Is iron treatment beneficial in, iron-deficient but non-anaemic (IDNA) endurance athletes? A systematic review and meta-analysis

Nonanemic Iron Deficiency in Cardiac Surgery: A Retrospective Observational Study

OBJECTIVES

Anemia and iron deficiency in patients having cardiac surgery increases their perioperative risk. Nonanemic iron deficiency (NAID) in this group is less well-described. We aimed to investigate the incidence and outcomes of patients with NAID undergoing cardiac surgery.

DESIGN

Retrospective observational study.

SETTING

A single, tertiary referral center.

PARTICIPANTS

Adult patients who were preassessed and underwent cardiac surgery during the study period had data collected. We enrolled 537 patients enrolled and divided them into 4 groups according to hemoglobin and ferritin: NAID, nonanemic iron replete, iron-deficiency anemia (IDA), and non-iron-deficiency anemia.

INTERVENTIONS

This study was not interventional, but assessed the impact of anemia and iron deficiency on patient outcomes.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the incidence of NAID. Secondary outcomes included the number of patients who became anemic awaiting surgery, allogeneic transfusion burden, length of stay, postoperative complications, and death. 179 of 537 patients (33.3%) had NAID. Seventeen patients (9.5%) became anemic in the NAID group compared with 7 (3.3%) in the nonanemic iron replete group while awaiting for surgery (p = 0.02). Patients with NAID were more likely to receive allogeneic transfusions (33% vs 23%; p = 0.04) and had poorer recovery of hemoglobin at follow-up (13.2 ± 1.46 g/dL vs 13.9 ± 1.46 g/dL; p < 0.001).

CONCLUSIONS

NAID is common and can lead to progression to anemia and increased transfusion. Iron replacement should be considered in patients with NAID in the preoperative setting. A prospective interventional trial is required to demonstrate the benefit of being iron replete.

Absolute and functional iron deficiency: Biomarkers, impact on immune system, and therapy

Iron is essential for numerous physiological processes and its deficiency often leads to anemia. Iron deficiency (ID) is a global problem, primarily affecting reproductive-age women and children, especially in developing countries. Diagnosis uses classical biomarkers like ferritin or transferrin saturation. Recent advancements include using soluble transferrin receptor (sTfR) or hepcidin for improved detection and classification of absolute and functional iron deficiencies, though mostly used in research. ID without anemia may present symptoms like asthenia and fatigue, even without relevant clinical consequences. ID impacts not only red-blood cells but also immune system cells, highlighting its importance in global health and immune-related comorbidities. Managing ID, requires addressing its cause and selecting appropriate iron supplementation. Various improved oral and intravenous products are available, but further research is needed to refine treatment strategies. This review updates on absolute and functional iron deficiencies, their relationships with the immune system and advancements in diagnosis and therapies.

Prevalence of anemia and iron deficiency and its association with body mass index in elite Japanese high school long-distance runners

OBJECTIVES

Anemia is a common condition in long-distance runners (LDRs). Recently, not only iron deficiency (ID) but also energy deficiency has been considered as a risk factor for anemia in athletes but no evidence has yet been established. The aim of this study was to investigate the prevalence of anemia and ID and the influence of body mass index (BMI) on anemia in high-school LDRs.

METHODS

The participants were 406 male and 235 female elite Japanese LDRs who competed in the All-Japan High-School Ekiden Championship 2019. They submitted their anthropometric data and results of a blood test within five days after the competition. The prevalence of anemia and ID and the influence of BMI on anemia were assessed retrospectively.

RESULTS

Mean hemoglobin concentrations (Hb) were 14.8 ± 0.9 g/dl in males and 13.2 ± 0.9 g/dl in females. The prevalence of anemia (Hb < 14 g/dl in males and < 12 g/dl in females) was significantly higher in males (16.3%) than females (6.4%), but males also showed higher prevalence of non-iron deficiency anemia (NIDA) than females (11.6% and 3.0%, respectively). No significant gender difference was found in the prevalence of iron deficiency anemia (IDA) (4.7% in males and 3.4% in females). ID (serum ferritin level < 25 ng/ml) was significantly more prevalent in females (37.4%) than males (18.5%). A binary logistic regression analysis revealed that low BMI was a contributor to anemia in females (odds ratios: 0.577 (95% CI: 0.369-0.901), p = 0.012).

CONCLUSION

In Japanese high-school LDRs, one in six males was anemic, but most males did not have ID. Conversely, one-third of females were diagnosed with ID. Lower BMI was identified as a risk for anemia in females, suggesting that leanness may also lead to anemia in females.

Efficacy of iron supplementation on physical capacity in non-anaemic iron-deficient individuals: protocol for an individual patient data meta-analysis

BACKGROUND

A deficiency in iron stores is associated with various adverse health complications, which, if left untreated, can progress to states of anaemia, whereby there is significant detriment to an individual's work capacity and quality of life due to compromised erythropoiesis. The most common methods employed to treat an iron deficiency include oral iron supplementation and, in persistent and/or unresponsive cases, intravenous iron therapy. The efficacy of these treatments, particularly in states of iron deficiency without anaemia, is equivocal. Indeed, both randomised control trials and aggregate data meta-analyses have produced conflicting evidence. Therefore, this study aims to assess the efficacy of both oral and intravenous iron supplementation on physical capacity, quality of life, and fatigue scores in iron-deficient non-anaemic individuals using individual patient data (IPD) meta-analysis techniques.

METHODS

All potential studies, irrespective of design, will be sourced through systematic searches on the following databases: Cochrane Central Register of Controlled Trials, MEDLINE Ovid, Embase Ovid, Web of Science: Science Citation Index Expanded, Web of Science: Conference Proceedings Citation Index-Science, ClinicalTrials.gov, and World Health Organization (WHO) International Clinical Trials Registry Platform. Individual patient data from all available trials will be included and subsequently analysed in a two-stage approach. Predetermined subgroup and sensitivity analyses will be employed to further explain results.

DISCUSSION

The significance of this IPD meta-analysis is one of consolidating a clear consensus to better inform iron-deficient individuals of the physiological response associated with iron supplementation. The IPD approach, to the best of our knowledge, is novel for this research topic. As such, the findings will significantly contribute to the current body of evidence.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020191739.

The relationship between menorrhagia, iron deficiency, and anaemia in recreationally active females: An exploratory population based screening study

OBJECTIVES

Iron deficiency, anaemia, and menorrhagia - or heavy menstrual bleeding - are interrelated conditions that are highly prevalent and commonly underrecognised in exercising females of reproductive age. This study utilised a screening tool to identify risk factors and symptoms associated with heavy menstrual bleeding, iron deficiency, and anaemia in this population.

DESIGN

An observational, cross sectional survey study was employed.

METHODS

1042 active females (aged 18-65) completed a comprehensive screening questionnaire and 887 (85 % compliance) provided a fingerprick blood sample for haemoglobin (Hb) concentration measurement. Women that presented as anaemic (defined as a [Hb] < 120 g/L) or deemed to be at risk of iron deficiency (120 < [Hb] < 130 g/L) were asked to complete follow-up blood tests to screen for iron studies.

RESULTS

Average [Hb] was 134.2 ± 12.1 g/L, with 94 individuals considered anaemic (10.6 %). Of the sample, 104 underwent follow-up blood tests; 51 (~49 %) presented with iron deficiency (defined as ferritin <30 μg/L). Based on survey responses, 274 (30.9 %) participants were determined to have heavy menstrual bleeding. Those presenting with heavy menstrual bleeding were younger, exercised fewer hours per week, and were more likely to have a history of iron deficiency or anaemia (all p < 0.05). Participants reporting a history of anaemia or iron deficiency were more likely to have heavy menstrual bleeding (anaemia: 39.7 %; iron deficiency; 36.9 %; both p < 0.05).

CONCLUSIONS

In this cohort of exercising females of reproductive age, the prevalence of anaemia was 10.6 %. There is a strong association between heavy menstrual bleeding and a self-reported history of iron deficiency and anaemia. Greater awareness of heavy menstrual bleeding and its relationship with iron deficiency and anaemia is needed in this population. Non-invasive screening should be conducted to raise awareness and further understand the associated risk factors and symptomatology.

