Iron, zinc, and copper concentrations in breast milk are independent of maternal mineral status

Overview of Nutrients in Human Milk

The WHO recommends exclusive breastfeeding for the first 6 mo of life to promote optimal infant health and development. Understanding the micro- and macronutrient concentrations of human milk and how each nutrient fluctuates with lactational stage, maternal factors, and supplementation is imperative for supporting good breastfeeding practices. Where maternal undernutrition compromises human milk quality, a thorough awareness of the effectiveness of interventions can direct efforts to achieve both maternal and infant nutrient sufficiency. This review of current knowledge covers trends in nutrient concentrations over the course of lactation and describes the influence of maternal intake, status, supplementation, and other factors on human milk concentrations of each nutrient.

Micronutrients in Human Milk: Analytical Methods

Exclusive breastfeeding is recommended by the WHO for the first 6 mo of life because human milk protects against gastrointestinal infections and supplies balanced and adequate nutrient contents to the infant. However, reliable data on micronutrient concentrations in human milk are sparse, especially because some micronutrients are affected by maternal diet. Microbiological and competitive protein-binding assays, nuclear magnetic resonance or inductively coupled plasma spectroscopy, and chromatographic analyses are among the methods that have been applied to human-milk micronutrient analysis. However, the validation or evaluation of analytical methods in terms of their suitability for the complex human-milk matrix has been commonly ignored in reports, even though the human-milk matrix differs vastly from blood, plasma, or urine matrixes. Thus, information on the validity, accuracy, and sensitivity of the methods is essential for the estimation of infant and maternal intake requirements to support and maintain adequate milk micronutrient concentrations for healthy infant growth and development. In this review, we summarize current knowledge on methods used for analyzing water- and fat-soluble vitamins as well as iron, copper, zinc, iodine, and selenium in human milk and their different forms in milk; the tools available for quality control and assurance; and guidance for preanalytical considerations. Finally, we recommend preferred methodologic approaches for analysis of specific milk micronutrients.

Iron and the Breastfed Infant

The first 6 months of life is a crucial time in meeting iron needs. The purpose of this review is to examine iron in mother’s milk and whether or not it meets the physiological needs of the growing infant. Key issues include iron content and iron transport from the mammary gland as well as when and what foods should be added to the solely breastfed infant. We examine these topics in light of new molecular biology findings in the mammary gland.

Analyses of Essential Elements and Heavy Metals by Using ICP-MS in Maternal Breast Milk from Şanlıurfa, Turkey

Maternal breast milk is a unique biological matrix that contains essential micronutrients. Potentially heavy metals may also affect infants' health and growth through maternal breast milk. The purpose of this study was to determine and compare the essential elements and heavy metals of maternal breast milk of nursery mothers residing in Şanlıurfa province, Turkey. Maternal breast milk concentrations of sodium, magnesium, phosphorus, potassium, calcium, iron, copper, zinc, arsenic, and lead were analyzed in a random sample of the first time in urban and suburban nursery Turkish mothers (n: 42). Eight essential elements and two heavy metals were analyzed using ICP-MS after microwave digestion. For bivariate analyses of variables, we use nonparametric Spearman's correlation coefficient test. The mean concentrations of essential elements and heavy metals were as follows: sodium 330 ± 417 mg/L, magnesium 32.6 ± 15.5 mg/L, phosphorus 156 ± 46.2 mg/L, potassium 488 ± 146 mg/L, calcium 193 ± 53.2 mg/L, iron 1.65 ± 1.43 mg/L, copper 0.54 ± 0.46 mg/L, zinc 2.89 ± 3.23 mg/L, arsenic < 1 μg/L, and lead < 1 μg/L. Concentrations of heavy metals in maternal breast milk may have the important implication that it is not affected by environmental pollution in this province. This study provides reliable information about maternal breast milk concentrations of nursery mothers residing in Şanlıurfa, Turkey, and also compares the relations between essential elements and socioeconomic conditions, residing areas, and using copper equipment for food preparation of which some have not previously been reported.

The effects of a lipid-based nutrient supplement and antiretroviral therapy in a randomized controlled trial on iron, copper, and zinc in milk from HIV-infected Malawian mothers and associations with maternal and infant biomarkers

We evaluated effects of antiretroviral (ARV) therapy and lipid-based nutrient supplements (LNSs) on iron, copper, and zinc in milk of exclusively breastfeeding HIV-infected Malawian mothers and their correlations with maternal and infant biomarkers. Human milk and blood at 2, 6, and 24 weeks post-partum and blood during pregnancy (≤30 weeks gestation) were collected from 535 mothers/infant-pairs in the Breastfeeding, Antiretrovirals, and Nutrition study. The participants received ARV, LNS, ARV and LNS, or no intervention from 0 to 28 weeks post-partum. ARVs negatively affected copper and zinc milk concentrations, but only at 2 weeks, whereas LNS had no effect. Among all treatment groups, approximately 80-90% of copper and zinc and <50% of iron concentrations met the current adequate intake for infants at 2 weeks and only 1-19% at 24 weeks. Pregnancy haemoglobin was negatively correlated with milk iron at 2 and 6 weeks (r = -.18, p < .02 for both). The associations of the milk minerals with each other were the strongest correlations observed (r = .11-.47, p < .05 for all); none were found with infant biomarkers. At 2 weeks, moderately anaemic women produced milk higher in iron when ferritin was higher or TfR lower. At 6 weeks, higher maternal α-1-acid glycoprotein and C-reactive protein were associated with higher milk minerals in mildly anaemic women. Infant TfR was lower when milk mineral concentrations were higher at 6 weeks and when mothers were moderately anaemic during pregnancy. ARV affects copper and zinc milk concentrations in early lactation, and maternal haemoglobin during pregnancy and lactation could influence the association between milk minerals and maternal and infant iron status and biomarkers of inflammation.

Subclinical mastitis (SCM) and proinflammatory cytokines are associated with mineral and trace element concentrations in human breast milk

The possibility that either subclinical mastitis (SCM), an inflammatory condition of the breast, or elevations in breast milk proinflammatory cytokines alter breast milk mineral and trace element composition in humans has not been investigated. In this cross-sectional study, breast milk samples (n=108) were collected from Guatemalan Mam-Mayan mothers at one of three stages of lactation (transitional, early and established), and categorized as SCM (Na:K >0.6) or non-SCM (Na:K ≤0.6). Milk concentrations of 12 minerals (calcium, copper, iron, magnesium, manganese, phosphorus, potassium, rubidium, selenium, sodium, strontium, and zinc) and 4 proinflammatory cytokines (IL-1β, IL-6, IL-8, TNF-α) were measured by inductively coupled plasma mass spectrometry (ICP-MS), Lachat analyzer or Luminex multiplex bead cytokine assay. SCM was more prevalent during transitional (30%) than early (15.6%) and established (8.9%) lactation. Analysis of variance revealed that breast milk minerals differed by stage of lactation and SCM status. Breast milk minerals with the exception of magnesium were lower in established lactation, whereas SCM was associated with higher selenium and lower phosphorus. Regression models that controlled for lactation stage also confirmed that SCM was associated with lower milk phosphorus and higher milk selenium concentrations. Furthermore, cytokine concentrations were independently associated with several mineral concentrations: IL-1β with higher phosphorus and iron, IL-6 with higher calcium, magnesium, copper and manganese, IL-8 with higher calcium and zinc, and TNF-α with lower iron and manganese. We conclude that milk mineral and trace element concentrations are affected not only by the presence of SCM but also by proinflammatory cytokines in breast milk.

