Placental Erythroferrone and Erythropoietin mRNA Expression is not Associated with Maternal or Neonatal Iron Status in Adolescents Carrying Singletons and Adult Women Carrying Multiples.

BACKGROUND: The iron regulatory hormones erythroferrone (ERFE), erythropoietin (EPO), and hepcidin, and the cargo receptor nuclear receptor coactivator 4 (NCOA4) are expressed in the placenta. However, determinants of placental expression of these proteins and their associations with maternal or neonatal iron status are unknown. OBJECTIVES: To characterize expression of placental ERFE, EPO, and NCOA4 mRNA in placentae from newborns at increased risk of iron deficiency and to evaluate these in relation to maternal and neonatal iron status and regulatory hormones. METHODS: Placentae were collected from 114 neonates born to adolescents carrying singletons (14-18 y) and 110 neonates born to 54 adults (20-46 y) carrying multiples. Placental EPO, ERFE, and NCOA4 mRNA expression were measured by RT-qPCR and compared with maternal and neonatal iron status indicators (SF, sTfR, total body iron, serum iron) and hormones. RESULTS: Placental ERFE, EPO, and NCOA4 mRNA were detected in all placentae delivered between 25 and 42 wk of gestation. Relationships between placental ERFE and EPO differed by cohort. In the multiples cohort, placental EPO and ERFE were positively correlated (P = 0.004), but only a positive trend (P = 0.08) was evident in the adolescents. Placental EPO and ERFE were not associated with maternal or neonatal iron status markers or hormones in either cohort. Placental NCOA4 was not associated with placental EPO or ERFE in either cohort but was negatively associated with maternal SF (P = 0.03) in the multiples cohort and positively associated with neonatal sTfR (P = 0.009) in the adolescents. CONCLUSIONS: The human placenta expresses ERFE, EPO, and NCOA4 mRNA as early as 25 wk of gestation. Placental expression of ERFE and EPO transcripts was not associated with maternal or neonatal iron status. Greater placental NCOA4 transcript expression was evident in women and newborns with poor iron status (lower SF and higher sTfR, respectively). Further research is needed to characterize the roles of these proteins in the human placenta. TRIAL REGISTRATION NUMBER: These clinical trials were registered at clinicaltrials.gov as NCT01019902 (https://clinicaltrials.gov/ct2/show/NCT01019902) and NCT01582802 (https://clinicaltrials.gov/ct2/show/NCT01582802).

Maternal Iron Status Is Dynamic Throughout Pregnancy and Might Predict Birth Outcomes in a Sex Dependent Manner: Results from the Alberta Pregnancy Outcomes and Nutrition (APrON) Cohort Study.

BACKGROUND: Developmental responses to nutrient deprivation may differ by fetal sex. Despite this, relationships between maternal prenatal iron biomarkers and birth outcomes when stratifying by offspring sex are poorly described, especially in healthy cohorts. OBJECTIVES: This study aimed to determine associations between maternal iron biomarkers and birth weights (BWs) and birth head circumferences (BHCs) among female and male newborns to assess whether the potential predictive ability of iron biomarkers on birth outcomes differs by offspring sex. METHODS: The Alberta Pregnancy Outcomes and Nutrition (APrON) cohort study recruited 2189 pregnant individuals from Calgary and Edmonton, Canada. Maternal blood was drawn at each trimester and 3 mo postpartum. Maternal serum ferritin (SF) concentrations were measured using chemiluminescent immunoassays and erythropoietin (EPO), hepcidin, and soluble transferrin receptor (sTfR) using enzyme-linked immunosorbent assays. Ratios of sTfR:SF and hepcidin:EPO were calculated and birth outcomes accessed through delivery records. Directed acyclic graphs informed multivariate regression models. RESULTS: The risk of maternal iron deficiency increased throughout pregnancy because ∼61% showed depleted iron stores (SF < 15 µg/L) by the third trimester. Maternal hepcidin, SF, sTfR, and sTfR:SF concentrations changed across time (P < 0.01), and participants carrying female fetuses consistently (across 6 biomarkers) showed a lower iron status during the third trimester compared with those with male fetuses (P < 0.05). Higher maternal SF and hepcidin:EPO during the third trimester was associated with lower BWs in males (P = 0.006 for SF; P = 0.03 for hepcidin:EPO) and females (P = 0.02 for SF; P = 0.02 for hepcidin:EPO). There were additional inverse associations between BWs and third trimester maternal hepcidin (P = 0.03) and hemoglobin (P = 0.004) and between BHCs and maternal SF (second trimester; P < 0.05) and Hb (third trimester P = 0.02) but only in males. CONCLUSIONS: Relationships between maternal iron biomarkers and BWs and BHCs may depend on the timing of pregnancy and offpsring sex. There was a high risk of third trimester iron storage depletion among generally healthy pregnant individuals.

