Iron metabolism in obesity: how interaction between homoeostatic mechanisms can interfere with their original purpose. Part I: underlying homoeostatic mechanisms of energy storage and iron metabolisms and their interaction

Electroacupuncture enhances cerebral blood perfusion by inhibiting HIF-1α in rat subarachnoid hemorrhage

OBJECTIVE

Cerebral blood perfusion (CBP) reduction is a prevalent complication following subarachnoid hemorrhage (SAH) in clinical practice, often associated with long-term cognitive impairment and prognosis. Electroacupuncture (EA), a widely utilized traditional Chinese therapy for central nervous system disorders, has demonstrated promising therapeutic effects. This study aims to investigate the therapeutic potential of EA in restoring CBP in SAH rats and to explore the mechanisms involving HIF-1α in this process.

METHODS

Rats were randomly assigned to one of five groups, including Sham, SAH, EA, EA + Saline, and EA + dimethyloxallyl glycine (DMOG) groups. EA treatment was administered for 10 min daily, while DMOG were intraperitoneally injected. Behavioral tests, cerebral blood flow monitoring, vascular thickness measurement, western blotting, and immunofluorescence staining were conducted to assess the therapeutic effects of EA on cerebral blood flow.

RESULTS

SAH resulted in elevated levels of HIF-1α, endothelin (ET), ICAM-1, P-SELECTIN, E-SELECTIN, and decreased level of eNOS in the brain. This led to cerebral vasospasm, decreased CBF, and cognitive deficits in the rat SAH model. EA intervention downregulated the expression of HIF-1α, ET, ICAM-1, P-SELECTIN, and E-SELECTIN, while increasing eNOS expression. This alleviated cerebral vasospasm, restored CBF, and improved cognitive function. However, the administration of the HIF-1α stabilizer (DMOG) counteracted the therapeutic effects of EA.

CONCLUSION

EA promotes the recovery of cerebral blood flow after SAH injury, attenuates cerebral vasospasm, and accelerates the recovery of cognitive dysfunction, and its mechanism of action may be related to the inhibition of the HIF-1α signaling pathway.

Iron Deficiency and Iron Deficiency Anemia in Women with and without Obesity: NHANES 2001-2006

Obesity has been linked to numerous health and nutritional problems, including impaired iron metabolism, a common cause of anemia. We aimed to determine the prevalence of anemia, iron deficiency (ID), and iron deficiency anemia (IDA) among women aged 20-49 years based on body mass index (BMI) status. We used measures of iron status and body mass index from the 2001-2006 National Health and Nutrition Examination Survey (NHANES). Mean serum ferritin, erythrocyte protoporphyrin, and soluble transferrin receptor were higher, while those of serum iron, percent transferrin saturation, and mean cell volume (MCV) were lower in women with obesity than those with normal weight (all p < 0.016). ID based on the ferritin model was 12.5 ± 1.0% vs. 22.9 ± 1.6% (p < 0.001); 9.0 ± 0.9% vs. 20.0 ± 1.3% (p < 0.001) based on the MCV model; and 8.1 ± 1.0% vs. 10.5 ± 1.2% (p > 0.05) based on the BII model for women with normal weight and women with obesity, respectively. Anemia prevalence was 5.5 ± 0.8% (normal) vs. 9.3 ± 1.0% (obese) (p = 0.005). The IDA estimates based on the ferritin and MCV models were similar but higher than that from the BII model (p < 0.001). Generally, the prevalence rates of ID and anemia (and IDA) were higher for women with obesity, but the method used to define deficiency mattered. The choice of iron indices is important for estimating ID and IDA in populations with obesity.

Prevalence of Anemia and Iron Deficiency in Women of Reproductive Age in Cuba and Associated Factors

This study aims to evaluate the prevalence of anemia and iron deficiency in women of reproductive age and the association with inflammation, global overweight, adiposity, and menorrhagia. A sample design of women of reproductive age from the Eastern, Central, and Havana Regions was carried out. Biochemical determinations of hemoglobin, serum ferritin, soluble transferrin receptors, leukocytes, C-reactive protein, alpha-1 acid glycoprotein, and homocysteine were performed. Serum ferritin was also adjusted by inflammation. Nutritional status was assessed, and menstrual characteristics were collected by survey. A total of 742 women were studied. The prevalence of anemia was 21.4%, iron storage deficiency at 16.0%, and erythropoietic dysfunction at 5.4%, with inflammation at 47.0% and elevated homocysteine at 18.6%. Global overweight was 46.2% and increased adiposity at 58.4%. Anemia is associated with iron deposition deficiency (OR = 3.023 (1.816-5.033)) and with erythropoietic deficiency (OR = 5.62 (3.03-10.39)), but not with inflammation, global overweight, and adiposity. Global overweight was found to be associated with inflammation (OR = 2.23 (1.41-3.53)). Anemia was associated with heavy menstrual bleeding (OR = 1.92 (1.34-2.76)). Homocysteine was associated with inflammation (OR = 2.05 (1.08-3.90)), but not with anemia. In conclusion, anemia in Cuba is classified as a moderate public health problem, but not iron deficiency. A high prevalence of overweight and obesity was found, associated with inflammation, but not with anemia or iron deficiency. Heavy menstrual bleeding is a factor associated with anemia.

