Iron status and exercise

Seasonal Variation in Vitamin D Status Does Not Interfere with Improvements in Aerobic and Muscular Endurance in Conscripts during Basic Military Training

Considering a lack of respective data, the primary objective of this study was to assess whether seasonal variation in vitamin D status (D-status) affects the extent of improvement in physical performance (PP) in conscripts during basic military training (BMT). D-status, PP and several blood parameters were measured repeatedly in conscripts whose 10-week BMT started in July (cohort S-C; n = 96) or in October (cohort A-C; n = 107). D-status during BMT was higher in S-C compared to A-C (overall serum 25(OH)D 61.4 ± 16.1 and 48.5 ± 20.7 nmol/L, respectively; p < 0.0001). Significant (p < 0.05) improvements in both aerobic and muscular endurance occurred in both cohorts during BMT. Pooled data of the two cohorts revealed a highly reliable (p = 0.000) but weak (R2 = 0.038-0.162) positive association between D-status and PP measures both at the beginning and end of BMT. However, further analysis showed that such a relationship occurred only in conscripts with insufficient or deficient D-status, but not in their vitamin D-sufficient companions. Significant (p < 0.05) increases in serum testosterone-to-cortisol ratio and decreases in ferritin levels occurred during BMT. In conclusion, a positive association exists between D-status and PP measures, but seasonal variation in D-status does not influence the extent of improvement in PP in conscripts during BMT.

Sex differences in iron status during military training: a prospective cohort study of longitudinal changes and associations with endurance performance and musculoskeletal outcomes

This study investigated sex differences in Fe status, and associations between Fe status and endurance and musculoskeletal outcomes, in military training. In total, 2277 British Army trainees (581 women) participated. Fe markers and endurance performance (2·4 km run) were measured at the start (week 1) and end (week 13) of training. Whole-body areal body mineral density (aBMD) and markers of bone metabolism were measured at week 1. Injuries during training were recorded. Training decreased Hb in men and women (mean change (-0·1 (95 % CI -0·2, -0·0) and -0·7 (95 % CI -0·9, -0·6) g/dl, both P < 0·001) but more so in women (P < 0·001). Ferritin decreased in men and women (-27 (95 % CI -28, -23) and -5 (95 % CI -8, -1) µg/l, both P ≤ 0·001) but more so in men (P < 0·001). Soluble transferrin receptor increased in men and women (2·9 (95 % CI 2·3, 3·6) and 3·8 (95 % CI 2·7, 4·9) nmol/l, both P < 0·001), with no difference between sexes (P = 0·872). Erythrocyte distribution width increased in men (0·3 (95 % CI 0·2, 0·4)%, P < 0·001) but not in women (0·1 (95 % CI -0·1, 0·2)%, P = 0·956). Mean corpuscular volume decreased in men (-1·5 (95 % CI -1·8, -1·1) fL, P < 0·001) but not in women (0·4 (95 % CI -0·4, 1·3) fL, P = 0·087). Lower ferritin was associated with slower 2·4 km run time (P = 0·018), sustaining a lower limb overuse injury (P = 0·048), lower aBMD (P = 0·021) and higher beta C-telopeptide cross-links of type 1 collagen and procollagen type 1 N-terminal propeptide (both P < 0·001) controlling for sex. Improving Fe stores before training may protect Hb in women and improve endurance and protect against injury.

Considerations for the Consumption of Vitamin and Mineral Supplements in Athlete Populations

Vitamins and minerals are of fundamental importance to numerous human functions that are essential to optimise athlete performance. Athletes incur a high turnover of key vitamins and minerals and are therefore dependent on sufficient energy intake to replenish nutrient stores. However, many athletes are poor at servicing their energy replenishment needs, especially female athletes, and although a 'food first approach' to meeting nutrient requirements is the primary goal, it may be important for some athletes to consider a vitamin and/or mineral supplement to meet their daily needs. When working to determine if an athlete requires vitamin or mineral supplements, practitioners should use a robust framework to assess the overall energy requirements, current dietary practices and the biological and clinical status of their athletes. Of note, any supplementation plan should account for the various factors that may impact the efficacy of the approach (e.g. athlete sex, the nutrient recommended dietary intake, supplement dose/timing, co-consumption of other foods and any food-drug interactions). Importantly, there are numerous vitamins and minerals of key importance to athletes, each having specific relevance to certain situations (e.g. iron and B vitamins are significant contributors to haematological adaptation, calcium and vitamin D are important to bone health and folate is important in the female athlete); therefore, the appropriate supplement for a given situation should be carefully considered and consumed with the goal to augment an athlete's diet.

Changes in Hematological Parameters of Iron Status and Total Iron Concentrations in Different Biological Matrices during a Sports Season in Women's Soccer Players

Iron (Fe) metabolism and concentrations change during a sports season. Fe deficiency affects a significant number of women athletes. The aims of the present study were: (i) to analyze changes in hematological parameters of Fe status and (ii) to analyze changes in Fe concentrations in different biological matrices (serum, plasma, urine, erythrocytes, and platelets) during a sports season. Twenty-four Spanish semi-professional women's soccer players (23.37 ± 3.95 years) participated in the present study. Three assessments were performed throughout the sports season (beginning, middle and end of the season). Nutritional intake was evaluated and female hormones, hematological parameters of Fe status and Fe concentrations in plasma, serum, urine, erythrocytes and platelets were determined. There were no differences in Fe intake. Hemoglobin and mean corpuscular hemoglobin concentrations increased at the end of the season compared to initial values (p < 0.05). There were no significant changes in extracellular Fe concentrations (plasma, serum, and urine). However, erythrocyte Fe concentrations were lower at the end of the season (p < 0.05). Hematological parameters of Fe status and intracellular Fe concentrations change throughout the sports season in women's soccer players.

Influence of iron supplementation on fatigue, mood states and sweating profiles of healthy non-anemic athletes during a training exercise: A double-blind, randomized, placebo-controlled, parallel-group study

Iron is specifically important to athletes, and attention has grown to the association between sports performance and iron regulation in the daily diets of athletes. The study presents new insights into stress, mood states, fatigue, and sweating behavior among the non-anemic athletes with sweating exercise habits who consumed a routine low dose (3.6 mg/day) of iron supplementation. In this double-blind, randomized, placebo-controlled, parallel-group study, both non-anemic male (N = 51) and female (N = 42) athletes were supplemented either with a known highly bioavailable iron formulation (SunActive® Fe) or placebo during the follow-up training exercise period over four weeks at their respective designated clinical sites. The effect of oral iron consumption was examined on fatigue, stress profiles, as well as the quality of life using the profile of mood state (POMS) test or a visual analog scale (VAS) questionnaire, followed by an exercise and well-being related fatigue-sweat. Also, their monotonic association with stress biomarkers (salivary α-amylase, salivary cortisol, and salivary immunoglobulin A) were determined using spearman's rank correlation coefficient test. Repeated measure multivariate analysis of variance (group by time) revealed that the total mood disturbance (TMD) score was significantly lower (P = 0.016; F = 6.26) between placebo and iron supplementation groups over the four weeks study period among female athletes. Also, a significant reduction in tired feeling/exhaustion after the exercise (P = 0.05; F = 4.07) between the placebo and iron intake groups was noticed. A significant within-group reduction (P ≤ 0.05) was noticed in the degree of sweat among both male and female athletes after 2 and 4 weeks of iron supplementation, while athletes of the placebo intake group experienced a non-significant within-group reduction in the degree of sweat. Overall, the result indicates routine use of low dose (3.6 mg/day) iron supplementation is beneficial for non-anemic endurance athletes to improve stress, mood states, subjective fatigue, and sweating conditions.

MiRNA-based “fitness score” to assess the individual response to diet, metabolism, and exercise

Background

Regular, especially sustained exercise plays an important role in the prevention and treatment of multiple chronic diseases. Some of the underlying molecular and cellular mechanisms behind the adaptive response to physical activity are still unclear, but recent findings suggest a possible role of epigenetic mechanisms, especially miRNAs, in the progression and management of exercise-related changes. Due to the combination of the analysis of epigenetic biomarkers (miRNAs), the intake of food and supplements, and genetic dispositions, a “fitness score” was evaluated to assess the individual response to nutrition, exercise, and metabolic influence.

