Effect of iron deficiency on simultaneous measures of behavior, brain activity, and energy expenditure in the performance of a cognitive task

Assessing the pattern electroretinogram as a proxy measure for dopamine in the context of iron deficiency

OBJECTIVES

Animal studies have suggested that dietary iron deficiency (ID) negatively affects dopamine (DA) synthesis and re-uptake, which in turn negatively affects memory and cognition. This study was intended to assess whether the pattern electroretinogram (pattern ERG) could be used as an indirect measure of DA in college-age women with and without ID by determining the extent to which features of the ERG were sensitive to iron status and were related to other indirect measures of DA.

METHODS

The pattern ERG was measured in 21 iron deficient non-anemic (IDNA) and 21 iron sufficient (IS) women, who also performed a contrast detection and probabilistic selection task, both with concurrent electroencephalography (EEG). Both spontaneous and task-related blink rates were also measured.

RESULTS

The implicit times of the A- and B-waves were significantly longer for the IDNA than for the IS women. Both the amplitudes and implicit times of the A- and B-waves were significantly correlated with levels of serum ferritin (sFt). Only the amplitude of the A-wave was correlated with spontaneous blink rate. It was possible to accurately identify a woman's iron status solely on the basis of the implicit time of the B-wave. Finally, the implicit times of the ERG features mediated the relationship between iron levels and accuracy in the probabilistic selection task.

CONCLUSIONS

Results suggest the utility of the pattern ERG in testing the hypothesis that iron deficiency affects DA levels in humans and that this may be one of the mechanisms by which iron deficiency negatively affects cognition.

Development of Iron Status Measures during Youth: Associations with Sex, Neighborhood Socioeconomic Status, Cognitive Performance, and Brain Structure

BACKGROUND

Iron is essential to brain function, and iron deficiency during youth may adversely impact neurodevelopment. Understanding the developmental time course of iron status and its association with neurocognitive functioning is important for identifying windows for intervention.

OBJECTIVES

This study aimed to characterize developmental change in iron status and understand its association with cognitive performance and brain structure during adolescence using data from a large pediatric health network.

METHODS

This study included a cross-sectional sample of 4899 participants (2178 males; aged 8-22 y at the time of participation, M [SD] = 14.24 [3.7]) who were recruited from the Children's Hospital of Philadelphia network. Prospectively collected research data were enriched with electronic medical record data that included hematological measures related to iron status, including serum hemoglobin, ferritin, and transferrin (33,015 total samples). At the time of participation, cognitive performance was assessed using the Penn Computerized Neurocognitive Battery, and brain white matter integrity was assessed using diffusion-weighted MRI in a subset of individuals.

RESULTS

Developmental trajectories were characterized for all metrics and revealed that sex differences emerged after menarche such that females had reduced iron status relative to males [all R2partial > 0.008; all false discovery rates (FDRs) < 0.05]. Higher socioeconomic status was associated with higher hemoglobin concentrations throughout development (R2partial = 0.005; FDR < 0.001), and the association was greatest during adolescence. Higher hemoglobin concentrations were associated with better cognitive performance during adolescence (R2partial = 0.02; FDR < 0.001) and mediated the association between sex and cognition (mediation effect = -0.107; 95% CI: -0.191, -0.02). Higher hemoglobin concentration was also associated with greater brain white matter integrity in the neuroimaging subsample (R2partial = 0.06, FDR = 0.028).

CONCLUSIONS

Iron status evolves during youth and is lowest in females and individuals of low socioeconomic status during adolescence. Diminished iron status during adolescence has consequences for neurocognition, suggesting that this critical period of neurodevelopment may be an important window for intervention that has the potential to reduce health disparities in at-risk populations.

A previously uncharacterized Factor Associated with Metabolism and Energy (FAME/C14orf105/CCDC198/1700011H14Rik) is related to evolutionary adaptation, energy balance, and kidney physiology

In this study we use comparative genomics to uncover a gene with uncharacterized function (1700011H14Rik/C14orf105/CCDC198), which we hereby name FAME (Factor Associated with Metabolism and Energy). We observe that FAME shows an unusually high evolutionary divergence in birds and mammals. Through the comparison of single nucleotide polymorphisms, we identify gene flow of FAME from Neandertals into modern humans. We conduct knockout experiments on animals and observe altered body weight and decreased energy expenditure in Fame knockout animals, corresponding to genome-wide association studies linking FAME with higher body mass index in humans. Gene expression and subcellular localization analyses reveal that FAME is a membrane-bound protein enriched in the kidneys. Although the gene knockout results in structurally normal kidneys, we detect higher albumin in urine and lowered ferritin in the blood. Through experimental validation, we confirm interactions between FAME and ferritin and show co-localization in vesicular and plasma membranes.

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).

