The effect of iron dosing schedules on plasma hepcidin and iron absorption in Kenyan infants

Oral iron therapy: Current concepts and future prospects for improving efficacy and outcomes

Iron deficiency (ID) and iron-deficiency anaemia (IDA) are global public health concerns, most commonly afflicting children, pregnant women and women of childbearing age. Pathological outcomes of ID include delayed cognitive development in children, adverse pregnancy outcomes and decreased work capacity in adults. IDA is usually treated by oral iron supplementation, typically using iron salts (e.g. FeSO4 ); however, dosing at several-fold above the RDA may be required due to less efficient absorption. Excess enteral iron causes adverse gastrointestinal side effects, thus reducing compliance, and negatively impacts the gut microbiome. Recent research has sought to identify new iron formulations with better absorption so that lower effective dosing can be utilized. This article outlines emerging research on oral iron supplementation and focuses on molecular mechanisms by which different supplemental forms of iron are transported across the intestinal epithelium and whether these transport pathways are subject to regulation by the iron-regulatory hormone hepcidin.

Intracellular Regulation Limits the Response of Intestinal Ferroportin to Iron Status in Suckling Rats

SCOPE

Iron status is regulated via iron absorption as there is no active iron excretion. Divalent metal-ion transporter-1 (DMT1) and ferroportin (FPN) are two key proteins vital for iron absorption, but the regulation of them in suckling mammals differs from that in adults. This study aims to explore regulation of iron transporters under different iron conditions during suckling.

METHODS AND RESULTS

This study developed suckling rats under different iron conditions. Unexpectedly, unchanged FPN at different iron status are detected. Since FPN is the only known iron exporter for mammals, unchanged FPN limits iron exported into blood during suckling. Thus, factors regulating FPN at transcriptional, post-transcriptional, and post-translational levels are detected. Results showed that Fpn mRNA is upregulated, while micro RNA-485(miR-485) which could silence Fpn mRNA is upregulated at low iron status limiting translation of Fpn mRNA. Besides, serum hepcidin and liver Hamp mRNA are upregulated, but ring finger protein 217( Rnf217) mRNA remained unchanged at high iron status leading to FPN not downregulated as adults.

CONCLUSIONS

Overall, this study indicates that translational regulation limits intestinal FPN protein response to iron deficiency and Rnf217 cannot effectively mediate the degradation of FPN at high iron status, which provides a reference for maintaining iron homeostasis during suckling.

Prebiotics increase iron absorption and reduce the adverse effects of iron on the gut microbiome and inflammation: a randomized controlled trial using iron stable isotopes in Kenyan infants

BACKGROUND

Iron fortificants tend to be poorly absorbed and may adversely affect the gut, especially in African children.

OBJECTIVE

We assessed the effects of prebiotic galacto-oligosaccharides/fructo-oligosaccharides (GOS/FOS) on iron absorption and gut health when added to iron-fortified infant cereal.

METHODS

We randomly assigned Kenyan infants (n = 191) to receive daily for 3 wk a cereal containing iron and 7.5 g GOS/FOS (7.5 g+iron group), 3 g (3-g+iron group) GOS/FOS, or no prebiotics (iron group). A subset of infants in the 2 prebiotic+iron groups (n = 66) consumed 4 stable iron isotope-labeled test meals without and with prebiotics, both before and after the intervention. Primary outcome was fractional iron absorption (FIA) from the cereal with or without prebiotics regardless of dose, before and after 3 wk of consumption. Secondary outcomes included fecal gut microbiota, iron and inflammation status, and effects of prebiotic dose.