Iron Status and Associated Factors among Canadian Women: Results from the Canadian Health Measures Survey

BACKGROUND

Iron deficiency and overload may negatively impact women's health. There has been limited assessment of iron status and its associated factors among Canadian women.

OBJECTIVES

This study investigated associations of various sociodemographic, lifestyle, medication, and dietary factors with body iron stores among pre- and postmenopausal women in Canada.

METHODS

Analyses were conducted using cross-sectional, nationally representative survey and biomarker data from women aged 20-79 y (n = 6362) in the Canadian Health Measures Survey (2009-2017). Body iron stores were assessed by measuring serum concentrations of ferritin (SF). Information on potential correlates was collected during an in-home interview. Multivariable linear regression analyses were performed to evaluate associations with SF concentration, and logistic regression was used to estimate associations with iron deficiency (SF <15 μg/L) or elevated iron stores (SF >150 μg/L).

RESULTS

Geometric mean SF concentrations were significantly higher in postmenopausal than in premenopausal women (73.2 versus 33.8 μg/L; P < 0.001). The prevalence of iron deficiency among pre- and postmenopausal women was 16.0% and 4.0%, respectively, whereas that of elevated iron stores was 2.7% and 21.0%, respectively. After simultaneous adjustment for multiple factors, including high-sensitivity CRP (inflammation marker), we found that age, East/Southeast Asian (versus White) race/ethnicity, alcohol, and red meat consumption were positively associated with SF concentration among pre- and postmenopausal women. In addition, aspirin use and dairy consumption were inversely associated with SF concentration among postmenopausal women only. Similar patterns were observed for associations with elevated iron stores among postmenopausal women, whereas higher grain consumption was associated with an increased prevalence of iron deficiency among premenopausal women.

CONCLUSIONS

Sociodemographic, lifestyle, medication, and dietary factors are correlated with iron status determined by SF concentration among Canadian women. The findings may have implications for intervention strategies aimed at optimizing body iron stores in pre- and postmenopausal women.

Inflammatory diets are associated with lower total iron binding capacity in sera of young adults

Chronic, systemic inflammation, which is associated with obesity and numerous other diseases, impairs iron status by increasing hepcidin concentration. Inflammation also decreases the concentration of transferrin, the main iron transport protein and a negative acute phase protein, which is indirectly assessed by measuring total iron binding capacity (TIBC). However, the contribution of diet-induced inflammation has not been studied. Data from two studies, namely Diet and Inflammation and Selenium and Inflammation Studies (total n=98) were used to assess the associations among Dietary Inflammatory Index (DII^®) scores derived from three-day dietary records, body mass index (BMI=weight[kg]/height[m]²), inflammatory and hematological markers among young adults with normal-weight, overweight or obesity. Subjects' diets were also categorized as less inflammatory diets (LID) and inflammatory diets (ID) using cluster analysis. Independent t-test and regression analyses were used to assess associations in the data. Intakes of iron, proteins, fat, fiber, and calories were higher in the LID group compared to the ID group (p<0.05). Demographic characteristics and concentrations of C-reactive protein (CRP) and iron status biomarkers did not differ significantly between the two groups (p>0.05). Higher DII score was associated with increasing CRP (β+SE=0.23+0.07, p=0.002) and lower TIBC (β+SE=-8.46+3.44, p=0.02), independent of BMI category. The LID diet was associated with higher TIBC (β+SE=29.87+10.75, p=0.007) compared to the ID diet. In conclusion, inflammatory diets may impair iron status by reducing the iron binding capacity of transferrin.

Severe Obesity in Women Can Lead to Worse Memory Function and Iron Dyshomeostasis Compared to Lower Grade Obesity

Objective

Obesity is one of the modifiable risk factors for dementia. Insulin resistance, the abundance of advanced glycated end-products, and inflammation are some of the mechanisms associated with the lower cognitive performance observed in obesity. This study aims to evaluate the cognitive function of subjects with distinct degrees of obesity, comparing class I and II obesity (OBI/II) to class III obesity (OBIII), and to investigate metabolic markers that can distinguish OBIII from OBI/II. Study Design. This is a cross-sectional study, in which 45 females with BMI varying from 32.8 to 51.9 kg/m² completed a set of 4 cognitive tests (verbal paired-associate test, stroop color, digit span, and Toulouse-Pieron cancellation test) and their plasma metabolites, enzymes, and hormones related to glycemia, dyslipidemia, and liver function, as well as the biomarkers of iron status, were concomitantly analyzed.