Daily Intake of a Functional Synbiotic Yogurt Increases Calcium Absorption in Young Adult Women.

BACKGROUND: Foods containing both prebiotics and probiotics (synbiotics) might enhance calcium bioavailability. OBJECTIVES: We investigated the acute effect in young adult women on calcium absorption of consuming (185 mL) a synbiotic yogurt (SYN) containing inulin (4 g) and Lactobacillus rhamnosus GG (>1 × 107 CFU/mL) compared with a control yogurt (CON). METHODS: Adult normal-weight women (25.0 ± 3.5 y, n = 30) participated in a 3-wk crossover study testing daily consumption of SYN compared with CON. Habitual dietary intake, bone mineral density (BMD), calcium biomarkers, and serum 25-hydroxyvitamin D were measured at baseline. Calcium absorption was tested after each phase of the study using a 42Ca oral tracer. Cumulative tracer recovery was measured in 0-4-h,  0-24-h, and 0-36-h urine pools collected postdosing. The SYN/CON tracer ratio from the timed urine pools was the primary outcome. A beneficial response to SYN was defined as 0-36-h SYN/CON tracer ratio >1. RESULTS: Net 42Ca recovered increased over time in each of the SYN and CON urine pools postdosing (Friedman, P < 0.001), with a trend for higher 42Ca recovery in the 0-36-h urine pool postdosing in the SYN (1.14%) compared with the CON (0.90%) study (Wilcoxon, P = 0.07). For CON, the majority of total tracer was recovered in the 0-24-h pool (86%), whereas for SYN only 50% of total tracer was recovered in the 0-24-h pool (Friedman, P = 0.001). The SYN/CON tracer ratio in the 0-36-h pool (1.24) was >1 (Wilcoxon, P = 0.015). About two-thirds (n = 19) of women studied responded to the SYN treatment. Responders had higher vegetable intake (P = 0.03), tended to have higher potassium and calcium intakes (P ≤ 0.08), and had higher total body BMD (P = 0.09), than nonresponders. CONCLUSIONS: Short-term daily consumption of a synbiotic yogurt enhanced calcium absorption relative to a control yogurt in adult women. Given the observed time delays in tracer recovery, enhancement of calcium absorption likely occurred in the large intestine.The study was registered at clinicaltrials.gov (study registration ID: NCT03420716).

Placental Iron Content Is Lower than Previously Estimated and Is Associated with Maternal Iron Status in Women at Greater Risk of Gestational Iron Deficiency and Anemia.

BACKGROUND: Based on limited data, it is estimated that the placenta retains 90 mg of iron. Little is known about determinants of placental iron content. Animal data indicate that the placenta prioritizes iron for its own needs, but this hypothesis has not been evaluated in humans. OBJECTIVES: To characterize placental iron content and placental iron concentration (p[Fe]) in pregnant women at risk of iron insufficiency and identify determinants of p[Fe]. METHODS: Placentas were collected from 132 neonates born to teens carrying singletons (≤18 y) and 101 neonates born to 48 women carrying multiples (20-46 y). Maternal and neonatal iron status indicators [hemoglobin, serum ferritin (SF), soluble transferrin receptor (sTfR), serum iron, total body iron (TBI)] and hormones (erythropoietin, hepcidin) were measured. p[Fe] was measured using inductively coupled plasma-mass spectrometry. Correlation analyses and mixed-effects models were constructed to identify determinants of p[Fe]. RESULTS: Mean placental iron content was 23 mg per placenta (95% CI: 15, 33 mg) in the multiples and 40 mg (95% CI: 31, 51 mg) in the teens (P = 0.03). Mean p[Fe] did not differ between the cohorts. p[Fe] was higher in anemic (175 µg/g; 95% CI: 120, 254 µg/g) compared with nonanemic (46 µg/g; 95% CI: 26, 82 µg/g) women carrying multiples (P = 0.009), but did not differ between anemic (62 µg/g; 95% CI: 40, 102 µg/g) and nonanemic (73 µg/g; 95% CI: 56, 97 µg/g) teens. In women carrying multiples, low maternal iron status [lower SF (P = 0.002) and lower TBI (P = 0.01)] was associated with higher p[Fe], whereas in teens, improved iron status [lower sTfR (P = 0.03) and higher TBI (P = 0.03)] was associated with higher p[Fe]. CONCLUSIONS: Placental iron content was ∼50% lower than previously estimated. p[Fe] is significantly associated with maternal iron status. In women carrying multiples, poor maternal iron status was associated with higher p[Fe], whereas in teens, improved iron status was associated with higher p[Fe]. More data are needed to understand determinants of p[Fe] and the variable iron partitioning in teens compared with mature women.