Effects of Oral Iron Supplementation on Blood Iron Status in Athletes: A Systematic Review, Meta-Analysis and Meta-Regression of Randomized Controlled Trials

BACKGROUND

Iron deficiency in athletes is initially treated with a nutritional intervention. If negative iron balance persists, oral iron supplementation (OIS) can be used. Despite the recent proposal for a refinement of treatment strategies for iron-deficient athletes, there is no general consensus regarding the actual efficiency, dosage, or optimal regimen of OIS.

OBJECTIVE

The aim of this meta-analysis was to evaluate to what extent OIS affects blood iron parameters and physical performance in healthy adult athletes.

METHODS

PubMed, Web of Science, PEDro, CINAHL, SPORTDiscus, and Cochrane were searched from inception to 2 November 2022. Articles were eligible if they satisfied the following criteria: recruited subjects were healthy, adult and physically active individuals, who used exclusively OIS, irrespective of sex and sports discipline.

EXCLUSION CRITERIA

simultaneous supplementation with iron and any other micronutrient(s), intravenous iron supplementation or recent exposure to altitude acclimatisation. The methodological quality of included studies was assessed with the PEDro scale, the completeness of intervention reporting with the TIDieR scale, while the GRADE scale was used for quality of evidence synthesis. The present study was prospectively registered in PROSPERO online registry (ID: CRD42022330230).

RESULTS

From 638 articles identified through the search, 13 studies (n = 449) were included in the quantitative synthesis. When compared to the control group, the results demonstrated that OIS increases serum ferritin (standardized mean difference (SMD) = 1.27, 95% CI 0.44-2.10, p = 0.006), whereas blood haemoglobin (SMD = 1.31, 95% CI - 0.29 to 2.93, p = 0.099), serum transferrin receptor concentration (SMD = - 0.74, 95% CI - 1.89 to 0.41, p = 0.133), and transferrin saturation (SMD = 0.69, 95% CI - 0.84 to 2.22, p = 0.330) remained unaltered. Following OIS, a trend of small positive effect on VO2max (SMD = 0.49, 95% CI - 0.09 to 1.07, p = 0.086) was observed in young healthy athletes. The quality of evidence for all outcomes ranged from moderate to low.

CONCLUSIONS

Increase in serum ferritin concentration after OIS was evident in subjects with initial pre-supplementation serum ferritin concentration ≤ 12 µg/l, while only minimal, if any effect, was observed in subjects with higher pre-supplementation serum ferritin concentration. The doses of OIS, that induced a beneficial effect on hematological parameters differed from 16 to 100 mg of elementary iron daily, over the period between 6 and 8 weeks. Shorter supplementation protocols have been shown to be ineffective.

Changes in haemoglobin and ferritin levels during basic combat training: relevance for attrition and injury frequency

INTRODUCTION

The primary aim of the present study was to assess interindividual and intraindividual variations in haemoglobin and ferritin concentrations in Swedish recruits over 5 months of basic combat training (BCT). The secondary aim was to find predictors for missing training (a precursor for attrition) and overuse injuries during BCT.

METHODS

In a cohort design, a total of 58 female and 104 male recruits provided complete data. We assessed the ferritin concentrations and haemoglobin concentrations at baseline and after 5 months of BCT and physical work capacity at baseline.

RESULTS

During BCT, haemoglobin concentrations increased significantly in both females and males. Ferritin concentrations decreased significantly in both sexes and the prevalence of iron deficiency (ID) (ie, ferritin levels <30 µg/L) increased significantly in females. The physical work capacity at baseline was related to the risk of missing training in fully adjusted models. In gender-adjusted analyses, baseline ferritin was related to the risk of overuse injury, but neither baseline nor change in iron status was related to injuries or risk of missing training when controlling for confounders. Body mass increased significantly in both genders, but we found no correlation between individual change in body mass and change in haemoglobin or ferritin nor was change in body mass related to the risk of overuse injury or missing training.

CONCLUSION

In the present study, the prevalence of ID increased over the course of 5 months, while haemoglobin concentrations increased. As baseline physical work capacity was related to missing training, there are reasons to support preparatory physical training before BCT. These findings may inform future preventive interventions aimed at preventing detrimental effects of ID.

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.

The science of micronutrients in clinical practice - Report on the ESPEN symposium

BACKGROUND & AIMS

The European Society for Clinical Nutrition and Metabolism published its first clinical guidelines for use of micronutrients (MNs) in 2022. A two-day web symposium was organized in November 2022 discussing how to apply the guidelines in clinical practice. The present paper reports the main findings of this symposium.

METHODS

Current evidence was discussed, the first day being devoted to clarifying the biology underlying the guidelines, especially regarding the definition of deficiency, the impact of inflammation, and the roles in antioxidant defences and immunity. The second day focused on clinical situations with high prevalence of MN depletion and deficiency.

RESULTS

The importance of the determination of MN status in patients at risk and diagnosis of deficiencies is still insufficiently perceived, considering the essential role of MNs in immune and antioxidant defences. Epidemiological data show that deficiencies of several MNs (iron, iodine, vitamin D) are a global problem that affects human health and well-being including immune responses such as to vaccination. Clinical conditions frequently associated with MN deficiencies were discussed including cancer, obesity with impact of bariatric surgery, diseases of the gastrointestinal tract, critical illness, and aging. In all these conditions, MN deficiency is associated with worsening of outcomes. The recurrent problem of shortage of MN products, but also lack of individual MN-products is a worldwide problem.

CONCLUSION

Despite important progress in epidemiology and clinical nutrition, numerous gaps in practice persist. MN depletion and deficiency are frequently insufficiently searched for in clinical conditions, leading to inadequate treatment. The symposium concluded that more research and continued education are required to improve patient outcome.

Sex, lies, and iron deficiency: a call to change ferritin reference ranges

Iron deficiency is a very common and treatable disorder. Of all the tests available to diagnose iron deficiency, the serum ferritin is the most able to discriminate iron deficiency from other disorders. However, the reference range for ferritin in many laboratories will lead to underdiagnosis of iron deficiency in women. Studies have shown that 30%-50% of healthy women will have no marrow iron stores, so basing ferritin cutoffs on the lowest 2.5% of sampled ferritins is not appropriate. In addition, several lines of evidence suggest the body physiologic ferritin "cutoff" is 50  ng/mL. Work is needed to establish more realistic ferritin ranges to avoid underdiagnosing a readily treatable disorder.

Prevalence of iron-deficient but non-anemic university athletes in Japan: an observational cohort study

BACKGROUND

Iron deficiency (ID) and iron deficiency anemia (IDA) are long-standing health problems in athletes, affecting both performance and health. ID prevalence in young athletes remains high and a matter of concern. ID and IDA can lead to fatigue, reduced endurance, and decreased oxygen transport, potentially compromising athletic performance. We hypothesized that ID would still be a major health concern in university athletes across sports clubs in Japan.

PURPOSE

The study aimed to investigate the prevalence of ID and IDA in athletes participating in Kendo, badminton, baseball, and handball at the University of Tsukuba (Tsukuba, Ibaraki Prefecture, Japan). The study also examined the correlation between hypoferritinemia and other variables, such as previous use of iron supplements, body mass index (BMI), energy intake, and years of athletics.

METHODS

Between January and December 2019, 126 university athletes, consisting of 79 males and 47 females, underwent physical measurements and blood tests. The blood test included complete blood count, levels of serum ferritin, serum iron, and total iron-binding capacity. The anemia was defined in accordance with the WHO criteria. Daily energy and iron intake were estimated with the food frequency questionnaire in Japanese (FFQg). Thirty-four female athletes responded to a survey about their menstruation and low-dose estrogen-progestin (LEP) usage.

RESULTS

While none of the athletes had anemia, 22 (47%) female athletes exhibited serum ferritin levels of 30 ng/mL or less, defining them as hypoferritinemia. The multivariate logistic regression model revealed that a shorter duration of the athletic experience (adjusted odd ratio [95% confidence interval]: 0.62 [0.43-0.90]), lower energy intake (0.994 [0.989-0.999]), and higher dietary iron intake (4.40 [1.12-17.26]) were associated with hypoferritinemia. Seventeen (50%) female athletes reported a decline in subjective performance during menstruation, albeit two took LEP regularly.

