Subclinical inflammation affects iron and vitamin A but not zinc status assessment in Senegalese children and Cambodian children and women

Zinc Supplementation Initiated Prior to or During Pregnancy Modestly Impacted Maternal Status and High Prevalence of Hypozincemia in Pregnancy and Lactation: The Women First Preconception Maternal Nutrition Trial

BACKGROUND

Data regarding effects of small-quantity-lipid-based nutrient supplements (SQ-LNS) on maternal serum zinc concentrations (SZC) in pregnancy and lactation are limited.

OBJECTIVES

The objectives of this study were to evaluate the effect of preconception compared with prenatal zinc supplementation (compared with control) on maternal SZC and hypozincemia during pregnancy and early lactation in women in low-resource settings, and assess associations with birth anthropometry.

METHODS

From ∼100 women/arm at each of 3 sites (Guatemala, India, and Pakistan) of the Women First Preconception Maternal Nutrition trial, we compared SZC at 12- and 34-wk gestation (n = 651 and 838, respectively) and 3-mo postpartum (n = 742) in women randomly assigned to daily SQ-LNS containing 15 mg zinc from ≥3 mo before conception (preconception, arm 1), from ∼12 wk gestation through delivery (early pregnancy, arm 2) or not at all (control, arm 3). Birth anthropometry was examined for newborns with ultrasound-determined gestational age. Statistical analyses were performed separately for each time point.

RESULTS

At 12-wk gestation and 3-mo postpartum, no statistical differences in mean SZC were observed among arms. At 34-wk, mean SZC for arms 1 and 2 were significantly higher than for arm 3 (50.3, 50.8, 47.8 μg/dL, respectively; P = 0.005). Results were not impacted by correction for inflammation or albumin concentrations. Prevalence of hypozincemia at 12-wk (<56 μg/dL) was 23% in Guatemala, 26% in India, and 65% in Pakistan; at 34 wk (<50 μg/dL), 36% in Guatemala, 48% in India, and 74% in Pakistan; and at 3-mo postpartum (<66 μg/dL) 79% in Guatemala, 91% in India, and 92% in Pakistan. Maternal hypozincemia at 34-wk was associated with lower birth length-for-age Z-scores (all sites P = 0.013, Pakistan P = 0.008) and weight-for-age Z-scores (all sites P = 0.017, Pakistan P = 0.022).

CONCLUSIONS

Despite daily zinc supplementation for ≥7 mo, high rates of maternal hypozincemia were observed. The association of hypozincemia with impaired fetal growth suggests widespread zinc deficiency in these settings. This trial is registered at clinicaltrials.gov as #NCT01883193.

Circulating microRNAs and hepcidin as predictors of iron homeostasis and anemia among school children: a biochemical and cross-sectional survey analysis

BACKGROUND

MicroRNAs (miRNAs) can control several biological processes. Thus, the existence of these molecules plays a significant role in regulating human iron metabolism or homeostasis.

PURPOSE

The study aimed to determine the role of circulating microRNAs and hepcidin in controlling iron homeostasis and evaluating possible anemia among school children.

METHODS

The study was based on a biochemical and cross-sectional survey study that included three hundred fifty school children aged 12-18 years old. RT-PCR and immunoassay analysis were accomplished to estimate iron concentration, Hgb, serum ferritin (SF), soluble transferrin receptor (sTfR), total body iron stores (TIBs), total oxidative stress (TOS), total antioxidant capacity (TAC), α-1-acid glycoprotein (AGP), high sensitive C-reactive protein (hs-CRP), and miRNAs; miR-146a, miR-129b, and miR-122 in 350 school adolescents.

RESULTS

Iron disorders were cross-sectionally predicted in 28.54% of the study population; they were classified into 14.26% with ID, 5.7% with IDA, and 8.6% with iron overload. The overall proportion of iron depletion was significantly higher in girls (20.0%) than in boys (8.6%). MicroRNAs; miR-146a, miR-125b, and miR-122 were significantly upregulated with lower hepcidin expression in adolescence with ID and IDA compared to iron-overloaded subjects, whereas downregulation of these miRNAs was linked with higher hepcidin. Also, a significant correlation was recorded between miRNAs, hepcidin levels, AGP, hs-CRP, TAC, and other iron-related indicators.