Results

OBIII showed lower scores in the verbal paired-associate test compared to OBI/II. In other cognitive tests, both groups showed similar performance. OBIII presented a lower iron status compared to OBI/II based on total iron binding capacity, degree of transferrin saturation, hemoglobin, mean corpuscular volume, and mean corpuscular hemoglobin. The levels of indicators for glycemia, liver function, and lipid metabolism were similar in both groups. Analysis of plasma metabolites showed that OBIII had lower levels of pyroglutamic acid, myoinositol, and aspartic acid and higher levels of D-ribose than OBI/II.

Conclusion

Iron is an essential micronutrient for several metabolic pathways. Thus, iron dyshomeostasis observed in severe obesity may aggravate the cognitive impairment by altering metabolic homeostasis and enhancing oxidative stress. These findings can contribute to searching for biomarkers that indicate cognitive performance in the population with obesity.

Essential role of systemic iron mobilization and redistribution for adaptive thermogenesis through HIF2-α/hepcidin axis

Iron is an essential biometal, but is toxic if it exists in excess. Therefore, iron content is tightly regulated at cellular and systemic levels to meet metabolic demands but to avoid toxicity. We have recently reported that adaptive thermogenesis, a critical metabolic pathway to maintain whole-body energy homeostasis, is an iron-demanding process for rapid biogenesis of mitochondria. However, little information is available on iron mobilization from storage sites to thermogenic fat. This study aimed to determine the iron-regulatory network that underlies beige adipogenesis. We hypothesized that thermogenic stimulus initiates the signaling interplay between adipocyte iron demands and systemic iron liberation, resulting in iron redistribution into beige fat. To test this hypothesis, we induced reversible activation of beige adipogenesis in C57BL/6 mice by administering a β3-adrenoreceptor agonist CL 316,243 (CL). Our results revealed that CL stimulation induced the iron-regulatory protein-mediated iron import into adipocytes, suppressed hepcidin transcription, and mobilized iron from the spleen. Mechanistically, CL stimulation induced an acute activation of hypoxia-inducible factor 2-α (HIF2-α), erythropoietin production, and splenic erythroid maturation, leading to hepcidin suppression. Disruption of systemic iron homeostasis by pharmacological HIF2-α inhibitor PT2385 or exogenous administration of hepcidin-25 significantly impaired beige fat development. Our findings suggest that securing iron availability via coordinated interplay between renal hypoxia and hepcidin down-regulation is a fundamental mechanism to activate adaptive thermogenesis. It also provides an insight into the effects of adaptive thermogenesis on systemic iron mobilization and redistribution.

Prevalence and Factors Associated with Iron Deficiency and Anemia among Residents of Urban Areas of São Paulo, Brazil

Anemia is a worldwide concern. This cross-sectional population-based study examined the prevalence of iron-deficiency anemia (IDA) among residents of São Paulo (n = 898; 12-93 years), considering sociodemographic factors, dietary iron inadequacy, and food contributors to iron intake. Blood cell count and iron biomarkers were quantified. Dietary iron intake was measured using two 24-h dietary recalls. Iron intake inadequacy was estimated using a probabilistic approach. The prevalence of anemia was 6.7%, depleted iron stores 5.1%, and IDA 1.1%. Women of all age groups, older adults, and those who were underweight or obese had the highest prevalence of anemia, and female adolescents had the highest prevalence of depleted iron stores. Female adolescents and adults were more vulnerable to depleted iron stores. Male adults and older adults had a considerable prevalence of iron overload. Except for female adolescents and adults, all groups had mild probabilities of inadequate iron intake. The main food iron contributor was wheat flour. Hemoglobin concentrations were directly associated with being an adult, having a higher income, and inversely associated with being female. Serum ferritin concentrations were directly associated with age and inversely correlated with female sex. Residents of São Paulo had a low prevalence of anemia, iron deficiency, and IDA, and sociodemographic factors interfered with these parameters.

Content of essential and toxic trace elements in organs of obese Wistar and Zucker leprfa rats receiving quercetin

BACKGROUND

The levels of a number of essential and toxic trace elements in organs and tissues are affected by the disruptions in body homeostasis caused by obesity. Some of these elements may also be influenced by the consumption of biologically active substances of polyphenolic origin, which possess potent abilities to complex with transition metal ions.