CONCLUSIONS

This study reveals that ID is a prevalent health concern among young female athletes across sports clubs. It underscores the need for their education on the importance of assessing ID status. Limitation includes the nature of single-site and observational study, the absence of hepcidin measurement, and an unspecified amount of exercise. Comprehensive investigations are needed to elucidate the causes and optimal treatments for ID in young athletes.

Iron Status and Physical Performance in Athletes

Iron is an important mineral in the body, essential for muscle function and oxygen transport. Adequate levels of iron in the blood are necessary for athletes, as iron-deficiency anemia can reduce physical performance. Several studies have investigated iron status and supplementation in iron-deficient athletes, and determined how physical strain can change iron balance and markers related to iron status. The question of how to influence and optimize iron status, as well as other markers that can affect iron metabolism, has been less thoroughly investigated. Therefore, the aim of this review is to take a closer look at the importance of iron values, iron markers, and factors that can change iron metabolism for physical performance and the extent to which physical performance can be influenced in a positive or negative way. A systematic search of the PubMed database was performed, with the use of « iron» or «iron deficiency» or «hemoglobin» AND «athletes» AND «athletic performance» as a strategy of the search. After the search, 11 articles were included in the review after the application of inclusion and exclusion criteria. Major findings include that iron supplementation had the best effect in athletes with the lowest iron status, and effects on physical performance were mostly achieved in those who were originally in a deficit. Iron supplementation could be beneficial for optimal erythropoietic response during altitude training, even in athletes with normal iron stores at baseline, but should be performed with caution. Alteration of the hepcidin response can affect the use of existing iron stores for erythropoiesis. Energy intake, and the amount of carbohydrates available, may have an impact on the post-exercise hepcidin response. Optimal vitamin D and B12 levels can possibly contribute to improved iron status and, hence, the avoidance of anemia.

Iron deficiency in young basketball players: Is a 100 μg/L ferritin cut-off appropriate for iron supplementation?: Results of a randomized placebo-controlled study

BACKGROUND

Iron deficiency (ID) is one of the most common factors that may reduce sports performance, supplementation forms and doses are still not standardized in athletes. Our aim was to assess the iron status of young male basketball players and to study the effect of iron supplementation in a randomized placebo-controlled study.

HYPOTHESIS

We hypothesized that due to the higher iron demand of athletes, the 100 μg/L ferritin cut-off may be appropriate to determine the non-anemic ID.

METHODS

During a sports cardiology screening, questionnaires, laboratory tests, electrocardiograms, echocardiography exams, and cardiopulmonary exercise tests were performed. Athletes with ID (ferritin <100 μg/L) were randomized into iron and placebo groups. Ferrous sulfate (containing 100 mg elemental iron [II] and 60 mg ascorbic acid) or placebo (50 mg vitamin C) was administered for 3 months. All exams were repeated after the supplementation period.

RESULTS

We included 65 (age 15.8 ± 1.7 years) basketball players divided into four age groups. Non-anemic ID was observed in 60 (92%) athletes. After supplementation, ferritin levels were higher in the iron group (75.5 ± 25.9 vs. 54.9 ± 10.4 μg/L, p < .01). Ferritin >100 μg/L level was achieved only in 15% of the athletes. There were no differences in performance between the groups (VO2 max: 53.6 ± 4.3 vs. 54.4 ± 5.7 mL/kg/min, p = .46; peak lactate: 9.1 ± 2.2 vs. 9.1 ± 2.6 mmol/L, p = .90).

CONCLUSIONS

As a result of the 3-month iron supplementation, the ferritin levels increased; however, only a small portion of the athletes achieved the target ferritin level, while performance improvement was not detectable.

The Perceived Impact of Iron Deficiency and Iron Therapy Preference in Exercising Females of Reproductive Age: A Cross-Sectional Survey Study

Background

Patient perceptions of iron deficiency and efficacy of iron therapy may differ from the interpretations of doctors. Qualitative investigation at an individual level related may help define patient expectations and therapeutic targets. Therefore, we aimed to explore this concept in exercising females of reproductive age.

Methods

Exercising females (n = 403) who either (a) were currently experiencing iron deficiency, or (b) have experienced iron deficiency in the past were included. A survey comprising open-ended text response questions explored three 'domains': (1) the impact of iron deficiency, (2) the impact of iron tablet supplementation (where applicable), and (3) the impact of iron infusion treatment (where applicable). Questions were asked about training, performance, and recovery from exercise. Survey responses were coded according to their content, and sentiment analysis was conducted to assess responses as positive, negative, or neutral.

Results

Exercising females showed negative sentiment toward iron deficiency symptoms (mean range = -0.94 to -0.81), with perception that fatigue significantly impacts performance and recovery. Iron therapies were perceived to improve energy, performance, and recovery time. Participants displayed a strong positive sentiment (mean range = 0.74 to 0.79) toward iron infusion compared to a moderately positive sentiment toward oral iron supplementation (mean range = 0.44 to 0.47), with many participants perceiving that oral iron supplementation had no effect.

Conclusion

In Australia, women prefer an iron infusion in treatment of iron deficiency compared to oral iron.

Cardiopulmonary exercise testing before and after intravenous iron in preoperative patients: a prospective clinical study

BACKGROUND

Anemia is associated with impaired physical performance and adverse perioperative outcomes. Iron-deficiency anemia is increasingly treated with intravenous iron before elective surgery. We explored the relationship between exercise capacity, anemia, and total hemoglobin mass (tHb-mass) and the response to intravenous iron in anemic patients prior to surgery.

METHODS

A prospective clinical study was undertaken in patients having routine cardiopulmonary exercise testing (CPET) with a hemoglobin concentration ([Hb]) < 130 g^.l^-1 and iron deficiency/depletion. Patients underwent CPET and tHb-mass measurements before and a minimum of 14 days after receiving intravenous (i.v.) Ferric derisomaltose (Monofer®) at the baseline visit. Comparative analysis of hematological and CPET variables was performed pre and post-iron treatment.

RESULTS

Twenty-six subjects were recruited, of whom 6 withdrew prior to study completion. The remaining 20 (9 [45%] male; mean ± SD age 68 ± 10 years) were assessed 25 ± 7 days between baseline and the final visit. Following i.v. iron, increases were seen in [Hb] (mean ± SD) from 109 ± 14 to 116 ± 12 g l^-1 (mean rise 6.4% or 7.3 g l^-1, p =  < 0.0001, 95% CI 4.5-10.1); tHb-mass from 497 ± 134 to 546 ± 139 g (mean rise 9.3% or 49 g, p =  < 0.0001, 95% CI 29.4-69.2). Oxygen consumption at anerobic threshold ([Formula: see text] O_{2 AT}) did not change (9.1 ± 1.7 to 9.8 ± 2.5 ml kg^-1 min^-1, p = 0.09, 95% CI - 0.13 - 1.3). Peak oxygen consumption ([Formula: see text] O_{2 peak}) increased from 15.2 ± 4.1 to 16 ± 4.4 ml^.kg^.-1 min^-1, p = 0.02, 95% CI 0.2-1.8) and peak work rate increased from 93 [67-112] watts to 96 [68-122] watts (p = 0.02, 95% CI 1.3-10.8).

CONCLUSION

Preoperative administration of intravenous iron to iron-deficient/deplete anemic patients is associated with increases in [Hb], tHb-mass, peak oxygen consumption, and peak work rate. Further appropriately powered prospective studies are required to ascertain whether improvements in tHb-mass and performance in turn lead to reductions in perioperative morbidity.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT 033 46213.

Nutritional Considerations for the Vegan Athlete

Accepting a continued rise in the prevalence of vegan-type diets in the general population is also likely to occur in athletic populations, it is of importance to assess the potential impact on athletic performance, adaptation, and recovery. Nutritional consideration for the athlete requires optimization of energy, macronutrient, and micronutrient intakes, and potentially the judicious selection of dietary supplements, all specified to meet the individual athlete's training and performance goals. The purpose of this review is to assess whether adopting a vegan diet is likely to impinge on such optimal nutrition and, where so, consider evidence based yet practical and pragmatic nutritional recommendations. Current evidence does not support that a vegan-type diet will enhance performance, adaptation, or recovery in athletes, but equally suggests that an athlete can follow a (more) vegan diet without detriment. A clear caveat, however, is that vegan diets consumed spontaneously may induce suboptimal intakes of key nutrients, most notably quantity and/or quality of dietary protein and specific micronutrients (eg, iron, calcium, vitamin B12, and vitamin D). As such, optimal vegan sports nutrition requires (more) careful consideration, evaluation, and planning. Individual/seasonal goals, training modalities, athlete type, and sensory/cultural/ethical preferences, among other factors, should all be considered when planning and adopting a vegan diet.