Methods

In response to a 12-week sports intervention, we analyzed genetic and epigenetic biomarkers in capillary blood from 61 sedentary, healthy participants (66.1% females, 33.9% males, mean age 33 years), including Line-1 methylation, three SNPs, and ten miRNAs using HRM and qPCR analysis. These biomarkers were also analyzed in a healthy, age- and sex-matched control group (n, 20) without intervention. Food frequency intake, including dietary supplement intake, and general health questionnaires were surveyed under the supervision of trained staff.

Results

Exercise training decreased the expression of miR-20a-5p, −22-5p, and −505-3p (p < 0.02) and improved the “fitness score,” which estimates eight different lifestyle factors to assess, nutrition, inflammation, cardiovascular fitness, injury risk, regeneration, muscle and hydration status, as well as stress level. In addition, we were able to determine correlations between individual miRNAs, miR-20a-5p, −22-5p, and −101-3p (p < 0.04), and the genetic predisposition for endurance and/or strength and obesity risk (ACE, ACTN3, and FTO), as well as between miRNAs and the body composition (p < 0.05). MiR-19b-3p and −101-3p correlated with the intake of B vitamins. Further, miR-19b-3p correlated with magnesium and miR-378a-3p with iron intake (p < 0.05).

Conclusions

In summary, our results indicate that a combined analysis of several biomarkers (miRNAs) can provide information about an individual’s training adaptions/fitness, body composition, nutritional needs, and possible recovery. In contrast to most studies using muscle biopsies, we were able to show that these biomarkers can also be measured using a minimally invasive method.

Iron Deficiency in Adolescent and Young Adult German Athletes-A Retrospective Study

Background: Iron deficiency is a common phenomenon in sports and may lead to impaired physical performance. The aim of the study was to determine the frequency of iron deficiency in competitive athletes and to discuss the resulting consequences. Methods: The data of 629 athletes (339 male, 290 female) who presented for their annual basic sports medicine examination were investigated. Depending on age (<14 years, 15−17 years, ≥18−30 years), four groups ((I.) normal hemoglobin (Hb) and ferritin level (≥30 ng/mL for adults and 15−18-year-olds; ≥20 ng/mL, respectively, ≥15 ng/mL for adolescents and children), (II.) prelatent iron deficiency (ID) (normal Hb, low ferritin), (III.) latent ID (additionally elevated soluble transferrin receptor or decreased transferrin saturation) and (IV.) manifest anemia) were distinguished. In addition, the iron status and exercise capacity of different types of sports were compared. Results: Overall we found an iron deficiency of 10.9% in male (mainly in adolescence) and 35.9% in female athletes (emphasized in adolescence and young adulthood). There were no significant differences in iron status in regard to the different sport types or in maximum performance for the different groups of iron deficiency. Conclusions: Adolescent and female athletes are more likely to have an iron deficiency. Therapy concepts for athletes therefore should pay attention to iron-rich diets.

Comparison of trace element (selenium, iron), electrolyte (calcium, sodium), and physical activity levels in COVID-19 patients before and after the treatment

OBJECTIVE

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), a worldwide health problem, is the cause of 2019 coronavirus disease. This study aimed to compare the trace element (selenium and iron), electrolyte (calcium and sodium), and physical activity levels of COVID-19 patients before and after COVID-19 treatment.

METHOD

This prospective study was conducted in patients diagnosed with COVID-19 (n = 15). Trace element (selenium and iron), electrolyte (calcium and sodium), and physical activity levels of the patients were compared before and after the treatment.

RESULT

Most of patients had selenium deficiency (86.7 %), iron deficiency (73.3 %), calcium deficiency (66.7 %) and sodium deficiency (46.7 %) before COVID-19 treatment. The most important improvements were seen in iron deficiency (from 73.3 % to 26.7 %) and sodium deficiency (from 46.7 % to 13.3 %) after the treatment. Selenium, iron, calcium, and sodium levels of the patients were significantly higher after the treatment (p < 0.05). The patients had low physical activity before and after COVID-19 treatment. In addition, no statistically significant difference was found in the comparison of physical activity levels (p > 0.05).

CONCLUSION

This study indicated that selenium, iron, calcium, and sodium levels and deficiencies might improve after treating patients with COVID-19. However, the results of this study showed that the physical activity levels of COVID-19 patients might remain stable and low throughout the treatment process.

Total Iron Concentrations in Different Biological Matrices-Influence of Physical Training

Iron (Fe) is one of the most widely studied trace mineral elements. Fe metabolism and homeostasis could be altered by physical training. The aim of this study was to analyze the influence of long-term physical training on serum, plasma, urine (extracellular), erythrocyte and platelet (intracellular) Fe concentrations. Forty men from the same geographical area divided into a training group (TG; n = 20; 18.15 ± 0.27 years) and a control group (CG; n = 20; 19.25 ± 0.39 years) participated in this study. The TG was composed of soccer players of the highest youth category. The CG consisted of young people who did not follow any training routine and had not practiced any sport for at least the previous six months. The TG showed higher plasma and serum Fe concentrations (p < 0.05), but lower concentrations in erythrocytes and platelets compared to the CG (p < 0.01). Due to the differences observed in the extracellular and intracellular compartments, it seems necessary to perform a global Fe analysis to assess Fe status.

How Do Male Football Players Meet Dietary Recommendations? A Systematic Literature Review

The aim of this review was to determine whether male football players meet dietary recommendations according to a UEFA expert group statement and to identify priority areas for dietetic intervention, including training periodization and field position. A database search of PubMed, Web of Science, EBSCO and Scopus was performed. To be included within the final review, articles were required to provide a dietary intake assessment of professional and semi-professional football players. A total of 17 studies met the full eligibility criteria. Several studies showed insufficient energy and carbohydrate intake compared to the recommendations. A majority of athletes consume adequate protein and fat intakes compared to the recommendations. In addition, several studies showed the insufficient intake of vitamins and minerals. This systematic review showed that football players do not meet the nutritional recommendations according to the UEFA expert group statement. Future research should be focused on how to apply nutritional recommendations specific for athletes in accordance with training periodization and positions on the field.

Heat acclimation does not attenuate hepcidin elevation after a single session of endurance exercise under hot condition

Purpose

We sought to determine the effects of heat acclimation on endurance exercise-induced hepcidin elevation under hot conditions.

Methods

Fifteen healthy men were divided into two groups: endurance training under hot conditions (HOT, 35 °C, n = 8) and endurance training under cool conditions (CON, 18 °C, n = 7). All subjects completed 10 days of endurance training (8 sessions in total), consisting of 60 min of continuous exercise at 50% of maximal oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{2\max }$$\end{document}V˙O2max) under their assigned environment condition. Subjects completed a heat stress exercise test (HST, 60 min exercise at 60% \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{2\max }$$\end{document}V˙O2max) to evaluate the exercise-induced thermoregulatory and hepcidin responses under hot conditions (35 °C) before (pre-HST) and after (post-HST) the training period.

Results

Core temperature during exercise in the post-HST decreased significantly in the HOT group compared to pre-HST (P = 0.004), but not in the CON group. The HOT and CON groups showed augmented exercise-induced plasma interleukin-6 (IL-6) elevation in the pre-HST (P = 0.002). Both groups had significantly attenuated increases in exercise-induced IL-6 in the post-HST; however, the reduction of exercise-induced IL-6 elevation was not different significantly between both groups. Serum hepcidin concentrations increased significantly in the pre-HST and post-HST in both groups (P = 0.001), no significant difference was observed between both groups during each test or over the study period.

Conclusion

10 days of endurance training period under hot conditions improved thermoregulation, whereas exercise-induced hepcidin elevation under hot conditions was not attenuated following the training.