AIMS

The aim of this study was to determine the content of essential and toxic trace elements in Wistar outbred and hereditary obese Zucker Lepr^fa (Z) rats consuming a standard balanced diet or hypercaloric diet with excess fat and fructose, supplemented with quercetin or not supplemented.

MATERIALS AND METHODS

Male Wistar and Z rats were fed a control AIN-93M-based semi-synthetic diet or a high-fat-high-carbohydrate diet (HFCD, with 30% fat by weight and 20% fructose provided in the drinking water). A portion of the animals in each line and diet group was administered quercetin at 50 mg/kg body weight. Essential trace elements were included in the diets as a high-purity salt mixture. After the termination of feeding on day 63, the livers, kidneys, and brains of the rats were excised and the content of 16 elements (Fe, Mg, Cu, Mn, Co, Se, Zn, Cr, Ni, Al, Cd, As, Pb, V, Cs, and Ag) was measured by inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

In the livers of the Z rats, the contents of Co, Zn, Mg, Fe, Se, and V were reduced and the content of Cr was increased compared to that of the Wistar rats. Supplementation with quercetin significantly decreased liver Fe, V, and Se content, which was more noticeable in the Wistar rats than in the Z rats. In kidneys of Z rats consuming control diet, the contents of Co, Cu, and Cs were decreased whereas those of Ni, Al, and Se were increased compared with the contents in the Wistar rats. The same trend was observed with HFCD feeding except for Cs content. Quercetin reduced kidney V content in both rat lines fed both diets, whereas it reduced Se and Cs only in the Z rats fed control diet. In the brains of the Z rats, a large increase was observed in some trace elements including Pb, Cd, Al, Cr, Ni, Fe, and V compared with the levels in the Wistar rat brains. Supplementation of the control diet with quercetin decreased Al and Ni in the brains of the Z rats.

CONCLUSION

There were significant differences in the mineral content of organs between the Wistar and Z rats, with different propensities for obesity. Moreover some of these effects had no straightforward association with decreased feed consumption or hepatic fat accumulation. When introduced into the diets, quercetin affected the content of essential and toxic elements, but with ambiguous physiological significance. Thus, indicators of essential and toxic trace elements deserve to be used in the protocols of preclinical as well as clinical trials of biologically active substances and food supplements.

Metabolic syndrome may be associated with a lower prevalence of iron deficiency in Ecuadorian women of reproductive age

The present study aimed to assess the associations of the stages of Fe deficiency (Fe deficiency without anaemia (ID) and Fe-deficiency anaemia (IDA)) and anaemia with metabolic syndrome (MetS) in Ecuadorian women. A cross-sectional study was conducted in 5894 women aged 20–59 years, based on data from the 2012 Ecuadorian National Health and Nutrition Survey. The sample was stratified by age. A χ² test was used to assess the possible associations of ID, IDA and anaemia with MetS. The prevalence ratio (PR) for each stage of Fe deficiency and anaemia was estimated considering women without MetS as a reference. The total prevalence of MetS, ID, IDA and anaemia was 32⋅3 % (se 0⋅6), 6⋅2 % (se 0⋅3), 7⋅1 % (se 0⋅3) and 5⋅0 % (se 0⋅3), respectively. In women aged 20–29, 30–39 and 40–49 years, MetS was associated with a lower prevalence of ID (PR (95 % CI; P-value)): 0⋅17 (0⋅06, 0⋅46; P < 0⋅001), 0⋅69 (0⋅48, 0⋅99; P = 0⋅044) and 0⋅44 (0⋅29, 0⋅67; P < 0⋅001), respectively. In women aged 50–59 years, MetS was associated with IDA and anaemia (PR (95 % CI; P-value)): 0⋅12 (0⋅02, 0⋅96; P = 0⋅026) and 0⋅22 (0⋅07, 0⋅64; P = 0⋅002), respectively. In conclusion, Ecuadorian women of reproductive age with MetS have a lower prevalence of ID compared with those without MetS. Furthermore, the MetS and IDA coexist at the population level. These findings require an analysis from a dietary pattern approach, which could provide key elements for developing public policies that simultaneously address all forms of malnutrition.

A mitophagic response to iron overload-induced oxidative damage associated with the PINK1/Parkin pathway in pancreatic beta cells

BACKGROUND

Iron overload can result in a disorder in glucose metabolism. However, the underlining mechanism through which iron overload induces beta cell death remains unknown.