Micronutrient supplement intakes among collegiate and masters athletes: A cross-sectional study

Objective

In our cross-sectional study, we evaluated micronutrient supplementation intake among Collegiate and Masters Athletes.

Methods

We conducted a cross-sectional study to assess micronutrient supplementation consumption in Collegiate and Masters Athletes, comparing sex and sport classification within each respective group. Micronutrient supplement consumption data were measured using a Food Frequency Questionnaire. A two-way analysis of variance was used to explore the differences among Collegiate and Masters Athletes' supplement intakes of the following vitamins and minerals: vitamins A, B6, B12, C, E, D, and calcium, folate, iron, magnesium niacin, riboflavin, selenium, thiamine, and zinc. When significant differences were found, a Bonferroni post hoc test was performed to identify specific group differences. The significance level was set a priori at p &lt; 0.05.

Results

A total of 198 athletes (105 females and 93 males) were included in the study. Participants were 36.16 ± 12.33 years of age. Collegiate male athletes had significantly greater vitamin A [1,090.51 ± 154.72 vs. 473.93 ± 233.18 mg retinol activity equivalents (RAE)/day] (p &lt; 0.036), folate [337.14 ± 44.79 vs. 148.67 ± 67.50 mcg dietary folate equivalents (DFE)/day] (p &lt; 0.027), and magnesium (65.35 ± 8.28 vs. 31.28 ± 12.48 mg/day) (p &lt; 0.031) intakes compared to Collegiate female athletes. Collegiate CrossFit Athletes (940.71 ± 157.54 mg/day) had a significantly greater vitamin C intake compared to Collegiate General Athletes (156.34 ± 67.79 mg/day) (p &lt; 0.005), Collegiate Triathletes (88.57 ± 148.53 mg/day) (p &lt; 0.027), Collegiate Resistance Training Athletes (74.28 ± 143.81 mg/day) (p &lt; 0.020), and Collegiate Powerlifters (175.71 ± 128.63 mg/day) (p &lt; 0.044). Masters females had significantly greater calcium intakes compared to Masters males (494.09 ± 65.73 vs.187.89 ± 77.23 mg/day, respectively) (p &lt; 0.002). Collegiate Runners (41.35 ± 6.53 mg/day) had a significantly greater iron intake compared to Collegiate Powerlifters (4.50 ± 6.53 mg/day) (p &lt; 0.024). Masters Swimmers (61.43 ± 12.10 mg/day) had significantly greater iron intakes compared to Masters General Athletes (13.97 ± 3.56 mg/day) (p &lt; 0.014), Masters Runners (17.74 ± 2.32 mg/day) (p &lt; 0.03), Masters Triathletes (11.95 ± 3.73 mg/day) (p &lt; 0.008), Masters CrossFit Athletes (15.93 ± 5.36 mg/day) (p &lt; 0.043), Masters Rowers (9.10 ± 3.36 mg/day) (p &lt; 0.003), and Masters Cyclists (1.71 ± 9.88 mg/day) (p &lt; 0.011). Masters Powerlifters (47.14 ± 9.65 mg/day) had significantly greater zinc intakes compared to Masters General Athletes (9.57 ± 2.84 mg/day) (p &lt; 0.015), Masters Runners (10.67 ± 1.85 mg/day) (p &lt; 0.017), Masters Triathletes (10.24 ± 2.98 mg/day) (p &lt; 0.020), Masters Rowers (9.33 ± 2.68 mg/day) (p &lt; 0.013), and Masters Cyclists (1.43 ± 7.88 mg/day) (p &lt; 0.019). There were no other significant differences among the other micronutrient supplement intakes between the sexes or among the sport classification.

Conclusion

We reported significant differences among female and male Collegiate and Masters Athletes. Additionally, we reported significant differences among Collegiate and Masters Athletes sport classifications. Further research should examine both dietary and micronutrient supplement intake among Collegiate and Masters Athletes to examine the extent that athletes exceed the Recommended Dietary Allowances (RDA), and the potential effects on health and performance.

Hemoglobin modulation affects physiology and patient reported outcomes in anemic and non-anemic subjects: An umbrella review

Background: An abnormal hemoglobin concentration has a substantial effect on a person's quality of life and physiology. Lack of tools that effectively evaluate hemoglobin-related outcomes leads to uncertainty regarding optimal hemoglobin levels, transfusion thresholds and treatment targets. We therefore aim to summarize reviews that assess the effects of hemoglobin modulation on the human physiology at various baseline hemoglobin levels, and identify gaps in existing evidence. Methods: We conducted an umbrella review of systematic reviews. PubMed, MEDLINE (OVID), Embase, Web of Science, Cochrane Library and Emcare were searched from inception to the 15th of April 2022 for studies that reported on physiological and patient reported outcomes following a hemoglobin change. Results: Thirty-three reviews were included of which 7 were scored as of high quality and 24 of critically low quality using the AMSTAR-2 tool. The reported data generally show that an increase in hemoglobin leads to improvement of patient reported and physical outcomes in anaemic and non-anaemic subjects. At lower hemoglobin levels, the effect of a hemoglobin modulation on quality of life measures appears more pronounced. Conclusion: This overview has revealed many knowledge gaps due to a lack of high-quality evidence. For chronic kidney disease patients, a clinically relevant benefit of increasing the hemoglobin levels up until 12 g/dL was found. However, a personalized approach remains necessary due to the many patient-specific factors that affect outcomes. We strongly encourage future trials to incorporate physiological outcomes as objective parameters together with subjective, but still very important, patient reported outcome measures.

Compliance compromises an interventional study on iron supplementation in female combatants

INTRODUCTION

Low iron levels are related to overuse injuries, poor physical performance and cognitive impairments in female recruits. The aim of this study was to evaluate iron supplement compliance in female combatants during basic training, and its effect on haemoglobin (Hgb), ferritin and injuries.

METHODS

329 female recruits to light infantry units filled induction questionnaires regarding smoking status, previous overuse injuries and iron deficiency. Blood was drawn for Hgb and ferritin. Subjects with ferritin levels below 20 ng/mL were considered iron depleted and were prescribed a ferrous fumarate supplement. After 4 months of basic training, the subjects completed a follow-up questionnaire regarding overuse injuries, reasons for failure to complete basic training and compliance with iron supplementation. Blood tests were repeated.

RESULTS

Mean ferritin levels declined during training (from 18.1±18.2 to 15.3±9.6, p=0.01). Compliance with iron supplementation was observed in 26 (26.3%) of the subjects. In compliant subjects, Hgb levels remained constant and ferritin levels increased by 2.9±5.4 (p=0.07). The main reasons for reported non-compliance were forgetfulness, 26 (35.6%), and gastrointestinal side effects, 17 (23.3%). Injuries during training were not found to be associated with iron status. Smokers had a significantly higher rate of reported injuries prior to training (p<0.01).

CONCLUSIONS

Ferritin levels decline during training. Compliance with iron supplementation is low. Iron supplementation has a significant effect on ferritin levels, even in the non-compliance group. Injuries were not related to iron status in this group. Further research is needed in order to clarify the most appropriate iron supplementation method.

Iron Deficiency and Anemia in Male and Female Adolescent Athletes Who Engage in Ball Games

The aim of this study was to assess the prevalence of iron deficiency (ID) and iron deficiency anemia (IDA) among male adolescent athletes who participate in non-calorie-restricting sports, and to compare the results with female athletes of the same age and sports. Data of the hemoglobin concentration (Hb) and serum ferritin (sFer) levels of male (n = 350) and female (n = 126) basketball and football players, aged 11-18, from two sport medicine centers in Israel were gathered and analyzed. Mild ID was defined as sFer ≤ 30 µg/L, moderate as sFer ≤ 20 µg/L, and severe as sFer ≤ 10 µg/L. IDA was defined as sFer ≤ 20 µg/L and Hb < 13 g/dL for males and sFer ≤ 20 µg/L and Hb < 12 g/dL for females. The prevalence of mild ID was 41.1% and 53.2%, moderate was 17.4% and 27.8%, and severe was 2% and 4.8% in males and females, respectively. The prevalence of IDA was 2.6% in males and 4% in females. Mild and moderate ID was significantly higher among females. In conclusion, non-anemic ID, which is known to be common among female athletes, especially in sports requiring leanness, is also highly prevalent among adolescent males playing ball games. Therefore, screening for hemoglobin and sFer is recommended for young athletes of both genders and in all sports.