The Ideal Time for Iron Administration in Anemia Secondary to Blood Loss-An Experimental Animal Model

BACKGROUND

Anemia and iron deficiency are two of the main public health problems worldwide, associated with negative outcomes in surgical patients. This experimental study aimed to create a model of acute iron deficiency with anemia through blood loss and extensive surgery. Afterwards, intravenous iron was administered to correct the iron deficiency and to improve the hematological parameters in distinct moments regarding the surgical time. To assess the optimum time for therapeutic intervention, experimental subjects were compared, performing clinical, paraclinical, and histological examinations, as well.

METHODS

Male rats (n = 35), aged 11-13 months, were randomly designated into six groups. Anemia and iron deficiency were obtained through a 15% blood volume loss, followed by major surgical intervention (femur fracture and osteosynthesis using Kirschner wire). Therapeutic intervention was obtained with an intravenous ferric carboxymaltose infusion, as follows: group II: intraoperative (n = 7), group III: 48 h after surgery (n = 7), group IV: 48 h before surgery (n = 5), and group V: seven days before surgery (n = 6). Group I (n = 5) was left anemic, while group 0 (n = 5) was nonanemic without therapeutic intervention.

RESULTS AND DISCUSSION

In group I, serum iron lower than in group 0 (27.04 ± 6.92 μg/dL versus 60.5 ± 2.34 μg/dL), as well as hemoglobin (10.4 ± 0.54 g/dL versus 14.32 ± 2.01 g/dL) and ferritin values (22.52 ± 0.53 ng/mL versus 29.86 ± 3.97 ng/mL), validated the experimental model. Regarding wound healing after surgical trauma, we observed that neovascularization was more significant in group III, followed by group V, with fewer neutrophils, a well-represented and rich in lymphomonocytes inflammatory infiltrate associated with the biggest collagen fiber dimensions. The periosteal reaction and callus area presented thicker trabeculae in groups II and III compared to the anemic group.

CONCLUSIONS

This original experimental study assessed the effect of perioperative intravenous iron administration at a specific time by comparing the weight, hematological, and iron status-defining parameters, as well as histological characteristics of the included subjects. The present findings highlight that correcting the iron deficiency in emergency settings through intravenous iron administration intraoperatively or 48 h postoperatively could determine the improved bioumoral parameters, as well as a better evolution of the postoperative wound and bone healing compared to the anemic group or subjects that received therapeutic intervention 48 h before surgery.

Intravenous Iron Treatment in the Prevention of Iron Deficiency and Anaemia After Roux-en-Y Gastric Bypass

Background

Iron absorption is disturbed after Roux-en-Y gastric bypass (RYGB) and iron deficiency with or without anaemia affects almost half of all patients. Intravenous iron is an option when per oral iron is insufficient or not tolerated. This study explores whether routinely offering intravenous iron treatment when iron stores are empty can prevent anaemia and iron deficiency after RYGB.

Methods

This is a study of prospectively registered data on clinical information, haematological tests and intravenous iron treatment from 644 RYGB patients who underwent surgery between 2004 and 2013, postoperatively followed more than 5 years. Intravenous iron treatment was offered to patients with ferritin ≤ 15 μg/L.

Results

Clinical information was available for all patients at baseline and for 553/644 patients at 5 years; laboratory results were available for 540/644 patients at baseline and 411/644 patients after 5 years. The mean age was 39.8 (± 9.7) years. Overall, 187/483 (38.7%) women and 9/161 (5.6%) men were given intravenous iron treatment in the observation period. From baseline to 5 years, mean haemoglobin decreased by 0.3 g/dL in both men and women. Anaemia occurred in 18/311 (5.8%) women and 9/100 (9%) men at 5 years. Depleted iron stores (ferritin ≤ 15 μg/L) were seen among 44/323(13.6%) women and 3/102 (2.9%) men, and low iron stores (ferritin 16–50 μg/L) occurred in 144/326 (44.6%) women and 38/102 (37.3%) men 5 years after RYGB.

Conclusion

By routinely offering intravenous iron treatment to patients with depleted iron stores after RYGB, haemoglobin levels were preserved. Half of the patients experienced low or depleted iron stores at 5 years.