METHODS

According to the concentration of ferric ammonium citrate (FAC) and N-acetylcysteine, INS-1 cells were randomly divided into four groups: normal control (FAC 0 μM) group, FAC 80 μM group, FAC 160 μM group, FAC 160μM + NAC group. Cell proliferation was assessed by Cell Counting Kit-8. Reactive oxygen species (ROS) level was further evaluated using flow cytometer with a fluorescent probe. The mitochondrial membrane potential was detected by JC-1 kit, and transmission electron microscopy was used to observe the mitochondrial changes. The related protein expressions were detected by western bolt to evaluate mitophagy status.

RESULTS

It was shown that FAC treatment decreased INS-1 cell viability in vitro, resulted in a decline in mitochondrial membrane potential, increased oxidative stress level and suppressed mitophagy. Furthermore, these effects could be alleviated by the ROS scavenger.

CONCLUSIONS

We proved that increased iron overload primarily increased oxidative stress and further suppressed mitophagy via PTEN-induced putative kinase 1/Parkin pathway, resulting in cytotoxicity in INS-1 cells.

Association of cord blood methylation with neonatal leptin: An epigenome wide association study

Background

Neonatal adiposity is a risk factor for childhood obesity. Investigating contributors to neonatal adiposity is important for understanding early life obesity risk. Epigenetic changes of metabolic genes in cord blood may contribute to excessive neonatal adiposity and subsequent childhood obesity. This study aims to evaluate the association of cord blood DNA methylation patterns with anthropometric measures and cord blood leptin, a biomarker of neonatal adiposity.

Methods

A cross-sectional study was performed on a multiethnic cohort of 114 full term neonates born to mothers without gestational diabetes at a university hospital. Cord blood was assayed for leptin and for epigenome-wide DNA methylation profiles via the Illumina 450K platform. Neonatal body composition was measured by air displacement plethysmography. Multivariable linear regression was used to analyze associations between individual CpG sites as well as differentially methylated regions in cord blood DNA with measures of newborn adiposity including anthropometrics (birth weight, fat mass and percent body fat) and cord blood leptin. False discovery rate was estimated to account for multiple comparisons.

Results

247 CpG sites as well as 18 differentially methylated gene regions were associated with cord blood leptin but no epigenetic changes were associated with birth weight, fat mass or percent body fat. Genes of interest identified in this study are DNAJA4, TFR2, SMAD3, PLAG1, FGF1, and HNF4A.

Conclusion

Epigenetic changes in cord blood DNA are associated with cord blood leptin levels, a measure of neonatal adiposity.

Effects of Pubertal Status and Inflammation on the Use of Ferritin to Define Iron Deficiency in Children With Overweight or Obesity

Background and aims:

A worldwide increase in childhood overweight (OW) and obesity (OB) has been reported. OB is an inflammatory state which affects iron metabolism and the sensibility of the tests to detect iron deficiency (ID). Our aim was to evaluate the adequacy of current ferritin cut-offs to define ID in children with OW/OB.

Methods:

This cross-sectional study included 152 children (54% girls) aged (median [Q1-Q3]) 11 (8-13) years with OW/OB. Complete blood count and iron metabolism were evaluated. Low ferritin, transferrin saturation (TSat), and anemia were defined by age- and sex-specific cut-offs recommended by National Guidelines. Iron intake was assessed in a subgroup (n = 80) by a 24-hour dietary recall. Analyses were made according to pubertal development and ferritin tertiles.

Results:

The overall prevalence of low ferritin, TSat, and anemia was 2.6%, 23.8%, and 5.2%, respectively. Among pre-pubertal children (n = 87), the frequency of low TSat rose across ferritin tertiles (P < .05), whereas it decreased among pubertal children (n = 65; P < .005). Cases of anemia among pre-pubertal children were found in the highest ferritin tertile, whereas 4/6 anemia cases in pubertal children were found in the lowest ferritin tertile (<39 µg/L). Pubertal children within the lowest ferritin tertile + low TSat (n = 11) showed lower hemoglobin (–9%; P < .005) and hematocrit (–8%, P < .01) than those in the same tertile + normal TSat (n = 16). The overall prevalence of children with ferritin < 39 µg/L + low TSat was 9.2%.

Conclusions:

Higher ferritin cut-off values are required to define ID in children with OW/OB. Such cut-off remains to be validated in larger, multi-ethnic cohorts of children with OW/OB.

Metabolic surgery and iron homeostasis

Iron deficiency and anaemia after metabolic surgery, potentially modifiable nutritional complications, are becoming an increasing cause for concern as prevalence increases with time and there is limited evidence supporting the effectiveness of the current guidelines for prophylactic oral iron supplementation and treatment for deficiency. Abnormalities in iron nutrition predisposing to deficiency are common in severely obese patients, and the low-grade systemic inflammation, also common to these patients, reduces the effectiveness of oral iron supplementation. The surgical procedures result in alterations of foregut anatomy and physiology, which limit iron absorptive capacity and daily food intake. These alterations and the limited effects of oral iron supplementation explain the high prevalence of postoperative iron deficiency and anaemia. This review outlines current mechanisms concerning the pathogenesis of disordered iron nutrition in patients with severe obesity, current gaps in knowledge, and opportunities for quality improvement.

