Iron supplementation benefits physical performance in women of reproductive age: a systematic review and meta-analysis

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.

Effectiveness of ferritin-guided donation intervals in whole-blood donors in the Netherlands (FIND'EM): a stepped-wedge cluster-randomised trial

BACKGROUND

Whole-blood donors are at increased risk for iron deficiency and anaemia. The current standard of haemoglobin monitoring is insufficient to ensure the maintenance of proper iron reserves and donor health. We aimed to determine the effects of ferritin-guided donation intervals for blood donor health and blood supply in the Netherlands.

METHODS

In this stepped-wedge cluster-randomised trial (FIND'EM), the 138 fixed and mobile donation centres in the Netherlands are organised into 29 geographical clusters and the clusters were randomly assigned to four treatment groups, with two groups being further split into two per a protocol amendment. Eligible donors were whole-blood donors who consented for use of their leftover material in the study. Each group was sequentially crossed over from the existing policy (haemoglobin-based screening; control) to a ferritin-guided donation interval policy over a 3-year period. In the intervention groups, in addition to the existing haemoglobin screening, ferritin was measured in all new donors and at every fifth donation in repeat donors. Subsequent donation intervals were extended to 6 months if ferritin concentrations were 15-30 ng/mL and to 12 months if they were less than 15 ng/mL. Outcomes were measured cross-sectionally across all donation centres at four timepoints. Primary outcomes were ferritin and haemoglobin concentrations, iron deficiency, and haemoglobin-based deferrals. We assessed all outcomes by sex and menopausal status and significance for primary outcomes was indicated by a p value of less than 0·0125. This trial is registered in the Dutch trial registry, NTR6738, and is complete.

FINDINGS

Between Sept 11, 2017, and Nov 27, 2020, 412 888 whole-blood donors visited a donation centre, and we did measurements on samples from 37 621 donations from 36 099 donors. Over 38 months, ferritin-guided donation intervals increased mean ferritin concentrations (by 0·18 log10 ng/mL [95% CI 0·15-0·22; p<0·0001] in male donors, 0·10 log10 ng/mL [0·06-0·15; p<0·0001] in premenopausal female donors, and 0·17 log10 ng/mL [0·12-0·21; p<0·0001] in postmenopausal female donors) and mean haemoglobin concentrations (by 0·30 g/dL [95% CI 0·22-0·38; p<0·0001] in male donors, 0·12 g/dL [0·03-0·20; p<0·0074] in premenopausal female donors, and 0·16 g/dL [0·05-0·27; p<0·0044] in postmenopausal female donors). Iron deficiency decreased by 36-38 months (odds ratio [OR] 0·24 [95% CI 0·18-0·31; p<0·0001] for male donors, 0·49 [0·37-0·64; p<0·0001] for premenopausal female donors, and 0·24 [0·15-0·37; p<0·0001] for postmenopausal female donors). At 36-38 months, haemoglobin-based deferral decreased significantly in male donors (OR at 36-38 months 0·21 [95% CI 0·10-0·40, p<0·0001]) but not significantly in premenopausal or postmenopausal female donors (0·81 [0·54-1·20; p=0·29] and 0·50 [95% CI 0·25-0·98; p=0·051], respectively).

INTERPRETATION

Ferritin-guided donation intervals significantly improved haemoglobin and ferritin concentrations and significantly decreased iron deficiency over the study period. Haemoglobin-based deferrals decreased significantly for male donors, but not female donors. Although this intervention is overall beneficial for maintenance of iron and haemoglobin concentrations in donors, increased efforts are needed to recruit and retain donors.

FUNDING

The Sanquin Research Programming Committee.

The Effects of the RANI Project on 6-Month Physical Activity Among Women Living in Rural India: A Randomized-Controlled Trial

Background

Anemia is associated with fatigue, low physical activity, and poor quality of life. The purpose of this study was to determine the effects of a field trial on 6-month change in anemia and physical activity among nonpregnant women living in rural India.

Methods

The Reduction in Anemia through Normative Innovations (RANI) Project is a cluster randomized controlled trial of a social norms-based intervention to reduce anemia among women (15-49 years). Participants (n = 292) performed a modified Queen's College Step Test (QCST) and wore an ActivPAL accelerometer for 3 days. Hemoglobin concentrations (g/dL) were determined using a HemoCue 301 photometer. Linear regression tested the effects of the intervention on 6-month change in hemoglobin and physical activity, while adjusting for age, body mass index, education, parity, and predicted VO2max.

Results

We observed no differences in hemoglobin (11.8 ± 1.2 vs.11.6 ± 1.4 g/dL) or overall physical activity (36.6 ± 2.1 vs. 35.3 ± 5.8 metabolic equivalent of task-hours/day) at 6 months between the treatment and control groups, respectively. In contrast, steps/day was significantly higher in the treatment, compared with the control group (β = 1353.83; 95% confidence interval: 372.46, 2335.31), independent of other covariables.

Conclusions

The potential to modify walking and other health-seeking behaviors using a social norms approach is worthy of further investigation among women living in rural India.Clinical Trial Registry - India: CTRI/2018/10/016186.

Iron deficiency in children with a focus on inflammatory conditions

Iron deficiency (ID) tends to be overlooked compared with anemia. However, its prevalence is estimated to be twice as high as that of ID anemia, and ID without anemia can be accompanied by clinical and functional impairments. The symptoms of ID are nonspecific, such as fatigue and lethargy, but can lead to neurodevelopmental disorders in children, restless legs syndrome, and recurrent infections due to immune system dysregulation. In particular, the risk of ID is high in the context of chronic inflammatory diseases (CIDs) due to the reaction of various cytokines and the resulting increase in hepcidin levels; ID further exacerbates these diseases and increases mortality. Therefore, the diagnosis of ID should not be overlooked through ID screening especially in high-risk groups. Ferritin and transferrin saturation levels are the primary laboratory parameters used to diagnose ID. However, as ferritin levels respond to inflammation, the diagnostic criteria differ among guidelines. Therefore, new tools and criteria for accurately diagnosing ID should be developed. Treatment can be initiated only with an accurate diagnosis. Oral iron is typically the first-line treatment for ID; however, the efficacy and safety of intravenous iron have recently been recognized. Symptoms improve quickly after treatment, and the prognosis of accompanying diseases can also be improved. This review highlights the need to improve global awareness of ID diagnosis and treatment, even in the absence of anemia, to improve the quality of life of affected children, especially those with CIDs.

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.

Long-term iron supplementation combined with vitamin B6 enhances maximal oxygen uptake and promotes skeletal muscle-specific mitochondrial biogenesis in rats

Introduction

Iron is an essential micronutrient that plays a crucial role in various biological processes. Previous studies have shown that iron supplementation is related to exercise performance and endurance capacity improvements. However, the underlying mechanisms responsible for these effects are not well understood. Recent studies have suggested the beneficial impact of iron supplementation on mitochondrial function and its ability to rescue mitochondrial function under adverse stress in vitro and rodents. Based on current knowledge, our study aimed to investigate whether the changes in exercise performance resulting from iron supplementation are associated with its effect on mitochondrial function.

Methods

In this study, we orally administered an iron-based supplement to rats for 30 consecutive days at a dosage of 0.66 mg iron/kg body weight and vitamin B6 at a dosage of 0.46 mg/kg.

Results

Our findings reveal that long-term iron supplementation, in combination with vitamin B6, led to less body weight gained and increased VO2 max in rats. Besides, the treatment substantially increased Complex I- and Complex II-driven ATP production in intact mitochondria isolated from gastrocnemius and cerebellum. However, the treatment did not change basal and succinate-induced ROS production in mitochondria from the cerebellum and skeletal muscle. Furthermore, the iron intervention significantly upregulated several skeletal muscle mitochondrial biogenesis and metabolism-related biomarkers, including PGC-1α, SIRT1, NRF-2, SDHA, HSL, MTOR, and LON-P. However, it did not affect the muscular protein expression of SIRT3, FNDC5, LDH, FIS1, MFN1, eNOS, and nNOS. Interestingly, the iron intervention did not exert similar effects on the hippocampus of rats.