Macro- and Micronutrients of Human Milk Composition: Are They Related to Maternal Diet? A Comprehensive Systematic Review

BACKGROUND

This study aims at systematically reviewing the observational and interventional studies on the association of maternal macro- and micronutrient intake with breast milk content.

METHODS

We systematically searched the Medline via PubMed, Scopus, and ISI Web of Knowledge till October 2016 with the following search strategy: ("human milk" OR "breast milk" OR "breast milk composition" OR "human breast milk composition" OR "composition breast milk" OR "mother milk" OR "human breast milk") AND ("maternal diet" OR "maternal nutrition"). We also searched Google scholar for increasing the sensitivity of our search. The search was not limited to title and abstract due to the possibility that the desired outcome might have been considered a secondary aim. We excluded conference papers, editorials, letters, commentary, short survey, and notes. The search was refined to English language, and we did not consider any time limitation. To increase the sensitivity and to select more studies, the reference list of the published studies was checked as well.

RESULTS

This review included 59 observational and 43 interventional studies on maternal diet related to breast milk composition. Different studies determined the associations and effects of some maternal dietary intake of micro and macronutrients and its reflection in human milk.

CONCLUSION

Maternal dietary intake, particularly fatty acids, and some micronutrients, including fat soluble vitamins, vitamin B₁, and vitamin C, was related to their content in breast milk composition.

Rare-earth elements in human colostrum milk

Rare-earth elements (REEs) are used in a growing number of applications, and their release to environment has increased over the decades. Knowledge of REEs in human milk and factors that could possibly influence their concentration is scarce. This study evaluated the concentrations of 16 REEs (Ce, Eu, Er, Gd, La, Nd, Pr, Sc, Sm, Dy, Ho, Lu, Tb, Tm, Y, and Yb) in human colostrum milk collected from Polish women (n = 100) with the ICP-OES technique. The concentrations (mean ± SD) of Pr (41.9 ± 13.2 μg L^-1), Nd (11.0 ± 4.0 μg L^-1), La (7.1 ± 5.2 μg L^-1), and Er (2.2 ± 0.8 μg L^-1) were found above detection limits. The total mean ± SD concentration of detected REEs was 60.9 ± 17.8 μg L^-1. Current smokers displayed significantly increased Nd concentrations compared to women who had never smoked. No other associations between REEs in colostrum milk and age, diet in pregnancy (food supplement use and frequency of fish, meat, and vegetable consumption) or place of living (urban/rural) were found. This study adds to general understanding of the occurrence and turnover of REEs in women and human fluids.

Concentrations of trace elements in human milk: Comparisons among women in Argentina, Namibia, Poland, and the United States

Human milk contains essential micronutrients for growth and development during early life. Environmental pollutants, such as potentially toxic metals, can also be transferred to the infant through human milk. These elements have been well-studied, but changing diets and environments and advances in laboratory technology require re-examining these elements in a variety of settings. The aim of this study was to characterize the concentrations of essential and toxic metals in human milk from four diverse populations. Human milk samples (n = 70) were collected in Argentina (n = 21), Namibia (n = 6), Poland (n = 23), and the United States (n = 20) using a standardized mid-feed collection procedure. Milk concentrations of calcium, zinc, iron, copper, manganese, lead, arsenic, and cadmium were determined using inductively coupled plasma mass spectrometry (ICP-MS). We used standard multiple linear regression models to evaluate differences among populations, while including infant age, infant sex, and maternal parity status (multiparous or primiparous) as covariates. Concentrations of all elements, except zinc, varied across populations after controlling for infant age, infant sex, and maternal parity. Calcium and magnesium showed more differences across populations than iron or copper. There were no significant differences among population in zinc concentrations. Mean concentrations of lead, but not arsenic, were low compared to recently published values from other populations. The concentrations of trace elements in human milk are variable among populations. Limitations due to small sample sizes and environmental contamination of some samples prevent us from drawing robust conclusions about the causes of these differences.

Trace elements, oxidative status and antioxidant capacity as biomarkers in very low birth weight infants

Reference data on trace elements, oxidative status and antioxidants in very low birth weight infants (VLBW) are limited and need to be updated for use in clinical settings. Serum and urine of 30 VLBW infants (mean weight, 1167g) at mean age of 23.8 (t0) and 37.8 (t1) days were analyzed. Cadmium (Cd), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), selenium (Se) and zinc (Zn), nitrate/nitrite (NOx), catalase (CAT), CuZnFeMn-superoxide dismutases (CuZnFeMn-SODs), total antioxidant capacity (SAC: sum of thiols, proteins, bilirubin, uric acid, β-beta-carotene, ascorbic acid, vitamin E) and total oxidative status (SOS: sum of lipo- and hydroperoxides) were determined. A higher urinary excretion of Cu and Zn was observed at t0 than at t1; while an increase in urine Cd was found at t1 respect to t0. A deficiency in serum levels of Cu and Zn was also found. A lower CAT activity, a higher total oxidants level (SOS) and a reduction of total antioxidant barriers (SAC) were observed in some infants. No Fe and Mn deficiency or Hg overload was found; also CuZnFeMn-SODs and NOx levels did not change. The findings showed that losses of trace elements and incomplete mineral body stores were more pronounced in the earlier life stage (at 23.8th day) than later on; moreover, antioxidant defenses were poor and lipo- and hydroperoxides were higher still at 5 weeks of infants' life.

Effects of iron supplementation on growth, gut microbiota, metabolomics and cognitive development of rat pups

BACKGROUND

Iron deficiency is common during infancy and therefore iron supplementation is recommended. Recent reports suggest that iron supplementation in already iron replete infants may adversely affect growth, cognitive development, and morbidity.

METHODS

Normal and growth restricted rat pups were given iron daily (30 or 150 μg/d) from birth to postnatal day (PD) 20, and followed to PD56. At PD20, hematology, tissue iron, and the hepatic metabolome were measured. The plasma metabolome and colonic microbial ecology were assessed at PD20 and PD56. T-maze (PD35) and passive avoidance (PD40) tests were used to evaluate cognitive development.

RESULTS

Iron supplementation increased iron status in a dose-dependent manner in both groups, but no significant effect of iron on growth was observed. Passive avoidance was significantly lower only in normal rats given high iron compared with controls. In plasma and liver of normal and growth-restricted rats, excess iron increased 3-hydroxybutyrate and decreased several amino acids, urea and myo-inositol. While a profound difference in gut microbiota of normal and growth-restricted rats was observed, with iron supplementation differences in the abundance of strict anaerobes were observed.

CONCLUSION

Excess iron adversely affects cognitive development, which may be a consequence of altered metabolism and/or shifts in gut microbiota.

Gene Expression Profiles Suggest Iron Transport Pathway in the Lactating Human Epithelial Cell

OBJECTIVES

The molecular background of iron excretion into breast milk has not been determined in humans. We determined the expression of known iron transporters in mRNA extracted from human milk fat globules to deduce which known transporters are responsible for iron excretion into human milk.