Iron status at opposite ends of the menstrual function spectrum

OBJECTIVES

Although exercising women are at high risk of poor iron status, it is unknown how non-pathological, physiological menstrual function affects iron status. As such, this study investigates the association between menstrual function and iron status in exercising women with amenorrhea and exercising women with ovulatory, eumenorrheic menstrual cycles.

DESIGN

Cross-sectional analysis of iron depletion prevalence, iron status indices, exercise parameters, and diet composition.

METHODS

Women aged 18-35 years performing at least 2 h per week of aerobic exercise were recruited. Women with amenorrhea (AMEN) were defined by the absence of menses for at least 90 days or less than 6 menses in the past 12 months (n = 82). Women with ovulatory, eumenorrheic menstrual cycles (OvEU) were defined by the presence of ovulatory cycles of 26-35 days in length for the past 6 months (n = 109). Group differences in serum ferritin (Ft), soluble transferrin receptor (sTfR), total body iron (TBI), hemoglobin (Hb), hematocrit (Hct), iron depletion prevalence (Ft <15 μg/L), peak oxygen consumption (VO_2peak), exercise minutes per week, and diet logs were assessed.

RESULTS

The prevalence of iron depletion was greater in OvEU when compared to AMEN (26% vs. 15%, p = 0.04). No significant differences were observed between AMEN and OvEU in Ft (30.2 ± 2.2 vs. 24.9 ± 2.6 μg/L; p = 0.62), sTfR (5.2 ± 1.4 vs. 4.9 ± 1.5 mg/L; p = 0.95), TBI (5.3 ± 2.7 vs. 4.8 ± 3.7 mg/kg; p = 0.42), Hb (13.2 ± 0.4 vs. 13.4 ± 0.6 g/dL; p = 0.80), Hct (39.5 ± 0.8% vs. 39.8 ± 4.1%; p = 0.93), or exercise parameters. AMEN consumed more vitamin C than OvEU (269 ± 180 vs. 129 ± 141 mg/day, p < 0.001), but all other dietary factors were similar between AMEN and OvEU.

CONCLUSION

Exercising women with ovulatory, eumenorrheic cycles are at a greater risk of iron depletion than exercising, amenorrheic women. Thus, menstrual function must be considered when screening for poor iron status in exercising women.

Ferroportin-Hepcidin Axis in Prepubertal Obese Children with Sufficient Daily Iron Intake

Iron metabolism may be disrupted in obesity, therefore, the present study assessed the iron status, especially ferroportin and hepcidin concentrations, as well as associations between the ferroportin-hepcidin axis and other iron markers in prepubertal obese children. The following were determined: serum ferroportin, hepcidin, ferritin, soluble transferrin receptor (sTfR), iron concentrations and values of hematological parameters as well as the daily dietary intake in 40 obese and 40 normal-weight children. The ferroportin/hepcidin and ferritin/hepcidin ratios were almost two-fold lower in obese children (p = 0.001; p = 0.026, respectively). Similar iron concentrations (13.2 vs. 15.2 µmol/L, p = 0.324), the sTfR/ferritin index (0.033 vs. 0.041, p = 0.384) and values of hematological parameters were found in obese and control groups, respectively. Iron daily intake in the obese children examined was consistent with recommendations. In this group, the ferroportin/hepcidin ratio positively correlated with energy intake (p = 0.012), dietary iron (p = 0.003) and vitamin B₁₂ (p = 0.024). In the multivariate regression model an association between the ferroportin/hepcidin ratio and the sTfR/ferritin index in obese children (β = 0.399, p = 0.017) was found. These associations did not exist in the controls. The results obtained suggest that in obese children with sufficient iron intake, the altered ferroportin-hepcidin axis may occur without signs of iron deficiency or iron deficiency anemia. The role of other micronutrients, besides dietary iron, may also be considered in the iron status of these children.