Do Triathletes Periodize Their Diet and Do Their Mineral Content, Body Composition and Aerobic Capacity Change during Training and Competition Periods?

The triathlon is a demanding endurance multisport, which may strongly affect the nutritional status of athletes. The aim of this study was to find whether there are any differences in energy value and nutrient intake, body mass and body composition, aerobic performance and hair mineral status between training and competition periods and to assess whether there is a link between hair mineral content and physical capacity and nutrition. This observational study covered 20 triathletes aged 32 ± 7 years. The results of our study indicated performance improvement during the competition period (longer time to exhaustion (p = 0.025) and lower maximal oxygen uptake at the ventilatory threshold (%VO_{2max_VT}; p = 0.047)). However, no differences were recorded in nutrition and body composition between two training vs. competition periods. There was a significant depletion in hair iron content during the competition period (p = 0.010). Furthermore, there were significant relationships between hair calcium content and absolute maximal oxygen uptake and %VO_{2max_VT} during the training period. It is necessary to introduce nutritional education in the group of triathletes focused on exercise-oriented nutritional periodization following the requirements of the training and competition periods, thus preventing the risk of nutrient deficiencies.

Systematic review and meta-analysis of intravenous iron therapy for adults with non-anaemic iron deficiency: An abridged Cochrane review

Iron is an essential nutrient for oxygen supply and aerobic metabolism. Iron deficiency impacts cellular respiration and mitochondrial energy metabolism, which can lead to reduced skeletal muscle function and muscle mass, causing sarcopenia. Intravenous iron offers the ability to rapidly correct iron deficiency, but the functional impact on patient mental and physical health is unclear. We assessed the effects of intravenous iron therapy on physical function and quality of life in the treatment of adults with non-anaemic iron deficiency. An update and reanalysis of a previously published Cochrane systematic review was performed to assess randomized controlled trials that compared any intravenous iron preparation with placebo in adults. The primary functional outcome measure was physical performance as defined by the trial authors. Secondary outcome measures included fatigue and quality-of-life scores, and adverse effects at the end of follow-up. Biochemical efficacy was assessed by change in serum ferritin and haemoglobin concentration levels. Twenty-one randomized controlled trials, comprising 3514 participants, were included. Intravenous iron compared with placebo resulted in significantly increased physical function measured by mean peak oxygen consumption (mean difference [MD] 1.77 mL/kg/min, 95% confidence interval [CI] 0.57 to 2.97). An overall improvement in fatigue was seen (standardized MD 0.30, 95% CI -0.52 to -0.09) but no overall difference in quality of life (MD 0.15, 95% CI -0.01 to 0.31). Biochemically, intravenous iron resulted in improved serum ferritin (MD 245.52 μg/L, 95% CI 152.1 to 338.9) and haemoglobin levels (MD 4.65 g/L, 95% CI 2.53 to 6.78). There was a higher risk of developing mild adverse events in the intravenous iron group compared with the placebo group (risk ratio 1.77, 95% CI 1.10 to 2.83); however, no differences were seen in serious adverse events (risk difference 0, 95% CI -0.01 to 0.01). The quality of evidence was rated 'low' and 'very low' for all outcome variables, except for fatigue, mainly due to most studies being judged as having a high risk of bias. In non-anaemic iron-deficient adults, the use of intravenous iron compared with placebo improved physical function and reduced fatigue scores. However, we remain uncertain about the efficacy in this population due to low-quality evidence, and there is a need for further studies to address potential impact on overall quality of life.

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.

Sports Obstetrics: Implications of Pregnancy in Elite Sportswomen, a Narrative Review

Increasing numbers of females are participating in elite sports, with a record number having competed at the Tokyo Olympic Games. Importantly, the ages of peak performance and fertility are very likely to coincide; as such, it is inevitable that pregnancy will occur during training and competition. Whilst there is considerable evidence to promote regular exercise in pregnancy, with benefits including a reduction in hypertensive disorders, gestational diabetes, and reduced rates of post-natal depression, few studies have been conducted which include elite athletes. Indeed, there are concerns that high-intensity exercise may lead to increased rates of miscarriage and preterm labour, amongst other pregnancy-related complications. There is minimal guidance on the obstetric management of athletes, and consequently, healthcare professionals frequently adopt a very conservative approach to managing such people. This narrative review summarises the evidence on the antenatal, intrapartum, and postpartum outcomes in elite athletes and provides recommendations for healthcare providers, demonstrating that generally, pregnant athletes can continue their training, with a few notable exceptions. It also summarises the physiological changes that occur in pregnancy and reviews the literature base regarding how these changes may impact performance, with benefits arising from pregnancy-associated cardiovascular adaptations at earlier gestations but later changes causing an increased risk of injury and fatigue.

Nutritional Assessment and Proximate Analysis of Selected Vegetables Grown in Larkana, Sindh, Pakistan

Food security and protection are the most crucial concerns worldwide. However, vegetables may significantly contribute to the macro and micro-nutrients for good health compared to dietary supplements. Eight vegetables of the Larkanadivision, namely spinach (Spinacia oleracea), brinjal (Solanum melongina L.), sponge gourd (Luffa acutangula), lotus root (Lelumbo nucifera), okra (Abelmoschus esculentus), coriander leave (Coriandrum sativum), fenugreek leave (Trigonella foenum graecum), and cauliflower (Brassica oleracea) were studied for their proximate, macro and micro-mineral contents to estimate their importance in human nutrition. The results showed that almost all vegetables contain appreciable amounts of essential nutrients. All the vegetables showed moisture contents of &gt;70.00%. Lotus and sponge gourd have a maximum level of carbohydrates (&gt;10.00%). Fiber was found in the range of 2.70 – 5.10%, with the highest in the okra. Protein and fat were found at &lt; 4.00%, with maximum protein in spinach and fat in fenugreek leaves. The studied vegetables showed maximum levels of K and Ca, followed by Na, Mg, Fe, Zn, and Cu while Cr and Mn were observed to be &lt; 5.00 µg/g. The macro and micro-minerals in the studied vegetables were within the maximum permissible limits recommended by WHO. Moreover, the eight studied vegetables of the Larkana division can also provide up to 1.00% of the required dietary daily intake of macro and micro-nutrients as recommended by the Food and Nutrition Board.

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.

Changes in dietary total and non-haem iron intake is associated with incident frailty in older men: The Concord Health and Ageing in Men Project

Background

Nutritional intake could influence the development of frailty. The aim was to evaluate the associations between dietary iron intakes and changes in dietary iron intakes with frailty.

Methods

Cross-sectional analyses involved 785 men with Fried frailty phenotype (FP) and 758 men with Rockwood frailty index (FI) data aged 75 years and older at nutrition assessment from the Concord Health and Ageing in Men Project prospective cohort study. Of these, 563 men who were FP robust or prefrail, and 432 men who were FI nonfrail were included in the longitudinal analyses for more than 3 years. Dietary intake was assessed at both timepoints using a validated diet history questionnaire. The dietary calculation was used to derive heme iron and nonheme iron intakes from total iron intakes. The associations were evaluated through binary logistic regression.

Results

Incidence of FP frailty was 15.3% (n = 86). In longitudinal analyses, maintaining total iron intakes (medium tertile −2.61–0.81 mg/d), increases in total iron and nonheme iron intakes (high tertiles ≥0.82 mg/d and ≥0.80 mg/d), and changes in nonheme iron intake (1 mg increment) were associated with reduced risks of incident FP frailty (OR: 0.47 [95% confindence interval (CI): 0.24, 0.93, p = .031], OR 0.48 [95% CI: 0.23, 0.99, p = .048], OR 0.41 [95% CI: 0.20, 0.88, p = .022], and OR 0.89 [95% CI: 0.82, 0.98, p = .017]).

Conclusion

Maintaining or increases in total dietary iron and increases or changes in dietary nonheme iron intakes more than 3 years were associated with reduced incidence of FP frailty in older men.