Erythroferrone contributes to iron mobilization for embryo erythropoiesis in iron-deficient mouse pregnancies.

Erythroferrone (ERFE) is an erythroblast-secreted regulator of iron metabolism. The production of ERFE increases during stress erythropoiesis, leading to decreased hepcidin expression and mobilization of iron. Pregnancy requires a substantial increase in iron availability to sustain maternal erythropoietic expansion and fetal development and is commonly affected by iron deficiency. To define the role of ERFE during iron-replete or iron-deficient pregnancy, we utilized mouse models expressing a range of ERFE levels: transgenic (TG) mice overexpressing ERFE, wild-type (WT), and ERFE knockout (KO) mice. We altered maternal iron status using diets with low or standard iron content and performed the analysis at E18.5. Iron deficiency increased maternal ERFE in WT pregnancy. Comparing different maternal genotypes, ERFE TG dams had lower hepcidin relative to their liver iron load but similar hematological parameters to WT dams on either diet. In ERFE KO dams, most hematologic and iron parameters were comparable to WT, but mean corpuscular volume (MCV) was decreased under both iron conditions. Similar to dams, TG embryos had lower hepcidin on both diets, but their hematologic parameters did not differ from those of WT embryos. ERFE KO embryos had lower MCV than WT embryos on both diets. The effect was exacerbated under iron-deficient conditions where ERFE KO embryos had higher hepcidin, lower Hb and Hct, and lower brain iron concentration compared to WT embryos, indicative of iron restriction. Thus, under iron-deficient conditions, maternal and embryo ERFE facilitate iron mobilization for embryonic erythropoiesis.

Umbilical Cord Erythroferrone Is Inversely Associated with Hepcidin, but Does Not Capture the Most Variability in Iron Status of Neonates Born to Teens Carrying Singletons and Women Carrying Multiples.

BACKGROUND: The developing fetus requires adequate iron and produces its own hormones to regulate this process. Erythroferrone (ERFE) is a recently identified iron regulatory hormone, and normative data on ERFE concentrations and relations between iron status and other iron regulatory hormones at birth are needed. OBJECTIVES: The objective of this study was to characterize cord ERFE concentrations at birth and assess interrelations between ERFE, iron regulatory hormones, and iron status biomarkers in 2 cohorts of newborns at higher risk of neonatal anemia. METHODS: Umbilical cord ERFE concentrations were measured in extant serum samples collected from neonates born to women carrying multiples (age: 21-43 y; n = 127) or teens (age: 14-19 y; n = 164). Relations between cord blood ERFE and other markers of iron status or erythropoiesis in cord blood were assessed by linear regression and mediation analysis. RESULTS: Cord ERFE was detectable in all newborns delivered between 30 and 42 weeks of gestation, and mean concentration at birth was 0.73 ng/mL (95% CI: 0.63, 0.85 ng/mL). Cord ERFE was on average 0.25 ng/mL lower in newborns of black as opposed to white ancestry (P = 0.04). Cord ERFE was significantly associated with transferrin receptor (ß: 1.17, P < 0.001), ferritin (ß: -0.27, P < 0.01), and hemoglobin (Hb) (ß: 0.04, P < 0.05). However, cord hepcidin and the hepcidin:erythropoietin (EPO) ratio captured the most variance in newborn iron and hematologic status (>25% of variance explained). CONCLUSIONS: Neonates born to teens and women carrying multiples were able to produce ERFE in response to neonatal cord iron status and erythropoietic demand. ERFE, however, did not capture significant variance in newborn iron or Hb concentrations. In these newborns, cord hepcidin and the hepcidin:EPO ratio explained the most variance in iron status indicators at birth.

Serum Erythroferrone During Pregnancy Is Related to Erythropoietin but Does Not Predict the Risk of Anemia.