METHODS

The expression of iron transporters in mRNA from human milk fat globules and mouse mammary epithelial cell lines was determined by quantitative real-time polymerase chain reaction.

RESULTS

The expression of the transferrin receptor 1 (TFRC), divalent metal transporter 1 (SLC11A2), transferrin (TF), and lactoferrin (LTF) was confirmed in RNA isolated from the human milk fat globule. Similar expression was observed in the mouse mammary epithelial cell line HC11 in resting and lactating phenotypes. No iron export protein could be determined in the RNA isolated from fat globules in human breast milk and a human mammary epithelial cell line.

CONCLUSIONS

The lack of iron exporters in the human mammary epithelia, in conjunction with the presence of lactoferrin suggests that transmembrane transport is not a major route of iron excretion into human milk.

Iron concentration in breast milk normalised within one week of a single high-dose infusion of iron isomaltoside in randomised controlled trial

AIM

We compared the iron concentration in breast milk after a single high dose of intravenous iron isomaltoside or daily oral iron for postpartum haemorrhage.

METHODS

In this randomised controlled trial, the women were allocated a single dose of intravenous 1200 mg iron isomaltoside or oral iron at a mean daily dose of 70.5 mg. We included 65 women with sufficient breast milk three days after inclusion - 30 from the intravenous iron group and 35 from the oral iron group - and collected breast milk and maternal blood samples three days and one week after allocation.

RESULTS

The mean (±SD) iron concentration in breast milk in the intravenous and oral groups was 0.72 ± 0.27 and 0.40 ± 0.18 mg/L at three days (p < 0.001) and 0.47 ± 0.17 and 0.44 ± 0.25 mg/L after one week (p = 0.64). Baseline samples were not available that soon after birth.

CONCLUSION

A single high dose of intravenous iron isomaltoside for postpartum haemorrhage led to a transient increase in the iron concentration in breast milk three days after treatment compared with oral iron. The difference disappeared one week after treatment, and mean iron concentrations were within the normal range in all samples.

Retinol, α-tocopherol, and selected minerals in breast milk of lactating women with full-term infants in South Korea

BACKGROUND/OBJECTIVES

This study was performed to measure fat-soluble vitamins and minerals in breast milk of Korean lactating mothers who exclusively breastfed their babies.

SUBJECTS/METHODS

Breast milk samples were collected from 334 mothers. Concentrations of retinol and α-tocopherol were analyzed by high performance liquid chromatography ultraviolet spectrometry while concentrations of minerals were measured by inductively coupled plasma optical emission spectrometry.

RESULTS

Retinol and α-tocopherol contents of breast milk were 39.58 ± 19.64 µg/dL and 0.23 ± 0.13 mg/dL, respectively. Average sodium, potassium, calcium, phosphorus, and magnesium levels in breast milk were 11.11 ± 5.16, 38.56 ± 9.01, 27.87 ± 6.10, 13.56 ± 3.30, and 3.05 ± 0.65 mg/dL, respectively. Contents of trace elements such as iron, zinc, copper, and manganese were 40.26 ± 46.21, 98.40 ± 62.47, 24.09 ± 9.03, and 0.90 ± 1.63 µg/dL, respectively. Fat-soluble vitamin concentration was positively correlated with total fat in milk samples, but no significant differences were observed in levels of retinol, α-tocopherol, or minerals based on whether or not lactating women were taking dietary supplements.

CONCLUSIONS

Micronutrient contents of breast milk samples from Korean lactating women were comparable to those of other nations. Retinol and α-tocopherol levels were correlated and also with total fat in breast milk.

The Effect of Low Dose Iron and Zinc Intake on Child Micronutrient Status and Development during the First 1000 Days of Life: A Systematic Review and Meta-Analysis

Adequate supply of micronutrients during the first 1000 days is essential for normal development and healthy life. We aimed to investigate if interventions administering dietary doses up to the recommended nutrient intake (RNI) of iron and zinc within the window from conception to age 2 years have the potential to influence nutritional status and development of children. To address this objective, a systematic review and meta-analysis of randomized and quasi-randomized fortification, biofortification, and supplementation trials in women (pregnant and lactating) and children (6–23 months) delivering iron or zinc in doses up to the recommended nutrient intake (RNI) levels was conducted. Supplying iron or zinc during pregnancy had no effects on birth outcomes. There were limited or no data on the effects of iron/zinc during pregnancy and lactation on child iron/zinc status, growth, morbidity, and psychomotor and mental development. Delivering up to 15 mg iron/day during infancy increased mean hemoglobin by 4 g/L (p < 0.001) and mean serum ferritin concentration by 17.6 µg/L (p < 0.001) and reduced the risk for anemia by 41% (p < 0.001), iron deficiency by 78% (ID; p < 0.001) and iron deficiency anemia by 80% (IDA; p < 0.001), but had no effect on growth or psychomotor development. Providing up to 10 mg of additional zinc during infancy increased plasma zinc concentration by 2.03 µmol/L (p < 0.001) and reduced the risk of zinc deficiency by 47% (p < 0.001). Further, we observed positive effects on child weight for age z-score (WAZ) (p < 0.05), weight for height z-score (WHZ) (p < 0.05), but not on height for age z-score (HAZ) or the risk for stunting, wasting, and underweight. There are no studies covering the full 1000 days window and the effects of iron and zinc delivered during pregnancy and lactation on child outcomes are ambiguous, but low dose daily iron and zinc use during 6–23 months of age has a positive effect on child iron and zinc status.

The reproductive ecology of iron in women

Reproductive ecology focuses on the sensitivity of human reproduction to environmental variation. While reproductive ecology has historically focused on the relationship between energy status and reproductive outcomes, iron status is equally critical to women's reproductive health, given the wide-ranging detrimental effects of iron-deficiency anemia on maternal and infant well-being. This review interprets the vast literature on iron status and women's reproduction through an evolutionary framework. First, it will critique the evidence for iron deficiency caused by blood loss during menstruation, reinterpreting the available data as ecological variation in menses within and between populations of women. Second, it will highlight the scant but growing evidence that iron status is implicated in fertility, a relationship that has deep evolutionary roots. Third, this review proposes a new hypothesis for the transfer of iron from mother to infant via pregnancy and breastfeeding: reproductive iron withholding. In this hypothesis, mothers transfer iron to infants in a manner that helps infants avoid iron-mediated infection and oxidative stress, but trades off with potential risk of maternal and infant iron deficiency. Finally, this review explores two main factors that can modify the relationship between iron status and the gestation-lactation cycle: (1) the relationship between long-term reproductive effort (parity) and iron status and (2) supplementation schemes before and during pregnancy. The review concludes by suggesting continued research into iron homeostasis in women using evolutionary, ecological, and biocultural frameworks.

Minerals and Trace Elements in Human Breast Milk Are Associated with Guatemalan Infant Anthropometric Outcomes within the First 6 Months

BACKGROUND

Breast milk is the recommended source of nutrients for infant growth, but its adequacy to meet infants' mineral and trace element needs is unknown.

OBJECTIVES

We used breast-milk mineral and trace element concentrations of Guatemalan mothers at 3 lactation stages to estimate total daily intakes and to determine whether intakes were associated with early infant growth.