Dietary Iron and the Elite Dancer

Dancers are an athlete population at high risk of developing iron deficiency (ID). The aesthetic nature of the discipline means dancers potentially utilise dietary restriction to meet physique goals. In combination with high training demands, this means dancers are susceptible to problems related to low energy availability (LEA), which impacts nutrient intake. In the presence of LEA, ID is common because of a reduced mineral content within the low energy diet. Left untreated, ID becomes an issue that results in fatigue, reduced aerobic work capacity, and ultimately, iron deficient anaemia (IDA). Such progression can be detrimental to a dancer’s capacity given the physically demanding nature of training, rehearsal, and performances. Previous literature has focused on the manifestation and treatment of ID primarily in the context of endurance athletes; however, a dance-specific context addressing the interplay between dance training and performance, LEA and ID is essential for practitioners working in this space. By consolidating findings from identified studies of dancers and other relevant athlete groups, this review explores causal factors of ID and potential treatment strategies for dancers to optimise absorption from an oral iron supplementation regime to adequately support health and performance.

Iron Metabolism following Twice a Day Endurance Exercise in Female Long-Distance Runners

Iron deficiency anemia (IDA) and iron deficiency (ID) are frequently observed among endurance athletes. The iron regulatory hormone hepcidin may be involved in IDA and/or ID. Endurance athletes incorporate multiple training sessions, but the influence of repeated bouts of endurance exercise within the same day on iron metabolism remains unclear. Therefore, the purpose of the present study was to investigate the influence of twice a day endurance exercise on iron metabolism, including the hepcidin level, in female long-distance runners. Thirteen female long-distance runners participated in this study. They completed the twice-a-day endurance exercise in the morning and afternoon. Blood samples were collected four times in total: at 06:00 (P0), 14:00 (P8), 20:00 (P14), and 06:00 the next day (P24). In addition to the blood variables, nutritional intake was assessed throughout the exercise day. Serum hepcidin levels were significantly elevated (compared to P0) until the following morning (P24). Moreover, dietary analysis revealed that subjects consumed a low volume of carbohydrates (<6 g/kg body mass/day). In conclusion, twice a day endurance exercise resulted in significant elevation of serum hepcidin level 24 h after completion of the exercise in female long-distance runners. Therefore, athletes with a high risk of anemia should pay attention to training frequency and nutritional intake in order to maintain optimal iron metabolism.

Global burden and inequality of iron deficiency: findings from the Global Burden of Disease datasets 1990-2017

BACKGROUND

Iron deficiency (ID) impairs patient physical activity, recognition and life quality, which is difficult to perceive but should not be underestimated. Worldwide efforts have been made to lower ID burden, however, whether it decreased equally in different regions and sexes is unclear. This study is to examine regional and sex inequalities in global ID from 1990 to 2017.

METHODS

We conducted a longitudinal, comparative burden-of-disease study. Disability-adjusted life-years (DALYs) of ID were obtained from Global Burden of Disease Report 2017. Human Development Index (HDI) data were obtained from Human Development Report 2017. Gini coefficient and the concentration index were calculated to assess the equities in global burden of ID.

RESULTS

A downward trend of global ID burden (from 569.3 (95% Uncertainty Interval [UI]: 387.8-815.6) to 403.0 (95% UI: 272.4-586.6), p < 0.001), age-adjusted DALYs per 100,000 population) but an uptrend of its inequalities (from 0.366 to 0.431, p < 0.001, Gini coefficients) was observed between 1990 and 2017. ID burden was heavier in women than that in men ([age-adjusted DALYs per 100,000 population from 742.2 to 514.3] vs [from 398.5 to 291.9]), but its inequalities were higher in men since 1990. The between-sex gap of ID burden was narrowed with higher HDI (β =  - 364.11, p < 0.001). East Asia & Pacific and South Asia regions made a big stride for ID control in both sexes over decades [age-adjusted DALYs per 100,000 population from 378.7 (95% UI: 255.8-551.7) in 1990 to 138.9 (95%UI: 91.8-206.5) in 2017], while a heavy burden among Sub-Saharan African men was persistent[age-adjusted DALYs per 100,000 population, 572.5 (95% UI: 385.3-815) in 1990 and 562.6 (95% UI: 367.9-833.3) in 2017].

CONCLUSIONS

Redistributing attention and resources to help countries with low HDI, especially take care of women with low socioeconomic status (SES) and men under high ID burden may help hold back the expanding ID inequality.

Planned Physical Workload in Young Tennis Players Induces Changes in Iron Indicator Levels but Does Not Cause Overreaching

The current study aimed to examine the impact of the training load of two different training camps on the immunological response in tennis players, including their iron metabolism. Highly ranked Polish tennis players, between the ages of 12 and 14 years, participated in two training camps that were aimed at physical conditioning and at improving technical skills. At baseline and after each camp, blood samples were analyzed, and the fatigue was assessed. The levels of pro- and anti-inflammatory indicators, iron, and hepcidin were determined. The levels of the heat shock proteins, (Hsp) 27 and 70, were also measured. All the effects were evaluated using magnitude-based inference. Although the training camps had different objectives, the physiological responses of the participants were similar. The applied programs induced a significant drop in the iron and hepcidin levels (a small-to-very-large effect) and enhanced the anti-inflammatory response. The tumor necrosis factor α levels were elevated at the beginning of each camp but were decreased towards the end, despite the training intensity being medium/high. The changes were more pronounced in the female players compared to the male players. Altogether, the results suggest that low-grade inflammation in young tennis athletes may be attenuated in response to adequately designed training. To this end, the applied physical workload with a controlled diet and rest-controlled serum iron levels could be the marker of well-designed training.

Levels and correlates of physical activity and capacity among HIV-infected compared to HIV-uninfected individuals

INTRODUCTION

In the HIV-infected individuals, physical activity improves physical strength, quality of life and reduces the risk of developing non-communicable diseases. In Sub-Saharan Africa, HIV-infected patients report being less active compared to HIV-uninfected individuals. We assessed the levels and correlates of objectively measured physical activity and capacity among HIV-infected antiretroviral therapy (ART)-naive individuals compared to HIV-uninfected individuals in Mwanza, Tanzania.

METHOD

We conducted a cross-sectional study among newly diagnosed HIV-infected ART-naive individuals and HIV-uninfected individuals frequency-matched for age and sex. Socio-demographic data, anthropometrics, CD4 counts, haemoglobin level, and C-reactive protein (CRP) were collected. Physical activity energy expenditure (PAEE) was assessed as measure of physical activity whereas sleeping heart rate (SHR) and grip strength were assessed as measures of physical capacity. Multivariable linear regression was used to assess the correlates associated with physical activity and capacity.

RESULTS

A total of 272 HIV-infected and 119 HIV-uninfected individuals, mean age 39 years and 60% women participated in the study. Compared to HIV-uninfected individuals, HIV-infected had poorer physical activity and capacity: lower PAEE (-7.3 kj/kg/day, 95% CI: -11.2, -3.3), elevated SHR (7.7 beats/min, 95%CI: 10.1, 5.3) and reduced grip strength (-4.7 kg, 95%CI: -6.8, -2.8). In HIV-infected individuals, low body mass index, moderate-severe anaemia, low CD4 counts and high CRP were associated with lower physical activity and capacity. In HIV-uninfected individuals, abdominal obesity and moderate anaemia were associated with lower physical activity and capacity.

CONCLUSION

HIV-infected participants had lower levels of physical activity and capacity than HIV-uninfected participants. Correlates of physical activity and capacity differed by HIV status. Management of HIV and related conditions needs to be provided effectively in health care facilities. Interventions promoting physical activity in these populations will be of importance to improve their health and reduce the risk of non-communicable diseases.

Anemia and nutritional aspects in adolescent athletes: a cross-sectional study in a reference sport organization

OBJECTIVE

To assess the association between anemia and nutritional aspects in adolescent athletes from a large sport club.

METHODS

This is a cross-sectional study, involving 298 athletes aged between 10 and 17 years, submitted to measurement of skin folds, weight and height, and collection of capillary blood in duplicate to determine hemoglobin values. It was carried out in a random sample composed of athletes from eight sport modalities.

