The effect of timing of iron supplementation on iron absorption and haemoglobin in post-malaria anaemia: a longitudinal stable isotope study in Malawian toddlers

Isotopic measurement of iron requirements in sub-Saharan African children

BACKGROUND

Prevention of iron deficiency in African children is a public health priority. Current WHO/FAO estimations of iron requirements are derived from factorial estimates based on healthy, iron-sufficient "model" children using data derived mainly from adults.

OBJECTIVES

In this study, we aimed to quantify iron absorption, loss, and balance in apparently healthy 5- to 7-y-old children living in rural Africa.

METHODS

We directly measured long-term iron absorption and iron loss in a 2-y observational study in Malawian children (n = 48) using a novel stable iron isotope method.

RESULTS

Of the 36 children with height-for-age and weight-for-age z scores ≥-2, 13 (36%) were iron deficient (soluble transferrin receptor >8.3 mg/L) and 23 were iron sufficient. Iron-deficient children weighed more than iron-sufficient children [mean difference (95% CI): +2.1 (1.4, 2.7) kg; P = 0.01]. Mean iron losses did not differ significantly between iron-deficient and iron-sufficient children and were comparable to WHO/FAO median estimates of 19 µg/(d × kg). In iron-sufficient children, median (95% CI) dietary iron absorption was 32 (28, 34) µg/(d × kg), comparable to WHO/FAO-estimated median requirements of 32 µg/(d × kg). In iron-deficient children, absorption of 28 (25, 30) µg/(d × kg) was not increased to correct their iron deficit, likely because of a lack of bioavailable dietary iron. Twelve children (25%) were undernourished (underweight, stunted, or both).

CONCLUSIONS

Our results suggest that WHO/FAO iron requirements are adequate for healthy iron-sufficient children in this rural area of Malawi, but iron-deficient children require additional bioavailable iron to correct their iron deficit.

The critical roles of iron during the journey from fetus to adolescent: Developmental aspects of iron homeostasis

Iron is indispensable for human life. However, it is also potentially toxic, since it catalyzes the formation of harmful oxidative radicals in unbound form and may facilitate pathogen growth. Therefore, iron homeostasis needs to be tightly regulated. Rapid growth and development require large amounts of iron, while (especially young) children are vulnerable to infections with iron-dependent pathogens due to an immature immune system. Moreover, unbalanced iron status early in life may have effects on the nervous system, immune system and gut microbiota that persist into adulthood. In this narrative review, we assess the critical roles of iron for growth and development and elaborate how the body adapts to physiologically high iron demands during the journey from fetus to adolescent. As a first step towards the development of clinical guidelines for the management of iron disorders in children, we summarize the unmet needs regarding the developmental aspects of iron homeostasis.

Iron supplementation in anemic Zanzibari toddlers is associated with greater loss in erythrocyte iron isotope enrichment

BACKGROUND

Heavy parasitic loads increase the risk of iron (Fe) deficiency anemia, which remains prevalent globally. Where parasites are common, understanding the influence of parasitic infections on Fe incorporation and erythropoiesis in toddlers is especially important.

OBJECTIVES

The aim of this study was to identify the impacts of malarial and helminth infections on red blood cell (RBC) Fe incorporation and subsequent changes in RBC Fe isotope enrichment for 84 days postdosing in toddlers at high risk for parasitic infections.

METHODS

Fe incorporation was measured in a group of Zanzibari toddlers (n = 71; 16-25 months) using a stable Fe isotopic method. At study entry, an oral stable Fe isotope was administered. Blood was collected 14 (D14) and 84 (D84) days postdosing for the assessment of Fe status indicators and RBC isotopic enrichment. Blood and stool samples were collected and screened for malaria and helminth parasites. Factors associated with changes in RBC Fe isotope enrichment were identified using regression models.

RESULTS

Toddlers who had larger weight-for-age z-scores, lower total body Fe, and helminth infections (n = 26) exhibited higher RBC Fe incorporation. RBC Fe isotope enrichment decreased from D14 to D84 by -2.75 percentage points (P < 0.0001; n = 66). Greater loss in RBC Fe isotope enrichment from D14 to D84 was observed in those who received Fe supplementation, those with either helminths or both malarial and helminth infections, and in those with greater RBC Fe incorporation on D14.

CONCLUSIONS

Toddlers who received Fe supplementation exhibited significantly greater losses of RBC Fe isotope enrichment over time. We speculate this greater loss of RBC Fe enrichment is indicative of increased erythropoiesis due to the provision of Fe among anemic or helminth-infected toddlers.