METHODS

In this cross-sectional study, breast-milk samples were collected from Mam-Mayan mothers during transitional (5-17 d, n = 56), early (18-46 d, n = 75), and established (4-6 mo, n = 103) lactation; z scores for weight (WAZ), length (LAZ), and head circumference (HCAZ) were measured. Concentrations of 11 minerals (calcium, potassium, magnesium, sodium, copper, iron, manganese, rubidium, selenium, strontium, and zinc) were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS). WHO equations were used to calculate the estimated energy requirement, which was divided by the energy density of breast milk to estimate daily milk volume, and this number was multiplied by breast-milk mineral concentrations to estimate intakes. Principal component analyses identified clusters of minerals; principal components (PCs) were used in regression analyses for anthropometric outcomes.

RESULTS

Estimated breast-milk intakes during established lactation were insufficient to compensate for the lower milk sodium, copper, manganese, and zinc concentrations in male infants and the lower sodium, iron and manganese concentrations in female infants. Estimated intakes of calcium, magnesium, potassium, sodium, and selenium were below the Institute of Medicine Adequate Intake for both sexes at all 3 stages of lactation. In early lactation, multiple linear regressions showed that PC1 (calcium, magnesium, potassium, rubidium, and strontium intakes) was positively associated with WAZ, LAZ, and HCAZ. In established lactation, the same PC with sodium added was positively associated with all 3 anthropometric outcomes; a second PC (PC2: zinc, copper, and selenium intakes) was associated with WAZ and LAZ but not HCAZ.

CONCLUSIONS

Breast milk may be inadequate in selected minerals and trace elements where higher estimated intakes were associated with greater infant growth.

Correlation between hemoglobin levels of mothers and children on exclusive breastfeeding in the first six months of life

OBJECTIVE

To evaluate the correlation between hemoglobin levels of mothers and their children on exclusive breastfeeding in the first six months of life.

METHODS

Cross-sectional study with 221 binomials (mother-child) enrolled in a breastfeeding support program, who were stratified into six groups according to the children's age group. The sample consisted of children born at term with normal weight, with no neonatal complications and whose mothers did not have anemia or infectious disease at the time of data collection. Interviews were carried out with the mothers, blood was collected by peripheral venipuncture from mothers and children, and children's anthropometric data were assessed. Pearson's correlation coefficients between the hemoglobin levels of mothers and children were calculated. Six multiple linear regression models were adjusted with regression coefficient estimates, considering as statistically significant associations with p≤0.05.

RESULTS

The correlation coefficients of hemoglobin levels of mothers and children ranged from 0.253, at three months, to 0.601, at five months. The hemoglobin level of mothers was correlated with the hemoglobin level of their children at four months (r=0.578) and at five months (r=0.601). In the adjusted multiple linear regression, the regression coefficients were higher at four months (β=1.134; p=0.002) and at five months (β=0.845; p<0.001).

CONCLUSION

These findings allow for the conclusion that there is a correlation between the hemoglobin of mothers and the hemoglobin of their children on exclusive breastfeeding in the first six months of life.

Zinc and infant nutrition

Zinc is essential for a wide variety of cellular processes in all cells. It is a critical dietary nutrient, particularly in the early stages of life. In the early neonatal period, adequate sources of zinc can be obtained from breast milk. In rare circumstances, the mammary gland produces zinc deficient milk that is potentially lethal for exclusively breast-fed infants. This can be overcome by zinc supplementation to the infant. Alterations to key zinc transporters provide insights into the mechanisms of cellular zinc homeostasis. The bioavailability of zinc in food depends on the presence of constituents that may complex zinc. In many countries, zinc deficiency is a major health issue due to poor nourishment. Young children are particularly affected. Zinc deficiency can impair immune function and contributes to the global burden of infectious diseases including diarrhoea, pneumonia and malaria. Furthermore, zinc deficiency may extend its influence across generations by inducing epigenetic effects that alter the expression of genes. This review discusses the significance of adequate zinc nutrition in infants, factors that influence zinc nutrition, the consequences of zinc deficiency, including its contribution to the global burden of disease, and addresses some of the knowledge gaps in zinc biology.

Supplementation with multiple micronutrients for breastfeeding women for improving outcomes for the mother and baby

BACKGROUND

Globally, more than two billion people are estimated to be deficient in key vitamins and minerals, particularly iodine, iron and zinc. The majority of these people live in low-income settings and are typically deficient in more than one micronutrient. However, micronutrient deficiency among breastfeeding mothers and their infants also remains an issue in high-income settings, specifically among women who avoid meat and/or milk, women who may lack sufficient supplies of vitamin B12 and vitamin D, and/or women who are iron-deficient. Young children, pregnant and lactating women are particularly vulnerable to micronutrient deficiencies. They not only have a relatively greater need for vitamins and minerals because of their physiological state, but are also more susceptible to the harmful consequences of deficiencies. Multiple-micronutrient supplementation might be an option to solve these problems.

OBJECTIVES

The objective of this review was to evaluate the effects of multiple-micronutrient supplementation in breastfeeding mothers on maternal and infant outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2015) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials of multiple-micronutrient supplementation of three or more micronutrients versus placebo, no supplementation or supplementation with two or fewer micronutrients, irrespective of dosage of micronutrients, in breastfeeding mothers.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.

MAIN RESULTS

We found no studies that compared multiple-micronutrient supplementation (with three or more micronutrients) versus supplementation with two or fewer micronutrients.Two small studies (involving a total of 52 women) were included. One study compared multiple micronutrients with placebo and the other study compared multiple micronutrients with a group who received no supplementation. The studies were carried out in Brazil (36 adolescent mothers) and the USA (16 women) and included women with a low socioeconomic status. A lack of information in the study reports meant that risk of bias could not be adequately assessed (unclear risk of bias for many domains). There were no quantitative data for any of this review's outcomes so meta-analysis was not possible.Neither of the studies reported on the primary outcomes of interest in this review: maternal morbidity (febrile illness, respiratory tract infection, diarrhoea), adverse effects of micronutrients within three days of receiving the supplement, infant mortality (defined as a child dying before completing the first year of age).One study reported qualitatively on maternal anaemia (a secondary outcome of this review) - the study found that multiple-micronutrient supplementation was effective for recuperating from anaemia but there were no data for inclusion in our analyses. Maternal satisfaction was not reported in the included studies. Similarly, none of this review's infant secondary outcomes were reported in the included studies: clinical micronutrient deficiency; morbidity episodes (febrile illness, respiratory tract infection, diarrhoea, other), adverse effects of micronutrients within three days of receiving the supplement.