RESULTS

Regarding nutritional status, 10.1% of athletes were overweight based on body mass index and 70 (23.5%) athletes had a percentage of body fat classified as high or very high. The prevalence of anemia was 16.4%, being more prevalent in judo (37.1%), basketball (34%) and futsal (20.5%) athletes. Low hemoglobin levels were significantly associated with shorter stature (p=0.006).

CONCLUSIONS

There was a significant association between anemia and short stature, suggesting that the athlete's height-weight development may be affected in suboptimal conditions of oxygen distribution.

Recommendations and Nutritional Considerations for Female Athletes: Health and Performance

Optimal nutrition is an important aspect of an athlete’s preparation to achieve optimal health and performance. While general concepts about micro- and macronutrients and timing of food and fluids are addressed in sports science, rarely are the specific effects of women’s physiology on energy and fluid needs highly considered in research or clinical practice. Women differ from men not only in size, but in body composition and hormonal milieu, and also differ from one another. Their monthly hormonal cycles, with fluctuations in estrogen and progesterone, have varying effects on metabolism and fluid retention. Such cycles can change from month to month, can be suppressed with exogenous hormones, and may even be manipulated to capitalize on ideal timing for performance. But before such physiology can be manipulated, its relationship with nutrition and performance must be understood. This review will address general concepts regarding substrate metabolism in women versus men, common menstrual patterns of female athletes, nutrient and hydration needs during different phases of the menstrual cycle, and health and performance issues related to menstrual cycle disruption. We will discuss up-to-date recommendations for fueling female athletes, describe areas that require further exploration, and address methodological considerations to inform future work in this important area.

Imidacloprid activates ROS and causes mortality in honey bees (Apis mellifera) by inducing iron overload

Imidacloprid, a neonicotinoid pesticide widely used for insect pest control, has become a potential pollutant to pollinators. Previous reports have demonstrated the toxicity of this drug in activating oxidative stress resulting in high mortality in the honey bee Apis mellifera. However, the mechanisms underlying the toxicity of imidacloprid have not been fully elucidated. In this study, sublethal (36 ng/bee) and median lethal (132 ng/bee) doses of imidacloprid were administered to bees. The results showed dose-dependent increases in reactive oxygen species (ROS), Fe2+, and mortality in bees. Notably, imidacloprid also induced upregulation of the gene encoding ferritin (AmFth), which plays a pivotal role in reducing Fe2+ overload. Upregulation of AmFth has been suggested to be closely related to ROS accumulation and high mortality in bees. To confirm the role played by AmFth in imidacloprid-activated ROS, dsAmFth double-strand was orally administered to bees after exposure to imidacloprid. The results revealed aggravated Fe2+ overload, higher ROS activation, and elevated mortality in the bees, indicating that imidacloprid activated ROS and caused mortality in the bees, probably by inducing iron overload. This study helps to elucidate the molecular mechanisms underlying the toxicity of imidacloprid from the perspective of iron metabolism.

The Hepcidin-25/Ferritin Ratio Is Increased in University Rugby Players with Lower Fat Mass

Hepcidin-25 is suggested as a surrogate iron status marker in athletes who show exercise-induced anemia; however, the implications of hepcidin concentration in this population remain poorly understood. This study aimed to investigate the relationship between hepcidin and body fat levels in rugby football players. We included 40 male university rugby football players (RUG) and 40 non-athlete controls. All participants underwent an anthropometric analysis and blood testing that included both hepcidin-25 and ferritin levels. The hepcidin-25 level was slightly (11.6%, p = 0.50) higher, and the ferritin level was significantly (35.9%, p < 0.05) lower, in the RUG group than in controls. The hepcidin-25 to-ferritin ratio was significantly higher (62.5%, p < 0.05) in the RUG group. While significant U-shaped correlations were observed between the body fat and ferritin levels in both groups, the correlations between the hepcidin levels and fat mass index were significantly higher in the RUG group (RUG: r = 0.79, controls: r = 0.45). Notably, the RUG with the lower fat mass index group had a higher hepcidin-25 level, lower ferritin level, and then significantly higher hepcidin-25/ferritin ratio. The hepcidin-25/ferritin ratio may serve as a biomarker for iron status in RUG, especially RUG with lower fat mass.

Rationale and design of the IRON-AF study: a double-blind, randomised, placebo-controlled study to assess the effect of intravenous ferric carboxymaltose in patients with atrial fibrillation and iron deficiency

INTRODUCTION

Atrial fibrillation (AF) is associated with significantly impaired quality-of-life. Iron deficiency (ID) is prevalent in patients with AF. Correction of ID in other patient populations with intravenous iron supplementation has been shown to be a safe, convenient and effective way of improving exercise tolerance, fatigue and quality-of-life. The IRON-AF (Effect of Iron Repletion in Atrial Fibrillation) study is designed to assess the effect of iron repletion with intravenous ferric carboxymaltose in patients with AF and ID.

METHODS AND ANALYSIS

The IRON-AF study is a double-blind, randomised controlled trial that will recruit at least 84 patients with AF and ID. Patients will be randomised to receive infusions of either ferric carboxymaltose or placebo, given in repletion and then maintenance doses. The study will have follow-up visits at weeks 4, 8 and 12. The primary endpoint is change in peak oxygen uptake from baseline to week 12, as measured by cardiopulmonary exercise testing (CPET) on a cycle ergometer. Secondary endpoints include changes in quality-of-life and AF disease burden scores, blood parameters, other CPET parameters, transthoracic echocardiogram parameters, 6-minute walk test distance, 7-day Holter/Event monitor burden of AF, health resource utilisation and mortality.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Central Adelaide Local Health Network Human Research Ethics Committee, Australia. The results of this study will be disseminated through publications in peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ACTRN12620000285954).

Prevalence and approaches to manage iron deficiency anemia (IDA)

Iron is a vital micronutrient required for growth and development at all stages of human life. Its deficiency is the primary cause of anemia that poses a significant global health problem and challenge for developing countries. Various risks are involved during iron deficiency anemia (IDA), such as premature delivery, low birth weight, etc. Further, it affects children's cognitive functioning, delays motor development, hampers physical performance and quality of life. It also speeds up the morbidity and mortality rate among women. The major reasons accountable are elevated iron demand in diet, socio-economic status, and disease condition. Various strategies have been adopted to reduce the IDA occurrence, such as iron supplementation, iron fortificants salts, agronomic practices, dietary diversification, biofortification, disease control measures, and nutritional education. Usually, the staple food groups for fortification are considered, but the selection of food fortificants and their combination must be safe for the consumers and not alter the finished product's stability and acceptability. Genetically modified breeding practices also increase the micronutrient levels of cereal crops. Therefore, multiple strategies could be relied on to combat IDA.

Comparisons Between Serum Levels of Hepcidin and Leptin in Male College-Level Endurance Runners and Sprinters

Background: Hepcidin-25 is a 25 amino acid hepatokine and a key regulator of iron metabolism related to iron deficiency anemia. Recent studies have suggested that an elevated hepcidin level is correlated with low energy availability. Leptin is an appetite-suppressing adipokine and has been reported to stimulate hepcidin production in animals and cultured cells. While leptin is modulated by exercise, it is known that endurance runners and sprinters practice different types of exercise. This study investigated and compared the relationships between hepcidin and leptin levels, iron status, and body fat to understand better the risk of iron deficiency anemia in endurance runners and sprinters. Methods: Thirty-six male college track and field athletes (15 endurance runners and 21 sprinters) were recruited for this study. Dietary intake, body composition, and blood levels of ferritin, hepcidin-25, leptin, and adiponectin were measured. Correlations between hepcidin levels and ferritin, body fat, leptin, and adiponectin were evaluated using Pearson's correlation coefficient for each group. Results: The endurance runners had lower hepcidin levels and higher leptin and adiponectin levels compared with sprinters. Ferritin was positively correlated with hepcidin-25 levels in both the endurance and sprinter groups. A positive correlation was observed between hepcidin-25 and body fat or leptin levels only in sprinters. Conclusion: This is the first study investigating the relationship between blood levels of hepcidin and leptin in athletes. The positive correlation between hepcidin-25 and leptin was observed in sprinters but not endurance runners.

