Iron status was studied in 126 female endurance athletes and 52 control subjects, all aged 16–20 years. The study aimed at identifying factors responsible for iron deficiency. Twenty-six percent of athletes and 50% of controls had latent iron-deficiency without anemia symptoms. A too low intake of iron (especially heme iron: 0.3 mg daily), and of nutrients influencing iron metabolism, were identified as main causes of iron deficiency in control subjects. In athletes, whose iron intake was sufficient (14.6 mg), the principal cause of iron deficiency were blood losses due to menstruation. High level of physical activity, expressed as training volume and experience, did not adversely affect iron stores, as these were higher than in control subjects and the incidence of iron deficiency was much lower than in the control group. It was concluded that an increased intake of iron and of dietary factors involved in iron metabolism prevented possible exercise-induced losses of iron in young athletes.
Jadwiga Malczewska, Grzegorz Raczynski and Romuald Stupnicki
Antoni Aguiló, Pere Tauler, Emilia Fuentespina, Gerardo Villa, Alfredo Córdova, Josep A. Tur and Antoni Pons
The aim of this work was to check the effects of antioxidant supplementation (vitamins E and C, and β-carotene) on the basal iron status of athletes prior to and following their training and competition season (3 months).
Eighteen amateur trained male athletes were randomly distributed in 2 groups: placebo (lactose) and antioxidant supplemented (vitamin E, 500 mg/d; vitamin C, 1 g/d; and β-carotene, 30 mg/d). The study was double blind. Hematological parameters, dietary intake, physical activity intensity, antioxidant status (GSH/GSSG ratio), and basal iron status (serum iron, transferrin, ferritin, and iron saturation index) were determined before and after the intervention trials.
Exercise decreased antioxidant defenses in the placebo group but not in the antioxidant-supplemented group. No changes were found in the number of erythrocytes, hematocrit, or hemoglobin concentration, or in values of serum iron parameters, after taking the antioxidant cocktail for 3 months, in spite of the exercise completed. The placebo group showed a high oxidative stress index, and decreases in serum iron (24%) and iron saturation index (28%), which can neither be attributed to aspects of the athletes’ usual diet, nor to hemoconcentration.
Antioxidant supplementation prevents the decrease of serum iron and the iron saturation index, and a link between iron metabolism and oxidative stress may also be suggested.
Lindy M. Castell, David C. Nieman, Stéphane Bermon and Peter Peeling
; micronutrients (e.g., iron, zinc, and magnesium) are important for competent immune function, as are vitamins A and D. Some nutrients must be provided in the diet, as they cannot be synthesized in mammalian cells ( Calder, 2013 ). Improved techniques such as metabolomics, proteomics, and lipidomics have revealed
Nenad Ponorac, Mira Popović, Dea Karaba-Jakovljević, Zorislava Bajić, Aaron Scanlan, Emilija Stojanović and Dragan Radovanović
Impaired iron status has been associated with typical symptoms, such as fatigue, lethargy, and negative mood states (Stage 1), and in more severe cases (e.g., iron-deficient erythropoiesis [IDE], iron deficiency anemia [IDA]), it compromises exercise capacity ( Sim et al., 2019 ). Although
Russell R. Pate, Bonnie J. Miller, J. Mark Davis, Chris A. Slentz and Lisa A. Klingshirn
This study was designed to observe iron status and prevalence of iron deficient conditions in adult female habitual runners (n=111) and inactive females of comparable age (n=65). The runners were significantly lower (p<.05) than the reference group in mean serum ferritin (SF), total iron binding capacity, and red blood cell count, but significantly higher (p<.05) in mean corpuscular hemoglobin. The groups did not differ significantly in hemoglobin concentration, hematocrit, serum iron, percent saturation of transfenin, or red cell protoporphyrin. Chi square analysis indicated that iron depletion (SF <20 ng·ml-1) was significantly more prevalent (p<.005) in the runners than in the controls. Anemia was extremely rare in both groups. A multiple regression analysis revealed significant negative associations between serum ferritin and coffeeltea intake (p<.001) and running activity (p<.05). These results indicate that habitual runners, as compared with inactive women, are at increased risk for iron deficient states but that full-blown anemia is a rare consequence of this deficient iron status.
Henry N. Williford, Michele Scharff Olson, Robert E. Keith, Jeffrey M. Barksdale, Daniel L. Blessing, Nai-Zhen Wang and Pete Preston
This investigation evaluated the iron and nutritional status of 12 highly trained aerobic dance instructors who did not take iron supplements (ANS) and 8 who did (AS). A control group (C) consisted of 10 age matched controls. The aerobic instructors had exercised for approximately 3.8 days/wk, 56 min/session for the past 7 yrs. There were no significant differences among groups for energy intake, carbohydrate, protein, fat, nonheme iron, heme iron, or total iron intake (excluding supplemental iron). But both exercise groups had lower ferritin values than the control group. There was also a significant difference in mean cell volume (MCV), with both exercise groups having greater values than the control group. There were no differences among groups for serum iron, total iron binding capacity, transferrin saturation, hematocrit, or hemoglobin. One in three aerobic dance instructors had serum ferritin values below 12 μg · L−1. Results indicate that women exercise leaders have iron profiles that are similar to other groups of female athletes. The increased MCV values suggest runners' macrocytosis or an exercise induced macrocytosis.