Abnormal whole-body energy metabolism in iron-deficient humans despite preserved skeletal muscle oxidative phosphorylation

Iron deficiency impairs skeletal muscle metabolism. The underlying mechanisms are incompletely characterised, but animal and human experiments suggest the involvement of signalling pathways co-dependent upon oxygen and iron availability, including the pathway associated with hypoxia-inducible factor (HIF). We performed a prospective, case-control, clinical physiology study to explore the effects of iron deficiency on human metabolism, using exercise as a stressor. Thirteen iron-deficient (ID) individuals and thirteen iron-replete (IR) control participants each underwent 31P-magnetic resonance spectroscopy of exercising calf muscle to investigate differences in oxidative phosphorylation, followed by whole-body cardiopulmonary exercise testing. Thereafter, individuals were given an intravenous (IV) infusion, randomised to either iron or saline, and the assessments repeated ~ 1 week later. Neither baseline iron status nor IV iron significantly influenced high-energy phosphate metabolism. During submaximal cardiopulmonary exercise, the rate of decline in blood lactate concentration was diminished in the ID group (P = 0.005). Intravenous iron corrected this abnormality. Furthermore, IV iron increased lactate threshold during maximal cardiopulmonary exercise by ~ 10%, regardless of baseline iron status. These findings demonstrate abnormal whole-body energy metabolism in iron-deficient but otherwise healthy humans. Iron deficiency promotes a more glycolytic phenotype without having a detectable effect on mitochondrial bioenergetics.

Iron Deficiency in Heart Failure: Mechanisms and Pathophysiology

Iron is an essential micronutrient for a myriad of physiological processes in the body beyond erythropoiesis. Iron deficiency (ID) is a common comorbidity in patients with heart failure (HF), with a prevalence reaching up to 59% even in non-anaemic patients. ID impairs exercise capacity, reduces the quality of life, increases hospitalisation rate and mortality risk regardless of anaemia. Intravenously correcting ID has emerged as a promising treatment in HF as it has been shown to alleviate symptoms, improve quality of life and exercise capacity and reduce hospitalisations. However, the pathophysiology of ID in HF remains poorly characterised. Recognition of ID in HF triggered more research with the aim to explain how correcting ID improves HF status as well as the underlying causes of ID in the first place. In the past few years, significant progress has been made in understanding iron homeostasis by characterising the role of the iron-regulating hormone hepcidin, the effects of ID on skeletal and cardiac myocytes, kidneys and the immune system. In this review, we summarise the current knowledge and recent advances in the pathophysiology of ID in heart failure, the deleterious systemic and cellular consequences of ID.

Micronutrients and athletic performance: A review

Optimising nutrition intake is a key component for supporting athletic performance and supporting adaption to training. Athletes often use micronutrient supplements in order to correct vitamin and mineral deficiencies, improve immune function, enhance recovery and or to optimise their performance. The aim of this review was to investigate the recent literature regarding micronutrients (specifically iron, vitamin C, vitamin E, vitamin D, calcium) and their effects on physical performance. Over the past ten years, several studies have investigated the impacts of these micronutrients on aspects of athletic performance, and several reviews have aimed to provide an overview of current use and effectiveness. Currently the balance of the literature suggests that micronutrient supplementation in well-nourished athletes does not enhance physical performance. Excessive intake of dietary supplements may impair the body's physiological responses to exercise that supports adaptation to training stress. In some cases, micronutrient supplementation is warranted, for example, with a diagnosed deficiency, when energy intake is compromised, or when training and competing at altitude, however these micronutrients should be prescribed by a medical professional. Athletes are encouraged to obtain adequate micronutrients from a wellbalanced and varied dietary intake.

The need to screen for anemia in exercising women

ABSTRACT

Anemia is common, affecting 1 in 3 women in their lifetime. Despite high prevalence rates, awareness is poor. This is relevant for women undertaking sport as anemia can lead to reduced physical performance. There is no current screening program for testing of anemia for exercising women. Therefore, the objective of the present study was to assess a simple screening tool to predict anemia in exercising women.Cross sectional survey study.National fitness festival.Three hundred exercising women.Screening methodology (Female Health Questionnaire and a haemoglobin concentration measurement).The Female Health Questionnaire inquired about; previous iron status, menstrual blood loss, diet, and motherhood. Participants were asked to self-report any symptoms of iron deficiency, including; brain fog, palpitations, shortness of breath, restless legs, hair loss, and pica. Results were compared to fingerprick haemoglobin levels with anemia defined as [Hb] < 120 g/L.Average age was 31.21years (s.d.7.72), average [Hb] was 131.76 g/L (s.d.11.5) and 36 (12%) had anemia. A history of iron deficiency was reported by 127 (43.49%), 127 (43.49%) reported heavy menstrual bleeding (HMB), 75 were vegetarian (18%) or vegan (8%) and 33 were mothers (11%). In total 80 reported taking time off work (total 1612 days). Women with anemia more commonly reported HMB (58.33% vs. 41.57%, P = .04), and those with HMB were more likely to report days off (39.37% vs. 18.18%, P < .001).Anemia was common in exercising women, particularly those with HMB. A simple screening tool for HMB and finger prick haemoglobin testing for anemia is recommended in women undertaking exercise.

The Effects of Crocodile Blood Supplementation on Delayed-Onset Muscle Soreness

Delayed-onset muscle soreness (DOMS) is associated with increases in acute inflammatory and biochemical markers, muscle swelling, pain, and reduced functional performance. This study aimed to investigate the preventative effects of crocodile blood supplementation on DOMS induced by eccentric exercise. Sixteen healthy males were randomly allocated to either a crocodile blood (CB, n = 8) or a placebo (PL, n = 8) treatment. Participants receiving the CB treatment consumed four capsules of freeze-dried CB powder (1 g day-1) over 18 days. Participants receiving the other treatment were administered a placebo over the same period. An eccentric exercise protocol was performed, and functional performance, visual analogue scale (VAS)-measured pain, knee range of movement (ROM), thigh circumference (swelling), and cytokines, enzymes, and biochemical parameters were assessed immediately after exercise as well as after 24 h, 48 h, and 72 h. CB supplementation could significantly maintain maximum voluntary isometric contraction (MVIC) at 24 h (p = 0.001) and 48 h after exercise (p = 0.001) when comparing values at different times for the CB group. In the CB group, thigh circumference decreased only immediately after eccentric exercise (p = 0.031) in comparison with pre-eccentric exercise values. An 18-day supplementation (1 g day-1) of crocodile blood does aid in the maintenance of functional performance and muscle swelling after eccentric exercise. Our data indicate that 1 g day-1 of crocodile blood supplementation should be safe for human consumption.

Clinician's Corner: Anemia at Altitude-Iron Deficiency and Other Acquired Anemias

DeLoughery, Thomas G. Clinician's corner: Anemia at altitude-Iron deficiency and other acquired anemias. High Alt Med Biol. 22:000-000, 2021.-Acquired anemias are common throughout the world. This article will discuss iron deficiency and other acquired causes of anemia such as inflammation and renal disease. Iron deficiency with or without anemia can detract from performance and may be a risk factor for altitude sickness. Anyone considering going to altitude should be screened for iron deficiency with a serum ferritin if they have risk factors for iron deficiency. The effects of other acquired anemias are less well defined. Several other diseases can also lead to anemia, and altitude challenges are more related to the underlying disease than to anemia.

The misogyny of iron deficiency

Anaemia is common, particularly in women and the commonest underlying cause, iron deficiency, is often overlooked. Anaemia is associated with increased morbidity and mortality in patients undergoing anaesthesia; however, women are defined as being anaemic at a lower haemoglobin level than men. In this narrative review, we present the history of iron deficiency anaemia and how women's health has often been overlooked. Iron deficiency was first described as 'chlorosis' and a cause of 'hysteria' in women and initial treatment was by iron filings in cold wine. We present data of population screening demonstrating how common iron deficiency is, affecting 12-18% of apparently 'fit and healthy' women, with the most common cause being heavy menstrual bleeding; both conditions being often unrecognised. We describe a range of symptoms reported by women, that vary from fatigue to brain fog, hair loss and eating ice. We also describe experiments exploring the physical impact of iron deficiency, showing that reduced exercise performance is related to iron deficiency independent of haemoglobin concentration, as well as the impact of iron supplementation in women improving oxygen consumption and fitness. Overall, we demonstrate the need to single out women and investigate iron deficiency rather than accept the dogma of normality and differential treatment; this is to say, the need to change the current standard of care for women undergoing anaesthesia.