Beyond the Mind-Serum Trace Element Levels in Schizophrenic Patients: A Systematic Review

The alterations in serum trace element levels are common phenomena observed in patients with different psychiatric conditions such as schizophrenia, autism spectrum disorder, or major depressive disorder. The fluctuations in the trace element concentrations might act as potential diagnostic and prognostic biomarkers of many psychiatric and neurological disorders. This paper aimed to assess the alterations in serum trace element concentrations in patients with a diagnosed schizophrenia. The authors made a systematic review, extracting papers from the PubMed, Web of Science, and Scopus databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Among 5009 articles identified through database searching, 59 of them were assessed for eligibility. Ultimately, 33 articles were included in the qualitative synthesis. This review includes the analysis of serum levels of the following trace elements: iron, nickel, molybdenum, phosphorus, lead, chromium, antimony, uranium, magnesium, aluminum, zinc, copper, selenium, calcium, and manganese. Currently, there is no consistency regarding serum trace element levels in schizophrenic patients. Thus, it cannot be considered as a reliable prognostic or diagnostic marker of schizophrenia. However, it can be assumed that altered concentrations of those elements are crucial regarding the onset and exaggeration of either psychotic or negative symptoms or cognitive dysfunctions.

Can Improved Legume Varieties Optimize Iron Status in Low- and Middle-Income Countries? A Systematic Review

Iron and zinc deficiencies are some of the most widespread micronutrient deficiencies in low- and middle-income countries (LMIC). Dietary diversification, food fortification, nutrition education, and supplementation can be used to control micronutrient deficiencies. Legumes are important staple foods in most households in LMIC. Legumes are highly nutritious (good sources of essential minerals, fiber, and low glycemic index) and offer potential benefits in addressing nutrition insecurity in LMIC. Several efforts have been made to increase micronutrient intake by use of improved legumes. Improved legumes have a higher nutrient bioavailability, lower phytate, or reduced hard-to-cook (HTC) defect. We hypothesize that consumption of improved legumes leads to optimization of zinc and iron status and associated health outcomes. Therefore, the objective of this review is to examine the evidence on the efficacy of interventions using improved legumes. Nine relevant studies are included in the review. Consumption of improved legumes resulted in a ≥1.5-fold increase in iron intake. Several studies noted modest improvements in biomarkers of iron status [hemoglobin (Hb), serum ferritin (SF), and transferrin receptor] associated with consumption of improved legumes. Currently, no efficacy studies assessing the relation between consumption of improved legumes and zinc status are available in the literature. Evidence shows that, in addition to repletion of biomarkers of iron status, consumption of improved legumes is associated with both clinical and functional outcomes. The prevalence of iron deficiency (ID) decreases with consumption of improved legumes, with increases of ≤3.0 g/L in Hb concentrations. Improvement in cognition and brain function in women has been reported as well. However, further research is necessary in more at-risk groups and also to show if the reported improvements in status markers translate to improved health outcomes. Evidence from the included studies shows potential from consumption of improved legumes suggesting them to be a sustainable solution to improve iron status.

Body iron and lead status in early childhood and its effects on development and cognition: a longitudinal study from urban Vellore

OBJECTIVE

Early childhood factors can have persisting effects on development and cognition in children. We propose to explore the trends of Fe deficiency and Pb toxicity in early childhood and their association with child development at 2 years of age and cognition at 5 years.

DESIGN

Longitudinal birth cohort study.

SETTING

Urban slum, Vellore, India.

PARTICIPANTS

Children enrolled at birth were followed up regularly in the first 2 years with developmental and cognitive assessments at 2 and 5 years of age, respectively.

RESULTS

The birth cohort enrolled 251 children with 228 children followed up at 2 years and 212 at 5 years of age. Fe deficiency (ID) was highest at 15 months of age and improved subsequently at 24 months. Blood Pb levels (BLL) remained high at all age groups with an increasing trend with age; 97 % at 36 months having high BLL. Persistent high mean BLL at 15 and 24 months had negative association with both cognition and expressive language raw scores of 24 months, while high mean BLL at 15, 24 and 36 months had no significant association with any of the domains of cognition at 5 years of age. Early childhood cumulative body Fe status at 7, 15 and 24 months did not show any association with child development at 2 years, but was associated with verbal, performance and processing speed components of cognition at 5 years.

CONCLUSIONS

Optimising body Fe status and limiting Pb exposure in early childhood can augment child development and school entry cognition.

Reticulocyte Hemoglobin Content (Ret He): A Simple Tool for Evaluation of Iron Status in Childhood Cancer

BACKGROUND

Cancer-related anemia is a common complication of cancer and its treatment that may be mediated by nutritional deficiency or inflammatory cytokines inhibiting erythropoiesis.

AIM

We evaluated the value of reticulocyte hemoglobin content (Ret He) as a marker of iron availability for erythropoiesis in childhood cancer and the impact of oral iron supplementation on hematologic parameters in patients with low Ret He.

MATERIALS AND METHODS

This prospective study included 100 pediatric patients with cancer on chemotherapy who were screened for the presence of anemia. Patients with anemia underwent testing for complete blood count including Ret He on Sysmex XE 2100 and assessment of reticulocyte count, serum iron, serum ferritin, transferrin saturation, total iron-binding capacity, and C-reactive protein. Patients were classified according to their level of Ret He into normal or low Ret He using a cutoff level of 28 pg. Patients with low Ret He were subjected to 6 weeks' treatment with oral ion and were followed up with complete blood count and iron profile.