CONCLUSION

Molecular microRNAs such as miR-146a, miR-125b, and miR-122 were shown to provide an additional means of controlling or regulating cellular iron uptake or metabolism either via the oxidative stress pathway or regulation of hepcidin expression via activating genes encoding Hfe and Hjv activators, which promote iron regulation. Thus, circulating miRNAs as molecular markers and serum hepcidin could provide an additional means of controlling or regulating cellular iron and be associated as valuable markers in diagnosing and treating cases with different iron deficiencies.

Menstrual Cycle-Associated Changes in Micronutrient Biomarkers Concentration: A Prospective Cohort Study

To evaluate variations in micronutrient biomarker concentrations and deficiencies across the menstrual cycle in a cohort of healthy women. This prospective cohort study was conducted among healthy women of reproductive age living in the State College area, Pennsylvania, (n = 45). Data collection occurred at the early follicular phase, the late follicular phase, and the midluteal phase. Fasting blood samples were collected to measure micronutrient biomarkers. At the early follicular phase, the mean ± SD concentrations for zinc, copper, magnesium, and retinol were 81.8 ± 16.2 µg/dL, 80.1 ± 12.8 µg/dL, 17.9 ± 1.4 mg/L, and 39.4 ± 9.3 µg/dL, respectively. The geometric mean (95% CI) for manganese, iron and ferritin concentrations were 1.51 [1.21, 1.87] µg/L, 106.7 [90.8, 125.4] µg/dL, and 26.4 [20.5, 34.0] µg/L, respectively. Mean concentrations of zinc and magnesium declined by 6.6% (p = 0.009) and 4.6% (p < 0.001) from the early follicular phase to the midluteal phase, respectively. Other biomarkers remained relatively constant across the cycle. At the early follicular phase, the prevalence of low serum concentrations for zinc, copper, magnesium, manganese, iron, and ferritin was 22%, 7%, 29%, 13%, 14%, and 28%, respectively. Also, in early follicular phase, 36% had anemia, and 13% specifically had iron deficiency anemia. The prevalence of magnesium deficiency was significantly higher at the midluteal phase vs. the early follicular phase (p = 0.025). Our study suggests that while many micronutrient concentrations are relatively constant across the menstrual cycle in healthy women, zinc and magnesium decline, and the prevalence of magnesium deficiency increases. Supplemental data for this article is available online at.

Re-Defining the Population-Specific Cut-Off Mark for Vitamin A Deficiency in Pre-School Children of Malawi

Retinol Binding Protein (RBP) is responsible for the transport of serum retinol (SR) to target tissue in the body. Since RBP is relatively easy and cheap to measure, it is widely used in national Micronutrient Surveys (MNS) as a proxy for SR to determine vitamin A status. By regressing RBP concentration against SR concentration measured in a subset of the survey population, one can define a population-specific threshold concentration of RBP that indicates vitamin A deficiency (VAD). However, the relationship between RBP and SR concentrations is affected by various factors including inflammation. This study, therefore, aimed to re-define the population-specific cut-off for VAD by examining the influence of inflammation on RBP and SR, among pre-school children (PSC) from the 2015-16 Malawi MNS. The initial association between RBP and SR concentrations was poor, and this remained the case despite applying various methods to correct for inflammation. The World Health Organization (WHO) recommends the threshold of 0.7 µmol/L to define VAD for SR concentrations. Applying this threshold to the RBP concentrations gave a VAD prevalence of 24%, which reduced to 10% after inflammation adjustments following methods developed by the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA). Further research is required to identify why SR and RBP were poorly associated in this population. Future MNS will need to account for the effect of inflammation on RBP to measure the prevalence of VAD in Malawi.

