Dietary iron absorption during early postnatal life

CREB-H is a stress-regulator of hepcidin gene expression during early postnatal development

Hepcidin, the hepatic iron hormone, is the central regulator of iron homeostasis. Cyclic AMP-Responsive Element-Binding protein 3-like 3 (CREB3L3/CREB-H) is a liver homeostatic regulator of essential nutrients (i.e. glucose and lipids) and has been previously involved in hepcidin response to pathologic stress signals. Here, we asked whether CREB-H has also a physiologic role in iron homeostasis through hepcidin. To this end, we analyzed hepcidin gene expression and regulation in the liver of wild type and Creb3l3 knockout mice during early postnatal development, as a model of "physiologic" stressful condition. The effect of iron challenge in vivo and BMP6 stimulation in vitro have been also addressed. In addition, we investigated the BMP signaling pathway and hepcidin promoter activity following CREB3L3 silencing and hepcidin promoter mutation in HepG2 cells. Creb3l3 knockout suckling and young-adult mice showed a prominent serum and hepatic iron accumulation, respectively, due to impaired hepcidin mRNA expression which progressively returned to normal level in adult mice. Interestingly, upon iron challenge, while the upstream BMP/SMAD signaling pathway controlling hepcidin was equally responsive in both strains, hepcidin gene expression was impaired in knockout mice and more iron accumulated in the liver. Accordingly, hepcidin gene response to BMP6 was blunted in primary CREB-H knockout hepatocytes and in HepG2 cells transfected with CREB-H siRNA or carrying a hepcidin promoter mutated in the CREB-H binding site. In conclusion, CREB-H has a role in maintaining the homeostatic balance of iron traffic through hepcidin during the critical postnatal period and in response to iron challenge. KEY MESSAGES: CREB-H KO mice develop liver iron overload shortly after weaning that normalizes in adulthood. CHEB-H is involved in hepcidin gene response to oral iron in vivo. CREB-H loss hampers hepcidin promoter response to BMP6. CREB-H is a key stress-sensor controlling hepcidin gene transcription in physiologic and pathophysiologic states.

Burden of Nutritional Deficiencies in China: Findings from the Global Burden of Disease Study 2019

From 1990 to 2019, the age-standardized incidence rate of nutritional deficiencies in China remained stable. However, the age-standardized disability-adjusted life-years (DALY) rate of nutritional deficiencies decreased from 1990 to 2019. Data were extracted from the GBD 2019 datasets. Estimated annual percentage changes (EAPCs) were calculated to assess the incidence rate, and DALY trends of nutritional deficiencies. Measures were stratified by subtypes, regions, and age groups. In 2019, the age-standardized DALY rates of dietary iron deficiency and protein-energy malnutrition reached their highest levels. The main population groups with protein-energy malnutrition and dietary iron deficiency were adults over the age of 70 and children under the age of five. The latter group also had a greater burden of vitamin A deficiency. Zhejiang, Beijing, and Guangdong reported the highest age-standardized incidence rates of nutritional deficiencies, which mainly pertained to protein-energy malnutrition and vitamin A deficiency. Tibet, Xinjiang, and Hainan had the highest age-standardized DALY rates of nutritional deficiencies, which mainly pertained to dietary iron deficiency and protein-energy malnutrition.

Microencapsulation of Fe2+ in Spray-Dried Lactose for Improved Bioavailability

The development of spray drying technology has been widely used for drying and preservation of food products. Though infant milk powder iron fortification is necessary for infants and children, iron fortification is accompanied by some limitations that reduce its quality and oxidation of Fe2+ into Fe3+, causing sensory problems and even a decrease in iron absorption, which does not meet the normal requirements of infant and child body development. To overcome this adverse effect and to improve the bioavailability of iron, a spray drying method was used to simulate the milk powder production process by codrying a mixture of ascorbic acid and ferrous sulfate, where ascorbic acid was uniformly coated on the outer layer of ferrous sulfate. It was demonstrated that ascorbic acid had a very obvious inhibitory effect on the oxidation of ferrous iron and could maintain the stability of ferrous iron in solid and solution for a long time, thus improving the bioavailability of iron.

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 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.

Hepcidin is a relevant iron status indicator in infancy: results from a randomized trial of early vs. delayed cord clamping

BACKGROUND

We aimed to evaluate whether serum hepcidin is a useful indicator of iron status in infants.