Alannah K. A. McKay, Ida A. Heikura, Louise M. Burke, Peter Peeling, David B. Pyne, Rachel P.L. van Swelm, Coby M. Laarakkers and Gregory R. Cox
concentrations of the inflammatory cytokine interleukin-6 (IL-6) ( Hennigar et al., 2017 ), which may have downstream implications for the iron-regulatory hormone hepcidin ( Badenhorst et al., 2015 ). Adherence to a low-CHO diet (3 g/kg) for 24 hr can amplify the immediate postexercise IL-6 and the 3-hr
Brian Dawson, Carmel Goodman, Tanya Blee, Gary Claydon, Peter Peeling, John Beilby and Alex Prins
Non-anemic, iron depleted women were randomly assigned to an injection group (IG) or oral group (OG) to assess which method is more efficient for increasing iron stores over a short time period. IG received a course of 5 × 2 mL intramuscular injections over 10 d, and OG received one tablet daily for 30 d. Fourteen, 21 and 28 d after commencing supplementation, ferritin concentration in OG significantly increased from baseline (means ± standard error: 27 ± 3 to 40 ± 5 to 41 ± 5 to 41 ± 5 µg/L; P < 0.01). Similarly, on days 15, 20, and 28 post the first injection, ferritin concentration in IG significantly increased from baseline (means ± standard error: 20 ± 2 to 71 ± 17 to 63 ± 11 to 63 ± 7 µg/L; P < 0.01), and was also significantly greater than OG at day 15 and 28 (P < 0.05). Iron injections are significantly more effective (both in time and degree of increase) in improving ferritin levels over 30 d than oral tablets.
Peter Peeling, Tanya Blee, Carmel Goodman, Brian Dawson, Gary Claydon, John Beilby and Alex Prins
This investigation examined the effect of intramuscular iron injections on aerobic-exercise performance in iron-deficient women. Sixteen athletes performed a 10-min steady-state sub maximal economy test, a VO2max test, and a timed test to exhaustion at VO2max workload. Subjects were randomly assigned to an iron-supplemented group (IG) receiving intramuscular iron injections or to a placebo group (PG). Twenty days after the first injection, exercise and blood testing were repeated. A final blood test occurred on Day 28. Post supplementation, no differences were found between the groups’ sub maximal or maximal VO2, heart rate, or blood lactate (P > 0.05). Time to exhaustion was increased in the IG (P < 0.05) but was not greater than that of the PG (P > 0.05). The IG’s serum ferritin (SF) was significantly increased on Days 20 and 28 (mean ± standard error: 19 ± 3 to 65 ± 11 to 57 ± 12 µg/L; P < 0.01), with a percentage change from baseline significantly greater than in the PG (P < 0.01). It was concluded that intramuscular iron injections can effectively increase SF without enhancing sub maximal or maximal aerobic-exercise performance in iron-depleted female athletes.
Naama W. Constantini, Alon Eliakim, Levana Zigel, Michal Yaaron and Bareket Falk
Much attention has focused on the nutrition and hematological profile of female athletes, especially gymnasts. The few studies on iron status of male adolescent athletes found a low incidence of iron deficiency. The present study investigated the iron status of male and female gymnasts (G) and compared it with athletes of other sports. Subjects were 68 elite athletes (43 M, 25 F) ages 12-18, of four sports: gymnasts (11 M, 12 F), swimmers (11 M, 6 F), tennis players (10 M, 4 F), and table tennis players (11 M, 3 F). All lived in the national center for gifted athletes, trained over 25 hr a week, ate in the same dining room, and shared a similar lifestyle. Mean levels of hemoglobin (Hb), red blood cell indexes, serum ferritin, serum iron, and transferrin were measured in venous blood. There was no difference in mean Rb among gymnasts (G) and nongymnasts (NG). However, Hb was less than 14 g/dL in 45% of M G vs. only 25% in NG, and less than 13 g/dL in 25% of premenarcheal FG vs. 15% in NG. Low transferrin saturation (< 20%) was detected in 18% of M G and 25% of FG vs. 6% and 8% in male and female NG, respectively (p < .05). The percentage of males suffering from low ferritin level (< 20 ng/ml) was twice as high in G (36%) vs. NG (19%), and about 30% in all females. In summary, iron stores were consistently lower in M G vs. NG. Adolescent athletes of both genders, G in particular, are prone to nonanemic iron deficiency, which might compromise their health and athletic performance.