BACKGROUND: Maintaining adequate iron status during pregnancy is important for the mother and her developing fetus. Iron homeostasis is influenced by 3 regulatory hormones: erythropoietin (EPO), hepcidin, and erythroferrone (ERFE). To date, normative data on ERFE across pregnancy and its relations to other hormones and iron status indicators are limited. OBJECTIVES: The objective of this study was to characterize maternal ERFE across pregnancy and at delivery and evaluate the utility of hepcidin, ERFE, and EPO in identifying women with increased iron needs. METHODS: ERFE was measured in extant serum samples collected from 2 longitudinal cohorts composed of women carrying multiple fetuses (n = 79) and pregnant adolescents (n = 218) at midgestation (∼26 wk) and delivery (∼39 wk). Receiver operating characteristic curves were generated to characterize the predictive ability of serum ERFE, hepcidin, and EPO and their ratios to identify women at increased risk of iron deficiency and anemia. RESULTS: In these pregnant women, mean ERFE was 0.48 ng/mL at both ∼25 wk of gestation and at delivery. ERFE was positively associated with EPO at midgestation (ß = 0.14, P = 0.002, n = 202) and delivery (ß = 0.12, P < 0.001, n = 225) but was not significantly associated with maternal hepcidin at any time point surveyed. Of all hormones measured at midgestation and delivery, EPO was best able to identify women with anemia (AUC: 0.86 and 0.75, respectively) and depleted iron stores (AUC: 0.77 and 0.84), whereas the hepcidin-to-EPO ratio was best able to identify women with iron deficiency anemia (AUC: 0.85 and 0.84). CONCLUSIONS: Maternal ERFE was significantly associated with EPO but was not able to identify women with gestational iron deficiency. At term, the hepcidin-to-EPO ratio, an index that accounts for both iron status and erythropoietic demand, and EPO were the strongest indicators of maternal iron deficiency and anemia. This trial was registered at clinicaltrials.gov as NCT04517734 (https://clinicaltrials.gov/ct2/show/NCT04517734).

Dairy intake and bone health across the lifespan: a systematic review and expert narrative.

Over the past 30-years, the U.S. Dietary Guidelines for Americans have included recommendations around dairy consumption, largely based on meeting recommendations for calcium intake with the intended purpose of osteoporosis prevention. Although dairy products provide more bone-beneficial nutrients (e.g., calcium, magnesium, potassium, zinc, phosphorus, and protein) per unit of energy than any other food group, the relevance of dairy products for long-term bone health and fracture prevention has resurged as some observational studies have suggested consumption to be associated with a greater risk of fractures. Given this controversy, we sought to synthesize the evidence on dairy consumption and bone health across the lifespan. We searched the PubMed, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials databases for English-language publications through June 2, 2020. Case-controlled, cross-sectional, prospective cohort or nestled case-control (or case cohort), and clinical trials reporting the effect of dairy products on bone mineral density, bone mineral content, and/or fractures were included in the systematic review. Two reviewers independently performed data extractions. Data from 91 publications, including 30 RCTs, 28 prospective cohorts, 23 cross-sectional studies, and 10 case-control studies were included in the systematic review. We assigned a "D" grade or "insufficient evidence" for the effect of dairy in infants and toddlers (0- to <36-months), children (3- to <10-years), and young adults (19- to <50-years). A "C" grade or "limited evidence" was assigned for the effect of dairy in adolescents (10- to <19-years). A "B" grade or "moderate" evidence was assigned for the effect of dairy in middle aged to older adults (≥50-years). Research on bone mass in adults between the ages of 20- to 50-years and individuals from other ethnic groups apart from Chinese females and Caucasians is greatly needed. Daily intake of low or nonfat dairy products as part of a healthy habitual dietary pattern may be associated with improved BMD of the total body and at some sites and associated with fewer fractures in older adults.

Prepregnancy Obesity Is Not Associated with Iron Utilization during the Third Trimester.

BACKGROUND: An adequate maternal iron supply is crucial for maternal red blood cell (RBC) expansion, placental and fetal growth, and fetal brain development. Obese women may be at risk for poor iron status in pregnancy due to proinflammatory-driven overexpression of hepcidin leading to decreased iron bioavailability. OBJECTIVE: The objective of this study was to determine the impact of prepregnancy (PP) obesity on third-trimester maternal iron utilization. DESIGN: Using the stable isotope 57Fe, we measured iron utilization in the third trimester in PP obese [BMI (in kg/m2): ≥30] and nonobese (BMI: 18.5-29.9) women. We also assessed iron status, hepcidin, inflammation, erythropoietin, dietary iron intake, and gestational weight gain. Descriptive and inferential statistical tests (e.g., Student t test, Pearson correlation) were used for data analysis. RESULTS: Fifty pregnant women (21 PP obese, 29 PP nonobese) were included. Mean age was 27.6 ± 6.8 y and mean gestational age at time of 57Fe administration was 32.7 ± 0.7 wk. Anemia (hemoglobin <11 g/dL for non-black and <10.2 g/dL for black women) affected 38% of women (43% PP obese compared with 35% PP nonobese; P = 0.55). Women with PP obesity had significantly higher C-reactive protein (8.5 compared with 3.4 mg/L, P = 0.0007) and total body iron corrected for inflammation (6.0 compared with 4.3 mg/kg, P = 0.04) compared with the nonobese women. There was no difference in serum hepcidin or iron utilization between the PP BMI groups. CONCLUSION: This is the first study to assess the impact of PP obesity on maternal iron utilization. We found no difference in iron utilization in the third trimester of pregnancy in women with and without PP obesity. Despite higher frequency of anemia, women with PP obesity had less depleted body iron stores, suggesting some degree of iron sequestration. This finding should be followed up and extended to understand effects on fetal iron bioavailability.