Iron deficiency without anaemia: a diagnosis that matters

Iron deficiency anaemia (IDA) currently affects 1.2 billion people and iron deficiency without anaemia (IDWA) is at least twice as common. IDWA is poorly recognised by clinicians despite its high prevalence, probably because of suboptimal screening recommendations. Diagnosing IDWA relies on a combination of tests, including haemoglobin and ferritin levels, as well as transferrin saturation. Although the causes of iron deficiency may sometimes be obvious, many tend to be overlooked. Iron sufficiency throughout pregnancy is necessary for maternal and foetal health. Preoperative IDWA must be corrected to reduce the risk of transfusion and postoperative anaemia. Oral iron is the first-line treatment for managing IDWA; however, intravenous supplementation should be used in chronic inflammatory conditions and when oral therapy is poorly tolerated or ineffective. This review considers the causes and clinical features of IDWA, calls for greater awareness of the condition, and proposes diagnostic and management algorithms.

Chronic Iron Overload Restrains the Benefits of Aerobic Exercise to the Vasculature

Physical exercise is a well-recognized effective non-pharmacological therapy for cardiovascular diseases. However, because iron is essential element in many physiological processes including hemoglobin and myoglobin synthesis, thereby playing a role on oxygen transport, many athletes use iron supplement to improve physical performance. Regarding this, iron overload is associated with oxidative stress and damage to various systems, including cardiovascular. Thus, we aimed to identify the vascular effects of aerobic exercise in a rat model of iron overload. Male Wistar rats were treated with 100 mg/kg/day iron-dextran, i.p., 5 days a week for 4 weeks, and then underwent aerobic exercise protocol on a treadmill at moderate intensity, 60 min/day, 5 days a week for 8 weeks. Exercise reduced vasoconstrictor response of isolated aortic rings by increasing participation of nitric oxide (NO) and reducing oxidative stress, but these benefits to the vasculature were not observed in rats previously subjected to iron overload. The reduced vasoconstriction in the exercised group was reversed by incubation with superoxide dismutase (SOD) inhibitor, suggesting that increased SOD activity by exercise was lost in iron overload rats. Iron overload groups increased serum levels of iron, transferrin saturation, and iron deposition in the liver, gastrocnemius muscle, and aorta, and the catalase was overexpressed in the aorta probably as a compensatory mechanism to the increased oxidative stress. In conclusion, despite the known beneficial effects of aerobic exercise on vasculature, our results indicate that previous iron overload impeded the anticontractile effect mediated by increased NO bioavailability and endogenous antioxidant response due to exercise protocol.

Ferritin readings in young adult, female university student recreational runners

BACKGROUND

Elite female athletes have shown vulnerability to various degrees of iron deficiency. Less is known about recreational fitness exercisers. A study was done to examine plasma ferritin, an assessor of iron status, in young adult, university student fitness runners.

METHODS

The present study examined serum ferritin concentrations, an indicator of iron status, in 39 female university students (age 18-25) who ran for fitness, but ran less than competition runners. Selected subjects all reported themselves as not anemic.

RESULTS

Mean + SD for 3 mile run time was 26.25 + 3.0 min. The mean ferritin reading was low: 12.4 + 12.3 ng/mL (+ SD). Out of the 39 women, 29 had readings that fell below 15 ng/mL, which some consider the cutoff for iron deficiency. In addition, all but 2 subjects had values below 35, which has been proposed as Stage 1 iron deficiency for athletes. Ferritin levels did not correlate with 3 mile run times (Pearson correlation coefficient, P > 0.05). A 1 mo intervention with 3 minerals that included iron (36 mg/day) significantly raised ferritin values when the iron was bisglycinate (p < 0.05), but not when it was ferrous sulfate (p > 0.05).

CONCLUSION

In this study, a degree of iron deficiency was seen in most of a group of female fitness runners (each of whom had self reported as not being anemic).

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.

Genotype scores in energy and iron-metabolising genes are higher in elite endurance athletes than in nonathlete controls

Information about the association of energy and iron-metabolising genes with endurance performance is scarce. The objective of this investigation was to compare the frequencies of polymorphic variations of genes involved in energy generation and iron metabolism in elite endurance athletes versus nonathlete controls. Genotype frequencies in 123 male elite endurance athletes (75 professional road cyclists and 48 elite endurance runners) and 122 male nonathlete participants were compared by assessing 4 genetic polymorphisms: AMPD1 c.34C/T (rs17602729), PPARGC1A c.1444G/A (rs8192678) HFE_H63D c.187C/G (rs1799945) and HFE_C282Y c.845G/A (rs1800562). A weighted genotype score (w-TGS; from 0 to 100 arbitrary units (a.u.)) was calculated by assigning a corresponding weight to each polymorphism. In the nonathlete population, the mean w-TGS value was lower (39.962 ± 14.654 a.u.) than in the group of elite endurance athletes (53.344 ± 17.053 a.u). The binary logistic regression analysis showed that participants with a w-TGS > 38.975 a.u had an odds ratio of 1.481 (95% confidence interval: 1.244-1.762; p < 0.001) for achieving elite athlete status. The genotypic distribution of polymorphic variations involved in energy generation and iron metabolism was different in elite endurance athletes vs. controls. Thus, an optimal genetic profile in these genes might contribute to physical endurance in athlete status. Novelty Genetic profile in energy generation and iron-metabolising genes in elite endurance athletes is different than that of nonathletes. There is an implication of an "optimal" genetic profile in the selected genes favouring endurance sporting performance.

Evaluation of Systematic Blood Testing at the Time of Recruitment to the Armed Forces: Retrospective Monocentric Study Among 726 French Army Soldiers

INTRODUCTION

In the French armed forces, the biological checkup required during the recruitment process comprises a urinalysis (urinary dipstick), a complete blood count (CBC), and measurement of serum levels of aspartate aminotransferase, alanine aminotransferase, fasting blood glucose, and creatinine. This study aimed to evaluate the benefits of this biological checkup and to determine the most relevant parameters.

MATERIALS AND METHODS

We conducted a monocentric retrospective study of all standardized and systematically conducted blood tests (CBC and measurement of aspartate aminotransferase, alanine aminotransferase, fasting blood glucose, and creatinine) over a 15-month period among 726 French Army recruits.

RESULTS

The population included mainly young males (85.4%, mean age 21.6 years). More than half (54.1%) of the blood tests had at least one abnormal parameter, most often concerning the CBC. Anemia occurred in 5.3% of the population and was mostly normocytic. Microcytosis was mostly not associated with anemia (72.3% of cases). Lymphopenia occurred in 20.1% of the population and was mostly mild. Eosinophilia was present in 5.1% of the population and was never severe. Thrombocytopenia occurred in 0.7% of the population and was never severe. Serum levels of aminotransferases were elevated in 8.1% of the population. Fasting plasma glucose averaged 84 mg/dL (SD: 0.07) ranging from 64 to 123 mg/dL, was abnormal in 0.4% of the population, and one case of diabetes was diagnosed. Serum creatinine concentration was elevated in 0.7% of the population.

CONCLUSION

CBCs gave useful information but iron deficiency was common and insufficiently detected by this single analysis. Assessing aminotransferase levels without screening for viral hepatitis and systematic measurement of fasting plasma glucose levels did not appear to be efficient. In addition, the only interest in systematic measurement of creatinine serum levels was to obtain a reference level for long-term follow-up. In addition to the urinary dipstick, the systematic biological checkup at recruitment could be limited to a CBC with measurement of plasma ferritin levels and Hepatitis B virus serology, providing that any CBC abnormalities, in particular cytopenia, eosinophilia, and microcytosis, are systematically investigated. For a public health approach, systematic screening for other sexually transmitted infections could be proposed.