Discussion

In conclusion, our study demonstrates that long-term iron supplementation, in combination with vitamin B6, increases VO2 max, possibly through its positive role in regulating skeletal muscle-specific mitochondrial biogenesis and energy production in rats.

Biology of Anemia: A Public Health Perspective

Our goal is to present recent progress in understanding the biological mechanisms underlying anemia from a public health perspective. We describe important advances in understanding common causes of anemia and their interactions, including iron deficiency (ID), lack of other micronutrients, infection, inflammation, and genetic conditions. ID develops if the iron circulating in the blood cannot provide the amounts required for red blood cell production and tissue needs. ID anemia develops as iron-limited red blood cell production fails to maintain the hemoglobin concentration above the threshold used to define anemia. Globally, absolute ID (absent or reduced body iron stores that do not meet the need for iron of an individual but may respond to iron supplementation) contributes to only a limited proportion of anemia. Functional ID (adequate or increased iron stores that cannot meet the need for iron because of the effects of infection or inflammation and does not respond to iron supplementation) is frequently responsible for anemia in low- and middle-income countries. Absolute and functional ID may coexist. We highlight continued improvement in understanding the roles of infections and inflammation in causing a large proportion of anemia. Deficiencies of nutrients other than iron are less common but important in some settings. The importance of genetic conditions as causes of anemia depends upon the specific inherited red blood cell abnormalities and their prevalence in the settings examined. From a public health perspective, each setting has a distinctive composition of components underlying the common causes of anemia. We emphasize the coincidence between regions with a high prevalence of anemia attributed to ID (both absolute and functional), those with endemic infections, and those with widespread genetic conditions affecting red blood cells, especially in sub-Saharan Africa and regions in Asia and Oceania.

The Physiological Requirements of and Nutritional Recommendations for Equestrian Riders

Equestrian sport is under-researched within the sport science literature, creating a possible knowledge vacuum for athletes and support personnel wishing to train and perform in an evidence-based manner. This review aims to synthesise available evidence from equitation, sport, and veterinary sciences to describe the pertinent rider physiology of equestrian disciplines. Estimates of energy expenditure and the contribution of underpinning energy systems to equestrian performance are used to provide nutrition and hydration recommendations for competition and training in equestrian disciplines. Relative energy deficiency and disordered eating are also considered. The practical challenges of the equestrian environment, including competitive, personal, and professional factors, injury and concussion, and female participation, are discussed to better highlight novelty within equestrian disciplines compared to more commonly studied sports. The evidence and recommendations are supported by example scenarios, and future research directions are outlined.

Access to basic sanitation facilities reduces the prevalence of anaemia among women of reproductive age in sub-saharan Africa

BACKGROUND

The prevalence (≈ 30%) of anaemia among women of reproductive age in Sub-Saharan Africa (SSA) is a significant concern. Additionally, less than half of households in the region have access to basic sanitation facilities, raising questions about the potential role of poor sanitation in increasing anaemia prevalence. To address this, we examined the relationship between access to basic sanitation facilities and the prevalence of anaemia among women of reproductive age in SSA.

METHODS

The study analysed cross-sectional household-level Demographic and Health Survey data from selected SSA countries. A total of 100,861 pregnant and non-pregnant women aged 15 to 49 from 27 countries were analysed. Access to basic sanitation and haemoglobin (Hb) levels were classified using WHO and UNICEF standards. To examine the link between access to basic sanitation facilities and the prevalence of anaemia, a multilevel regression analysis was conducted, which adjusted for country fixed-effects to ensure that the findings were not biassed by variations in country-level factors.

RESULTS

Nearly 37% (95% CI: 36.4, 37.9) of households had access to basic sanitation facilities, and 41% (95% CI: 40.8, 42.1) of women had Hb levels that indicated anaemia. Women with access to basic sanitation had a lower risk of anaemia than those without access (AOR = 0.95; 95% CI: 0.93, 0.98, p < 0.01). Factors, including maternal age, education, marital status, breastfeeding, health insurance enrollment, and wealth group, were also associated with anaemia prevalence.

CONCLUSIONS

Anaemia is a severe public health problem among women of reproductive age across all 27 SSA countries analysed, with nearly four in ten being affected. Access to basic sanitation facilities was associated with a reduced anaemia risk. However, only slightly over a third of households had access to such facilities. Further research is required to examine the underlying mechanisms and inform effective interventions.

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.

Role of iron in the reduction of anemia among women of reproductive age in low-middle income countries: insights from systematic review and meta-analysis

BACKGROUND

Iron deficiency anemia is a common public health issue among women of reproductive age (WRA) because it can result in adverse maternal and birth outcomes. Although studies are undertaken to assess iron efficacy, some gaps and limitations in the existing literature need to be addressed. To fill the gaps, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) assessing the role of iron in reducing anemia among WRA in low-middle-income countries (LMICs).

METHODS

A comprehensive search strategy was used to search Medline through PubMed, Embase, and Science Direct for RCTs published between 2000 and 2020. The primary outcome was the mean change in hemoglobin level. We used standardized mean differences and their respective 95% CI to estimate the pooled effect. We used I² statistics and Egger's test to assess heterogeneity and publication bias, respectively. This review was carried out in accordance with revised guidelines based on the Preferred Reporting Items for Systematic Review and Meta-analysis.

RESULTS

The findings showed that iron therapy improved hemoglobin and ferritin levels, though the results varied across studies. An overall pooled effect estimate for the role of iron therapy in improving the hemoglobin levels among WRA was -0.71 (95% CI: -1.27 to -0.14) (p = 0.008). Likewise, the overall pooled effect estimate for the role of iron therapy in improving the ferritin levels among WRA was -0.76 (95% CI: -1.56 to 0.04) (p = 0.04). The heterogeneity (I²) across included studies was found to be statistically significant for studies assessing hemoglobin (Q = 746.93, I² = 97.59%, p = 0.000) and ferritin level (Q = 659.95, I² = 97.88%, p = 0.000).

CONCLUSION

Iron therapy in any form may reduce anemia's burden and improve hemoglobin and ferritin levels, indicating improvement in iron-deficiency anemia. More evidence is required, however, to assess the morbidity associated with iron consumption, such as side effects, work performance, economic outcomes, mental health, and adherence to the intervention, with a particular focus on married but non-pregnant women planning a pregnancy in the near future.

TRIAL REGISTRATION

Registered with PROSPERO and ID is CRD42020185033.

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.

Microbial bowel infections-induced biochemical and biological abnormalities and their effects on young Egyptian swimmers

Swimmers' personal hygiene affects the spread of microbes in pools. The present study aimed to determine the incidence of microbial infections among young Egyptian swimmers and its impact on swimmers' scores. From January 2020 to June 2021, 528 public club swimmers were examined cross-sectionally. Swimmers were divided into two groups according to their star tests and their scores in the competition (group 1 with a high score and group 2 with a low score). Stool samples, biochemical and biological parameters were assessed. Microbial infections were 54% for intestinal parasitosis and 2.8% for Helicobacter pylori. The rate of intestinal parasitosis was higher among Gp2 as compared to Gp1. The results also revealed higher prevalence of Cryptosporidium spp., Giardia lamblia, Entameba histolytica, and Cyclospora among Gp2 than Gp1. Swimming frequency, and duration influenced the infectious status that induced anemia, abnormal blood pressure, and heart rate. Infected swimmers with cryptosporidiosis had higher alanine transaminase levels, white blood cells, and differential cells but lower aspartate transaminase levels. Giardiasis showed higher reduction in the biochemical markers including ferritin, lactoferrin, iron, and transferrin among Gp 2, compared to Gp 1 and thus affected the swimmers' scores. Thus, raising swimmers' hygiene awareness and targeting health education is obliged.