The Importance of Iron Status for Young Children in Low- and Middle-Income Countries: A Narrative Review

Early childhood is characterised by high physiological iron demand to support processes including blood volume expansion, brain development and tissue growth. Iron is also required for other essential functions including the generation of effective immune responses. Adequate iron status is therefore a prerequisite for optimal child development, yet nutritional iron deficiency and inflammation-related iron restriction are widespread amongst young children in low- and middle-income countries (LMICs), meaning iron demands are frequently not met. Consequently, therapeutic iron interventions are commonly recommended. However, iron also influences infection pathogenesis: iron deficiency reduces the risk of malaria, while therapeutic iron may increase susceptibility to malaria, respiratory and gastrointestinal infections, besides reshaping the intestinal microbiome. This means caution should be employed in administering iron interventions to young children in LMIC settings with high infection burdens. In this narrative review, we first examine demand and supply of iron during early childhood, in relation to the molecular understanding of systemic iron control. We then evaluate the importance of iron for distinct aspects of physiology and development, particularly focusing on young LMIC children. We finally discuss the implications and potential for interventions aimed at improving iron status whilst minimising infection-related risks in such settings. Optimal iron intervention strategies will likely need to be individually or setting-specifically adapted according to iron deficiency, inflammation status and infection risk, while maximising iron bioavailability and considering the trade-offs between benefits and risks for different aspects of physiology. The effectiveness of alternative approaches not centred around nutritional iron interventions for children should also be thoroughly evaluated: these include direct targeting of common causes of infection/inflammation, and maternal iron administration during pregnancy.

Malaria causes long-term effects on markers of iron status in children: a critical assessment of existing clinical and epidemiological tools

Background

Most epidemiological studies on the interplay between iron deficiency and malaria risk classify individuals as iron-deficient or iron-replete based on inflammation-dependent iron markers and adjustment for inflammation by using C-reactive protein (CRP) or α-1-acid glycoprotein (AGP). The validity of this approach and the usefulness of fibroblast growth factor 23 (FGF23) as a proposed inflammation-independent iron marker were tested.

Methods

Conventional iron markers and FGF23 were measured in children with acute falciparum malaria and after 1, 2, 4, and 6 weeks. Children, who were transfused or received iron supplementation in the follow-up period, were excluded, and iron stores were considered to be stable throughout. Ferritin levels 6 weeks after admission were used as a reference for admission iron status and compared with iron markers at different time points.

Results

There were long-term perturbations in iron markers during convalescence from acute malaria. None of the tested iron parameters, including FGF23, were independent of inflammation. CRP and AGP normalized faster than ferritin after malaria episodes.

Conclusion

Malaria may bias epidemiological studies based on inflammation-dependent iron markers. Better markers of iron status during and after inflammation are needed in order to test strategies for iron supplementation in populations at risk of malaria.

Iron Fortified Complementary Foods Containing a Mixture of Sodium Iron EDTA with Either Ferrous Fumarate or Ferric Pyrophosphate Reduce Iron Deficiency Anemia in 12- to 36-Month-Old Children in a Malaria Endemic Setting: A Secondary Analysis of a Cluster-Randomized Controlled Trial

Iron deficiency anemia (IDA) is a major public health problem in sub-Saharan Africa. The efficacy of iron fortification against IDA is uncertain in malaria-endemic settings. The objective of this study was to evaluate the efficacy of a complementary food (CF) fortified with sodium iron EDTA (NaFeEDTA) plus either ferrous fumarate (FeFum) or ferric pyrophosphate (FePP) to combat IDA in preschool-age children in a highly malaria endemic region. This is a secondary analysis of a nine-month cluster-randomized controlled trial conducted in south-central Côte d'Ivoire. 378 children aged 12-36 months were randomly assigned to no food intervention (n = 125; control group), CF fortified with 2 mg NaFeEDTA plus 3.8 mg FeFum for six days/week (n = 126; FeFum group), and CF fortified with 2 mg NaFeEDTA and 3.8 mg FePP for six days/week (n = 127; FePP group). The outcome measures were hemoglobin (Hb), plasma ferritin (PF), iron deficiency (PF < 30 μg/L), and anemia (Hb < 11.0 g/dL). Data were analyzed with random-effect models and PF was adjusted for inflammation. The prevalence of Plasmodium falciparum infection and inflammation during the study were 44-66%, and 57-76%, respectively. There was a significant time by treatment interaction on IDA (p = 0.028) and a borderline significant time by treatment interaction on iron deficiency with or without anemia (p = 0.068). IDA prevalence sharply decreased in the FeFum (32.8% to 1.2%, p < 0.001) and FePP group (23.6% to 3.4%, p < 0.001). However, there was no significant time by treatment interaction on Hb or total anemia. These data indicate that, despite the high endemicity of malaria and elevated inflammation biomarkers (C-reactive protein or α-1-acid-glycoprotein), IDA was markedly reduced by provision of iron fortified CF to preschool-age children for 9 months, with no significant differences between a combination of NaFeEDTA with FeFum or NaFeEDTA with FePP. However, there was no overall effect on anemia, suggesting most of the anemia in this setting is not due to ID. This trial is registered at clinicaltrials.gov (NCT01634945).