The association of HFE gene H63D polymorphism with endurance athlete status and aerobic capacity: novel findings and a meta-analysis

PURPOSE

Iron is an important component of the oxygen-binding proteins and may be critical to optimal athletic performance. Previous studies have suggested that the G allele of C/G rare variant (rs1799945), which causes H63D amino acid replacement, in the HFE is associated with elevated iron indexes and may give some advantage in endurance-oriented sports. The aim of the present study was to investigate the association between the HFE H63D polymorphism and elite endurance athlete status in Japanese and Russian populations, aerobic capacity and to perform a meta-analysis using current findings and three previous studies.

METHODS

The study involved 315 international-level endurance athletes (255 Russian and 60 Japanese) and 809 healthy controls (405 Russian and 404 Japanese). Genotyping was performed using micro-array analysis or by PCR. VO2max in 46 male Russian endurance athletes was determined using gas analysis system.

RESULTS

The frequency of the iron-increasing CG/GG genotypes was significantly higher in Russian (38.0 vs 24.9%; OR 1.85, P = 0.0003) and Japanese (13.3 vs 5.0%; OR 2.95, P = 0.011) endurance athletes compared to ethnically matched controls. The meta-analysis using five cohorts (two French, Japanese, Spanish, and Russian; 586 athletes and 1416 controls) showed significant prevalence of the CG/GG genotypes in endurance athletes compared to controls (OR 1.96, 95% CI 1.58-2.45; P = 1.7 × 10-9). Furthermore, the HFE G allele was associated with high V̇O2max in male athletes [CC: 61.8 (6.1), CG/GG: 66.3 (7.8) ml/min/kg; P = 0.036].

CONCLUSIONS

We have shown that the HFE H63D polymorphism is strongly associated with elite endurance athlete status, regardless ethnicities and aerobic capacity in Russian athletes.

Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence

Vitamins and minerals are essential to humans as they play essential roles in a variety of basic metabolic pathways that support fundamental cellular functions. In particular, their involvement in energy-yielding metabolism, DNA synthesis, oxygen transport, and neuronal functions makes them critical for brain and muscular function. These, in turn, translate into effects on cognitive and psychological processes, including mental and physical fatigue. This review is focused on B vitamins (B1, B2, B3, B5, B6, B8, B9 and B12), vitamin C, iron, magnesium and zinc, which have recognized roles in these outcomes. It summarizes the biochemical bases and actions of these micronutrients at both the molecular and cellular levels and connects them with cognitive and psychological symptoms, as well as manifestations of fatigue that may occur when status or supplies of these micronutrients are not adequate.

Intravenous iron therapy for non-anaemic, iron-deficient adults

BACKGROUND

Iron deficiency is one of the most common nutritional deficiencies, and has a number of physiological manifestations. Early, or non-anaemic iron deficiency can result in fatigue and diminished exercise capacity. Oral iron preparations have a high incidence of intolerable side effects, and are ineffective in certain forms of iron deficiency. Consequently, intravenous iron preparations are increasingly used in the treatment of non-anaemic iron deficiency. The newer, more stable iron preparations in particular purport to have a lower incidence of side effects, and are now used across a range of different patient populations.

OBJECTIVES

To assess the effects of intravenous iron therapy in the treatment of adults with non-anaemic iron deficiency.

SEARCH METHODS

On 18 October 2019 we electronically searched CENTRAL, MEDLINE, Embase, two further databases and two trials registries 2019. We handsearched the references of full-text extracted studies, and contacted relevant study authors for additional data.

SELECTION CRITERIA

We included randomised controlled trials that compared any intravenous iron preparation to placebo in adults. We excluded other forms of comparison such as oral iron versus placebo, intramuscular iron versus placebo, or intravenous iron studies where other iron preparations were used as the comparator. We also excluded studies involving erythropoietin therapy or obstetric populations.

DATA COLLECTION AND ANALYSIS

Two review authors screened references for eligibility, extracted data and assessed risk of bias. We resolved differences in opinion through discussion and consensus, and where necessary, involved a third review author to adjudicate disputes. We contacted study authors to request additional data where appropriate. The primary outcome measures were haemoglobin concentration at the end of follow-up, and quality-of-life scores at end of follow-up. Secondary outcome measures were serum ferritin, peak oxygen consumption (as measured by cardiopulmonary exercise testing), adverse effects (graded as mild to moderate and severe) and bacterial infection. We pooled data for continuous outcomes, which we then reported as mean differences (MDs) with 95% confidence intervals (CIs). We reported quality-of-life metrics as standardised mean difference (SMD), and then converted them back into a more familiar measure, the Piper Fatigue Scale. We analysed dichotomous outcomes as risk ratios (RRs). Given an expected degree of heterogeneity, we used a random-effects model for all outcomes. We performed the analysis with the software package Review Manager 5.

MAIN RESULTS

This review includes 11 studies with 1074 participants. Outcome metrics for which data were available (haemoglobin concentration, quality-of-life scores, serum ferritin, peak oxygen consumption and mild to moderate adverse effects) were similar across the included studies. The incidence of severe adverse events across all studies was zero. None of the studies measured bacterial infection as a specific outcome metric. Substantial heterogeneity influenced the results of the meta-analysis, arising from differing patient populations, definitions of iron deficiency, iron preparations and dosing regimens, and time to end of follow-up. Consequently, many outcomes are reported with small group sizes and wide confidence intervals, with a subsequent downgrading in the quality of evidence. The level of bias in many included studies was high, further reducing confidence in the robustness of the results. We found that intravenous iron therapy may lead to a small increase in haemoglobin concentration of limited clinical significance compared to placebo (MD 3.04 g/L, 95% CI 0.65 to 5.42; I2 = 42%; 8 studies, 548 participants; low-quality evidence). Quality-of-life scores (Piper Fatigue Scale MD 0.73, 95% CI 0.29 to 1.18; I2 = 0%; studies = 3) and peak oxygen consumption (MD 2.77 mL/kg/min, 95% CI -0.89 to 6.43; I2 = 36%; 2 studies, 32 participants) were associated with very low-quality evidence, and we remain uncertain about the role of intravenous iron for these metrics. We were unable to present pooled estimates for the outcomes of serum ferritin at the end of follow-up or mild to moderate adverse effects due to extreme statistical heterogeneity. Ultimately, despite the results of the meta-analysis, the low- or very low-quality evidence for all outcomes precludes any meaningful interpretation of results beyond suggesting that further research is needed. We performed a Trial Sequential Analysis for all major outcomes, none of which could be said to have reached a necessary effect size.

AUTHORS' CONCLUSIONS

Current evidence is insufficient to show benefit of intravenous iron preparations for the treatment of non-anaemic iron deficiency across a variety of patient populations, beyond stating that it may result in a small, clinically insignificant increase in haemoglobin concentration. However, the certainty for even this outcome remains limited. Robust data for the effectiveness of intravenous iron for non-anaemic iron deficiency is still lacking, and larger studies are required to assess the effect of this therapy on laboratory, patient-centric, and adverse-effect outcomes.

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.

The Role of Mineral and Trace Element Supplementation in Exercise and Athletic Performance: A Systematic Review

Minerals and trace elements (MTEs) are micronutrients involved in hundreds of biological processes. Deficiency in MTEs can negatively affect athletic performance. Approximately 50% of athletes have reported consuming some form of micronutrient supplement; however, there is limited data confirming their efficacy for improving performance. The aim of this study was to systematically review the role of MTEs in exercise and athletic performance. Six electronic databases and grey literature sources (MEDLINE; EMBASE; CINAHL and SportDISCUS; Web of Science and clinicaltrials.gov) were searched, in accordance with PRISMA guidelines. Results: 17,433 articles were identified and 130 experiments from 128 studies were included. Retrieved articles included Iron (n = 29), Calcium (n = 11), Magnesium, (n = 22), Phosphate (n = 17), Zinc (n = 9), Sodium (n = 15), Boron (n = 4), Selenium (n = 5), Chromium (n = 12) and multi-mineral articles (n = 5). No relevant articles were identified for Copper, Manganese, Iodine, Nickel, Fluoride or Cobalt. Only Iron and Magnesium included articles of sufficient quality to be assigned as 'strong'. Currently, there is little evidence to support the use of MTE supplementation to improve physiological markers of athletic performance, with the possible exception of Iron (in particular, biological situations) and Magnesium as these currently have the strongest quality evidence. Regardless, some MTEs may possess the potential to improve athletic performance, but more high quality research is required before support for these MTEs can be given. PROSPERO preregistered (CRD42018090502).