RESULTS

Median (25th-75th percentiles) FIAs from meals before intervention were as follows: 16.3% (8.0%-27.6%) without prebiotics compared with 20.5% (10.4%-33.4%) with prebiotics (Cohen d = 0.53; P < 0.001). FIA from the meal consumed without prebiotics after intervention was 22.9% (8.5%-32.4%), 41% higher than from the meal without prebiotics before intervention (Cohen d = 0.36; P = 0.002). FIA from the meal consumed with prebiotics after intervention was 26.0% (12.2%-36.1%), 60% higher than from the meal without prebiotics before intervention (Cohen d = 0.45; P = 0.007). After 3 wk, compared with the iron group, the following results were observed: 1) Lactobacillus sp. abundances were higher in both prebiotic+iron groups (P < 0.05); 2) Enterobacteriaceae sp. abundances (P = 0.022) and the sum of pathogens (P < 0.001) were lower in the 7.5-g+iron group; 3) the abundance of bacterial toxin-encoding genes was lower in the 3-g+iron group (false discovery rate < 0.05); 4) fecal pH (P < 0.001) and calprotectin (P = 0.033) were lower in the 7.5-g+iron group.

CONCLUSIONS

Adding prebiotics to iron-fortified infant cereal increases iron absorption and reduces the adverse effects of iron on the gut microbiome and inflammation in Kenyan infants. This trial was registered at clinicaltrials.gov as NCT03894358.

Regulation of iron absorption in infants

BACKGROUND

Iron programs in low- and middle-income countries often target infants and young children. Limited data from human infants and mouse models suggest that homeostatic control of iron absorption is incomplete in early infancy. Excess iron absorption during infancy may have detrimental effects.

OBJECTIVES

Our aims were to 1) investigate determinants of iron absorption in infants aged 3-15 mo and assess whether regulation of iron absorption is fully mature during this period and 2) define the threshold ferritin and hepcidin concentrations in infancy that trigger upregulation of iron absorption.

METHODS

We performed a pooled analysis of standardized, stable iron isotope absorption studies performed by our laboratory in infants and toddlers. We used generalized additive mixed modeling (GAMM) to examine relationships between ferritin, hepcidin, and fractional iron absorption (FIA).

RESULTS

Kenyan and Thai infants aged 2.9-15.1 mo (n = 269) were included; 66.8% were iron deficient and 50.4% were anemic. In regression models, hepcidin, ferritin, and serum transferrin receptor were significant predictors of FIA, whereas C-reactive protein was not. In the model including hepcidin, hepcidin was the strongest predictor of FIA (β = -0.435). In all models, interaction terms, including age, were not significant predictors of FIA or hepcidin. The fitted GAMM trend of ferritin versus FIA showed a significant negative slope until ferritin of 46.3 μg/L (95% CI: 42.1, 50.5 μg/L), which corresponded to an FIA decrease from 26.5% to 8.3%; above this ferritin value, FIA remained stable. The fitted GAMM trend of hepcidin versus FIA showed a significant negative slope until hepcidin of 3.15 nmol/L (95% CI: 2.67, 3.63 nmol/L), above which FIA remained stable.

CONCLUSIONS

Our findings suggest that the regulatory pathways of iron absorption are intact in infancy. In infants, iron absorption begins to increase at threshold ferritin and hepcidin values of ∼46 μg/L and ∼3 nmol/L, respectively, similar to adult values.

Alternate day versus daily oral iron for treatment of iron deficiency anemia: a randomized controlled trial

Oral iron is the mainstay of treating iron deficiency anemia. Recent studies indicate better fractional iron absorption with alternate day supplementation. However, the optimal supplementation strategy is unclear. We compared effectiveness of daily versus alternate day supplementation of oral iron for treatment of iron deficiency anemia. This double blind, active control, randomized controlled trial was conducted on two hundred adults having hemoglobin 10 g/dL or less with microcytic hypochromic anemia and/or serum ferritin below 50 ng/mL. They were randomized to receive either two Ferrous sulfate tablets containing 60 mg elemental iron (120 mg total) on alternate days or single tablet of 60 mg elemental iron daily for 8 weeks. Primary outcome was mean change in hemoglobin at week 8 from baseline. Mean hemoglobin was 6.53 (± 1.89) and 6.68 (± 1.89) g/dL in the alternate day and daily arms respectively. Mean change in hemoglobin was + 1.05 ± 1.34 g/dL in alternate day arm and + 1.36 ± 1.51 g/dL in daily arm (p = 0.47) at week 8. There were no statistically significant differences between the arms with respect to any secondary outcome. There is no significant difference between alternate day and daily iron administration in improving hemoglobin. Randomized controlled trials enrolling more participants for longer periods of supplementation and evaluating clinically relevant outcomes like change in hemoglobin may be useful in identifying the ideal dosing strategy.Trial Registration: Clinical Trial Registry of India (CTRI/2019/01/017169).