Speed and Blood Parameters Differ between Arabian and Žemaitukai Horses during Endurance Racing

Fédération Equestre Internationale (FEI) has described equine endurance racing as the second largest discipline in the world, above which is only show jumping. The Žemaitukai is an ancient indigenous Lithuanian horse breed known since the 6th or 7th century. The Arabian horse breed is one of the oldest human-developed horse breeds in the world. Compared with other race horse breeds, the muscle tissue of Arabian horses is characterized by significant differences in structure-a predominance of oxidative fiber type I is observed in Arabians, making them the prevailing breed in endurance racing. The Arabian horses are recognized as the leading breed in endurance competitions. Speed, pace, and total time in the race strategy have been extensively studied in human sports, and in contrast, this strategy appears to have been virtually ignored in equestrian sport, despite the potential for contributing to performance optimization. In relation to speed and total time in the race, there are limited data on postrace physical, biochemical, and blood gas parameters of endurance horses. Thus, this study was carried out to investigate the effects of speed on the blood parameters of the Arabian and Žemaitukai horses during an endurance race. Blood samples were taken before and immediately after the exercise. Biochemical and blood gas indicators were analyzed. The study showed significant increases in mean blood gasometrical indicators, such as partial carbon dioxide pressure (8.09-15.18%, p < 0.001); base excess in the extracellular fluid (14.01%, p < 0.001 in the Arabian horses and 172.01% in the Žemaitukai breed, p = 0.006); decreases of the blood electrolyte ionized calcium (4.38-8.72%, p < 0.001) and the hematocrit and hemoglobin values (20.05-20.12%, p < 0.001 in the Arabian horses and 6.22-6.23% in the Žemaitukai breed, p = 0.003-0.004); and decreases in the base excess in the blood values (29.24-39.38%, p < 0.001) and lactate (13.45-31.97%, p < 0.001) in the blood of both breeds in the post-competition horses. Significant increases after competition were determined for the values of creatinine (21.34-30.82%, p = 0.001-0.004), total bilirubin (50.84-56.24%, PH < 0.001), and albumin (2.63-4.48%, p = 0.048-0.001) for both breeds. For the faster Arabian horse breed, recovering after racing took half the time that the local Žemaitukai breed did.

Menstrual phase and ambient temperature do not influence iron regulation in the acute exercise period

The current study investigated whether ambient heat augments the inflammatory and postexercise hepcidin response in women and if menstrual phase and/or self-pacing modulate these physiological effects. Eight trained females (age: 37 ± 7 yr; V̇o_2max: 46 ± 7 mL·kg^-1·min^-1; peak power output: 4.5 ± 0.8 W·kg^-1) underwent 20 min of fixed-intensity cycling (100 W and 125 W) followed by a 30-min work trial (∼75% V̇o_2max) in a moderate (MOD: 20 ± 1°C, 53 ± 8% relative humidity) and warm-humid (WARM: 32 ± 0°C, 75 ± 3% relative humidity) environment in both their early follicular (days 5 ± 2) and midluteal (days 21 ± 3) phases. Mean power output was 5 ± 4 W higher in MOD than in WARM (P = 0.02) such that the difference in core temperature rise was limited between environments (-0.29 ± 0.18°C in MOD, P < 0.01). IL-6 and hepcidin both increased postexercise (198% and 38%, respectively); however, neither was affected by ambient temperature or menstrual phase (all P > 0.15). Multiple regression analysis demonstrated that the IL-6 response to exercise was explained by leukocyte and platelet count (r² = 0.72, P < 0.01), and the hepcidin response to exercise was explained by serum iron and ferritin (r² = 0.62, P < 0.01). During exercise, participants almost matched their fluid loss (0.48 ± 0.18 kg·h^-1) with water intake (0.35 ± 0.15 L·h^-1) such that changes in body mass (-0.3 ± 0.3%) and serum osmolality (0.5 ± 2.0 osmol·kgH₂O^-1) were minimal or negligible, indicating a behavioral fluid-regulatory response. These results indicate that trained, iron-sufficient women suffer no detriment to their iron regulation in response to exercise with acute ambient heat stress or between menstrual phases on account of a performance-physiological trade-off.

Hepcidin response to three consecutive days of endurance training in hypoxia

PURPOSE

The purpose of this study was to determine the effects of 3 consecutive days of endurance training in hypoxia on hepcidin responses.

METHOD

Nine active healthy males completed two trials, consisting of 3 consecutive days of endurance training in either hypoxia [fraction of inspired oxygen (F_iO₂): 14.5%) or normoxia (F_iO₂: 20.9%). On days 1-3, participants performed one 90 min session of endurance training per day, consisting of high-intensity endurance interval exercise [10 × 4 min of pedaling at 80% of maximal oxygen uptake ([Formula: see text]O_2max) with 2 min of active rest at 30% of [Formula: see text]O_2max] followed by 30 min of continuous exercise at 60% of [Formula: see text]O_2max. Venous blood samples were collected prior to exercise each day during the experimental period (days 1-4) to determine serum hepcidin, iron, ferritin, haptoglobin, and ketone body concentrations.

RESULT

Serum iron (p < 0.0001), ferritin (p = 0.005) and ketone body (p < 0.0001) concentrations increased significantly in both trials on days 2-4 compared with day 1, with no significant differences between trials. No significant changes in serum haptoglobin concentrations were observed throughout the experimental period in either trial. Serum hepcidin concentrations also increased significantly on days 2-4 compared with day 1 in both trials (p = 0.004), with no significant differences observed between trials.

CONCLUSION

3 consecutive days of endurance training in hypoxia did not affect hepcidin concentrations compared with endurance training in normoxia.

Key Nutritional Considerations for Youth Winter Sports Athletes to Optimize Growth, Maturation and Sporting Development

Despite a wealth of sport nutrition guidelines for adult athletes, there are currently no nutrition guidelines for youth winter sports athletes. Whilst it may be pragmatic to apply nutrition guidelines for adult athletes to youth winter sports athletes, it is inappropriate. Due to a paucity of research on youth athletes, it is impossible to provide evidence-based guidelines for this population, so careful extrapolation from the theoretical and practical considerations that apply to other athletic groups is necessary. Youth winter sport athletes undergo rapid biological growth and maturation which influences their nutritional requirements. A varied and balanced diet that ensures sufficient energy availability for optimal growth and maturation as well as sporting performance is the cornerstone of youth athlete nutrition and should also allow for youth athletes to meet their micronutrient requirements. In some cases, micronutrient status (e.g., vitamin D and iron) should be monitored and optimized if appropriate by a medical professional. Dietary supplement use is prevalent amongst youth athletes, however is often unnecessary. Education of youth athletes, their parents and coaches on best nutritional practices as well as the risks associated with dietary supplements is vital for their long-term athletic development. Further research in youth winter sports athletes across different stages of growth and maturation competing in a variety of sports is urgently required in order to inform nutritional guidelines for this population.

Effect of endurance training on copper, zinc, iron and magnesium status

BACKGROUND

Physical activity related energy expenditure, environmental stresses, body composition, dietary intake, etc., are key factors influencing the nutritional requirements of minerals. The present study was designed to study the nutritional status of metals with respect to extensive endurance training.

METHODS

The participants of the study were navy sailors (N.=37, mean age±SD: 25.2±4.8 y) undergoing one month of endurance training. Nutritional status was assessed by determining their body composition using bioelectrical impedance (BIA), food intake and urinary excretion levels. Fasting blood samples were taken to separate plasma and red blood cells for analysis of copper, zinc, magnesium and iron and certain metal dependent enzymatic biomarkers.

RESULTS

Endurance training significantly decreased the plasma levels of copper (P<0.01), zinc and iron (P<0.05) while in erythrocytes a significant (P<0.001) decrease was observed only for Mg and Zn. There was a concomitant increase (P<0.05) in urinary Zn excretion. In addition, the concentrations of certain metal dependent enzymatic biomarkers like RBC metallothionein (P<0.05) and carbonic anhydrase (P<0.01) (Zn biomarker), plasma ferritin (Fe biomarker) (P<0.001) and RBC Mg ATPase (Mg biomarker) (P<0.05) decreased after physical activity.