AUTHORS' CONCLUSIONS

We found no evidence to quantitatively assess the effectiveness of multiple-micronutrient supplementation in improving health outcomes in mother and baby. The results of this review are limited by the small numbers of studies available, small sample sizes and the studies not reporting on the outcomes of interest in this review. There is no evidence to evaluate potential adverse effects of multiple-micronutrient supplements, particularly excess dosages.There is a need for high-quality studies to assess the effectiveness and safety of multiple-micronutrient supplementation for breastfeeding women for improving outcomes for the mother and her baby. Further research should focus on whether multiple-micronutrient supplementation during lactation compared with none, a placebo or supplementation with fewer than two micronutrients is beneficial to maternal and infant health outcomes. Future studies should collect data on outcomes beyond micronutrient concentrations, for example: maternal and infant morbidity, adverse effects, maternal satisfaction, the risks of excess supplementation, and potential adverse interactions between the micronutrients and the other outcomes. This would help to bridge the gap between research on intermediary outcomes and health outcomes in order to develop sound policy in this field. Future studies could more precisely assess a variety of multiple-micronutrient combinations and different dosages and look at how these affect maternal and infant health outcomes. Larger studies with longer follow-up would improve the quality of studies and provide stronger evidence. In most of the included studies, bias could not be adequately assessed due to lack of information, therefore attention should be given to adequate methods of randomisation and allocation concealment, adequate methods of blinding of the participants, providers and the outcome assessors to improve the methodological quality of studies in this field.

Association of Maternal Diet With Zinc, Copper, and Iron Concentrations in Transitional Human Milk Produced by Korean Mothers

The aims of this study were to evaluate zinc, copper, and iron concentrations in the transitory milk of Korean lactating mothers and to investigate the relationship between these concentrations and maternal diet. Human milk samples were collected between 5 and 15 days postpartum from 96 healthy, lactating mothers in postpartum care centers in Seoul, Korea. Dietary intake during lactation was determined based on a 3-day dietary record. The mean zinc, copper, and iron concentrations in the human milk samples collected were 3.88 ± 1.74 mg/L, 0.69 ± 0.25 mg/L, and 5.85 ± 8.53 mg/L, respectively. The mothers who consumed alcoholic beverages during pregnancy had tended to have lower concentrations of zinc and copper, as well as significantly lower concentrations of iron, in their milk (p < 0.047). In contrast, the mothers who took daily supplements had much higher iron concentrations in their milk (p = 0.002). Dietary intakes of zinc, copper, and iron during lactation did not affect the concentrations of zinc, copper, and iron in the milk samples analyzed. Intakes of vitamin C, selenium, and iodine were associated with the concentration of copper in the milk samples analyzed, and consumption of food categorized as 'meat and meat products' was positively associated with the concentration of zinc. Consumption of rice was the top contributor to the concentrations of all three minerals. In conclusion, associations between maternal diet and nutrient concentrations in transitory human milk can provide useful information, particularly in regard to infant growth.

Optimisation of Direct Copper Determination in Human Breast Milk Without Digestion by Zeeman Graphite Furnace Atomic Absorption Spectrophotometry with Two Chemical Modifiers

Milk is an important food in the human diet, and copper (Cu) in human milk is indispensable to children's normal growth and development. It is consequently important that Cu deficiency, occurring in malnourished women or in malabsorption following bariatric surgery, be prevented. The objective of this work is to provide hospital-based paediatricians with a tool enabling rapid measurement of Cu in human breast milk through a technique that biology laboratories can easily apply. Using electrothermal atomic absorption spectrophotometry with Zeeman correction, we have optimized this method with two chemical modifiers and without digestion for analytical procedure. Detection limits and quantification limits for Cu in human milk were found to be 0.077 and 0.26 μmol/L, respectively. Within-run (n = 30) and between-run (n = 15) variations in a pool of human milk samples were 1.50 and 3.62%, respectively. Average recoveries ranged from 98.67 to 100.61%. The reliability of this method was also confirmed by analysing certified reference material (10%). In breast milk samples collected from 100 lactating mothers, Cu mean (±1 SD) was 7.09 ± 1.60 μmol/L. In conclusion, with minimal preparation and quick determination, the method proposed is suitable for measurement of Cu in human breast milk.

Anaemia prevalence and associated factors among lactating mothers in Ethiopia: evidence from the 2005 and 2011 demographic and health surveys

OBJECTIVE

To identify factors associated with anaemia in lactating mothers in Ethiopia.

DESIGN

A cross-sectional secondary analysis of data pooled from two rounds of the 2005 and 2011 Ethiopian Demographic and Health Survey (EDHS) was used. A multivariate logistic regression model was applied to determine the factors associated with anaemia.

POPULATION

A total of 7332 lactating mothers (2285 from EDHS 2005 and 5047 from EDHS 2011) were included from 11 administrative states of Ethiopia.

MAIN OUTCOME MEASURES

Lactating mothers considered anaemic if haemoglobin level <12 g/dL.

RESULTS

The overall prevalence of anaemia among lactating mothers was 22.1% (95% CI 21.13% to 23.03%). The highest prevalence was 48.7% (95% CI 40.80% to 56.62%) found in the Somali region, followed by 43.8% (95% CI 31.83% to 56.87%) in the Afar region. The multivariate statistical model showed that having a husband who had attended primary education (adjusted OR (AOR) 0.79; 95% CI 0.68 to 0.91), working during the 12 months preceding the survey (AOR 0.71; 95% CI 0.63 to 0.80), having a normal maternal body mass index (18.5-24.99 kg/m(2)) (AOR 0.78; 95% CI 0.68 to 0.89), being in the middle wealth quintile (AOR 0.83; 95% CI 0.71 to 0.98) or rich wealth quintile (AOR 0.83; 95% CI 0.70 to 0.98), having ever used family planning (AOR 0.68; 95% CI 0.57 to 0.80), having attended antenatal care (ANC) for the indexed pregnancy four times or more (AOR 0.73; 95% CI 0.59 to 0.91), having experienced time variation between the two surveys (AOR 0.73; 95% CI 0.64 to 0.85), and breastfeeding for 2 years (AOR 0.76; 95% CI 0.66 to 0.87) were factors associated with lower odds of having anaemia in lactating mothers.

CONCLUSIONS

Anaemia is highly prevalent among lactating mothers, particularly in the pastoralist communities of Somali and Afar. Promoting partner education, improving maternal nutritional status, and creating behavioural change to use family planning and ANC services at health facilities are recommended interventions to reduce the prevalence of anaemia among lactating mothers in Ethiopia.

A pilot study of synbiotic supplementation on breast milk mineral concentrations and growth of exclusively breast fed infants

Despite the crucial role of breast milk mineral contents for health and growth of the infants, they decrease with the duration of lactation. So, this pilot study aimed to determine the effects of synbiotic supplementation on breast milk mineral composition and infants' growth. In this pilot, randomized, double-blind, placebo-controlled trial, 57 lactating mothers were randomly divided into two groups to receive a daily supplement of synbiotic (n=30) or a placebo (n=27) for 30 days. Breast milk zinc, copper, Iron, magnesium and, calcium concentrations were determined by flame atomic absorption spectrometry. Weight for age Z-score (WAZ) and height for age Z-score (HAZ) were assessed for infants. Dietary intake was collected from lactating women using the 24-h recall method. Data analyses were carried out using nutritionist IV, Epi Info and SPSS soft wares. Synbiotic supplementation led to an insignificant increase of the mean breast milk levels of zinc (from 2.44±0.65 to 2.55±0.55mgL(-1)), copper (from 0.35±0.24 to 0.40±0.26mgL(-1)), iron (from 0.28±0.42 to 0.31±0.38mgL(-1)), magnesium (from 17.14±1.35 to 17.17±1.09mgL(-1)), and calcium (from 189±25.3 to 189.9±21.7mgL(-1)); whilst in the placebo group, these variables decreased significantly (P=0.001). The observed changes between two groups were statistically significant (P<0.05). Although WAZ and HAZ of infants increased slightly in the supplemented group (from 1.19±0.79 to 1.20±0.69 and 0.36±0.86 to 0.37±0.85 respectively), these two parameters decreased in the placebo group which was significant only for WAZ (P=0.01). Moreover, no significant association was found between mineral intake and breast milk mineral contents. It seems, synbiotic supplementation may have positive effects on breast milk mineral contents.