Using stable isotope tracers to study bone metabolism in children.

Skeletal mineralization is initiated in utero and continues throughout childhood and adolescence. During these key periods of the life cycle, calcium retention must increase significantly to provide sufficient mineral for bone deposition and skeletal growth. Stable calcium isotopes have served as a fundamental tool to non-invasively characterize the dynamic changes in calcium physiology that occur from infancy through adolescence. These approaches have helped define the dynamics of calcium absorption and utilization in healthy children and in children with chronic diseases. As data in this area have accumulated, new areas of emphasis are beginning to characterize the determinants of variability in mineral retention, the genetic determinants of bone turnover and calcium flux and the impact of the gut microbiome on whole body and niche specific calcium dynamics. Advances in these areas will help define calcium utilization in paediatric populations and provide information that may be useful in maximizing bone acquisition across this critical phase of the life cycle.

Umbilical Cord Serum Ferritin Concentration is Inversely Associated with Umbilical Cord Hemoglobin in Neonates Born to Adolescents Carrying Singletons and Women Carrying Multiples.

BACKGROUND: It has been proposed that the fetus prioritizes iron for hemoglobin production over delivery to tissues. However, few studies have evaluated the interrelations between hemoglobin and multiple iron status biomarkers in umbilical cord blood. A full understanding is needed of how these parameters influence each other within cord blood to fully interpret iron and hematologic status at birth. OBJECTIVES: We evaluated the determinants of neonatal hemoglobin and assessed the interrelations between hemoglobin, serum iron status indicators, and serum iron regulatory hormones in healthy neonates. METHODS: This was an observational study that assessed umbilical cord hemoglobin (Hb), serum ferritin (SF), erythropoietin (EPO), soluble transferrin receptor (sTfR), serum iron, hepcidin, vitamin B-12, folate, IL-6, and CRP measured in 234 neonates born to adolescents or to women carrying multiples. Correlations between these indicators were evaluated and mediation models consistent with the observed significant determinants of cord Hb concentrations were developed. RESULTS: A highly significant inverse association was found between cord SF and Hb concentrations that was not attributable to neonatal or maternal inflammation (as measured by IL-6 and CRP). The inverse association was present in the combined cohort, as well as in the adolescent and multiples cohorts independently. Mediation analyses found that EPO and hepcidin had significant indirect effects on cord Hb, associations that are explicable by mediation through SF and sTfR. CONCLUSION: In contrast to observations made in older infants, a highly significant inverse association between Hb and SF, as well positive associations between Hb and both sTfR and EPO, were observed in umbilical cord blood from neonates born to adolescents or women carrying multiples. These findings, combined with review of the published literature, indicate a need for analysis of the relations between multiple parameters to assess iron and hematologic status at birth. These clinical trials were registered at clinicaltrials.gov as NCT01582802 (https://clinicaltrials.gov/ct2/show/NCT01582802) and NCT01019902 (https://clinicaltrials.gov/ct2/show/NCT01019902).

Umbilical Cord Hepcidin Concentrations Are Positively Associated with the Variance in Iron Status among Multiple Birth Neonates.

Background: Hepcidin is a systemic regulator of iron homeostasis. Little is known about the relative role of maternal compared with cord hepcidin on neonatal iron homeostasis. Objective: This study was undertaken to evaluate inter- and intrauterine variance in neonatal iron status, vitamin B-12, folate, and inflammatory markers in a cohort of twins (n = 50), triplets (n = 14), and quadruplets (n = 1) born to 65 women. Methods: Umbilical cord blood was obtained from 144 neonates born at 34.8 ± 2.7 wk of gestation with a mean birth weight of 2236 ± 551 g (means ± SDs). Cord hemoglobin and cord serum measures of ferritin (SF), soluble transferrin receptor (sTfR), hepcidin, erythropoietin (EPO), iron, vitamin B-12, folate, interleukin 6, and C-reactive protein were evaluated. Results: Intraclass correlation coefficient (ICC) analyses were used to examine inter- and intrauterine variance in neonatal iron indicators. A greater variability in cord hepcidin (ICC = 0.39) was found between siblings. Cord hepcidin had the greatest association with cord iron indicators because cord hepcidin alone captured 63.8%, 48.4%, 44.4%, and 31.3% of the intrauterine variance in cord hemoglobin, SF, sTfR, and EPO, respectively, whereas maternal hepcidin had no effect on cord iron indicators. Significantly greater differences in cord SF (P = 0.03), sTfR (P = 0.03), hepcidin (P = 0.0003), and EPO (P = 0.03) were found between di- and trichorionic siblings than between monochorionic siblings. In contrast, cord folate (ICC = 0.79) and vitamin B-12 (ICC = 0.74) exhibited a greater variability between unrelated neonates. Conclusions: In summary, fetally derived hepcidin might have more control on intrauterine variance in iron indicators than maternal hepcidin and appears to be capable of regulating fetal iron status independently of maternal hepcidin. The use of a multiple-birth model provides a unique way to identify factors that may contribute to placental nutrient transport and iron stores at birth.

