal blood tests were evaluated. The athletes presented mean hematimetric and serum iron values (p = .020) higher than those of the control group. The bilirubin result discarded any hemolytic alteration in both groups. The haptoglobin results were lower in the athlete group (p = .002), confirming the incidence of exercise-induced hemolysis. Both groups presented low iron intake. The results suggest that artistic gymnastics practice leads to exerciseinduced hemolysis and partially changes the hematological profile, although not causing iron deficiency or iron-deficiency anemia, even in the presence of low iron intake.

Restricted access

Diane M. DellaValle and Jere D. Haas

The objective of this study was to determine the impact of iron depletion without anemia on performance in a sample of female collegiate rowers at the beginning of a training season (August 2008, January 2009, and September 2009). One hundred sixty-five female collegiate rowers from 5 colleges and universities in central New York State participated in a screening of iron status. Blood hemoglobin (Hgb), serum ferritin (sFer), and soluble transferrin receptor were measured to determine prevalence of iron depletion and anemia. Rowers’ habitual moderate and vigorous physical activity, as well as their best time to complete a 2-km simulated race during the previous 3 months, were self-reported. Sixteen rowers (10%) were identified as anemic (Hgb <12.0 g/dl). Using a sFer cutoff of <20.0 μg/L, 30% (n = 44) of the nonanemic rowers were identified as iron depleted without anemia and reported 2-km times ~21 s slower (p < .004) than rowers with normal iron status. Given the high prevalence of iron depletion reported in this and other studies, screening for low iron stores at the start of a training program in female athletes involved in an endurance sport may be clinically useful. In this study, irondepleted rowers (sFer <20–25 μg/L) reported a decrease in performance time compared with those with normal iron stores.

Restricted access

Mitsuo Neya, Taisuke Enoki, Nao Ohiwa, Takashi Kawahara and Christopher J. Gore

Purpose:

To quantify the changes of hemoglobin mass (Hbmass) and maximum oxygen consumption (VO2max) after 22 days training at 1300–1800 m combined with nightly exposure to 3000-m simulated altitude. We hypothesized that with simulated 3000-m altitude, an adequate beneficial dose could be as little as 10 h/24 h.

Methods:

Fourteen male collegiate runners were equally divided into 2 groups: altitude (ALT) and control (CON). Both groups spent 22 days at 1300–1800 m. ALT spent 10 h/night for 21 nights in simulated altitude (3000 m), and CON stayed at 1300 m. VO2max and Hbmass were measured twice before and once after the intervention. Blood was collected for assessment of percent reticulocytes (%retics), serum erythropoietin (EPO), ferritin, and soluble transferrin receptor (sTfR) concentrations.

Results:

Compared with CON there was an almost certain increase in absolute VO2max (8.6%, 90% confidence interval 4.8–12.6%) and a likely increase in absolute Hbmass (3.5%; 0.9–6.2%) at postintervention. The %retics were at least very likely higher in ALT than in CON throughout the 21 nights, and sTfR was also very likely higher in the ALT group until day 17. EPO of ALT was likely higher than that of CON on days 1 and 5 at altitude, whereas serum ferritin was likely lower in ALT than CON for most of the intervention.

Conclusions:

Together the combination of the natural and simulated altitude was a sufficient total dose of hypoxia to increase both Hbmass and VO2max.

Restricted access

Nenad Ponorac, Mira Popović, Dea Karaba-Jakovljević, Zorislava Bajić, Aaron Scanlan, Emilija Stojanović and Dragan Radovanović

, such as serum concentration of soluble transferrin receptor ( Di Santolo et al., 2008 ; Milic et al., 2011 ). Second, iron status was measured at the end of the season, which may negatively affect iron metabolism ( Merkel et al., 2009 ). Therefore, future studies are encouraged to investigate

Open access

D. Enette Larson-Meyer, Kathleen Woolf and Louise Burke

-grains, vegetables, black strap molasses, dried fruit Several measures performed simultaneously provide best assessment and determine stage of deficiency (see Table  5 ) e Recommended measures: serum ferritin (↓stage I), transferrin saturation, serum iron transferrin receptor, zinc protoporphyrin, hemoglobin (HGB