CONCLUSIONS

The findings of the present study suggested the increased requirements of these minerals during physical activity.

Iron Metabolism: Interactions with Energy and Carbohydrate Availability

The provision or restriction of select nutrients in an athlete's diet can elicit a variety of changes in fuel utilization, training adaptation, and performance outcomes. Furthermore, nutrient availability can also influence athlete health, with one key system of interest being iron metabolism. The aim of this review was to synthesize the current evidence examining the impact of dietary manipulations on the iron regulatory response to exercise. Specifically, we assessed the impact of both acute and chronic carbohydrate (CHO) restriction on iron metabolism, with relevance to contemporary sports nutrition approaches, including models of periodized CHO availability and ketogenic low CHO high fat diets. Additionally, we reviewed the current evidence linking poor iron status and altered hepcidin activity with low energy availability in athletes. A cohesive understanding of these interactions guides nutritional recommendations for athletes struggling to maintain healthy iron stores, and highlights future directions and knowledge gaps specific to elite athletes.

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

Football is a global game which is constantly evolving, showing substantial increases in physical and technical demands. Nutrition plays a valuable integrated role in optimising performance of elite players during training and match-play, and maintaining their overall health throughout the season. An evidence-based approach to nutrition emphasising, a 'food first' philosophy (ie, food over supplements), is fundamental to ensure effective player support. This requires relevant scientific evidence to be applied according to the constraints of what is practical and feasible in the football setting. The science underpinning sports nutrition is evolving fast, and practitioners must be alert to new developments. In response to these developments, the Union of European Football Associations (UEFA) has gathered experts in applied sports nutrition research as well as practitioners working with elite football clubs and national associations/federations to issue an expert statement on a range of topics relevant to elite football nutrition: (1) match day nutrition, (2) training day nutrition, (3) body composition, (4) stressful environments and travel, (5) cultural diversity and dietary considerations, (6) dietary supplements, (7) rehabilitation, (8) referees and (9) junior high-level players. The expert group provide a narrative synthesis of the scientific background relating to these topics based on their knowledge and experience of the scientific research literature, as well as practical experience of applying knowledge within an elite sports setting. Our intention is to provide readers with content to help drive their own practical recommendations. In addition, to provide guidance to applied researchers where to focus future efforts.

Refining Treatment Strategies for Iron Deficient Athletes

Iron deficiency (ID) is a prevailing nutritional concern amongst the athletic population due to the increased iron demands of this group. Athletes' ability to replenish taxed iron stores is challenging due to the low bioavailability of dietary sources, and the interaction between exercise and hepcidin, the primary iron-regulatory hormone. To date, copious research has explored the link between exercise and iron regulation, with a more recent focus on optimising iron treatment applications. Currently, oral iron supplementation is typically the first avenue of iron replacement therapy beyond nutritional intervention, for treatment of ID athletes. However, many athletes encounter associated gastrointestinal side-effects which can deter them from fulfilling a full-term oral iron treatment plan, generally resulting in sub-optimal treatment efficacy. Consequently, various strategies (e.g. dosage, composition, timing) of oral iron supplementation have been investigated with the goal of increasing fractional iron absorption, reducing gastric irritation, and ultimately improving the efficacy of oral iron therapy. This review explores the various treatment strategies pertinent to athletes and concludes a contemporary strategy of oral iron therapy entailing morning supplementation, ideally within the 30 min following morning exercise, and in athletes experiencing gut sensitivity, consumed on alternate days or at lower doses.

Effect of low energy availability during three consecutive days of endurance training on iron metabolism in male long distance runners

We investigated the effect of low energy availability (LEA) during three consecutive days of endurance training on muscle glycogen content and iron metabolism. Six male long distance runners completed three consecutive days of endurance training under LEA or neutral energy availability (NEA) conditions. Energy availability was set at 20 kcal/kg fat-free mass (FFM)/day for LEA and 45 kcal/kg FFM/day for NEA. The subjects ran for 75 min at 70% of maximal oxygen uptake ( V ˙ O2max ) on days 1-3. Venous blood samples were collected following an overnight fast on days 1-4, immediately and 3 hr after exercise on day 3. The muscle glycogen content on days 1-4 was evaluated by carbon-magnetic resonance spectroscopy. In LEA condition, the body weight and muscle glycogen content on days 2-4, and the FFM on days 2 and 4 were significantly lower than those on day1 (p < .05 vs. day1), whereas no significant change was observed throughout the training period in NEA condition. On day 3, muscle glycogen content before exercise was negatively correlated with serum iron level (immediately after exercise, 3 hr after exercise), serum hepcidin level immediately after exercise, and plasma IL-6 level immediately after exercise (p < .05). Moreover, serum hepcidin level on day 4 was significantly higher in LEA condition than that in NEA condition (p < .05). In conclusion, three consecutive days of endurance training under LEA reduced the muscle glycogen content with concomitant increased serum hepcidin levels in male long distance runners.

Effects of exposure to high temperatures on serum, urine and sweat concentrations of iron and copper

The objective of this research was to determine the acute effect of a maximum test until exhaustion in normothermia and hyperthermia, and after repeated exposure to heat at high temperatures on the homeostasis of Fe and Cu. The sample was composed of twenty-nine male university students. The participants were divided into a control group (CG) and an experimental group (EG). All of them underwent an incremental test until exhaustion in normothermia and hyperthermia before and after the repeated exposure of EG to heat at high temperatures, consisting of 9 heat acclimatisation sessions in the sauna. Samples of urine and blood were taken before and after each test. Additionally, sweat samples were collected in the hyperthermia test. The samples were frozen at -80 °C for further analysis by ICP-MS. None of the metal concentrations in serum were affected by hyperthermia or exposure to heat. Urinary Fe increased in CG in the hyperthermia test before Heat exposure at High Temperature (HEHT)(p < 0.05) and in both groups after HEHT (p < 0.05). In EG there was an increase in the urinary excretion of Cu after HEHT (p < 0.01) in both trials. Fe suffered a decrease in sweat in EG after exposure to heat (p < 0.05). The concentrations of Fe and Cu in serum were not affected by acute exercise and exposure to high temperatures. However, there was a decrease in excretion of Fe in sweat due to HEHT, and an increase in urinary excretion in both. Therefore, we think that in conditions of high temperatures for long periods of time, attention should be paid to the body levels of these metals.

Resistance exercise causes greater serum hepcidin elevation than endurance (cycling) exercise

BACKGROUND

Hepcidin is an iron regulating hormone, and exercise-induced hepcidin elevation is suggested to increase the risk of iron deficiency among athletes.

OBJECTIVE

We compared serum hepcidin responses to resistance exercise and endurance (cycling) exercise.

METHODS

Ten males [mean ± standard error: 172 ± 2 cm, body weight: 70 ± 2 kg] performed three trials: a resistance exercise trial (RE), an endurance exercise trial (END), and a rest trial (REST). The RE consisted of 60 min of resistance exercise (3-5 sets × 12 repetitions, 8 exercises) at 65% of one repetition maximum, while 60 min of cycling exercise at 65% of [Formula: see text] was performed in the END. Blood samples were collected before exercise and during a 6-h post-exercise (0h, 1h, 2h, 3h, 6h after exercise).

RESULTS

Both RE and END significantly increased blood lactate levels, with significantly higher in the RE (P < 0.001). Serum iron levels were significantly elevated immediately after exercise (P < 0.001), with no significant difference between RE and END. Both the RE and END significantly increased serum growth hormone (GH), cortisol, and myoglobin levels (P < 0.01). However, exercise-induced elevations of GH and cortisol were significantly greater in the RE (trial × time: P < 0.001). Plasma interleukin-6 (IL-6) levels were significantly elevated after exercise (P = 0.003), with no significant difference between the trials. Plasma hepcidin levels were elevated after exercise (P < 0.001), with significantly greater in the RE (463 ± 125%) than in the END (137 ± 27%, P = 0.03). During the REST, serum hepcidin and plasma IL-6 levels did not change significantly.