Hepcidin-guided screen-and-treat interventions for young children with iron-deficiency anaemia in The Gambia: an individually randomised, three-arm, double-blind, controlled, proof-of-concept, non-inferiority trial

BACKGROUND

Iron deficiency is the most prevalent nutritional disorder worldwide. Iron supplementation has modest efficacy, causes gastrointestinal side-effects that limit compliance, and has been associated with serious adverse outcomes in children across low-income settings. We aimed to compare two hepcidin-guided screen-and-treat regimens designed to reduce overall iron dosage by targeting its administration to periods when children were safe and ready to receive iron supplementation, with WHO's recommendation of universal iron supplementation.

METHODS

We conducted an individually randomised, three-arm, double-blind, controlled, proof-of-concept, non-inferiority trial in 12 rural communities across The Gambia. Eligible participants were children aged 6-23 months with anaemia. Participants were randomly assigned (1:1:1) to either the WHO recommended regimen of one sachet of multiple micronutrient powder (MMP) daily containing 12·0 mg iron as encapsulated ferrous fumarate (control group); to MMP with 12·0 mg per day iron for the next 7 days if plasma hepcidin concentration was less than 5·5 μg/L, or to MMP without iron for the next 7 days if plasma hepcidin concentration was at least 5·5 μg/L (12 mg screen-and-treat group); or to MMP with 6·0 mg per day iron for the next 7 days if plasma hepcidin concentration was less than 5·5 μg/L, or to MMP without iron for the next 7 days if plasma hepcidin concentration was at least 5·5 μg/L (6 mg screen-and-treat group). Randomisation was done by use of a permuted block design (block size of 9), with stratification by haemoglobin and age, using computer-generated numbers. Participants and the research team (except for the data manager) were masked to group allocation. The primary outcome was haemoglobin concentration, with a non-inferiority margin of -5 g/L. A per-protocol analysis, including only children who had consumed at least 90% of the supplements (ie, supplement intake on ≥75 days during the study), was done to assess non-inferiority of the primary outcome at day 84 using a one-sided t test adjusted for multiple comparisons. Safety was assessed by use of ex-vivo growth tests of Plasmodium falciparum in erythrocytes and three species of sentinel bacteria in plasma samples from participants. This trial is registered with the ISRCTN registry, ISRCTN07210906.

FINDINGS

Between April 23, 2014, and Aug 7, 2015, we prescreened 783 children, of whom 407 were enrolled into the study: 135 were randomly assigned to the control group, 136 to the 12 mg screen-and-treat group, and 136 to the 6 mg screen-and-treat group. 345 (85%) children were included in the per-protocol population: 115 in the control group, 116 in the 12 mg screen-and-treat group, and 114 in the 6 mg screen-and-treat group. Directly observed adherence was high across all groups (control group 94·8%, 12 mg screen-and-treat group 95·3%, and 6 mg screen-and-treat group 95·0%). 82 days of iron supplementation increased mean haemoglobin concentration by 7·7 g/L (95% CI 3·2 to 12·2) in the control group. Both screen-and-treat regimens were significantly less efficacious at improving haemoglobin (-5·6 g/L [98·3% CI -9·9 to -1·3] in the 12 mg screen-and-treat group and -7·8 g/L [98·3% CI -12·2 to -3·5] in the 6 mg screen-and-treat group) and neither regimen met the preset non-inferiority margin of -5 g/L. The 12 mg screen-and-treat regimen reduced iron dosage to 6·1 mg per day and the 6 mg screen-and-treat regimen reduced dosage to 3·0 mg per day. 580 adverse events were observed in 316 participants, of which eight were serious adverse events requiring hospitalisation mainly due to diarrhoeal disease (one [1%] participant in the control group, three [2%] in the 12 mg screen-and-treat group, and four [3%] in the 6 mg screen-and-treat group). The most common causes of non-serious adverse events (n=572) were diarrhoea (145 events [25%]), upper respiratory tract infections (194 [34%]), lower respiratory tract infections (62 [11%]), and skin infections (122 [21%]). No adverse events were deemed to be related to the study interventions.