Using Capillary Whole Blood to Quantitatively Measure Ferritin: A Validation Trial of a Point-of-Care System

Iron deficiency is a public health problem with devastating health, developmental and behavioral effects which often exacerbated due to affordability and access to screening and diagnosis. Using IronScan™ a portable, point-of-care diagnostic system capable of quantitatively measuring ferritin in blood, we validated IronScan™ ferritin measurements using whole blood and serum with a lab-based, regulator-approved analytical device for measuring ferritin in venous serum. Capillary (finger stick) and venous whole blood samples were obtained from 44 male and female volunteers. Venous serum (vSer) ferritin concentrations were measured on Immulite 2000 Xpi (gold standard). Capillary whole blood (cWB), venous whole blood (vWB), and vSer ferritin levels were measured by IronScan™. cWB ferritin concentrations from IronScan™ were significantly correlated (R2 = 0.86) with vSer measured with the FDA-approved Immulite system. The results from the multiple regression analysis indicate that 10% of the variability was due to the method of blood collection (venous vs. capillary) and 6% was due to the form of blood analysis (whole blood vs. serum). The sensitivity of diagnosing iron deficiency using the WHO cutoff of <30 ng/mL is 90%, with a specificity of 96%. In conclusion, IronScan™ is a rapid viable option for measuring ferritin as a point-of-care system.

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.

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.

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.

Modeling relationships between iron status, behavior, and brain electrophysiology: evidence from a randomized study involving a biofortified grain in Indian adolescents

Background

Iron deficiency (ID) and iron deficiency anemia (IDA) are highly-prevalent nutrient deficiencies and have been shown to have a range of negative effects on cognition and brain function. Human intervention studies including measures at three levels—blood, brain, and behavior—are rare and our objective was to model the relationships among measures at these three levels in school-going Indian adolescents.

Methods

Male and female adolescents in rural India were screened for ID/IDA. Subjects consumed 2 meals/day for 6 months; half were randomly assigned to consume meals made from a standard grain (pearl millet) and half consumed meals made from an iron biofortified pearl millet (BPM). Prior to and then at the conclusion of the feeding trial, they completed a set of cognitive tests with concurrent electroencephalography (EEG).

Results

Overall, serum ferritin (sFt) levels improved over the course of the study. Ten of 21 possible measures of cognition showed improvements from baseline (BL) to endline (EL) that were larger for those consuming BPM than for those consuming the comparison pearl millet (CPM). Critically, the best model for the relationship between change in iron status and change in cognition had change in brain measures as a mediating factor, with both change in serum ferritin as a primary predictor and change in hemoglobin as a moderator.

Conclusions

A dietary intervention involving a biofortified staple grain was shown to be efficacious in improving blood iron biomarkers, behavioral measures of cognition, and EEG measures of brain function. Modeling the relationships among these variables strongly suggests multiple mechanisms by which blood iron level affects brain function and cognition.

Trial registration

Registered at ClinicalTrials.gov, NCT02152150, 02 June 2014.

Supplementary Information

The online version contains supplementary material available at (10.1186/s12889-022-13612-z).

Iron homeostasis in heart transplant recipients randomized to ferric derisomaltose or placebo

INTRODUCTION

The randomized IronIC trial evaluated the effect of intravenous ferric derisomaltose on physical capacity in iron-deficient, maintenance heart transplant (HTx) recipients. Iron deficiency was defined as in heart failure with high cut-points for ferritin to compensate for inflammation. However, intravenous iron did not improve physical capacity except in patients with ferritin <30 μg/L. We aimed to explore determinants of iron status in the 102 IronIC participants to better define iron deficiency in the HTx population.

METHODS

We assessed key governors of iron homeostasis, such as hepcidin, soluble transferrin receptor (sTfR), and interleukin-6 (IL-6). We also measured growth factors and inflammatory markers with relevance for iron metabolism. The results were compared to those of 21 healthy controls.

RESULTS

Hepcidin did not differ between HTx recipients and controls, even though markers of inflammation were modestly elevated. However, HTx recipients with ferritin <30 μg/L or sTfR above the reference range had significantly reduced hepcidin levels suggestive of true iron deficiency. In these patients, intravenous iron improved peak oxygen uptake. Hepcidin correlated positively with ferritin and negatively with sTfR.

CONCLUSION

HTx recipients with iron deficiency as defined in heart failure do not have elevated hepcidin levels, although inflammatory markers are modestly increased. The high ferritin cut-offs used in heart failure may not be suitable to define iron deficiency in the HTx population. We suggest that hepcidin and sTfR should be measured to identify patients with true iron deficiency, who might benefit from treatment with intravenous iron.

Ferritin-guided iron supplementation in whole blood donors: optimal dosage, donor response, return and efficacy (FORTE)-a randomised controlled trial protocol

BACKGROUND

Frequent whole blood donors have an increased risk of developing iron deficiency. Iron deficiency can have detrimental health effects when left untreated. Donation intervals are commonly too short to replenish iron stores and extending these reduces donor availability. Oral iron supplementation is known to shorten iron store recovery time but may also induce gastrointestinal complaints. We aim to optimise the effectiveness of iron supplements while minimising the risks of side effects. Therefore, we will evaluate the impact of different iron supplementation protocols in terms of dosage and frequency on ferritin and haemoglobin levels, gastrointestinal side effects, iron deficiency-related symptoms and donor return compared with placebo supplementation.

METHODS

Twelve hundred whole blood donors with ferritin levels ≤30 µg/L are included into a double-blind, randomised controlled trial. Participants are randomly allocated to one of six arms, administering capsules containing 0 mg, 30 mg or 60 mg of iron, either on alternate days or daily for 56 days. At baseline and 56, 122 and 182 days of follow-up, ferritin and haemoglobin levels are measured, and compliance, donor return, dietary iron intake, gastrointestinal, iron deficiency-related symptoms and general health are assessed by questionnaire.

ETHICS AND DISSEMINATION

This study will provide a comprehensive overview of the effects of different frequencies and dosages of administration of iron supplements on iron status and health effects, thereby considering individual differences in treatment adherence and lifestyle. The outcome will provide scientific evidence to guide the debate if and how oral iron supplements may support the recovery of whole blood donors with low ferritin levels.

TRIAL REGISTRATION NUMBER

NL8590; The Dutch trial registry.

Prevalence of anemia and its associated factors among married women in 19 sub-Saharan African countries

Background

Sub-Saharan Africa (SSA) remains the region with the highest burden of anemia globally. Since anemia has both health and non-health-related consequences, its reduction is one of the Sustainable Development Goals. Therefore, this study aimed to examine the prevalence of anemia and its associated factors among married women in SSA.

Methods

Using Stata version-14 software, the analysis was done on 89,029 married women from the Demographic and Health Surveys of 19 countries in SSA. Pearson Chi-Square test and Binary logistic regression analyses were used to examine the factors associated with anemia. The results were presented using adjusted Odds Ratio (aOR) at a 95% Confidence Interval (CI). A p-value less than or equal to 0.05 (p ≤ 0.05) was considered statistically significant.

Results

The pooled analysis showed that 49.7% of married women were anemic. Of these, 1.04% and 15.05% were severely and moderately anemic respectively, and the rest 33.61% were mildly anemic. Husband education (primary school-aOR = 0.84, 95% CI; 0.71–0.99), wealth index (middle-aOR = 0.81, 95% CI; 0.68–0.96, richer-aOR = 0.69, 95% CI; 0.57–0.84, richest-aOR = 0.68, 95% CI; 0.51–0.91), modern contraceptive use (yes-aOR = 0.68, 95% CI; 0.56–0.81) and religion (Muslim-aOR = 1.27, 95% CI; 1.11–1.46, others-aOR = 0.73, 95% CI; 0.59–0.90) were factors associated with anemia among married women.

Conclusion

The findings show that nearly half of the married women are affected by anemia. Enhancing partners’ educational levels, and economic empowerment of women, strengthening family planning services, and working with religious leaders to reduce the perception and religious beliefs related to food restrictions can be the main focus to reduce the burden of anemia among married women in SSA.