CONCLUSION

Resistance exercise caused a greater exercise-induced elevation in hepcidin than did endurance (cycling) exercise. The present findings indicate that caution will be required to avoid iron deficiency even among athletes in strength (power) types of events who are regularly involved in resistance exercise.

Beneficial Effect of Ubiquinol on Hematological and Inflammatory Signaling during Exercise

Strenuous exercise (any activity that expends six metabolic equivalents per minute or more causing sensations of fatigue and exhaustion to occur, inducing deleterious effects, affecting negatively different cells), induces muscle damage and hematological changes associated with high production of pro-inflammatory mediators related to muscle damage and sports anemia. The objective of this study was to determine whether short-term oral ubiquinol supplementation can prevent accumulation of inflammatory mediators and hematological impairment associated to strenuous exercise. For this purpose, 100 healthy and well-trained firemen were classified in two groups: Ubiquinol (experimental group), and placebo group (control). The protocol was two identical strenuous exercise tests with rest period between tests of 24 h. Blood samples were collected before supplementation (basal value) (T1), after supplementation (T2), after first physical exercise test (T3), after 24 h of rest (T4), and after second physical exercise test (T5). Hematological parameters, pro- and anti-inflammatory cytokines and growth factors were measured. Red blood cells (RBC), hematocrit, hemoglobin, VEGF, NO, EGF, IL-1ra, and IL-10 increased in the ubiquinol group while IL-1, IL-8, and MCP-1 decreased. Ubiquinol supplementation during high intensity exercise could modulate inflammatory signaling, expression of pro-inflammatory, and increasing some anti-inflammatory cytokines. During exercise, RBC, hemoglobin, hematocrit, VEGF, and EGF increased in ubiquinol group, revealing a possible pro-angiogenic effect, improving oxygen supply and exerting a possible protective effect on other physiological alterations.

Influence of physical training on erythrocyte concentrations of iron, phosphorus and magnesium

BACKGROUND

The present study aimed to determine changes occurring in the erythrocyte concentrations of Iron (Fe), Magnesium (Mg) and Phosphorous (P) of subjects with different levels of physical training living in the same area of Extremadura (Spain).

METHODS

Thirty sedentary subjects (24.34 ± 3.02 years) without sports practice and a less active lifestyle, formed the control group (CG); 24 non-professional subjects (23.53 ± 1.85 years), who perform between 4 and 6 h/week of moderate sports practice without any performance objective and without following systematic training formed the group of subjects with a moderate level of training (MTG), and 22 professional cyclists (23.29 ± 2.73 years) at the beginning of their sports season, who performed more than 20 h/week of training, formed the high-level training group (HTG). Erythrocyte samples from all subjects were collected and frozen at - 80 °C until analysis. Erythrocyte analysis of Fe, Mg and P was performed by inductively coupled plasma mass spectrometry (ICP-MS). All results are expressed in μg/g Hb.

RESULTS

The results showed that there were statistically significant lower concentrations of erythrocyte Fe, Mg and P in MTG and HTG than CG. All parameters (Fe, Mg and P concentrations in erythrocytes) correlated inversely with physical training.

CONCLUSIONS

Physical exercise produces a decrease in erythrocyte concentrations of Fe, Mg and P. This situation could cause alterations in the performance of athletes given the importance of these elements. For this reason, we recommend an erythrocyte control at the beginning, and during the training period, to avoid harmful deficits.

Professional Female Athletes Are at a Heightened Risk of Iron-Deficient Erythropoiesis Compared With Nonathletes

This study primarily aimed to quantify and compare iron status in professional female athletes and nonathletes. Furthermore, this study also aimed to identify differences in iron status according to sporting discipline and explore the relationship between ferritin concentration and weekly training volume in professional athletes. A total of 152 participants were included in this study, including 85 athletes who were members of senior teams (handball, n = 24; volleyball, n = 36; soccer, n = 19; and judo, n = 6) involved at the highest level of competition and 67 nonathletes. A significantly greater proportion (p = .05) of athletes (27%) demonstrated iron-deficient erythropoiesis (IDE) compared with nonathletes (13%). There were nonsignificant differences (p > .05) in the prevalence of iron deficiency (ID; 49% vs. 46%) and iron deficiency anemia (IDA; 2% vs. 4%) between athletes and nonathletes. Similarly, the prevalence of ID, IDE, and IDA was not significantly different between sports (p > .05). Furthermore, training volume was negatively correlated with ferritin concentration in athletes (r: −.464, moderate, p < .001). Professional female athletes are at a heightened risk of IDE compared with nonathletes; therefore, they should be periodically screened for ID to reduce the deleterious effects on training and performance. The similar prevalence of ID, IDE, and IDA found across athletes competing in different sports suggests that overlaps exist between handball, volleyball, soccer, and judo athletes regarding risk of disturbance in iron metabolism.

The Short Tandem Repeat of the DMT1 Gene as a Molecular Marker of Elite Long-Distance Runners

The DMT1 gene encodes divalent metal transporter 1, a membrane iron transport protein. Divalent metal transporter 1 influences cellular iron availability, which might further affect aerobic exercise capacity. Short tandem repeat (STR) polymorphisms have been used as genetic markers in the literature, yet the STR polymorphisms of the DMT1 gene have not been well studied. In this current study, we explored the polymorphisms of the DMT1 gene in a group of elite long-distance runners and controls, by using the PCR-RFLP (Restriction Fragment Length Polymorphism) and Gene scan technology. We found that the genotype frequency of the homozygous 258 bp STR polymorphism of the DMT1 gene (258 bp/258 bp) was significantly higher in the athlete group than in the controls (χ² = 14.01, p = 0.006) so does the allele frequency of the 258 bp STR polymorphism (χ² = 12.867, p = 0.008). These data suggested that the STR polymorphism of the DMT1 gene might be correlated with aerobic exercise capacity and the 258 bp homozygous (25 bp/258 bp) could be used as a molecular marker for the talent identification of elite long-distance runners.

Iron insufficiency diminishes the erythropoietic response to moderate altitude exposure

The effects of iron stores and supplementation on erythropoietic responses to moderate altitude in endurance athletes were examined. In a retrospective study, red cell compartment volume (RCV) responses to 4 wk at 2,500 m were assessed in athletes with low ( n = 9, ≤20 and ≤30 ng/mL for women and men, respectively) and normal ( n = 10) serum ferritin levels ([Ferritin]) without iron supplementation. In a subsequent prospective study, the same responses were assessed in athletes ( n = 26) with a protocol designed to provide sufficient iron before and during identical altitude exposure. The responses to a 4-wk training camp at sea level were assessed in another group of athletes ( n = 13) as controls. RCV and maximal oxygen uptake (V̇o2max) were determined at sea level before and after intervention. In the retrospective study, athletes with low [Ferritin] did not increase RCV (27.0 ± 2.9 to 27.5 ± 3.8 mL/kg, mean ± SD, P = 0.65) or V̇o2max (60.2 ± 7.2 to 62.2 ± 7.5 mL·kg−1·min−1, P = 0.23) after 4 wk at altitude, whereas athletes with normal [Ferritin] increased both (RCV: 27.3 ± 3.1 to 29.8 ± 2.4 mL/kg, P = 0.002; V̇o2max: 62.0 ± 3.1 to 66.2 ± 3.7 mL·kg−1·min−1, P = 0.003). In the prospective study, iron supplementation normalized low [Ferritin] observed in athletes exposed to altitude ( n = 14) and sea level ( n = 6) before the altitude/sea-level camp and maintained [Ferritin] within normal range in all athletes during the camp. RCV and V̇o2max increased in the altitude group but remained unchanged in the sea-level group. Finally, the increase in RCV correlated with the increase in V̇o2max [( r = 0.368, 95% confidence interval (CI): 0.059–0.612, P = 0.022]. Thus, iron deficiency in athletes restrains erythropoiesis to altitude exposure and may preclude improvement in sea-level athletic performance.