INTERPRETATION

The hepcidin-guided screen-and-treat strategy to target iron administration succeeded in reducing overall iron dosage, but was considerably less efficacious at increasing haemoglobin and combating iron deficiency and anaemia than was WHO's standard of care, and showed no differences in morbidity or safety outcomes.

FUNDING

Bill & Melinda Gates Foundation and UK Medical Research Council.

The incidence, complications, and treatment of iron deficiency in pregnancy

Iron deficiency and/or iron deficiency anemia (IDA) complicate nearly 50% of pregnancies globally, negatively impacting both maternal and fetal outcomes. Iron deficiency can cause a range of symptoms that range from aggravating to debilitating including fatigue, poor quality of life, pagophagia, and restless leg syndrome. Iron deficiency and IDA are also associated with maternal complications including preterm labor, increased rates of cesarean delivery, postpartum hemorrhage, and maternal death. Fetal complications include increased rates of low birth weight and small for gestational age newborns. Prenatal maternal anemia has also been associated with autism spectrum disorders in the neonate, although causation is not established. Deficiency in the newborn is associated with compromised memory, processing, and bonding, with some of these deficits persisting into adulthood. Despite the prevalence and consequences associated with iron deficiency in pregnancy, data show that it is routinely undertreated. Due to the physiologic changes of pregnancy, all pregnant individuals should receive oral iron supplementation. However, the bioavailability of oral iron is poor and it is often ineffective at preventing and treating iron deficiency. Likewise, it frequently causes gastrointestinal symptoms that can worsen the quality of life in pregnancy. Intravenous iron formulations administered in a single or multiple dose series are now available. There is increasing data suggesting that newer intravenous formulations are safe and effective in the second and third trimesters and should be strongly considered in pregnant individuals without optimal response to oral iron repletion.

The magnitude of anemia and preventive practices in mothers with children under five years of age in Dodi Papase, Volta region of Ghana

Background

Socio-demographic factors influence the magnitude of anemia in endemic areas. The purpose of this study is to establish the magnitude of anemia and to determine anemia preventive practices carried out by mothers with children under five years of age in the Kadjebi District of the Volta region of Ghana.

Methods

This purposive sampling study involved women of reproductive age with children less than five years of age from Saint Mary Theresa Hospital and nurses practicing in the pediatric ward of the hospital. A questionnaire and interview guide were administered respectively, and the data collected were analyzed using the Statistical Package for Social Sciences version 21.

Results

A total of 150 participants were studied; among which analysis of anemia was carried out on 129 women whose children had their hemoglobin levels checked and recorded in the laboratory. Hemoglobin levels recorded for these children showed that 85.3% were anemic, even though 93.8% of the mothers had been given iron supplements during their pregnancy. Furthermore, anemia prevention practices comprised whether the child had been given any anti-malaria prophylaxis (98.4% denied), if the child had been dewormed in the last three months (89.9% denied), whether the child was given iron supplements in the last three months (59.7% denied), if the child had been given vitamin supplements in the last three months (24.0% denied).

Conclusion

Most of the children in the study were anemic. Mothers practiced exclusive breastfeeding, iron, and vitamin supplementation, and ensured that children slept under insecticide-treated mosquito nets as a means of preventing malaria.

Iron-deficiency anaemia: the perils of excessive milk-drinking

Iron-deficiency anaemia is a widespread and largely preventable problem in the paediatric population, with numerous potential sequelae. We describe the case of a 2-year-old girl presenting with non-specific symptoms, who was found to be iron-deficient and anaemic, in the context of excessive cow's milk consumption. We explore the patient's diagnostic journey, including a neurological deterioration and the link between her iron deficiency and the final diagnosis.