Assessment of Trace Elements Supply in Canned Tuna Fish Commercialized for Human Consumption in Brazil

This study evaluates the elemental content in 4 types of canned tuna fish groups, each with 4 brands that are commercialized for human consumption in Brazil. The results are based on trace elements in canned tuna fish quantified by ICP OES and a comparison to limit levels set by the FAO/WHO. We also checked the carcinogenic risk (CR), non-carcinogenic risk (Hazard Index (HI) and Hazard Quotient (HQ)), and pollution index (PI) for the studied canned tuna samples. As and Se concentrations in all groups are above the intake values set by FAO/WHO considering specific groups. The carcinogenic risk values for arsenic (As) in groups are considerably unacceptable (≥10-4). Hazard quotients (HQ) were >1 for As in all groups, while no sample was below 1 for HI. The pollution index (PI) results show that the main canned tuna fish contaminant is aluminum, then selenium and arsenic, respectively. Only half of the samples did not present elemental contaminant levels. All studied brands of canned tuna presented elemental concentrations that could pose a health risk to human consumption, that could be from CR, HQ, HI, or PI. The contaminant levels are alarming and should raise a red flag for the intake of these products, especially a long-term one. These results urge the authorities to supervise and enforce better practices for this type of food, protecting their population from health hazards.

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.

Iron intake and multiple health outcomes: Umbrella review

Iron is an essential trace element, while excess iron can lead to different levels of physical abnormalities or diseases. This umbrella review aimed to conduct a systematic evaluation of the possible relationships between iron intake and various health outcomes. We retrieved PubMed, Embase, Web of Science, Scopus, and the Cochrane Database of Systematic Reviews from inception through May 2021. A total of 34 meta-analyses with 46 unique health outcomes were identified. Heme iron intake was positively associated with nine outcomes, including colorectal cancer, type 2 diabetes mellitus, and cardiovascular disease mortality, while dietary total iron intake could decrease the risk of colorectal adenoma, esophageal cancer, coronary heart disease, and depression. Iron supplementation was a protective factor against eight outcomes. However, it was associated with decreased length and weight gain. The quality of evidence for most outcomes was "low" or "very low" with the remaining eleven as "high" or "moderate". All outcomes were categorized as class III, IV, or NS based on evidence classification. Although high iron intake has been identified to be significantly associated with a range of outcomes, firm universal conclusions about its beneficial or negative effects cannot be drawn given the low quality of evidence for most outcomes.

Nutrition-specific interventions for preventing and controlling anaemia throughout the life cycle: an overview of systematic reviews

BACKGROUND

Anaemia is a prevalent health problem worldwide. Some types are preventable or controllable with iron supplementation (pills or drops), fortification (sprinkles or powders containing iron added to food) or improvements to dietary diversity and quality (e.g. education or counselling).

OBJECTIVES

To summarise the evidence from systematic reviews regarding the benefits or harms of nutrition-specific interventions for preventing and controlling anaemia in anaemic or non-anaemic, apparently healthy populations throughout the life cycle.

METHODS

In August 2020, we searched MEDLINE, Embase and 10 other databases for systematic reviews of randomised controlled trials (RCTs) in anaemic or non-anaemic, apparently healthy populations. We followed standard Cochrane methodology, extracting GRADE ratings where provided. The primary outcomes were haemoglobin (Hb) concentration, anaemia, and iron deficiency anaemia (IDA); secondary outcomes were iron deficiency (ID), severe anaemia and adverse effects (e.g. diarrhoea, vomiting).

MAIN RESULTS

We included 75 systematic reviews, 33 of which provided GRADE assessments; these varied between high and very low. Infants (6 to 23 months; 13 reviews) Iron supplementation increased Hb levels and reduced the risk of anaemia and IDA in two reviews. Iron fortification of milk or cereals, multiple-micronutrient powder (MMNP), home fortification of complementary foods, and supplementary feeding increased Hb levels and reduced the risk of anaemia in six reviews. In one review, lipid-based nutrient supplementation (LNS) reduced the risk of anaemia. In another, caterpillar cereal increased Hb levels and IDA prevalence. Food-based strategies (red meat and fortified cow's milk, beef) showed no evidence of a difference (1 review). Preschool and school-aged children (2 to 10 years; 8 reviews) Daily or intermittent iron supplementation increased Hb levels and reduced the risk of anaemia and ID in two reviews. One review found no evidence of difference in Hb levels, but an increased risk of anaemia and ID for the intermittent regime. All suggested that zinc plus iron supplementation versus zinc alone, multiple-micronutrient (MMN)-fortified beverage versus control, and point-of-use fortification of food with iron-containing micronutrient powder (MNP) versus placebo or no intervention may increase Hb levels and reduce the risk of anaemia and ID. Fortified dairy products and cereal food showed no evidence of a difference on the incidence of anaemia (1 review). Adolescent children (11 to 18 years; 4 reviews) Compared with no supplementation or placebo, five types of iron supplementation may increase Hb levels and reduce the risk of anaemia (3 reviews). One review on prevention found no evidence of a difference in anaemia incidence on iron supplementation with or without folic acid, but Hb levels increased. Another suggested that nutritional supplementation and counselling reduced IDA. One review comparing MMN fortification with no fortification observed no evidence of a difference in Hb levels. Non-pregnant women of reproductive age (19 to 49 years; 5 reviews) Two reviews suggested that iron therapy (oral, intravenous (IV), intramuscular (IM)) increased Hb levels; one showed that iron folic acid supplementation reduced anaemia incidence; and another that daily iron supplementation with or without folic acid or vitamin C increased Hb levels and reduced the risk of anaemia and ID. No review reported interventions related to fortification or dietary diversity and quality. Pregnant women of reproductive age (15 to 49 years; 23 reviews) One review apiece suggested that: daily iron supplementation with or without folic acid increased Hb levels in the third trimester or at delivery and in the postpartum period, and reduced the risk of anaemia, IDA and ID in the third trimester or at delivery; intermittent iron supplementation had no effect on Hb levels and IDA, but increased the risk of anaemia at or near term and ID, and reduced the risk of side effects; vitamin A supplementation alone versus placebo, no intervention or other micronutrient might increase maternal Hb levels and reduce the risk of maternal anaemia; MMN with iron and folic acid versus placebo reduced the risk of anaemia; supplementation with oral bovine lactoferrin versus oral ferrous iron preparations increased Hb levels and reduced gastrointestinal side effects; MNP for point-of-use fortification of food versus iron and folic acid supplementation might decrease Hb levels at 32 weeks' gestation and increase the risk of anaemia; and LNS versus iron or folic acid and MMN increased the risk of anaemia. Mixed population (all ages; 22 reviews) Iron supplementation versus placebo or control increased Hb levels in healthy children, adults, and elderly people (4 reviews). Hb levels appeared to increase and risk of anaemia and ID decrease in two reviews investigating MMN fortification versus placebo or no treatment, iron fortified flour versus control, double fortified salt versus iodine only fortified salt, and rice fortification with iron alone or in combination with other micronutrients versus unfortified rice or no intervention. Each review suggested that fortified versus non-fortified condiments or noodles, fortified (sodium iron ethylenediaminetetraacetate; NaFeEDTA) versus non-fortified soy sauce, and double-fortified salt versus control salt may increase Hb concentration and reduce the risk of anaemia. One review indicated that Hb levels increased for children who were anaemic or had IDA and received iron supplementation, and decreased for those who received dietary interventions. Another assessed the effects of foods prepared in iron pots, and found higher Hb levels in children with low-risk malaria status in two trials, but no difference when comparing food prepared in non-cast iron pots in a high-risk malaria endemicity mixed population. There was no evidence of a difference for adverse effects. Anaemia and malaria prevalence were rarely reported. No review focused on women aged 50 to 65 years plus or men (19 to 65 years plus).

AUTHORS' CONCLUSIONS

Compared to no treatment, daily iron supplementation may increase Hb levels and reduce the risk of anaemia and IDA in infants, preschool and school-aged children and pregnant and non-pregnant women. Iron fortification of foods in infants and use of iron pots with children may have prophylactic benefits for malaria endemicity low-risk populations. In any age group, only a limited number of reviews assessed interventions to improve dietary diversity and quality. Future trials should assess the effects of these types of interventions, and consider the requirements of different populations.