NEW & NOTEWORTHY Hypoxic exposure increases iron requirements and utilization for erythropoiesis in athletes. This study clearly demonstrates that iron deficiency in athletes inhibits accelerated erythropoiesis to a sojourn to moderate high altitude and may preclude a potential improvement in sea-level athletic performance with altitude training. Iron replacement therapy before and during altitude exposure is important to maximize performance gains after altitude training in endurance athletes.

Lifestyle behaviours, ethnicity and menstruation have little added value in prediction models for low haemoglobin deferral in whole blood donors

OBJECTIVE

To investigate the added value of questionnaire-based predictors to existing prediction models for low haemoglobin (Hb) deferral in whole blood donors.

BACKGROUND

Prediction models for Hb deferral risk can be applied in the invitation process of donors for a blood donation. Existing prediction models are based on routinely collected data. The model performance might be improved by the addition of predictive factors.

METHODS

The added value of food consumption, smoking, physical activity, ethnicity and menstruation in the prediction of Hb deferral was assessed by comparing the existing models with extended models using the following measures: model X² , concordance (c)-statistic and net reclassification improvement (NRI).

RESULTS

Addition of one candidate predictor to the models did not substantially improve the model performance. Addition of multiple new candidate predictors significantly increased the model X² (from 137 to 159 for men, and from 157 to 199 for women) and resulted in a non-significant increase of the c-statistic (from 0.85 to 0.87 for men, and from 0.78 to 0.81 for women). The NRI for men was 11.4% and for women 1.5% after addition of multiple predictors.

CONCLUSION

Addition of lifestyle behaviours, ethnicity or menstruation to prediction models for low Hb deferral in whole blood donors improved the model performance, but not substantially. For easy use in practice, we do not recommend addition of the investigated predictors to the prediction models.

Common Medical Concerns of the Female Athlete

Women are increasingly participating in more and more sporting activities. For years, women athletes have been treated as the "female" equivalent of male athletes, with similar medical approaches but this is changing. The concept that women are unique in their "athletic arena" is further underscored with emerging scientific evidence--from the physiologic details not visible to the eye, to the more overt biomechanical and anatomic differences. We review a handful of conditions active women potentially may encounter: pregnancy, the female athlete triad, patellofemoral pain, potential injuries to the anterior cruciate ligament, and anemia.

Chronic Adherence to a Ketogenic Diet Modifies Iron Metabolism in Elite Athletes

PURPOSE

The short-term restriction of carbohydrate (CHO) can potentially influence iron regulation via modification of postexercise interleukin-6 (IL-6) and hepcidin levels. This study examined the effect of a chronic ketogenic low-CHO high-fat (LCHF) diet on iron status and iron-regulatory markers in elite athletes.

METHODS

International-level race walkers (n = 50) were allocated to one of three dietary interventions: (i) a high-CHO diet (n = 16), (ii) a periodized CHO availability (n = 17), or (iii) an LCHF diet (n = 17) while completing a periodized training program for 3 wk. A 19- to 25-km race walking test protocol was completed at baseline and after adaptation, and changes in serum ferritin, IL-6, and hepcidin concentrations were measured. Results from high-CHO and periodized CHO were combined into one group (CHO; n = 33) for analysis.

RESULTS

The decrease in serum ferritin across the intervention period was substantially greater in the CHO group (37%) compared with the LCHF (23%) group (P = 0.021). After dietary intervention, the postexercise increase in IL-6 was greater in LCHF (13.6-fold increase; 95% confidence interval [CI] = 7.1-21.4) than athletes adhering to a CHO-rich diet (7.6-fold increase; 95% CI = 5.5-10.2; P = 0.033). Although no significant differences occurred between diets, CI values indicate that 3 h postexercise hepcidin concentrations were lower after dietary intervention compared with baseline in CHO (β = -4.3; 95% CI = -6.6 to -2.0), with no differences evident in LCHF.

CONCLUSION

Athletes who adhered to a CHO-rich diet experienced favorable changes to the postexercise IL-6 and hepcidin response, relative to the LCHF group. Lower serum ferritin after 3 wk of additional dietary CHO might reflect a larger more adaptive hematological response to training.

Importance of Initial Complete Parenteral Iron Repletion on Hemoglobin Level Normalization and Health Care Resource Utilization: A Retrospective Analysis

STUDY OBJECTIVE

Iron deficiency anemia is the most common form of anemia, and parenteral iron therapy is necessary in select patients. The objective of this analysis was to assess the impact of initial complete parenteral iron repletion on serum hemoglobin (Hgb) level normalization and on health care resource utilization in real-world practice.

DESIGN

Retrospective observational study.

DATA SOURCE

Decision Resources Group Real-World Data Repository (United States databases).

PATIENTS

A total of 2966 patients who had a baseline Hgb level below normal (< 12 g/dl for females and < 13.5 g/dl for males) and were treated with parenteral iron between March 2015 and February 2017.

MEASUREMENTS AND MAIN RESULTS

The effect of receiving the required parenteral iron dose to replete the deficit, calculated by a modified Ganzoni formula, within 3 weeks of the first parenteral iron therapy claim (index date) on the likelihood of Hgb level normalization, was estimated by using logistic regression. All analyses were adjusted for sex, age, comorbidities, and use of prescription oral iron therapy. The adjusted mean numbers of all-cause inpatient admissions, outpatient visits, and emergency department (ED) visits within 6 months and 1 year after the index date were compared between patients with and without normalized Hgb levels by using negative binomial regression. Of the 2966 included patients, 33.9% received the required iron dose within 3 weeks of the index date, and 19.6%, 48.2%, and 53.9% had a normalized Hgb level within 8 weeks of the index date, within 1 year of the index date, and until the end of data availability, respectively. Patients who received the required iron dose within 3 weeks of the index date were significantly more likely to have a normalized Hgb level within 8 weeks of the index date and at any time during the study period than those who did not: adjusted odds ratio (OR) (95% confidence interval [CI]) 2.67 (2.20, 3.24) and 2.33 (1.96, 2.77), respectively. Hgb level normalization within 1 year of the index date was associated with fewer inpatient admissions and outpatient visits and a similar number of ED visits compared with no Hgb level normalization 1 year after the index date.

CONCLUSION

The results of these analyses underscore the importance of initial complete parenteral iron repletion for rapidly improving clinical outcomes. Prompt achievement of a normalized Hgb level may also provide an opportunity to reduce health care resource utilization in patients with iron deficiency anemia receiving parenteral iron therapy.

Physiological and Dietary Determinants of Iron Status in Spanish Vegetarians

Vegetarian diets may compromise iron status, as they provide non-haem iron which has low bioavailability. Spanish lacto-ovo vegetarians (n = 49) and vegans (n = 55) were recruited and haematological and biochemical iron parameters were analysed. Food and supplements consumption, body composition, physical activity, menstrual blood losses and hormonal contraceptive use were assessed. Four groups were studied: Iron deficiency anaemia (IDA), iron depletion (ferritin <15 ng/mL), iron deficiency (ferritin ≥15 to ≤30 ng/mL), and iron sufficiency (ferritin >30 ng/mL). IDA was uncommon (n = 5, 4.8%), 27.9% of participants were iron-depleted, and 30.8% were iron-deficient. Serum ferritin was lower in women than men (p < 0.001) and IDA and iron depleted individuals were all women. There were no differences attributed to diet type, time being vegetarian or physical activity. The menstrual period length was negatively associated with transferrin saturation (ρ = −0.364, p = 0.001) and hormonal contraceptive use (ρ = −0.276, p = 0.014). Iron supplements were consumed most frequently by IDA and iron-deficient subjects (p = 0.031). Conclusions: Iron status did not vary between lacto-ovo vegetarians and vegans and there was not an influence of the time following a vegetarian diet. Although men were iron-sufficient, iron deficiency was frequent in women, who should apply strategies to increase iron bioavailability, especially if they experience intense menstrual blood losses.

Iron considerations for the athlete: a narrative review

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.