Delaying Iron Therapy until 28 Days after Antimalarial Treatment Is Associated with Greater Iron Incorporation and Equivalent Hematologic Recovery after 56 Days in Children: A Randomized Controlled Trial

BACKGROUND

Iron therapy begun concurrently with antimalarial treatment may not be well absorbed because of malaria-induced inflammation. Delaying the start of iron therapy may permit better iron absorption and distribution.

OBJECTIVE

We compared erythrocyte iron incorporation in children who started iron supplementation concurrently with antimalarial treatment or 28 d later. We hypothesized that delayed iron supplementation would be associated with greater incorporation and better hematologic recovery.

METHODS

We enrolled 100 children aged 6-59 mo with malaria and hemoglobin concentrations of 50.0-99.9 g/L who presented to Mulago Hospital, Kampala, into a randomized trial of iron therapy. All children were administered antimalarial treatment. Children with zinc protoporphyrin (ZPP) ≥80 μmol/mol heme were randomly assigned to start iron supplementation concurrently with the antimalarial treatment [immediate iron (I) group] or 28 d later [delayed iron (D) group]. All children were administered iron-stable isotope (57)Fe on day 0 and (58)Fe on day 28. We compared the percentage of iron incorporation at the start of supplementation (I group at day 0 compared with D group at day 28, aim 1) and hematologic recovery at day 56 (aim 2).

RESULTS

The percentage of iron incorporation (mean ± SE) was greater at day 28 in the D group (16.5% ± 1.7%) than at day 0 in the I group (7.9% ± 0.5%; P < 0.001). On day 56, concentrations of hemoglobin and ZPP and plasma ferritin, soluble transferrin receptor (sTfR), hepcidin, and C-reactive protein did not differ between the groups. On day 28, the hemoglobin (mean ± SD) and plasma iron markers (geometric mean; 95% CI) reflected poorer iron status in the D group than in the I group at this intervening time as follows: hemoglobin (105 ± 15.9 compared with 112 ± 12.4 g/L; P = 0.04), ferritin (39.3 μg/L; 23.5, 65.7 μg/L compared with 79.9 μg/L; 58.3, 110 μg/L; P = 0.02), sTfR (8.9 mg/L; 7.4, 10.7 mg/L compared with 6.7 mg/L; 6.1, 7.5 mg/L; P = 0.01), and hepcidin (13.3 ng/mL; 8.3, 21.2 ng/mL compared with 38.8 ng/mL; 28.3, 53.3 ng/mL; P < 0.001).

CONCLUSIONS

Delaying the start of iron improves incorporation but leads to equivalent hematologic recovery at day 56 in Ugandan children with malaria and anemia. These results do not demonstrate a clear, short-term benefit of delaying iron. This trial was registered at clinicaltrials.gov as NCT01754701.

Cereals and pulse-based ready-to-use therapeutic food as an alternative to the standard milk- and peanut paste-based formulation for treating severe acute malnutrition: a noninferiority, individually randomized controlled efficacy clinical trial

BACKGROUND

The cost of current standard ready-to-use therapeutic food (RUTF) is among the major obstacles to scaling up community-based management of acute malnutrition (CMAM), an important child survival strategy. Identifying a cheaper alternative is a global public health priority.

OBJECTIVE

We sought to compare the efficacy of soya-maize-sorghum RUTF (SMS-RUTF) with that of standard peanut paste-based RUTF (P-RUTF).

DESIGN

We used a nonblinded, parallel-group, simple randomized controlled trial along with a day care approach that enrolled 2 groups of children aged 6-23 and 24-59 mo, respectively, with severe acute malnutrition (SAM).

RESULTS

Intention-to-treat (ITT) and per-protocol (PP) analyses showed noninferiority of SMS-RUTF compared with P-RUTF for the recovery rate [ITT: Δ = -2.0% (95% CI: -7.6%, 3.6%); PP: -1.9% (95% CI: -5.3%, 1.4%)], weight gain [Δ = -0.7 g · kg(-1)· d(-1)(95% CI: -1.3, 0.0 g · kg(-1)· d(-1))], and length of stay [Δ = 2.0 d (95% CI: -1.7, 5.8 d)] in children ≥24 mo of age. In children ≤23 mo of age, the recovery rate of SMS-RUTF was inferior to that of P-RUTF [ITT: Δ = -20.8% (95% CI: -29.9%, -11.7%); PP: -17.2% (95% CI: -25.6%, -8.7%)]. Treatment with SMS-RUTF resulted in a greater increase in hemoglobin [0.670 g/dL (95% CI: 0.420, 0.921 g/dL);P< 0.001]. Treatment with both RUTFs resulted in the replenishment of all of the amino acids tested except for methionine. There were no differences at discharge between RUTF groups in fat mass [Δ = 0.3 kg (95% CI: -0.6, 1.6 kg);P= 0.341] or fat mass index [Δ = 0.4 kg/m(2)(95% CI: -0.3, 1.1 kg/m(2));P= 0.262]. By contrast, comparisons of fat-free mass indicated lower concentrations than the community controls after treatment with either of the 2 RUTFs [Δ = -1.3 kg (95% CI: -2.4, -0.1 kg) andP= 0.034 for comparison between community controls and the SMS-RUTF group; Δ = -1.8 kg (95% CI: -2.9, -0.6 kg) andP= 0.003 for comparison between community controls and the P-RUTF group].