Paradoxical Relationships between Serum 25(OH)D and Ferritin with Body Composition and Burnout: Variation by Sex and Sports Team

Adequate serum vitamin D and iron levels are thought to influence physical training adaptations and mood positively. The primary purpose of this prospective, observational study was to investigate relationships between serum 25-OH vitamin D/25(OH)D and serum ferritin levels with body composition and athlete burnout symptoms. Seventy-three collegiate athletes (female: n = 49; male: n = 24) from indoor (swimming, basketball) and outdoor (soccer, cross-country) sports were tested pre-season and post-season for serum 25(OH)D and serum ferritin (nutrient biomarkers) via venipuncture; body composition (total lean mass, bone mineral density/BMD, and % body fat) via dual energy X-ray absorptiometry (DXA) scans; and athlete burnout symptoms (post-season) via the athlete burnout questionnaire (ABQ). When male and female cohorts were combined, significant correlations (Pearson’s r) were noted between pre-season serum 25(OH)D versus the change (∆: post-season minus pre-season) in both BMD (r = −0.34; p = 0.0003) and % body fat (r = −0.28; p = 0.015). Serum ferritin ∆ was significantly associated with lean mass ∆ (r = −0.34; p = 0.003). For burnout symptoms, serum 25(OH)D ∆ significantly explained 20.6% of the variance for devaluation of the sport in the male cohort only. Across time, serum 25(OH)D levels decreased while serum ferritin levels increased, non-significantly, in both males and females. Relationships between nutrient biomarkers and body composition were opposite of physiological expectations.

Evaluation of Hemoglobin Cutoff Levels to Define Anemia Among Healthy Individuals

Importance

Anemia, defined as low hemoglobin (Hb) concentration insufficient to meet an individual's physiological needs, is the most common blood condition worldwide.

Objective

To evaluate the current World Health Organization (WHO) Hb cutoffs for defining anemia among persons who are apparently healthy and to assess threshold validity with a biomarker of tissue iron deficiency and physiological indicator of erythropoiesis (soluble transferrin receptor [sTfR]) using multinational data.

Design, Setting, and Participants

In this cross-sectional study, data were collected and evaluated from 30 household, population-based nutrition surveys of preschool children aged 6 to 59 months and nonpregnant women aged 15 to 49 years during 2005 to 2016 across 25 countries. Data analysis was performed from March 2020 to April 2021.

Exposure

Anemia defined according to WHO Hb cutoffs.

Main Outcomes and Measures

To define the healthy population, persons with iron deficiency (ferritin <12 ng/mL for children or <15 ng/mL for women), vitamin A deficiency (retinol-binding protein or retinol <20.1 μg/dL), inflammation (C-reactive protein >0.5 mg/dL or α-1-acid glycoprotein >1 g/L), or known malaria were excluded. Survey-specific, pooled Hb fifth percentile cutoffs were estimated. Among individuals with Hb and sTfR data, Hb-for-sTfR curve analysis was conducted to identify Hb inflection points that reflect tissue iron deficiency and increased erythropoiesis induced by anemia.

Results

A total of 79 950 individuals were included in the original surveys. The final healthy sample was 13 445 children (39.9% of the original sample of 33 699 children; 6750 boys [50.2%]; mean [SD] age 32.9 [16.0] months) and 25 880 women (56.0% of the original sample of 46 251 women; mean [SD] age, 31.0 [9.5] years). Survey-specific Hb fifth percentile among children ranged from 7.90 g/dL (95% CI, 7.54-8.26 g/dL in Pakistan) to 11.23 g/dL (95% CI, 11.14-11.33 g/dL in the US), and among women from 8.83 g/dL (95% CI, 7.77-9.88 g/dL in Gujarat, India) to 12.09 g/dL (95% CI, 12.00-12.17 g/dL in the US). Intersurvey variance around the Hb fifth percentile was low (3.5% for women and 3.6% for children). Pooled fifth percentile estimates were 9.65 g/dL (95% CI, 9.26-10.04 g/dL) for children and 10.81 g/dL (95% CI, 10.35-11.27 g/dL) for women. The Hb-for-sTfR curve demonstrated curvilinear associations with sTfR inflection points occurring at Hb of 9.61 g/dL (95% CI, 9.55-9.67 g/dL) among children and 11.01 g/dL (95% CI, 10.95-11.09 g/dL) among women.

Conclusions and Relevance

Current WHO cutoffs to define anemia are higher than the pooled fifth percentile of Hb among persons who are outwardly healthy and from nearly all survey-specific estimates. The lower proposed Hb cutoffs are statistically significant but also reflect compensatory increased erythropoiesis. More studies based on clinical outcomes could further confirm the validity of these Hb cutoffs for anemia.

Inorganic Iron Supplementation Rescues Hematological Insufficiency Even Under Intense Exercise Training in a Mouse Model of Iron Deficiency with Anemia

Iron deficiency anemia (IDA) due to malnutrition and/or blood loss is a common condition, especially in women of reproductive age. Intense exercise can induce anemia via an inflammatory response, but whether intense exercise affects the efficacy of iron supplementation to treat IDA is unclear. Here, we show in a mouse model of IDA that acute intense swimming increased IL-6 levels in the blood, but did not affect the maximum elevation of plasma iron following oral administration of 0.5 mg/kg Bw iron. However, compared with the control group without intense exercise, acute intense swimming was associated with a significant decrease in plasma iron 2 and 4 h after iron loading that could be attributed to rapid iron absorption in peripheral tissues. In the chronic experiment, IDA mice administered 0.36, 1.06, or 3.2 mg/kg Bw iron per day that were subjected to 11 intense swimming sessions over 3 weeks showed significantly decreased recovery levels for hemoglobin and red blood cell count during the early phase of the experimental period. At the end of the experimental period, significant, dose-dependent effects of iron, but not the main effect of intense exercise, were seen for recovery of hemoglobin and red blood cell counts, consistent with the acute exercise study. These results suggested that intense exercise in the presence of IDA does not inhibit iron absorption from the gastrointestinal tract and that iron supplementation can enhance the recovery process even after intense exercise.

Anemia and Nutritional Status of Syrian Refugee Mothers and Their Children under Five Years in Greater Beirut, Lebanon

The objective was to assess the prevalence of anemia and nutritional status of mothers and children under five years among Syrian refugees in Lebanon and to identify nutritional deficiencies among pregnant, lactating, and non-pregnant non-lactating (NPNLM) mothers. A cross-sectional study was conducted among Syrian refugee mothers with children under five years in Greater Beirut, Lebanon (n = 433). Data on socio-economic status, maternal health, lifestyle characteristics, dietary intake, anthropometric measurements, and hemoglobin concentrations were collected. The prevalence of anemia was 21.7% among mothers and 30.5% among children. NPNLM with overweight/obesity and an at-risk waist circumference (WC) had 14.7-times and 10.9-times higher odds of anemia than mothers with normal WC and weight. Children of anemic mothers had 2.7-times and 4.4-times higher odds of total and mild anemia than those of non-anemic. Higher odds of mild anemia were found among children of lactating mothers than of NPNLM. A high percent energy intake of total fat and sugar was found among all mothers. Nutritional inadequacy was identified in higher proportions of lactating and pregnant mothers than NPNLM. Our findings highlighted the co-existence of overnutrition and anemia among Syrian refugee mothers and undernutrition among children from the same household. Culture-specific interventions are needed to support maternal nutrition, to ensure the health and wellbeing of their offspring.

Serum or plasma ferritin concentration as an index of iron deficiency and overload

BACKGROUND

Reference standard indices of iron deficiency and iron overload are generally invasive, expensive, and can be unpleasant or occasionally risky. Ferritin is an iron storage protein and its concentration in the plasma or serum reflects iron stores; low ferritin indicates iron deficiency, while elevated ferritin reflects risk of iron overload. However, ferritin is also an acute-phase protein and its levels are elevated in inflammation and infection. The use of ferritin as a diagnostic test of iron deficiency and overload is a common clinical practice.

OBJECTIVES

To determine the diagnostic accuracy of ferritin concentrations (serum or plasma) for detecting iron deficiency and risk of iron overload in primary and secondary iron-loading syndromes.