METHODS

Term infants (n = 400) were randomized to delayed (≥180 s) or early (≤10 s) cord clamping (CC). Iron status was assessed at 4 and 12 months. In all cases with iron depletion or iron deficiency (ID) (as defined in "Methods") (n = 30) and 97 randomly selected iron-replete infants, we analyzed hepcidin and explored its correlation to the intervention, iron status, and perinatal factors.

RESULTS

Serum hepcidin concentrations were significantly lower in the early CC group at both time points and in ID infants at 4 months. Median (2.5th-97.5th percentile) hepcidin in non-ID infants in the delayed CC group (suggested reference) was 64.5 (10.9-142.1), 39.5 (3.5-157.7), and 32.9 (11.2-124.2) ng/mL in the cord blood and at 4 and 12 months, respectively. The value of 16 ng/mL was a threshold detecting all cases of iron depletion/ID at 4 months. No similar threshold for ID was observed at 12 months. The strongest predictor of hepcidin at both ages was ferritin.

CONCLUSIONS

Hepcidin is relevant as iron status indicator in early infancy and may be useful to detect ID. Levels <16 ng/mL at 4 months of age indicates ID.

IMPACT

Serum hepcidin is a relevant indicator of iron status in early infancy. Normal reference in healthy infants is suggested in this study. Serum hepcidin may be useful in clinical practice to detect iron deficiency.

High Quantum Yield Fluorescent Carbon Nanodots for detection of Fe (III) Ions and Electrochemical Study of Quenching Mechanism

Carbon nanodots (CNDs) offer potential applications in photocatalysis, optoelectronics, bio-imaging, and sensing due to their excellent photoluminescence (PL) properties, biocompatibility, aqueous solubility, and easy functionalization. Recent emphasis on CNDs in the selective detection of metal ions is due to the growing concern for human and environmental safety. In this work, two types of fluorescent carbon nanodots (CNDs) are synthesized economically from ethylene diamine (E-CNDs) or urea (U-CNDs) in a single step microwave process. The as-prepared CNDs exhibit excellent PL at an excitation wavelength of 350 nm with a quantum yield of 64% for E-CNDs and 8.4% for U-CNDs with reference to quinine sulfate. Both E-CNDs and U-CNDs demonstrate high selectivity towards Fe (III) ions among different metal ions, by fluorescence quenching in a dose dependent manner. The limit of detection of E-CNDs and U-CNDs is observed to be 18 nM and 30 nM, respectively, in the linear response range of 0-2000 μM with a short response time (seconds). The CNDs detect Fe (III) ions in tap water and serum sample with no spiking and the recovery was ~100% with the Fe (III) samples. Cellular internalization studies confirm the localization of the CNDs and the optical imaging sensing of Fe (III) ions inside living cells. A charge transfer fluorescence quenching mechanism, specifically between the CNDs and Fe (III), is proposed and examined using cyclic voltammetry. The overall characteristics of the E-CNDs provides a potential sensing platform in highly sensitive and selective detection of Fe (III) ions.

Infant growth, neurodevelopment and gut microbiota during infancy: which nutrients are crucial?

PURPOSE OF REVIEW

To update the role of specific nutrients during infant development.

RECENT FINDINGS

Several bioactive nutrients such as long-chain polyunsaturated fatty acids (LC-PUFAs), iron, vitamins, proteins, or carbohydrates have been identified to exert an important role during the first 1000 days of life on infant growth, neurodevelopment, and gut microbiota establishment and maturation. LC-PUFAs are structural constituents of the central nervous system (CNS), being essential in retinal development or hippocampal plasticity. Recently, components of the milk fat globule membrane (MFG) are being added to infant formulas because of their key role in infant's development. A high intake of proteins induces a faster weight gain during infancy which correlates with later obesity. Digestible carbohydrates provide glucose, crucial for an adequate functioning of CNS; nondigestible carbohydrates [e.g. human milk oligosaccharides (HMOs)] are the main carbon source for gut bacteria. Iron-deficiency anemia during infancy has been associated with alterations of mental and psychomotor development. Folate metabolism, closely related to vitamins B6 and B12, controls epigenetic changes, whereas inadequate status of vitamin D affects bone development, but may also increase intestinal permeability and alter gut microbiota composition.

SUMMARY

LC-PUFAs, proteins, carbohydrates, iron, and vitamins during early life are critical for infant's growth, neurodevelopment, and the establishment and functioning of gut microbiota.

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.