CONCLUSION

SMS-RUTF can be used to treat SAM in children aged ≥24 mo to reduce the costs of CMAM programs. More research is required to optimize SMS-RUTF for younger children. This trial was registered in the Pan African Clinical Trial Registry as PACTR201303000475166.

Comparison of iron status 28 d after provision of antimalarial treatment with iron therapy compared with antimalarial treatment alone in Ugandan children with severe malaria

BACKGROUND

The provision of iron with antimalarial treatment is the standard of care for concurrent iron deficiency and malaria. However, iron that is given during a malaria episode may not be well absorbed or used, particularly in children with severe malaria and profound inflammation.

OBJECTIVES

We aimed to 1) determine baseline values of iron and inflammatory markers in children with severe malarial anemia (SMA), children with cerebral malaria (CM), and community children (CC) and 2) compare markers in iron-deficient children in each group who received 28 d of iron supplementation during antimalarial treatment with those in children who did not receive iron during treatment..

DESIGN

Seventy-nine children with CM, 77 children with SMA, and 83 CC who presented to Mulago Hospital, Kampala, Uganda, were enrolled in a 28-d iron-therapy study. Children with malaria received antimalarial treatment. All children with CM or SMA, as well as 35 CC, had zinc protoporphyrin (ZPP) concentrations ≥80 μmol/mol heme and were randomly assigned to receive a 28-d course of iron or no iron. We compared iron markers at day 0 among study groups (CM, SMA, and CC groups) and at day 28 between children in each group who were randomly assigned to receive iron or to not receive iron.

RESULTS

At day 0, children with CM and SMA had greater values of C-reactive protein, ferritin, and hepcidin than those of CC. At day 28, interactions between study and treatment group were NS. Children in the no-iron compared with iron groups had similar mean values for hemoglobin (115 compared with 113 g/L, respectively; P = 0.73) and ZPP (124 compared with 124 μmol/mol heme, respectively; P = 0.96) but had lower median ferritin [101.0 μg/L (95% CI: 84.2, 121.0 μg/L) compared with 152.9 μg/L (128.8, 181.6 μg/L), respectively; P ≤ 0.001] and hepcidin [45.8 ng/mL (36.8, 56.9 ng/mL) compared with 83.1 ng/mL (67.6, 102.2 ng/mL), respectively; P < 0.011].

CONCLUSIONS

Severe inflammation is a characterization of children with CM and SMA. The withholding of iron from children with severe malaria is associated with lower ferritin and hepcidin at day 28 but not a lower hemoglobin concentration. This trial was registered at clinicaltrials.gov as NCT01093989.

Integration to Implementation and the Micronutrient Forum: A Coordinated Approach for Global Nutrition. Case Study Application: Safety and Effectiveness of Iron Interventions

Paramount among the challenges to our ability to address the role of food and nutrition in health promotion and disease prevention is how to design and implement context-specific interventions and guidance. The Integration to Effective Implementation (I-to-I) concept is intended to address the complexities of the global health context through engagement of the continuum of stakeholders involved in the food and nutrition enterprise. The 2014 Micronutrient Forum (MNF) Global Conference held in Addis Ababa, Ethiopia, in June 2014 offered the opportunity to apply the I-to-I approach with the use of current concerns about the safety and effectiveness of interventions to prevent and treat iron deficiency (ID) as a case study. ID is associated with a range of adverse outcomes, especially in pregnant and nonpregnant women, infants, and primary school-age children. Strategies to combat ID include iron supplementation, multiple micronutrient powders, and food-based interventions to enhance dietary iron intake. Recent reports indicate potential increased adverse risks when iron is provided in areas with high infection burdens (e.g., malaria). This paradox has weakened iron intervention programs. Furthermore, the selection and interpretation of available biomarkers for assessing iron nutrition have been found to be compromised by the inflammatory process. These issues highlight the need for a comprehensive approach that considers basic biology, assessment, interventions, and how these can be translated into appropriate programs and policies. The application of the I-to-I with the use of the MNF offered an opportunity to explore how that might be achieved.