SEARCH METHODS

We searched the following databases (10 June 2020): DARE (Cochrane Library) Issue 2 of 4 2015, HTA (Cochrane Library) Issue 4 of 4 2016, CENTRAL (Cochrane Library) Issue 6 of 12 2020, MEDLINE (OVID) 1946 to 9 June 2020, Embase (OVID) 1947 to week 23 2020, CINAHL (Ebsco) 1982 to June 2020, Web of Science (ISI) SCI, SSCI, CPCI-exp & CPCI-SSH to June 2020, POPLINE 16/8/18, Open Grey (10/6/20), TRoPHI (10/6/20), Bibliomap (10/6/20), IBECS (10/6/20), SCIELO (10/6/20), Global Index Medicus (10/6/20) AIM, IMSEAR, WPRIM, IMEMR, LILACS (10/6/20), PAHO (10/6/20), WHOLIS 10/6/20, IndMED (16/8/18) and Native Health Research Database (10/6/20). We also searched two trials registers and contacted relevant organisations for unpublished studies.

SELECTION CRITERIA

We included all study designs seeking to evaluate serum or plasma ferritin concentrations measured by any current or previously available quantitative assay as an index of iron status in individuals of any age, sex, clinical and physiological status from any country.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods. We designed the data extraction form to record results for ferritin concentration as the index test, and bone marrow iron content for iron deficiency and liver iron content for iron overload as the reference standards. Two other authors further extracted and validated the number of true positive, true negative, false positive, false negative cases, and extracted or derived the sensitivity, specificity, positive and negative predictive values for each threshold presented for iron deficiency and iron overload in included studies. We assessed risk of bias and applicability using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 tool. We used GRADE assessment to enable the quality of evidence and hence strength of evidence for our conclusions.

MAIN RESULTS

Our search was conducted initially in 2014 and updated in 2017, 2018 and 2020 (10 June). We identified 21,217 records and screened 14,244 records after duplicates were removed. We assessed 316 records in full text. We excluded 190 studies (193 records) with reasons and included 108 studies (111 records) in the qualitative and quantitative analysis. There were 11 studies (12 records) that we screened from the last search update and appeared eligible for a future analysis. We decided to enter these as awaiting classification. We stratified the analysis first by participant clinical status: apparently healthy and non-healthy populations. We then stratified by age and pregnancy status as: infants and children, adolescents, pregnant women, and adults. Iron deficiency We included 72 studies (75 records) involving 6059 participants. Apparently healthy populations Five studies screened for iron deficiency in people without apparent illness. In the general adult population, three studies reported sensitivities of 63% to 100% at the optimum cutoff for ferritin, with corresponding specificities of 92% to 98%, but the ferritin cutoffs varied between studies. One study in healthy children reported a sensitivity of 74% and a specificity of 77%. One study in pregnant women reported a sensitivity of 88% and a specificity of 100%. Overall confidence in these estimates was very low because of potential bias, indirectness, and sparse and heterogenous evidence. No studies screened for iron overload in apparently healthy people. People presenting for medical care There were 63 studies among adults presenting for medical care (5042 participants). For a sample of 1000 subjects with a 35% prevalence of iron deficiency (of the included studies in this category) and supposing a 85% specificity, there would be 315 iron-deficient subjects correctly classified as having iron deficiency and 35 iron-deficient subjects incorrectly classified as not having iron deficiency, leading to a 90% sensitivity. Thresholds proposed by the authors of the included studies ranged between 12 to 200 µg/L. The estimated diagnostic odds ratio was 50. Among non-healthy adults using a fixed threshold of 30 μg/L (nine studies, 512 participants, low-certainty evidence), the pooled estimate for sensitivity was 79% with a 95% confidence interval of (58%, 91%) and specificity of 98%, with a 95% confidence interval of (91%, 100%). The estimated diagnostic odds ratio was 140, a relatively highly informative test. Iron overload We included 36 studies (36 records) involving 1927 participants. All studies concerned non-healthy populations. There were no studies targeting either infants, children, or pregnant women. Among all populations (one threshold for males and females; 36 studies, 1927 participants, very low-certainty evidence): for a sample of 1000 subjects with a 42% prevalence of iron overload (of the included studies in this category) and supposing a 65% specificity, there would be 332 iron-overloaded subjects correctly classified as having iron overload and 85 iron-overloaded subjects incorrectly classified as not having iron overload, leading to a 80% sensitivity. The estimated diagnostic odds ratio was 8.

AUTHORS' CONCLUSIONS

At a threshold of 30 micrograms/L, there is low-certainty evidence that blood ferritin concentration is reasonably sensitive and a very specific test for iron deficiency in people presenting for medical care. There is very low certainty that high concentrations of ferritin provide a sensitive test for iron overload in people where this condition is suspected. There is insufficient evidence to know whether ferritin concentration performs similarly when screening asymptomatic people for iron deficiency or overload.

High Concentration of Heavy Metal and Metalloid Levels in Edible Campomanesia adamantium Pulp from Anthropic Areas

This study aimed to quantify the extent of heavy metal, non-metal and metalloid levels in the Campomanesia adamantium pulp obtained from an area crossed by road experiencing high large vehicle traffic and intensive agriculture modern farming, to monitor the health risks associated with pulp consumption by humans. For this purpose, in three spots located within this area, ripe fruits were collected on the roadside, bush and farm-margin. Pulp samples were digested by microwave-assisted equipment, and chemical elements were quantified by ICP OES. The concentrations of K, Pb, Se, Fe, Mo, Zn, Co, Ni and Mn in the pulp collected in roadside/bush points showed statistical differences (p < 0.05). The heavy metals and metalloid concentrations that exceeded FAO/WHO standards were ordered Pb > As > Mo > Co > Ni > Mn > Cr. Therefore, among these metalloid and heavy metals, As, Pb and Cr were found to be higher in farm-margin > roadside > bush (1.5 × 10⁻³, 1.1 × 10⁻³ and 6.2 × 10⁻⁴), respectively. Therefore, As is the most important metalloid with higher levels in farm-margin, roadside and bush (1.5 × 10⁻³, 1.0 × 10⁻³ and 6.0 × 10⁻⁴ > 10⁻⁶–10⁻⁴ and 3.33, 2.30 and 1.34 > 1), respectively, to total cancer risk and hazard quotient, if 10 g daily of pulp are consumed.

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

Iron deficiency is one of the leading contributors to the global burden of disease, and particularly affects children, premenopausal women, and people in low-income and middle-income countries. Anaemia is one of many consequences of iron deficiency, and clinical and functional impairments can occur in the absence of anaemia. Iron deprivation from erythroblasts and other tissues occurs when total body stores of iron are low or when inflammation causes withholding of iron from the plasma, particularly through the action of hepcidin, the main regulator of systemic iron homoeostasis. Oral iron therapy is the first line of treatment in most cases. Hepcidin upregulation by oral iron supplementation limits the absorption efficiency of high-dose oral iron supplementation, and of oral iron during inflammation. Modern parenteral iron formulations have substantially altered iron treatment and enable rapid, safe total-dose iron replacement. An underlying cause should be sought in all patients presenting with iron deficiency: screening for coeliac disease should be considered routinely, and endoscopic investigation to exclude bleeding gastrointestinal lesions is warranted in men and postmenopausal women presenting with iron deficiency anaemia. Iron supplementation programmes in low-income countries comprise part of the solution to meeting WHO Global Nutrition Targets.

Iron

Iron deficiency anemia affects approximately one-third of the world's population, and about half the cases are due to iron deficiency. The latest research on iron metabolism published in original articles and systematic reviews is described, and references to recent reviews provided. The topics include dietary sources and bioavailability, iron homeostasis, functions of iron in the body, and biomarkers of status. The consequences of iron deficiency and excess are discussed, with particular focus on vulnerable populations such as pregnant women, infants and the elderly. The newest dietary recommendations, including dietary reference values and food based dietary guidelines, are briefly summarized, followed by the latest developments in food fortification and iron supplementation.