[Breastfeeding: health benefits for child and mother]

The prevalence of breastfeeding in France is one of the lowest in Europe: 65% of infants born in France in 2010 were breastfed when leaving the maternity ward. Exclusive breastfeeding allows normal growth until at least 6 months of age, and can be prolonged until the age of 2 years or more, provided that complementary feeding is started after 6 months. Breast milk contains hormones, growth factors, cytokines, immunocompetent cells, etc., and has many biological properties. The composition of breast milk is influenced by gestational and postnatal age, as well as by the moment of the feed. Breastfeeding is associated with slightly enhanced performance on tests of cognitive development. Exclusive breastfeeding for at least 3 months is associated with a lower incidence and severity of diarrhoea, otitis media and respiratory infection. Exclusive breastfeeding for at least 4 months is associated with a lower incidence of allergic disease (asthma, atopic dermatitis) during the first 2 to 3 years of life in at-risk infants (infants with at least one first-degree relative presenting with allergy). Breastfeeding is also associated with a lower incidence of obesity during childhood and adolescence, as well as with a lower blood pressure and cholesterolemia in adulthood. However, no beneficial effect of breastfeeding on cardiovascular morbidity and mortality has been shown. Maternal infection with hepatitis B and C virus is not a contraindication to breastfeeding, as opposed to HIV infection and galactosemia. A supplementation with vitamin D and K is necessary in the breastfed infant. Very few medications contraindicate breastfeeding. Premature babies can be breastfed and/or receive mother's milk and/or bank milk, provided they receive energy, protein and mineral supplements. Return to prepregnancy weight is earlier in breastfeeding mothers during the 6 months following delivery. Breastfeeding is also associated with a decreased risk of breast and ovarian cancer in the premenopausal period, and of osteoporosis in the postmenopausal period.

Maternal intake of supplemental iron and risk of autism spectrum disorder

Iron deficiency affects 40%-50% of pregnancies. Iron is critical for early neurodevelopmental processes that are dysregulated in autism spectrum disorder (ASD). We examined maternal iron intake in relation to ASD risk in California-born children enrolled in a population-based case-control study (the Childhood Autism Risks from Genetics and the Environment (CHARGE) Study) from 2003 to 2009 with a diagnosis of ASD (n = 520) or typical development (n = 346) that was clinically confirmed using standardized assessments. Mean maternal daily iron intake was quantified on the basis of frequency, dose, and brands of supplements and cereals consumed each month from 3 months before pregnancy through the end of pregnancy and during breastfeeding (the index period), as reported in parental interviews. Mothers of cases were less likely to report taking iron-specific supplements during the index period (adjusted odds ratio = 0.63, 95% confidence interval: 0.44, 0.91), and they had a lower mean daily iron intake (51.7 (standard deviation, 34.0) mg/day) than mothers of controls (57.1 (standard deviation, 36.6) mg/day; P = 0.03). The highest quintile of iron intake during the index period was associated with reduced ASD risk compared with the lowest (adjusted odds ratio = 0.49, 95% confidence interval: 0.29, 0.82), especially during breastfeeding. Low iron intake significantly interacted with advanced maternal age and metabolic conditions; combined exposures were associated with a 5-fold increased ASD risk. Further studies of this link between maternal supplemental iron and ASD are needed to inform ASD prevention strategies.

Changes in soluble transferrin receptor and hemoglobin concentrations in Malawian mothers are associated with those values in their exclusively breastfed, HIV-exposed infants

Infant iron status at birth is influenced by maternal iron status during pregnancy; however, there are limited data on the extent to which maternal iron status is associated with infant iron status during exclusive breastfeeding. We evaluated how maternal and infant hemoglobin and iron status [soluble transferrin receptors (TfR) and ferritin] were related during exclusive breastfeeding in HIV-infected women and their infants. The Breastfeeding, Antiretrovirals, and Nutrition Study was a randomized controlled trial in Lilongwe, Malawi, in which HIV-infected women were assigned with a 2 × 3 factorial design to a lipid-based nutrient supplement (LNS), or no LNS, and maternal, infant, or no antiretroviral drug, and followed for 24 wk. Longitudinal models were used to relate postpartum maternal hemoglobin (n = 1926) to concurrently measured infant hemoglobin, adjusting for initial infant hemoglobin values. In a subsample, change in infant iron status (hemoglobin, log ferritin, log TfR) between 2 (n = 352) or 6 wk (n = 167) and 24 wk (n = 519) was regressed on corresponding change in the maternal indicator, adjusting for 2 or 6 wk values. A 1 g/L higher maternal hemoglobin at 12, 18, and 24 wk was associated with a 0.06 g/L (P = 0.01), 0.10 g/L (P < 0.001), and 0.06 g/L (P = 0.01), respectively, higher infant hemoglobin. In the subsample, a reduction in maternal log TfR and an increase in hemoglobin from initial measurement to 24 wk were associated with the same pattern in infant values (log TfR β = -0.18 mg/L, P < 0.001; hemoglobin β = 0.13 g/L, P = 0.01). Given the observed influence of maternal and initial infant values, optimizing maternal iron status in pregnancy and postpartum is important to protect infant iron status. This trial was registered at clinicaltrials.gov as NCT00164736.

Nutrient transport in the mammary gland: calcium, trace minerals and water soluble vitamins

Milk nutrients are secreted by epithelial cells in the alveoli of the mammary gland by several complex and highly coordinated systems. Many of these nutrients are transported from the blood to the milk via transcellular pathways that involve the concerted activity of transport proteins on the apical and basolateral membranes of mammary epithelial cells. In this review, we focus on transport mechanisms that contribute to the secretion of calcium, trace minerals and water soluble vitamins into milk with particular focus on the role of transporters of the SLC series as well as calcium transport proteins (ion channels and pumps). Numerous members of the SLC family are involved in the regulation of essential nutrients in the milk, such as the divalent metal transporter-1 (SLC11A2), ferroportin-1 (SLC40A1) and the copper transporter CTR1 (SLC31A1). A deeper understanding of the physiology and pathophysiology of these transporters will be of great value for drug discovery and treatment of breast diseases.

Cadmium, lead, copper and zinc in breast milk in Poland

Mother's milk is the fundamental food for infants. It contains proteins, fat, carbohydrates and essential metals which are necessary to ensure correct functioning of the organism. Unfortunately, breast milk is a potential source of toxic metals, which are dangerous for a baby. In Poland, previous research concerning the content of metals in breast milk was very scarce or its results were unavailable. The present study aimed at assessing the content of Cd, Pb, Cu and Zn in human breast milk, as well as estimating the mean weekly intake of these metals by breast-fed infants from Poland. The average concentrations of Cd, Pb, Cu and Zn were 2.114 μg/l, 6.331 μg/l, 0.137 mg/l and 1.623 mg/l, respectively. The admissible levels of supply of these toxic metals has not been exceeded, but their contents were high, particularly in 6-month-old infants (nearly 85 % TWI for Cd and nearly 70 % BMDL₀₁ for Pb). The daily intake of Cu and Zn did not fully satisfy the infant's requirements determined by Polish standards and WHO recommendations. Since the lifestyle of lactating women has a direct influence on the content of these elements in breast milk, women should be educated in this respect with particular focus on eliminating tobacco smoking, both by breastfeeding mothers and by their direct environment.