A methodology for examining the association between plasma volume and micronutrient biomarker mass and concentration in healthy eumenorrheic women

BACKGROUND

Accurate estimation and interpretation of nutritional biomarker concentrations are important in nutritional research, clinical care, and public health surveillance. Plasma volume (PV) may affect the interpretation of plasma biomarkers but is rarely measured. We aimed to examine the association between plasma volume (PV) and micronutrient biomarker concentrations and mass as part of pilot work to develop methods.

METHODS

Nine healthy women with regular menstrual cycles provided fasting blood samples to measure micronutrient biomarkers. Indocyanine green was injected, and five timed blood draws were taken from 2 to 5 min to measure PV. Visits were scheduled around menstrual cycle day 2. Retinol, 25-hydroxyvitamin D, riboflavin, alpha-tocopherol, zinc, copper, magnesium, manganese, cobalt, iron, and ferritin concentrations were measured in serum. Total circulating micronutrient biomarker mass was calculated from PV and concentration.

RESULTS

The mean PV was 2067 ±  470 mL. PV correlated positively with concentration of iron (r = 0.87, P = 0.005); other correlations were weaker with p > 0.05. PV and total mass of retinol (r = 0.90), 25(OH)D (r = 0.75), zinc (r = 0.88), copper (r = 0.83), magnesium (r = 0.93), manganese (r = 0.72), and iron (r = 0.92) were strongly correlated (all p < 0.05). PV was positively correlated with circulating micronutrient mass for most biomarkers, implying that concentrations are maintained at different volumes of plasma. Larger studies are needed to further examine these relationships.

CONCLUSION

Though there appear to be some association between micronutrient biomarker mass and plasma volume, we are unable to draw a firm conclusion about any relationship from these results because of the small sample size. We consider these findings as a preliminary analysis to establish methods for future studies.

Contribution of Amaranthus cruentus and Solanum macrocarpon Leaves Flour to Nutrient Intake and Effect on Nutritional Status of Rural School Children in Volta Region, Ghana

BACKGROUND

Plant-based foods are staple diets and main micronutrient sources of most rural Ghanaian households. The objective of this study was to determine the effect of Amaranthus cruentus and Solanum macrocarpon leafy vegetable flour on micronutrient intake and nutritional status of rural Ghanaian school children.

METHOD

This study was a randomized controlled trial that consisted of baseline data collection and a three-month nutrition intervention feeding program. Two groups of 53 children, age 4-9 years, involved in the Ghana School Feeding Program took part in the study. An experimental group consumed Amaranthus cruentus and Solanum macrocarpon leaves flour (ACSMLVF) stews and soup. The control group consumed stews and soup without ACSMLVF. Haemoglobin and serum vitamin A concentrations were determined. Dietary and anthropometric data were collected and analysed. Participants were screened for malaria parasitaemia and hookworm.

RESULTS

Anaemia was present in 41.5% and 37.3%, respectively, of the intervention and control groups at baseline. It was present in 28.3% and 53.3%, respectively, at the end of the study. This was significantly different (p=0.024). There was a low vitamin A concentration in 66.0% and 64.7% at baseline and 20.8% and 23.4% at the end of the study in the intervention and control groups, respectively. The mean iron, zinc, and provitamin A (beta-carotene) intakes of the intervention group were 14.2 ± 7.1 mg, 5.7 ± 2.1 mg, and 214.5 ± 22.6 μg, respectively, at baseline. Those of the control were 13.7 ± 6.1 mg, 5.4 ± 2.1 mg, and 210.6 ± 20.1 μg, respectively. At the end of the study, the mean intake of iron, zinc, and beta-carotene for the intervention group was 24.1 ± 10.9 mg, 13.8 ± 8.2 mg, and 694.2 ± 33.1 μg, respectively. The intake of these micronutrients for the control at the end of the study was 14.8 ± 6.2 mg, 5.9 ± 2.3 mg, and 418.4 ± 34.7 μg, respectively.

CONCLUSION

Consumption of ACSMLVF stews and soup increased iron, zinc, and beta-carotene intakes. Anaemia prevalence was lower in the intervention group at the end of the study.