Anemia and Iron Status Among Different Body Size Phenotypes in Chinese Adult Population: a Nation-Wide, Health and Nutrition Survey

Previous studies have shown that there is a controversial relationship between iron homeostasis and obesity. This study aims to explore the relationship of anemia and iron status with different body size phenotypes in adult Chinese population. Using information on iron status-related parameters and lifestyle data from 8462 participants of the 2009 wave of China Health and Nutrition Survey (2009 CHNS), we performed multivariable logistic regression analyses to estimate the odds ratios (ORs) for the risk of anemia and iron parameters according to different body size phenotypes. Participants with higher body mass index (BMI) had a lower anemia prevalence with significant trends in both metabolic status groups (P < 0.001). Serum ferritin, transferrin, and soluble transferrin receptor (sTfR)/log ferritin index were significant in different metabolic status groups and in different body size phenotypes, respectively. The ORs for higher ferritin and transferrin increased across different body size phenotypes in both genders, and for sTfR/log ferritin index decreased (P < 0.01 for trend). This association was still statistically significant after adjustment for multiple confounders. We found an inverse association of BMI levels with the prevalence of anemia and strong association of serum ferritin and transferrin with higher risk of obesity or overweight in both metabolic status groups.

Perspective: What Makes It So Difficult to Mitigate Worldwide Anemia Prevalence?

Anemia can be related to decreased production or increased loss of erythrocytes, or both, leading to many underlying and often overlapping causes. A largely cereal-based diet with plenty of phytates, polyphenols, and other ligands that inhibit intestinal iron absorption predominated in preindustrial Europe and predominates in present-day developing countries alike. In both situations, we find poor hygienic conditions, which frequently lead to anemia of inflammation. The large number of possible causes and their interaction shows why it is so difficult to mitigate anemia prevalence. Diagnostic biomarkers are required to differentiate the different types of anemia and to treat them appropriately. Some of them are well established in adults [e.g., concentrations of serum ferritin, soluble transferrin receptor (sTfR), and serum iron or the ratio of sTfR to log ferritin]. Others, such as serum hepcidin, hold considerable promise, although they are not yet widely used. A particular issue is to establish reference values for biomarkers in infants and children at different ages. The fact that resource-rich postindustrial societies have a very low prevalence of iron-deficiency anemia offers hope that common types of anemia can be eliminated. In contrast, inborn forms of anemia, such as thalassemia, and anemias related to underlying diseases (e.g., bleeding tumors or peptic ulcers, gynecologic blood losses, or renal diseases) require an operational health system to be addressed appropriately.

Anaemia of Chronic Disease: An In-Depth Review

Anaemia is the most common haematological disorder affecting humanity and is usually observed in chronic disease states such as non-specific anaemia, which may cause diagnostic difficulties. In chronically ill patients with anaemia, this has a negative impact on quality of life as well as survival. This paper aims at reviewing the pathogenesis of this form of anaemia with a view to suggesting future targets for therapeutic intervention. The ability to diagnose this disorder depends on the ability of the physician to correlate the possible clinical pathways of the underlying disease with the patients' ferrokinetic state. It is important to rule out iron deficiency and other causes of anaemia as misdiagnosis will in most cases lead to refractoriness to standard therapy. The cytokines and acute-phase proteins play important roles in the pathogenesis of anaemia of chronic disease. Alterations in the metabolism of iron via the molecule hepcidin and ferritin are largely responsible for the consequent anaemia. Concomitant iron deficiency might be present and could affect the diagnosis and therapeutic protocol. Treatment options involve the use of erythropoiesis-stimulating agents, blood transfusion, and iron supplementation, in addition to treating the underlying disease.

Effect of Spirulina maxima Supplementation on Calcium, Magnesium, Iron, and Zinc Status in Obese Patients with Treated Hypertension

The effects of Spirulina maxima supplementation on calcium, magnesium, iron, and zinc status were studied in a double-blind placebo-controlled trial of 50 obese subjects with treated hypertension, each randomized to receive 2 g of spirulina or a placebo daily for 3 months. At baseline and after treatment, the calcium, magnesium, iron, and zinc concentration in plasma was assessed. It was found that 3 months of S. maxima supplementation resulted in a significant decrease in the iron level in the plasma of obese patients. In conclusion, this is the first clinical study on the influence of spirulina supplementation on mineral status in obese patients with hypertension. Spirulina supplementation affects the iron status of obese Caucasians with well-treated hypertension.