Iron requirements of infants and toddlers

Iron deficiency (ID) is the most common micronutrient deficiency worldwide and young children are a special risk group because their rapid growth leads to high iron requirements. Risk factors associated with a higher prevalence of ID anemia (IDA) include low birth weight, high cow's-milk intake, low intake of iron-rich complementary foods, low socioeconomic status, and immigrant status. The aim of this position paper was to review the field and provide recommendations regarding iron requirements in infants and toddlers, including those of moderately or marginally low birth weight. There is no evidence that iron supplementation of pregnant women improves iron status in their offspring in a European setting. Delayed cord clamping reduces the risk of ID. There is insufficient evidence to support general iron supplementation of healthy European infants and toddlers of normal birth weight. Formula-fed infants up to 6 months of age should receive iron-fortified infant formula, with an iron content of 4 to 8 mg/L (0.6-1.2 mg(-1) · kg(-1) · day(-1)). Marginally low-birth-weight infants (2000-2500 g) should receive iron supplements of 1-2 mg(-1) · kg(-1) · day(-1). Follow-on formulas should be iron-fortified; however, there is not enough evidence to determine the optimal iron concentration in follow-on formula. From the age of 6 months, all infants and toddlers should receive iron-rich (complementary) foods, including meat products and/or iron-fortified foods. Unmodified cow's milk should not be fed as the main milk drink to infants before the age of 12 months and intake should be limited to <500 mL/day in toddlers. It is important to ensure that this dietary advice reaches high-risk groups such as socioeconomically disadvantaged families and immigrant families.

Iron supplementation in pregnancy and breastfeeding and iron, copper and zinc status of lactating women from a human milk bank

This study evaluated the influence of iron supplementation in pregnancy and breastfeeding on iron status of lactating women from a Brazilian Human Milk Bank. Blood and mature breast milk samples were collected from 145 women for assessment of iron status, as well as copper and zinc status. Haemoglobin, serum iron and ferritin were determined, respectively, by electronic counting, colorimetry and chemiluminescence. Transferrin and ceruloplasmin were analysed by nephelometry. Serum copper and zinc were measured by atomic absorption spectrophotometry, and serum alkaline phosphatase was measured by a colorimetric method. Iron, zinc and copper in breast milk were determined by spectrometry. Mean values of iron, copper and zinc (blood and breast milk) were compared by ANOVA, followed by Tukey's test. Iron supplementation was beneficial to prevent anaemia in pregnancy but not effective to treat anaemia. During breastfeeding, iron supplementation had a negative effect on maternal copper status, confirming an interaction between these micronutrients.

Effect of increasing concentrations of zinc on the absorption of iron from iron-fortified milk

The cofortification of milk with iron (Fe) and zinc (Zn) is a strategy used to prevent these deficiencies during childhood. Given that Zn can negatively interact with iron in aqueous solutions, the objective of the present study was to determine the effect of Zn on Fe absorption of milk fortified with Fe and Zn. Twenty-eight women between 33 and 47 years of age, with contraception and a negative pregnancy test, participated in one of two absorption studies. They received on four different days, after an overnight fast, 200 mL of milk (26 % fat) fortified with 10 mg Fe/L, as (A) ferrous sulfate, or the same milk but with graded doses of added Zn, as Zn sulfate of (B) 5, (C) 10, and (D) 20 mg/L (study 1, n = 15). In study 2 (n = 13), subjects received the same milk formulations, but these were also fortified with ascorbic acid (70 mg/L). Milk was labeled with radioisotopes ⁵⁹Fe or ⁵⁵Fe, and the absorption of iron was measured by erythrocyte incorporation of radioactive Fe. The geometric mean and range of ±1 SD of Fe absorption in study 1 were as follows: formula A = 6.0 % (2.8-13.0 %); B = 6.7 % (3.3-13.6 %); C = 5.4 % (2.2-13.2 %); and D = 5.2 % (2.8-10.0 %) (ANOVA for repeated measures, not significant). For study 2, data are as follows: 8.2 % (3.6-18.7 %); B = 6.4 % (2.5-16.4 %); C = 7.7 % (3.2-18.9 %); and D = 5.2 (1.8-14.8 %) (ANOVA for repeated measures, not significant). In conclusion, according to the results from this study, it appears that the addition of zinc up to 20 mg/L does not significantly inhibit iron absorption from milk fortified with 10 mg/L of iron.

Polymorphisms of SLC30A2 and selected perinatal factors associated with low milk zinc in Chinese breastfeeding women

The variability of breast-milk zinc concentration is high among breastfeeding women, and it is known to be independent of dietary zinc intake. As a result, transient neonatal zinc deficiency is not rare in the breastfed infants due to low milk zinc concentration in their breastfeeding mothers. Up to now, SLC30A2 has been documented the only candidate gene showing correlation with human milk zinc trait. In this study, 750 breastfeeding women were recruited and 10ml foremilk was collected on 42nd postpartum day. The milk zinc concentration was measured, and genomic DNA was isolated from breast-milk. Direct sequencing and Taqman assay were used to identify the SLC30A2 polymorphisms associated with low-milk-zinc. Subsequently, the factors associated with breast-milk zinc were investigated using regression model. The correlation study showed that SLC30A2/-697G>T and SLC30A2/1031A>G polymorphisms were associated with low-milk-zinc in our subjects. These two polymorphisms explained 3.23% of total variance in milk zinc level. For non-genetic variables, the obese breastfeeding women (BMI>25) secreted less zinc into their breast-milk. The variation of milk zinc was independent of pregnant age, birth weight, infant gender, cesarean delivery, preterm delivery and vitamin D supplementation. In conclusion, our results indicated that -697G>T and 1031A>G polymorphisms in the SLC30A2 gene may be associated with low-milk-zinc in Chinese breastfeeding women. Maternal BMI is significantly correlated with milk zinc level in negative manner. Our study demonstrated that both genetic and non-genetic factors could modulate milk zinc level.

Maternal zinc intakes and homeostatic adjustments during pregnancy and lactation

Zinc plays critical roles during embryogenesis, fetal growth, and milk secretion, which increase the zinc need for pregnancy and lactation. Increased needs can be met by increasing the dietary zinc intake, along with making homeostatic adjustments in zinc utilization. Potential homeostatic adjustments include changes in circulating zinc, increased zinc absorption, decreased zinc losses, and changes in whole body zinc kinetics. Although severe zinc deficiency during pregnancy has devastating effects, systematic reviews and meta-analysis of the effect of maternal zinc supplementation on pregnancy outcomes have consistently shown a limited benefit. We hypothesize, therefore, that zinc homeostatic adjustments during pregnancy and lactation improve zinc utilization sufficiently to provide the increased zinc needs in these stages and, therefore, mitigate immediate detrimental effects due to a low zinc intake. The specific questions addressed are the following: How is zinc utilization altered during pregnancy and lactation? Are those homeostatic adjustments influenced by maternal zinc status, dietary zinc, or zinc supplementation? These questions are addressed by critically reviewing results from published human studies on zinc homeostasis during pregnancy and lactation carried out in different populations worldwide.