Gestational Age and Maternal Serum 25-hydroxyvitamin D Concentration Interact to Affect the 24,25-dihydroxyvitamin D Concentration in Pregnant Adolescents.

Background: Interpretation of serum vitamin D biomarkers across pregnancy is complex due to limited understanding of pregnancy adaptations in vitamin D metabolism. During pregnancy, both gestational age and serum 25-hydroxyvitamin D [25(OH)D] concentrations may influence the concentrations of 1,25-dihydroxyvitamin D [1,25(OH)2D], 24,25-dihydroxyvitamin D [24,25(OH)2D], and parathyroid hormone (PTH). Objective: We aimed to identify predictors of change in serum 25(OH)D across gestation in pregnant adolescents and to assess the contribution made by cholecalciferol (vitamin D3) supplementation. We sought to determine whether gestational age and 25(OH)D concentration interacted to affect serum 1,25(OH)2D, 24,25(OH)2D, or PTH. Methods: Pregnant adolescents (n = 78, 59% African American, mean ± SD age: 17 ± 1 y) living in Rochester, NY (latitude 43°N) were supplemented with 200 IU or 2000 IU vitamin D3/d and allowed to continue their daily prenatal supplement that contained 400 IU vitamin D3. Serum was collected at study entry (18 ± 5 wk of gestation), halfway through study participation, and at delivery (40 ± 2 wk). Serum concentrations of the biochemical markers were modeled with linear mixed-effects regression models. Results: Vitamin D3 supplement intake and season of delivery determined change in 25(OH)D across pregnancy. Fall-winter delivery was associated with a decline in 25(OH)D unless vitamin D3 supplement intake was >872 IU/d. The interaction of gestational age and 25(OH)D affected 24,25(OH)2D concentrations. For a given 25(OH)D concentration, model-predicted serum 24,25(OH)2D increased across gestation except when 25(OH)D was <13 ng/mL. Below this threshold, 24,25(OH)2D was predicted to decline over time. Mean serum 1,25(OH)2D was elevated (>100 pg/mL) throughout the study. Conclusion: Our results suggest that when maternal serum 25(OH)D was low, its catabolism into 24,25(OH)2D decreased or remained stable as pregnancy progressed in order to maintain persistently elevated serum 1,25(OH)2D. Furthermore, in adolescents living at latitude 43°N, standard prenatal supplementation did not prevent a seasonal decline in 25(OH)D during pregnancy. This study was registered at clinicaltrials.gov as NCT01815047.

Predictors of anemia and iron status at birth in neonates born to women carrying multiple fetuses.

BACKGROUND: Iron (Fe) status of neonates born to women carrying multiple fetuses might be compromised as a consequence of the high prevalence of maternal Fe deficiency and anemia coupled with an increased risk of preterm birth. This study aimed to characterize and identify determinants of anemia in this neonatal population. METHODS: Umbilical cord blood obtained from 183 neonates was utilized to assess hemoglobin (Hb), ferritin (SF), soluble transferrin receptor (sTfR), hepcidin, serum Fe, erythropoietin, folate, vitamin B-12, C-reactive protein, and interleukin-6. Associations with maternal Fe status were explored. RESULTS: Cord Hb or SF did not change significantly as a function of gestational age at birth (25-38 wks). Neonates born to women who were obese prior to pregnancy or smoked cigarettes during pregnancy had a 4-5-fold greater odds of anemia at birth. Cord sTfR was the strongest indicator of cord Hb (P < 0.0001), and it was significantly associated with maternal sTfR at mid-gestation (P = 0.01) and delivery (P = 0.002). Cord Fe indicators were significantly associated with cord hepcidin, but not maternal hepcidin. CONCLUSION: Screening for Fe status in neonates born to women carrying multiple fetuses is warranted, especially for those born to smokers or to women who are obese at entry into pregnancy.

Umbilical Cord Coiling in High-risk Pregnancies: Associations With Determinants of Adverse Birth Outcomes and Iron Status.