Effects of iron supplementation in mice with hypoferremia induced by obesity

Iron is an important micronutrient, but it can also act as a dangerous element by interfering with glucose homeostasis and inflammation, two features that are already disturbed in obese subjects. In this work, we study the effects of systemic iron supplementation on metabolic and inflammatory responses in mice with hypoferremia induced by obesity to better characterize whether iron worsens the parameters that are already altered after 24 weeks of a high-fat diet (HFD). Mice were maintained on a control diet or a HFD for 24 weeks and received iron-III polymaltose (50 mg/kg/every 2 days) during the last two weeks. Glucose homeostasis (basal glucose and insulin test tolerance) and systemic and visceral adipose tissue (VAT) inflammation were assessed. Iron levels were measured in serum. The Prussian blue reaction was used in isolated macrophages to detect iron deposition. Iron supplementation resulted in an increased number of VAT macrophages that were positive for Prussian blue staining as well as increased serum iron levels. Systemic hepcidin, leptin, resistin, and monocyte chemoattractant protein-1 (MCP-1) levels were not altered by iron supplementation. Local adipose tissue inflammation was also not made worse by iron supplementation because the levels of hepcidin, MCP-1, leptin, and interleukin (IL)-6 were not altered. In contrast, iron supplementation resulted in an increased production of IL-10 by adipose tissue and VAT macrophages. Leukocytosis and VAT plasminogen activator inhibitor-1 (PAI-1) level were reduced, but insulin resistance was not altered after iron supplementation. In conclusion, systemic iron supplementation in mice with hypoferremia induced by obesity did not worsen inflammatory marker or adipose tissue inflammation or the metabolic status established by obesity. Iron deposition was observed in adipose tissue, mainly in macrophages, suggesting that these cells have mechanisms that promote iron incorporation without increasing the production of inflammatory mediators.

Conflicting effects of BMI and waist circumference on iron status

The association between obesity and iron status has a long history and is still receiving attention. However comparative analysis of the association between general obesity (BMI) and visceral obesity (waist circumference) with iron status has not been extensively researched. The aim of the present study is thus to determine if body mass index and waist circumference have the same correlation with iron status. One thousand one hundred and thirty people (225 men and 905 women) aged 30 years and above participated in this study. Anthropometric parameters, haemoglobin, iron and total iron binding capacity concentrations were measured using standard methods. Percentage transferrin saturation was calculated and ferritin concentrations were measured using an enzyme linked immunosorbent assay. Obese or overweight women had significantly lower iron and transferrin saturation concentration when compared to non-obese women. In contrast, women with high waist circumference had comparable plasma iron and transferrin saturation to women with normal waist circumference. Partial correlation analysis and linear regression analysis showed that BMI is negatively and significantly associated with plasma iron, transferrin saturation, Hb and ferritin concentration, whilst waist circumference is positively but insignificantly associated with plasma iron, transferrin saturation, Hb and ferritin concentration. Binary regression analysis showed that obese or overweight people are more likely to have iron deficiency, whilst those with raised waist circumference are more likely to have iron overload. Multivariate analysis showed that body mass index is negatively and significantly associated with low iron status, while waist circumference is positively and insignificantly associated with iron status. This is supported by a comparison of plasma iron, transferrin saturation and ferritin concentrations in participants with high body mass index and normal waist circumference and participants with normal body mass index and high waist circumference to those participants having normal body mass index and normal waist circumference. The present study suggests that in women body mass index is associated with low plasma iron, transferrin saturation and ferritin concentrations, while waist circumference is associated with high plasma iron, transferrin saturation and ferritin concentrations.

Inflammation neither increases hepatic hepcidin nor affects intestinal (59)Fe-absorption in two murine models of bowel inflammation, hemizygous TNF(ΔARE/+) and homozygous IL-10(-/-) mice

Hepcidin-synthesis was reported to be stimulated by inflammation. In contrast, hepcidin synthesis was inhibited by TNFα and serum hepcidin was low. To elucidate these contradictions, we compare data on hepcidin expression, on iron absorption and homoeostasis and markers of inflammation between two murine models of intestinal inflammation and corresponding wild-types as determined by standard methods. In TNF(ΔARE/+) and IL-10(-/-)-mice hepatic hepcidin expression and protein content was significantly lower than in corresponding wild-types. However, (59)Fe whole-body retention showed no difference between knock-outs and corresponding wild-types 7d after gavage, in neither strain. Compared to wild-types, body weight, hepatic non-haem iron content, hemoglobin and hematocrit were significantly decreased in TNF(ΔARE/+) mice, while erythropoiesis increased. These differences were not seen in IL-10(-/-) mice. Duodenal IL-6 and TNFα content increased significantly in TNF(ΔARE/+) mice, while ferritin-H decreased along with hepatic hepcidin expression, ferritin L, and non-haem iron. In IL-10(-/-) mice, these changes were less marked or missing for non-haem iron. Duodenal ferritin-L and ferroportin increased significantly, while HFE decreased. Our results corroborate the conflicting combination of low hepcidin with inflammation and without increased intestinal iron absorption. Speculating on underlying mechanism, decreased hepcidin may result from stimulated erythropoiesis. Unaltered intestinal iron-absorption may compromise between the stimulation by increased erythropoiesis and inhibition by local and systemic inflammation. The findings suggest intense interaction between counterproductive mechanisms and ask for further research.