Lead levels in breast milk, blood plasma and intelligence quotient: a health hazard for women and infants

Lead levels in human breast milk and blood plasma or serum were analyzed and qualitatively their intelligence quotient (I.Q.) studied. Samples at different stages of lactation, from 5 days to 51 weeks post partum, were collected from 25 healthy breast-feeding mothers in Ranipet Industrial area of Vellore district of Tamil Nadu and from 25 lactating mothers in the non-industrial areas of the same district. The samples from mothers in non-industrial area showed lower lead levels ranging from 5 to 25 μg/L whereas samples from mothers in industrial area showed higher lead levels ranging between 15 and 44.5 μg/L. It was generally noticed that the lactating mothers from industrial area have lower I.Q. levels compared to mothers from non-industrial area.

Cord blood iron profile and breast milk micronutrients in maternal iron deficiency anemia

BACKGROUND

Micronutrient deficiencies among pregnant women are widespread in low-income countries, including Egypt. Iron deficiency anemia (IDA) is the most frequent nutritional deficiency during pregnancy, with an impact on maternal and fetal morbidity and mortality. We aimed to evaluate the effect of maternal IDA and nutritional status on birth anthropometry, cord blood iron profile and breast milk micronutrients in 50 anemic (hemoglobin <11 g/dl) and 30 healthy pregnant women.

PROCEDURE

Maternal and neonatal anthropometric measures were recorded. Hemoglobin, red blood cell (RBC) indices, and indices of iron nutriture were measured in maternal and cord blood. Breast milk minerals; iron, copper, zinc, calcium, and magnesium were assessed.

RESULTS

Hemoglobin, RBC indices, and iron profile showed significant differences in the neonates born to anemic mothers compared to controls, particularly in moderate to severe anemia and linear correlations with maternal hemoglobin, iron, and ferritin levels were found (P < 0.01). Anthropometric measurements of anemic mothers and their neonates were positively correlated (P < 0.05). Breast milk micronutrients were significantly reduced in all anemic mothers showing significant relations with maternal serum iron (P < 0.01).

CONCLUSIONS

Maternal IDA wields a significant influence on maternal and fetal nutritional status. IDA during pregnancy adversely affects both cord blood iron and breast milk mineral status, particularly in moderate to severe anemia and concurrent micronutrient deficiencies occur in maternal IDA. Further investigations including larger population of pregnant women with severe anemia are needed to verify the nutritional interrelation between maternal anemia and breast milk mineral status.

Maternal body mass index, dietary intake and socioeconomic status: differential effects on breast milk zinc, copper and iron content

BACKGROUND

As breast milk micronutrients content are essential for health and growth of the infants, this study was conducted to determine the breast milk zinc, copper and iron concen-trations and their possible correlations with maternal nutritional status, dietary intakes as well as socioeconomic status.

METHODS

Breast milk samples and information on maternal anthropometric characteristics and dietary intake were collected from 90 Iranian lactating women with 3 different socioeco-nomic status who exclusively breastfed their infants. Concentrations of trace elements were analyzed using atomic absorption spectrophotometry. Nutritionist III program, Multiple Re-gression and ANOVA test were used for data analyses.

RESULTS

The mean milk zinc, copper, and iron concentrations were 1.93 ± 0.71, 0.58 ± 0.32, and 0.81 ± 0.2 mg/l, respectively. In all three SES groups only zinc mean level was lower than the recommended range. A significant difference was observed in breast milk zinc, copper and iron concentration between high and low SES groups (Zn (P<0.001), Cu (P<0.001) and Fe (P<0.044)) and also moderate and low SES groups (Zn (P<0.03), Cu (P<0.001) and Fe (P<0.049)). After adjusting for maternal body mass index (BMI), socioeconomic status, mean dietary energy, zinc, copper, and iron intakes, there was a negative and significant association between maternal age and breast milk zinc (β=-0.28, P<0.034), copper (β=-0.18, P<0.048), and iron (β=-0.22, P<0.04) concentrations.

CONCLUSION

In low socioeconomic group with lower mean age, breast milk mineral levels were higher than others and there was no significant correlation between mineral levels and dietary intake. Hence it is supposed that maternal age may be better predictor of breast milk mineral levels.

In which regions is breast-feeding safer from the impact of toxic elements from the environment?

Owing to its unique nutritional and immunological characteristics, breast milk is the most important food source for infants. But, children are at greater risk for exposure to environmental toxicants from breast milk. The aim of this study was to evaluate the influence of environmental pollution on essential and toxic element contents of breast milk and determine the risky locations in our population. This study was conducted on women who were breastfeeding (n=90). Milk samples were collected at three locations in Marmara region, Turkey: highly industrialized region highly affected by pollution, urbanized region moderately and rural area that is affected little. Breast milk samples (5 mL) were collected at approximately one month postpartum (mature milk). The concentrations of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in milk samples were compared to the milk samples coming from different locations.Lead, cadmium, nickel, chromium, iron and manganese levels in the breast milk are highest and engrossing especially in rural areas compared to the other regions but cobalt, copper, zinc levels are highest in highly industrial areas. The levels of essential and toxic elements in breast milk can vary in different regions. The levels presented in our study are above some countries' data albeit not at toxic levels. Because of global effects, environmental pollution is not the problem for industrializing regions only. Rural area also may not be safe for breastfeed babies.

Micronutrient status in lactating mothers before and after introduction of fortified flour: cross-sectional surveys in Maela refugee camp

Background

Deficiency of micronutrients is common in refugee populations.

Objectives

Identify deficiencies and whether provided supplements and wheat flour fortified with 10 micronutrients impacts upon status among breast-feeding women from Maela refugee camp.

Methods

Two sequential cross-sectional studies were conducted in different groups of lactating mothers at 12 weeks postpartum. The first survey was before and the second 4–5 months after micronutrient fortified flour (MFF) had been provided to the camp (in addition to the regular food basket). Iron status and micronutrients were measured in serum, whole blood, and in breast milk samples.

Results

Iron and zinc deficiency and anemia were highly prevalent while low serum retinol and thiamine deficiency were rarely detected. Iron and zinc deficiency were associated with anemia, and their proportions were significantly lower after the introduction of MFF (21 vs. 35% with soluble transferrin receptor (sTfR) >8.5 mg/L, P = 0.042, and 50 vs. 73% with serum zinc <0.66 mg/L, P = 0.001). Serum sTfR, whole-blood thiamine diphosphate (TDP) and serum β-carotene were significant predictors (P < 0.001) of milk iron, thiamine and β-carotene, respectively. Lower prevalence of iron deficiency in the MFF group was associated with significantly higher iron and thiamine in breast milk.

Conclusions

High whole-blood TDP and breast milk thiamine reflected good compliance to provided thiamine; high prevalence of iron deficiency suggested insufficient dietary iron and low acceptance to ferrous sulfate supplements. MFF as an additional food ration in Maela refugee camp seemed to have an effect in reducing both iron and zinc deficiency postpartum.