Abnormal umbilical cord coiling has been associated with adverse neonatal outcomes, but the etiology of these findings remains poorly characterized. This study was undertaken to examine associations between cord coiling and maternal iron (Fe) status and to identify potential determinants of hypo- and hypercoiling in 2 higher risk obstetric groups: pregnant adolescents (≤18 years, n = 92) and adult women carrying twins (n = 49), triplets (n = 11), or quadruplets (n = 1). Umbilical cords were classified as hypo-, normo-, or hypercoiled using digital photographs to assess gross appearance. Hypocoiling and hypercoiling were observed in 44% (n = 86/195) and 13% (n = 26/195) of the combined study population. The prevalence of hypocoiling among women carrying multiples was over 3-fold higher than the prevalence in singleton pregnancies based on the published data. Within the entire study population, hypocoiling was associated with a lower gestational age at birth when compared to normocoiling and hypercoiling (36.3 ± 3.6 weeks [n = 86] vs 37.8 ± 2.7 [n = 83], P < .01, and 38.2 ± 2.6 [n = 26], P < .01, respectively), whereas hypercoiling was associated with significantly lower serum ferritin when compared to normocoiling ( P < .01) and hypocoiling ( P < .001). In the multiples cohort only, hypercoiling was significantly associated with multiparity ( P < .01) and lower birth weight ( P < .05). Further studies are needed to identify the determinants and consequences of cord coiling.

Positive Selection on a Regulatory Insertion-Deletion Polymorphism in FADS2 Influences Apparent Endogenous Synthesis of Arachidonic Acid.

Long chain polyunsaturated fatty acids (LCPUFA) are bioactive components of membrane phospholipids and serve as substrates for signaling molecules. LCPUFA can be obtained directly from animal foods or synthesized endogenously from 18 carbon precursors via the FADS2 coded enzyme. Vegans rely almost exclusively on endogenous synthesis to generate LCPUFA and we hypothesized that an adaptive genetic polymorphism would confer advantage. The rs66698963 polymorphism, a 22-bp insertion-deletion within FADS2, is associated with basal FADS1 expression, and coordinated induction of FADS1 and FADS2 in vitro. Here, we determined rs66698963 genotype frequencies from 234 individuals of a primarily vegetarian Indian population and 311 individuals from the US. A much higher I/I genotype frequency was found in Indians (68%) than in the US (18%). Analysis using 1000 Genomes Project data confirmed our observation, revealing a global I/I genotype of 70% in South Asians, 53% in Africans, 29% in East Asians, and 17% in Europeans. Tests based on population divergence, site frequency spectrum, and long-range haplotype consistently point to positive selection encompassing rs66698963 in South Asian, African, and some East Asian populations. Basal plasma phospholipid arachidonic acid (ARA) status was 8% greater in I/I compared with D/D individuals. The biochemical pathway product-precursor difference, ARA minus linoleic acid, was 31% and 13% greater for I/I and I/D compared with D/D, respectively. This study is consistent with previous in vitro data suggesting that the insertion allele enhances n-6 LCPUFA synthesis and may confer an adaptive advantage in South Asians because of the traditional plant-based diet practice.

Maternal iron status during pregnancy compared with neonatal iron status better predicts placental iron transporter expression in humans.

The placenta richly expresses nonheme and heme Fe transport proteins. To address the impact of maternal and neonatal Fe status and hepcidin on the regulation of these proteins, mRNA expression and protein abundance of nonheme and heme Fe transport proteins were evaluated in placental tissue from 154 adolescents. Regression analyses found maternal Fe status was significantly associated with multiple placental nonheme and heme transporters, whereas neonatal Fe status was related to only 3 heme transporters. Across statistical analyses, maternal Fe status was consistently associated with the placental nonheme Fe importer transferrin receptor 1 (TfR1). Protein abundance of TfR1 was related to midgestation maternal serum ferritin (SF) (ß = -0.32; P = 0.005) and serum TfR (ß = 0.25; P = 0.024). Protein abundance of the heme importer, proton-coupled folate transporter, was related to neonatal SF (ß = 0.30; P = 0.016) and serum TfR (ß = -0.46; P < 0.0001). Neonatal SF was also related to mRNA expression of the heme exporter feline leukemia virus subgroup C receptor 1 (ß = -0.30; P = 0.004). In summary, maternal Fe insufficiency during pregnancy predicts increased expression of the placental nonheme Fe transporter TfR1. Associations between placental heme Fe transporters and neonatal Fe status require further study.-Best, C. M., Pressman, E. K., Cao, C., Cooper, E., Guillet, R., Yost, O. L., Galati, J., Kent, T. R., O'Brien, K. O. Maternal iron status during pregnancy compared with neonatal iron status better predicts placental iron transporter expression in humans.

Elemental content of the placenta: A comparison between two high-risk obstetrical populations, adult women carrying multiples and adolescents carrying singletons.