Iron status is associated with worker productivity, independent of physical effort in Indian tea estate workers

Iron deficiency is the most common nutrient deficiency in the world, affecting roughly 40% of women in nonindustrialized countries. Iron is the essential element in hemoglobin, the major carrier of blood oxygen and oxidative metabolism that supports physical and cognitive performance. The relationship between iron and physical work capacity suggests that iron deficient individuals could experience reduced work output. Participants were 138 experienced tea pluckers aged 18–55 years from the Panighatta Tea Estate in Darjeeling District of northern West Bengal, India. Hemoglobin, serum ferritin, and soluble transferrin receptor were measured from venous blood. Energy expenditure was estimated from accelerometry and heart rate, and plucking productivity was measured as amount of tea plucked during the morning work session when temperature and rainfall conditions are optimal. At a given level of energy expenditure, iron deficient, anemic, and iron deficient anemic women plucked less tea during a 3-h period. The results warrant further research as to whether interventions providing supplemental iron might improve worker productivity and work efficiency. Further study should examine evidence of economic incentives for policies and programs targeting nutritional deficiencies.

Novelty Anemia predicts up to 2.02 kg (9.1%) less tea plucked per 3 h, or 4.0% lower wage per 3 h, compared with nonanemic women, controlling for physical effort. An increase of 1.0 g/L in hemoglobin concentration predicts 0.71 kg (3.3%) more tea plucked over 3 h. An increase of 1.0 g/L in hemoglobin concentration predicts a 1.6% wage increase.

Current dietary advice and challenges for adolescents

BACKGROUND

The major risk factors driving the global burden of disease are diet related. Adolescence presents a window of opportunity for establishing healthy dietary trajectories. Yet around the world, adolescents experience many barriers that prevent them from consuming diets that would give them the foundation for long, healthy and productive adult lives.

SOURCES OF DATA

A narrative literature search of most relevant original, review and meta-analyses, restricted to English was conducted in Medline, Web of Science and PubMed up to December 2019 together with published papers known to the author concerning the current dietary advice and challenges for adolescent nutrition.

AREAS OF AGREEMENT

Adolescence is a critical period of growth and development and adequate nutrition is essential. Sufficient population data indicate adolescents are not meeting dietary recommendations and are a vulnerable population group for malnutrition in all its forms.

AREAS OF CONTROVERSY

Despite extensive studies on dietary risk factors and the global burden of disease and population data demonstrating inadequate nutritional intake in adolescent populations, few effective interventions and policies have been scaled up to support adolescent nutrition.

GROWING POINTS

Improving the diets of adolescents, especially vulnerable adolescents from low- and middle-income countries and socioeconomically disadvantaged backgrounds, has the potential to impact individuals, societies and economies.

AREAS TIMELY FOR DEVELOPING RESEARCH

Future research should focus on vulnerable adolescent populations by addressing food environments, food insecurity and ensuring effective programmes and strategies are integrated within broader adolescent health strategies and implemented into government policies.

Association of red blood cell size and physical fitness in a military male cohort: The CHIEF study

Anemia manifested as reduced red blood cell (RBC) amounts or hemoglobin levels has been associated with lower cardiorespiratory fitness. However, the relationship of smaller RBC with physical fitness was unknown. We included 2933 non-anemic military males (hemoglobin levels: 11.1-15.9 g/dL and mean corpuscular volume (MCV) <100 fL) in Taiwan during 2014. Aerobic fitness was assessed by time for a 3000-meter run, and anaerobic fitness was evaluated by numbers of sit-ups and push-ups, each performed within 2 minutes. Multiple linear and logistic regression models adjusting for age, service specialty, lipid profiles, and hemoglobin levels were used to determine the associations. Microcytosis and normocytosis were defined as MCV ≤ 70 fL (n = 190) and MCV > 70 fL (n = 2743), respectively. The linear regression shows that as compared with microcytosis, normocytosis was associated with more numbers of sit-ups performed within 2 minutes (β = 1.51, P-value = 0.02). The logistic regression also reveals that those males with microcytosis had higher probability as the worst 10% performers in the 2-minute push-up test (odds ratio: 1.91, 95% confidence intervals: 1.18-3.12). By contrast, there was no association of microcytosis with 3000-meter running time. Our study suggests that non-anemic microcytosis was associated with lower anaerobic fitness but not with aerobic fitness. Whether the causative factors for microcytosis such as iron deficiency status and thalassemia trait unavailable in the study might account for the relationship needs further investigations.

Increased Iron Status during a Feeding Trial of Iron-Biofortified Beans Increases Physical Work Efficiency in Rwandan Women

BACKGROUND

Iron-biofortified staple foods can improve iron status and resolve iron deficiency. However, whether improved iron status from iron biofortification can improve physical performance remains unclear.

OBJECTIVE

This study aimed to examine whether changes in iron status from an iron-biofortified bean intervention affect work efficiency.

METHODS

A total of 125 iron-depleted (ferritin <20 μg/L) female Rwandan university students (18-26 y) were selected from a larger sample randomly assigned to consume iron-biofortified beans (Fe-Bean; 86.1 mg Fe/kg) or conventional beans (control: 50.6 mg Fe/kg) twice daily for 18 wk (average of 314 g beans consumed/d). Blood biomarkers of iron status (primary outcome) and physical work efficiency (secondary outcome) were measured before and after the intervention. Work performed was assessed during 5-min steady-state periods at 0-, 25-, and 40-W workloads using a mechanically braked cycle ergometer. Work efficiency was calculated at 25 W and 40 W as the work accomplished divided by the energy expended at that workload above that expended at 0 W. General linear models were used to evaluate the relation between changes in iron status biomarkers and work efficiency.

RESULTS

The Fe-Bean intervention had significant positive effects on hemoglobin, serum ferritin, and body iron stores but did not affect work efficiency. However, 18-wk change in hemoglobin was positively related to work efficiency at 40 W in the full sample (n = 119; estimate: 0.24 g/L; 95% CI: 0.01, 0.48 g/L; P = 0.044) and among women who were anemic (hemoglobin <120 g/L) at baseline (n = 43; estimate: 0.64 g/L; 95% CI: 0.05, 1.23 g/L; P = 0.036). Among women who were nonanemic at baseline, change in serum ferritin was positively related to change in work efficiency at 40 W (n = 60; estimate: 0.50 μg/L; 95% CI: 0.06, 0.95 μg/L; P = 0.027).

CONCLUSIONS

Increasing iron status during an iron-biofortified bean feeding trial improves work efficiency in iron-depleted, sedentary women. This trial was registered at clinicaltrials.gov as NCT01594359.

The Effect of Lactobacillus plantarum 299v on Iron Status and Physical Performance in Female Iron-Deficient Athletes: A Randomized Controlled Trial

Iron is an essential micronutrient for oxygen transport and mitochondrial metabolism and is critical for physical performance. Compromised iron stores are more commonly found among athletes, and females are especially at risk. Iron deficiency is generally treated using oral iron supplements. However, only a small proportion of ingested iron is absorbed, necessitating higher intakes, which may result in adverse side effects, reduced compliance, and inefficient repletion of iron stores. The probiotic strain Lactobacillus plantarum 299v (Lp299v) significantly increases intestinal iron absorption in meal studies. The present study was conducted to explore the effects of 20 mg of iron with or without Lp299v on iron status, mood state, and physical performance. Fifty-three healthy non-anemic female athletes with low iron stores (ferritin < 30 μg/L) were randomized, and 39 completed the study. Intake of Lp299v with iron for four weeks increased ferritin levels more than iron alone (13.6 vs. 8.2 µg/L), but the difference between the groups was not significant (p = 0.056). The mean reticulocyte hemoglobin content increased after intake of Lp299v compared to control (1.5 vs. 0.82 pg) after 12 weeks, but the difference between the group was not significant (p = 0.083). The Profile of Mood States (POMS) questionnaire showed increased vigor with Lp299v vs. iron alone after 12 weeks (3.5 vs. 0.1, p = 0.015). No conclusive effects on physical performance were observed. In conclusion, Lp299v, together with 20 mg of iron, could result in a more substantial and rapid improvement in iron status and improved vigor compared to 20 mg of iron alone. A larger clinical trial is needed to further explore these findings as well as the impact of Lp299v on physical performance.