Efficacy and safety of ferric derisomaltose (FDI) compared with iron sucrose (IS) in patients with iron deficiency anemia after bariatric surgery

Purpose

Iron deficiency is common following bariatric surgery, and treatment with intravenous iron is often required. This post hoc analysis of data from two randomized, open-label, multicenter trials evaluated the efficacy and safety of ferric derisomaltose (FDI; formerly iron isomaltoside 1000) versus iron sucrose (IS) over 4 weeks in adults with iron deficiency anemia (IDA) resulting from prior bariatric surgery.

Materials and methods

Data were pooled for participants who received FDI or IS in the PROVIDE or FERWON-IDA trials for the treatment of IDA post bariatric surgery. Efficacy outcomes included changes in hemoglobin (Hb) and iron parameters; safety outcomes included the incidence of adverse drug reactions (ADRs), serious or severe hypersensitivity reactions (HSRs), and hypophosphatemia.

Results

The analysis included 159 patients. Mean (standard deviation) cumulative iron doses were 1199 (± 347) mg for FDI and 937 (± 209) mg for IS. Compared with IS, FDI resulted in a faster and more pronounced Hb response, and a higher proportion of responders (Hb level increase ≥ 2 g/dL from baseline) at all time points. The incidence of ADRs was similar with FDI and IS (15.1% and 18.2%, respectively), with no serious ADRs or serious or severe HSRs reported. The incidence of hypophosphatemia was low and similar in both treatment groups, with no cases of severe hypophosphatemia observed.

Conclusions

In patients with IDA resulting from bariatric surgery, FDI produced a faster and more pronounced Hb response than IS. Both FDI and IS were well tolerated.

Graphical abstract

Iron Bioavailability from Infant Cereals Containing Whole Grains and Pulses: A Stable Isotope Study in Malawian Children

BACKGROUND

Compared with infant cereals based on refined grains, an infant cereal containing whole grains (WGs) and pulses with adequate amounts of ascorbic acid to protect against absorption inhibitors could be a healthier source of well-absorbed iron. However, iron absorption from such cereals is uncertain.

OBJECTIVE

We measured iron bioavailability from ferrous fumarate (Fefum) added to commercial infant cereals containing 1) refined wheat flour (reference meal), 2) WG wheat and lentil flour (WG-wheat-lentil), 3) WG wheat and chickpea flour (WG-wheat-chickpeas), and 4) WG oat flour (WG-oat) and from ferrous bisglycinate (FeBG) added to the same oat-based cereal (WG-oat-FeBG).

METHODS

In a prospective, single-blinded randomized crossover study, 6- to 14-mo-old Malawian children (n = 30) consumed 25-g servings of all 5 test meals containing 2.25 mg stable isotope-labeled iron and 13.5 mg ascorbic acid. Fractional iron absorption (FIA) was assessed by erythrocyte incorporation of isotopes after 14 d. Comparisons were made using linear mixed models.

RESULTS

Seventy percent of the children were anemic and 67% were iron deficient. Geometric mean FIA percentages (-SD, +SD) from the cereals were as follows: 1) refined wheat, 12.1 (4.8, 30.6); 2) WG-wheat-lentil, 15.8 (6.6, 37.6); 3) WG-wheat-chickpeas, 12.8 (5.5, 29.8); and 4) WG-oat, 9.2 (3.9, 21.5) and 7.4 (2.9, 18.9) from WG-oat-FeBG. Meal predicted FIA (P ≤ 0.001), whereas in pairwise comparisons, only WG-oat-FeBG was significantly different compared with the refined wheat meal (P = 0.02). In addition, FIAs from WG-wheat-lentil and WG-wheat-chickpeas were significantly higher than from WG-oat (P = 0.002 and P = 0.04, respectively) and WG-oat-FeBG (P < 0.001 and P = 0.004, respectively).

CONCLUSION

In Malawian children, when given with ascorbic acid at a molar ratio of 2:1, iron bioavailability from Fefum-fortified infant cereals containing WG wheat and pulses is ≈13-15%, whereas that from FeBG- and Fefum-fortified infant cereals based on WG oats is ≈7-9%.

Vaccine efficacy and iron deficiency: an intertwined pair?