BACKGROUND: The placenta is responsible for the exchange of nutrients and for preventing harmful compounds from entering the fetal circulation. With increasing industrialization, exposures to commercial and toxic metals become a concern for both pregnant women and those planning a pregnancy. The understanding of transport mechanisms and pharmacokinetics for most inorganic elements is incomplete and limited to normal term deliveries. OBJECTIVES: To obtain novel data on 46 inorganic elements in placentae from two high-risk obstetric populations, women carrying multiples and adolescents carrying singletons, evaluating differences, if present, and identifying predictors of placental content. METHODS: Placental tissue was collected from adolescents carrying singletons and adults carrying multiples. Elemental content was analyzed using inductively coupled plasma-mass spectrometry (ICP-MS). Multivariate regression and factor analyses were used. RESULTS: With the exception of Au and Pt, almost all placentae contained quantifiable concentrations of each element analyzed. All placentae contained the essential elements Ca, Fe, Mg, Se and Zn, which clustered together onto the same factor. Most elements were higher in placentae from women carrying multiples. Differences in placental content disappeared after adjusting for maternal age. Rare earth elements (REEs) clustered together and remained higher in the multiples even after adjusting for maternal age. CONCLUSION: Human placentae contain a wide range of elements, including REEs. Ranges differed considerably between cohorts. Elements with similar chemical properties, like REEs or nutritionally essential elements, clustered together. Maternal age, and therefore longer environmental exposure, was significantly associated with elevated element concentrations in the placenta. Placental concentrations of several metals that are known to be nutritionally essential (e.g., Fe, Ca, Mg, and Zn) did not differ significantly between cohorts, suggesting tight regulation, whereas concentrations of environmental contaminants differed significantly between groups, even after adjusting for maternal age.

Prevalence of anemia and associations between neonatal iron status, hepcidin, and maternal iron status among neonates born to pregnant adolescents.

BACKGROUND: Little is known about anemia and iron status in US newborns because screening for anemia is typically not undertaken until 1 y of age. This study was undertaken to characterize and identify determinants of iron status in newborns born to pregnant adolescents. METHODS: Pregnant adolescents (≤ 18 y, n = 193) were followed from ≥ 12 wk gestation until delivery. Hemoglobin, ferritin, soluble transferrin receptor, serum iron, hepcidin, erythropoietin (EPO), IL-6, and C-reactive protein were assessed in maternal and cord blood. RESULTS: At birth, 21% of the neonates were anemic (Hb < 13.0 g/dl) and 25% had low iron stores (ferritin < 76 µg/l). Cord serum ferritin concentrations were not significantly associated with gestational age (GA) at birth across the range of 37-42 wk. Neonates born to mothers with ferritin < 12 µg/l had significantly lower ferritin (P = 0.003) compared to their counterparts. Hepcidin and IL-6 were significantly (P < 0.05) higher in neonates born to mothers with longer durations of active labor. CONCLUSION: Given the importance of the iron stores at birth on maintenance of iron homeostasis over early infancy, additional screening of iron status at birth is warranted among those born to this high risk obstetric population.

Iron Absorption from an Intrinsically Labeled Lentil Meal Is Low but Upregulated in Women with Poor Iron Status.

BACKGROUND: Low iron absorption from important staple foods may contribute to iron deficiency in developing countries. To date, few studies have examined the iron bioavailability of pulse crops as commonly prepared and consumed by humans. OBJECTIVE: The objectives were to characterize the iron absorption from a test meal of intrinsically labeled (57)Fe lentils prepared as dal, to compare the bioavailability of iron from (57)Fe in dal with that observed for a reference dose of (58)Fe as ferrous sulfate, and to assess associations between iron absorption and iron status indicators. METHODS: This crossover study included 19 nonpregnant women (n = 6 anemic; hemoglobin: <12.0 g/dL) who consumed 2 test meals on consecutive days in a counter-balanced order, ferrous sulfate (7 mg FeSO4 plus 1 mg (58)Fe) and 330 g dal (lentils enriched to 85.1% with (57)Fe, 8 mg native (57)Fe). Iron absorption was determined by analyzing blood samples taken 14 d after dosing with the use of magnetic sector thermal ionization mass spectrometry. RESULTS: We found that the mean iron absorption from the dal was 2.20% ± 3.40% and was significantly lower than the 23.6% ± 13.2% observed from the same iron load given as ferrous sulfate (P < 0.001). Absorption of non-heme iron from dal and from ferrous sulfate was inversely associated with serum ferritin (SF; r = -0.50, P = 0.05 and r = -0.81, P < 0.001, respectively) and serum hepcidin (r = -0.45, P = 0.05 and r = -0.60, P = 0.007, respectively). Anemic women absorbed more iron from either source (1.20% from dal, P = 0.10; 18.3% from ferrous sulfate, P = 0.001) compared with women who were iron replete. CONCLUSIONS: Iron absorption from the dal was low overall but upregulated in anemic women. Both SF and hepcidin were inversely associated with iron absorption from both a supplemental and a food-based non-heme iron source in nonanemic and anemic women.