RESULTS

Thirty-one (77.5%) patients had normal Ret He, and 9 (22.5%) had low Ret He. Ret He was positively correlated with red cell indices, but not with iron parameters. After oral iron supplementation, a significant increase in hemoglobin, reticulocyte count, and iron was found.

CONCLUSIONS

We suggest that Ret He could be used as an easy and affordable tool for the assessment of iron deficiency anemia in childhood cancer during chemotherapy treatment. A trial of oral iron in patients with low Ret He may be useful to correct the associated anemia.

Alférez M, Díaz-Castro J. Fermented Goat Milk Consumption Enhances Brain Molecular Functions during Iron Deficiency Anemia Recovery

Iron deficiency anemia (IDA) is one of the most prevalent nutritional deficiencies worldwide. Iron plays critical roles in nervous system development and cognition. Despite the known detrimental consequences of IDA on cognition, available studies do not provide molecular mechanisms elucidating the role of iron in brain functions during iron deficiency and recovery with dairy components. In this study, 100 male Wistar rats were placed on a pre-experimental period of 40 days and randomly divided in two groups: a control group receiving a normal-Fe diet, (45 mg/kg), and an Fe-deficient group receiving a low-Fe diet (5 mg/kg). At day 40, 10 rats per group were sacrificed to anemia control, and 80 rats were divided into eight experimental groups fed with fermented goat or cow milk-based diets, with normal Fe content or Fe overload (450 mg/kg) for 30 days. IDA decreased most of the parameters related to brain molecular functions, namely dopamine, irisin, MAO-A, oxytocin, β-endorphin, and α-MSH, while it increased synaptophysin. These alterations result in an impairment of brain molecular functions. In general, during anemia recovery, fermented goat milk diet consumption increased dopamine, oxytocin, serotonin, synaptophysin, and α-MSH, and decreased MAO-A and MAO-B, suggesting a potential neuroprotective effect in brain functions, which could enhance brain molecular functions.

Iron Metabolism and Brain Development in Premature Infants

Iron is important for a remarkable array of essential functions during brain development, and it needs to be provided in adequate amounts, especially to preterm infants. In this review article, we provide an overview of iron metabolism and homeostasis at the cellular level, as well as its regulation at the mRNA translation level, and we emphasize the importance of iron for brain development in fetal and early life in preterm infants. We also review the risk factors for disrupted iron metabolism that lead to high risk of developing iron deficiency and subsequent adverse effects on neurodevelopment in preterm infants. At the other extreme, iron overload, which is usually caused by excess iron supplementation in iron-replete preterm infants, might negatively impact brain development or even induce brain injury. Maintaining the balance of iron during the fetal and neonatal periods is important, and thus iron status should be monitored routinely and evaluated thoroughly during the neonatal period or before discharge of preterm infants so that iron supplementation can be individualized.

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.

[Association between iron deficiency and brain developmental disorder in children]

Iron deficiency (ID) is the most common trace element deficiency in childhood. Recent studies have shown that late fetus period, neonatal period, and infancy are important periods for brain development, and ID during these periods may cause irreversible damage to brain development, including abnormal emotion and behavior, cognitive decline, and attention deficit, which may still be present in adulthood. Therefore, it should be taken seriously. This article summarizes the research advances in major mechanisms involved in brain developmental disorder due to ID in the early stage of life and related intervention measures.

Child Physical Abuse, Non-anemic Iron Deficiency and Behavior Problems

PURPOSE

Child abuse is regarded as a life-course social determinant of health problems. However, little is known about the nutritional status of physically abused children and their cumulative effect on child behavior. The present study aimed to examine the non-anemic iron deficiency status of abused children and the combined effect of physical abuse and non-anemic iron deficiency on child behavior in China.

METHODS

This cross-sectional study comprised 314 children aged 11-14 (12.30±0.57) years old from Jintan, China. Children self-reported their physical abuse experiences and behavior problems. Blood iron and hemoglobin concentrations were also measured.

RESULTS

Thirty-eight percent of children reported physical abuse experience, 17.5% had non-anemic iron deficiency, and the two risk factors co-occurred in 8.0% children. Physically abused children were more likely to be affected by non-anemic iron deficiency than their non-abused counterparts. Children who had experienced both physical abuse and non-anemic iron deficiency reported more behavior problems than children with neither or either risk factors.

CONCLUSIONS

Physically abused children are more likely to have non-anemic iron deficiency. Children with the presence of both physical abuse experience and non-anemic iron deficiency have more behavior problems. There is a need to prevent both child abuse and non-anemic iron deficiency simultaneously to maintain normal child behavior development.