Vaccines are the most effective measure to prevent deaths and illness from infectious diseases. Nevertheless, the efficacy of several paediatric vaccines is lower in low-income and middle-income countries (LMICs), where mortality from vaccine-preventable infections remains high. Vaccine efficacy can also be decreased in adults in the context of some common comorbidities. Identifying and correcting the specific causes of impaired vaccine efficacy is of substantial value to global health. Iron deficiency is the most common micronutrient deficiency worldwide, affecting more than 2 billion people, and its prevalence in LMICs could increase as food security is threatened by the COVID-19 pandemic. In this Viewpoint, we highlight evidence showing that iron deficiency limits adaptive immunity and responses to vaccines, representing an under-appreciated additional disadvantage to iron deficient populations. We propose a framework for urgent detailed studies of iron-vaccine interactions to investigate and clarify the issue. This framework includes retrospective analysis of newly available datasets derived from trials of COVID-19 and other vaccines, and prospective testing of whether nutritional iron interventions, commonly used worldwide to combat anaemia, improve vaccine performance.

Consumption of a Single Dose of Prebiotic Galacto-Oligosaccharides Does Not Enhance Iron Absorption from Micronutrient Powders in Kenyan Infants: A Stable Iron Isotope Study

BACKGROUND

Long-term feeding of prebiotic galacto-oligosaccharides (GOS) increases iron absorption in African infants, but the underlying mechanism and how long GOS need to be fed to infants to achieve an increase in absorption is uncertain.

OBJECTIVES

In Kenyan infants, we tested whether the addition of GOS to a single test meal would affect iron absorption from a micronutrient powder (MNP) containing ferrous sulfate (FeSO4) and another MNP containing ferrous fumarate (FeFum) and sodium iron ethylenediaminetetraacetate (NaFeEDTA).

METHODS

In a randomized-entry, prospective crossover study, iron deficient (87%) and anemic (70%) Kenyan infants (n  = 23; mean ± SD age, 9.9 ± 2.1 months) consumed 4 stable iron isotope-labeled maize porridge meals fortified with MNPs containing 5 mg iron as FeFum + NaFeEDTA, or FeSO4, either without or with 7.5 g GOS. The primary outcome, fractional iron absorption (FIA), was assessed by erythrocyte incorporation of isotopic labels. Data were analyzed using a 2-way repeated-measures ANOVA.

RESULTS

There was no significant interaction between GOS and the iron compounds on FIA, and the addition of GOS did not have a significant effect on FIA. There was a statistically significant difference in FIA between the meals fortified with FeSO4 and with FeFum + NaFeEDTA (P  < 0.001).Given with GOS, FIA from FeSO4 was 40% higher than from FeFum + NaFeEDTA (P  < 0.001); given without GOS, it was 51% higher (P  < 0.01).

CONCLUSIONS

The addition of GOS to a single iron-fortified maize porridge test meal in Kenyan infants did not significantly increase iron absorption, suggesting long-term feeding of GOS may be needed to enhance iron absorption at this age. This study was registered at clinicaltrials.gov as NCT02666417.

Iron deficiency in infancy: current insights

PURPOSE OF REVIEW

Iron deficiency is the most common micronutrient deficiency and infants are at particular risk. The purpose of this review is to summarize recent studies that explored the metabolism of iron in infants as well as the risks and benefits of iron supplementation in different populations.

RECENT FINDINGS

The ability of infants to regulate iron homeostasis is not fully known but most likely different from adults. Reducing iron deficiency has beneficial effects on neurodevelopment but iron overload may have adverse functional effects including diarrhea and even poor neurodevelopment. Recent studies have confirmed benefits of delayed cord clamping and supplementation of infants in risk groups while iron supplementation to pregnant women has shown limited effect in the offspring with regard to iron status and neurodevelopment. Further support is given to the recommendation that exclusive breast feeding, without supplementation, is safe for normal birth weight infants until 6 months whereafter an iron-rich diet should be given.

SUMMARY

Iron deficiency negatively impacts global health but efforts to identify optimal interventions are progressing. Yet, questions remain, particularly regarding long-term risks, benefits and optimal interventions for low birth weight infants as well as the level of iron fortification in infant formula.