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.

The effect of donation activity dwarfs the effect of lifestyle, diet and targeted iron supplementation on blood donor iron stores

The iron status of blood donors is a subject of concern for blood establishments. The Finnish Red Cross Blood Service addresses iron loss in blood donors by proposing systematic iron supplementation for demographic at-risk donor groups. We measured blood count, ferritin and soluble transferrin receptor (sTfR) and acquired lifestyle and health information from 2200 blood donors of the FinDonor 10000 cohort. We used modern data analysis methods to estimate iron status and factors affecting it with a special focus on the effects of the blood service's iron supplementation policy. Low ferritin (< 15 μg/L), an indicator of low iron stores, was present in 20.6% of pre-menopausal women, 10.6% of post-menopausal women and 6% of men. Anemia co-occurred with iron deficiency more frequently in pre-menopausal women (21 out of 25 cases) than in men (3/6) or post-menopausal women (1/2). In multivariable regression analyses, lifestyle, dietary, and blood donation factors explained up to 38% of the variance in ferritin levels but only ~10% of the variance in sTfR levels. Days since previous donation were positively associated with ferritin levels in all groups while the number of donations during the past 2 years was negatively associated with ferritin levels in pre-menopausal women and men. FRCBS-provided iron supplementation was negatively associated with ferritin levels in men only. Relative importance analyses showed that donation activity accounted for most of the explained variance in ferritin levels while iron supplementation explained less than 1%. Variation in ferritin levels was not significantly associated with variation in self-reported health. Donation activity was the most important factor affecting blood donor iron levels, far ahead of e.g. red-meat consumption or iron supplementation. Importantly, self-reported health of donors with lower iron stores was not lower than self-reported health of donors with higher iron stores.

Predicting potential to benefit from an iron intervention: a randomized controlled trial of double-fortified salt in female Indian tea pluckers

OBJECTIVE

The present study examines characteristics of those who benefited from a dietary Fe intervention comprised of salt double-fortified with iodine and Fe (DFS).

DESIGN

Data from a randomized controlled trial were analysed to identify predictors of improved Fe status and resolution of Fe deficiency (serum ferritin (sFt) < 12 μg/l) and low body Fe (body Fe (BI) < 0·0 mg/kg) using non-parametric estimations and binomial regression models.

SETTING

A tea estate in West Bengal, India.

PARTICIPANTS

Female tea pluckers, aged 18-55 years.

RESULTS

Consuming DFS significantly (P = 0·01) predicted resolution of Fe deficiency (relative risk (RR) = 2·31) and of low BI (RR = 2·78) compared with consuming iodized salt. Baseline sFt (β = -0·32 (se 0·03), P < 0·001) and treatment group (β = 0·13 (se 0·03), P < 0·001) significantly predicted change in sFt. The interaction of baseline BI with treatment group (β = -0·11 (se 0·06), P = 0·08) predicted the change in BI. DFS did not significantly predict change in Hb and marginally predicted resolution of anaemia (Hb < 120 g/l).

CONCLUSIONS

Baseline Fe status, as assessed by sFt and BI, and consumption of DFS predict change in Fe status and resolution of Fe deficiency and low BI. Anaemia prevalence and Hb level, although simple and inexpensive to measure, may not be adequate to predict resolution of Fe deficiency in response to an intervention of DFS in similar populations with high prevalence of Fe deficiency and multiple nutritional causes of anaemia. These findings will guide appropriate targeting of future interventions.

Changes in Iron Status Are Related to Changes in Brain Activity and Behavior in Rwandan Female University Students: Results from a Randomized Controlled Efficacy Trial Involving Iron-Biofortified Beans

BACKGROUND

Evidence suggests that iron deficiency (ID) affects cognitive performance, as measured in behavior. Although such effects must be mediated by changes in the brain, very few studies have included measures of brain activity to assess this relation.

OBJECTIVE

We tested the hypothesis that provision of iron-biofortified beans would result in improvements in measures of iron status, brain dynamics, and behavior.

METHODS

A double-blind, randomized, intervention study was conducted in 55 women aged 18-27 y with low iron status (serum ferritin <20 µg/L). Women were randomly assigned to consume iron-biofortified (86.1 ppm iron) or comparison beans (50.1 ppm iron) daily for 18 wk. Iron status was assessed by hemoglobin, ferritin, transferrin receptor, and body iron; cognitive performance with 5 computerized tasks; and brain dynamics by concurrent electroencephalography (EEG). All measures were taken at baseline and endline.

RESULTS

The groups did not differ on any measures at baseline. Intention-to-treat analyses revealed significant (all P < 0.05) improvements in hemoglobin (partial effect size attributable to the independent variable, η2 = 0.16), ferritin (η2 = 0.17), and body iron (η2 = 0.10), speed of responding in attentional and mnemonic tasks (η2 = 0.04-0.29), sensitivity and efficiency of memory retrieval (η2 = 0.12-0.55), and measures of EEG amplitude and spectral power (η2 = 0.08 to 0.49). Mediation models provided evidence in support of the hypothesis that changes in iron status produce changes in behavior by way of changes in brain activity.

CONCLUSIONS

Behavioral performance and brain activity, as measured by EEG, are sensitive to iron status, and the consumption of iron-biofortified beans for 18 wk resulted in improvements in measures of both, relative to what was obtained with a comparison bean, in a sample of female university students. Furthermore, the results support the conclusion that changes in brain activity resulting from consumption of biofortified beans mediate the relations between changes in iron biomarkers and changes in cognition. Clinical trial registry: ClinicalTrials.gov Reg No. NCT01594359.

Increasing Iron Status through Dietary Supplementation in Iron-Depleted, Sedentary Women Increases Endurance Performance at Both Near-Maximal and Submaximal Exercise Intensities

BACKGROUND

Iron deficiency persists as the most common micronutrient deficiency globally, despite having known detrimental effects on physical performance. Although iron supplementation and aerobic exercise have been examined individually and are known to improve physical performance, the impact of simultaneous iron supplementation and aerobic training remains unclear.

OBJECTIVE

The aim of this study was to examine the individual and combined effects of iron supplementation and aerobic training on improving maximal and submaximal physical performance in iron-depleted, nonanemic (IDNA) women. We hypothesized that women receiving iron would improve their endurance performance but not their estimated maximal oxygen consumption (eVO2max).

METHODS

Seventy-three sedentary, previously untrained IDNA (serum ferritin <25 µg/L and hemoglobin >110 g/L) women aged 18-26 y with a body mass index (kg/m2) of 17-25 participated in a double-blind, 8-wk, randomized controlled trial with a 2 × 2 factorial design including iron supplementation (42 mg elemental Fe/d) or placebo and aerobic exercise training (5 d/wk for 25 min at 75-85% of age-predicted maximum heart rate) or no training. Linear models were used to examine relations between training, supplement, and changes in the primary outcomes of observed maximal oxygen consumption (VO2peak) and eVO2max and ventilatory threshold (absolute oxygen consumption and percentage of maximum). Re-evaluation of a published meta-analysis was used to compare effects of iron supplementation on maximal oxygen consumption (VO2max) and VO2peak.

RESULTS

There were significant training-by-supplement interactions for VO2peak, volume of oxygen consumption at the ventilatory threshold, and the percentage of eVO2max where the threshold occurred, with the iron-untrained group performing better than the placebo-untrained group. There was no beneficial effect of iron supplementation for VO2max (mean difference: 0.53; 95% CI: -0.75, 1.81; P = 0.42), but a significant benefit was observed for VO2peak (mean difference: 1.87; 95% CI: 0.15, 3.60; P = 0.03).

CONCLUSIONS

Iron supplementation increases endurance performance at submaximal and maximal (VO2peak) exercise intensities in IDNA women. However, increasing iron status does not increase eVO2max. This trial was registered at clinicaltrials.gov as NCT03002090.