Inflammation Adjustment by Two Methods Decreases the Estimated Prevalence of Zinc Deficiency in Malawi

Serum zinc concentration (SZC) is used widely to assess population-level zinc status. Its concentration decreases during inflammatory responses, which can affect the interpretation of the results. This study aimed to re-estimate the prevalence of zinc deficiency in Malawi based on the 2015-2016 Malawi Micronutrient Survey (MNS) data, by adjusting SZC measures with markers of inflammation. SZC and inflammation data from 2760 participants were analysed. Adjustments were made using: (1) The Internal Correction Factor (ICF) method which used geometric means, and (2) The Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) method, which used linear regression. Mean SZC values increased significantly when adjustments were made by either ICF or BRINDA (p < 0.001). The national prevalence of zinc deficiency decreased from 62% to 59%, after ICF adjustment, and to 52% after BRINDA adjustment. ICF and BRINDA values of SZC were highly correlated (p < 0.001, r = 0.99), but a Bland-Altman plot showed a lack of agreement between the two methods (bias of 2.07 µg/dL). There was no association between the adjusted SZC and stunting, which is a proxy indicator for zinc deficiency. Inflammation adjustment of SZC, using ICF or BRINDA, produces lower estimates of zinc deficiency prevalence, but the lack of agreement between the adjustment methods warrants further research. Furthermore, the lack of association between SZC and stunting highlights the need to explore other biomarkers and proxies of population zinc assessment. This study demonstrates the importance of considering inflammatory confounders when reporting SZC, to ensure accuracy and to support policy decision making.

Malaria early in the first pregnancy: Potential impact of iron status

BACKGROUND & AIMS

Low iron stores may protect from malaria infection, therefore improving iron stores in early pregnancy in line with current recommendations could increase malaria susceptibility. To test this hypothesis we compared iron biomarkers and red cell indices in nulliparae and primigravidae who participated in a randomized controlled trial of long-term weekly iron supplementation.

METHODS

Cross-sectional and longitudinal data analysis from a randomized controlled trial of long-term weekly iron supplementation in rural Burkina Faso. Malaria parasitaemia was monitored and biomarkers and red cell indices measured at study end-points: plasma ferritin, transferrin receptor (sTfR), zinc protoporphyrin, hepcidin, sTfR/log₁₀ ferritin ratio, body iron, haemoglobin, red cell distribution width; mean corpuscular haemoglobin concentration/volume, and C-reactive protein. Correlation coefficients between biomarkers and red cell indices were determined. A regression correction approach based on ferritin was used to estimate iron body stores, allowing for inflammation. Body iron differences were compared between nulliparae and primigravidae, and the association determined of iron biomarkers and body iron stores with malaria.

RESULTS

Iron and haematological indices of 972 nulliparae (mean age 16.5 years) and 314 primigravidae (median gestation 18 weeks) were available. Malaria prevalence was 54.0% in primigravidae and 41.8% in nulliparae (relative risk 1.28, 95% CI 1.13-1.45, P < 0.001), anaemia prevalence 69.7% and 43.4% (P < 0.001), and iron deficient erythropoiesis (low body iron) 8.0% and 11.7% (P = 0.088) respectively. Unlike other biomarkers the sTfR/log₁₀ ferritin ratio showed no correlation with inflammation as measured by CRP. Most biomarkers indicated reduced iron deficiency in early pregnancy, with the exception of haemoglobin. Body iron increased by 0.6-1.2 mg/kg in early gestation, did not differ by malaria status in nulliparae, but was higher in primigravidae with malaria (6.5 mg/kg versus 5.0 mg/kg; relative risk 1.53, 95% CI 0.67-2.38, P < 0.001).

CONCLUSION

In primigravidae, early pregnancy haemoglobin was not a good indicator of requirement for iron supplementation, which could be detrimental given the association of better iron status with increased malaria infection.

TRIAL REGISTRATION

clinicaltrials.gov:NCT01210040. Until placed in a public repository, data relating to the current study can be requested from the corresponding author and will be made available following an end user data agreement and sponsor approval.