Toxic and essential trace elements in human milk from Greek lactating women: association with dietary habits and other factors

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.

Exposure to lead and mercury through breastfeeding during the first month of life: A CHECK cohort study

Mercury and lead are naturally occurring toxicants and are responsible for various health issues including neurobehavioral and developmental disorders. Because of crucial synchronized developmental processes occurring at the early stage of life, infancy and childhood are considered as among the most susceptible windows to the exposure to these metals. Breastmilk is often the only source of nutrition during the first months of life. As breastmilk can be contaminated with these metals, breastfeeding may serve as a significant route of heavy metal exposure among infants. In order to understand current levels of exposure to mercury and lead through breastfeeding, and their associated risks, a total of 157 lactating mothers were recruited from Children's Health and Environmental Chemicals of Korea (CHECK) cohort, and breastmilk samples were collected at 15 and 30days after delivery (n=207). Mercury was detected from 100% of breastmilk with a median concentration of 0.59μg/L, and lead was detected in 77% of the samples with a median at 4.71μg/L. Higher concentrations of lead were found in the 30- day breastmilk than in the 15-day. Up to 45% of the breastmilk samples exceeded the normal range of the breastmilk lead suggested by WHO. Based on Monte Carlo simulation, about 71% of 15days old infants and 56% of 30days old infants were estimated at risk due to lead exposure through breastfeeding. Considering vulnerability of infants and well-known neurological toxicity of these metals, further studies to identify major exposure sources that contribute the lead concentration in breastmilk and health implication of early life stage exposure to lead among the breastfed infants are warranted.

Lead, cadmium and arsenic in human milk and their socio-demographic and lifestyle determinants in Lebanon

INTRODUCTION

Exposure of newborns to toxic metals is of special interest due to their reported contamination in breast milk and potential harm. The aim of this study was to assess the occurrence and factors associated with lead, cadmium and arsenic contamination in breast milk collected from lactating mothers in Lebanon.

METHODS

A total of 74 breast milk samples were collected from primaparas according to guidelines set by the World Health Organization. A survey was administered to determine the demographic and anthropometric characteristics of participating lactating mothers. Dietary habits were assessed using a semi-quantitative food frequency questionnaire. The milk samples were analyzed for the presence of arsenic, cadmium and lead using microwave-assisted digestion and atomic absorption spectrophotometry.

RESULTS

Arsenic contamination was found in 63.51% of breast milk samples (mean 2.36 ± 1.95 μg/L) whereas cadmium and lead were detected in 40.54% and 67.61% of samples respectively (means 0.87 ± 1.18 μg/L and 18.18 ± 13.31 μg/L). Regression analysis indicated that arsenic contamination was associated with cereal and fish intake (p = 0.013 and p = 0.042 respectively). Residence near cultivation activities (p = 0.008), smoking status before pregnancy (p = 0.046), potato consumption (p = 0.046) and education level (p = 0.041) were associated with lead contamination. Cadmium contamination was significantly associated with random smoke exposure (p = 0.002).

CONCLUSION

Our study is the first in Lebanon to report toxic metal contamination in breast milk. Although estimated weekly infant intake of these metals from breast milk was found to be lower than the limit set by international guidelines, our results highlight the need for developing strategies to protect infants from exposure to these hazardous substances.

Relation between polyphenols, malondialdehyde, antioxidant capacity, lactate dehydrogenase and toxic elements in human colostrum milk

The present study investigated the interrelationships between the concentration of total polyphenols (TP), malondialdehyde (MDA), total antioxidant capacity (TAC), lactate dehydrogenase activity (LDH) and content of toxic elements (Al, As, Cd, Ni, Pb) in human colostrum milk (n = 75), and further assessed their potential association with maternal lifestyle characteristics. As and Cd were always below detection limits while Al, Ni and Pb were found at the level of 89.7, 6.2 and 1.3 μg L^-1, respectively. Concentrations of TP and MDA, in the studied group were 46.91 ± 21.25 mg GAE L^-1 and 0.66 ± 0.27 nmol mL^-1, respectively, and were inversely correlated (Rs = -0.32; p < 0.01). TP and TAC increased significantly with maternal consumption of vegetables (Rs = 0.25 and Rs = 0.37, respectively; p < 0.05). Concentration of Al was positively correlated with MDA (Rs = 0.21; p < 0.01) and negatively with TP (Rs = -0.28; p < 0.01). Positive correlation was also found between Pb and MDA (Rs = 0.32; p < 0.01). No association with place of living (urban/rural), women's age and former smoking were found for any studied milk parameter. The results add to the general understanding of factors influencing redox balance in milk and potentially affecting its quality.

Microplastic pollution in deposited urban dust, Tehran metropolis, Iran

Environmental pollutants such as microplastics have become a major concern over the last few decades. We investigated the presence, characteristics, and potential health risks of microplastic dust ingestion. The plastic load of 88 to 605 microplastics per 30 g dry dust with a dominance of black and yellow granule microplastics ranging in size from 250 to 500 μm was determined in 10 street dust samples using a binocular microscope. Fluorescence microscopy was found to be ineffective for detecting and counting plastic debris. Scanning electron microscopy, however, was useful for accurate detection of microplastic particles of different sizes, colors, and shapes (e.g., fiber, spherule, hexagonal, irregular polyhedron). Trace amounts of Al, Na, Ca, Mg, and Si, detected using energy dispersive X-ray spectroscopy, revealed additives of plastic polymers or adsorbed debris on microplastic surfaces. As a first step to estimate the adverse health effects of microplastics in street dust, the frequency of microplastic ingestion per day/year via ingestion of street dust was calculated. Considering exposure during outdoor activities and workspaces with high abundant microplastics as acute exposure, a mean of 3223 and 1063 microplastic particles per year is ingested by children and adults, respectively. Consequently, street dust is a potentially important source of microplastic contamination in the urban environment and control measures are required.

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.

Assessment of cadmium levels in human breast milk and the affecting factors: A systematic review, 1971-2014

BACKGROUND

This is a first systematic review summarizing 43 years of research from 36 countries for the assessment of cadmium in breast milk, a suitable matrix in human biomonitoring.

OBJECTIVES

To report from the published literature the levels of cadmium in breast milk, and the affecting factors causing increase in cadmium concentrations. In addition, to gather several quantitative data that might be useful to evaluate the international degrees of maternal and infant exposure.

METHODS

We reviewed the literature published between 1971 and 2014, available on Pubmed, Science Direct, and Google Scholar, reporting quantitative data about cadmium levels in human breast milk. Information about the aim of the study, name of the country, period of collection of samples, size of samples, sampling method, time of lactation, mother's age, area of residence, cadmium concentration, and other data were extracted.

RESULTS

Sixty-seven studies were selected and included in this systematic review. Some concentrations greatly exceed the limit set by the World Health Organization (WHO); however, about 50% of the studies had less than 1 µg/L cadmium concentration (recommended by the WHO); as well as many factors have shown their implication in breast milk contamination.

CONCLUSIONS

Breast milk is a pathway of maternal excretion of cadmium. It is also a biological indicator of the degree of environmental pollution and cadmium exposure of the lactating woman and the nourished infant. Therefore, preventive measures and continuous monitoring are necessary.

Zinc concentrations in human milk and infant serum during the first six months of lactation

Normal supply of zinc to the newborn via milk is essential for normal development. Using ICP-OES, we analyzed changes in the level of Zn in milk and infant serum in the neonatal period (Day 1 and Day 28 post partum) and at 6 months after delivery, in the cohort of 60 mothers and exclusively breastfed babies. Zn level in the serum showed increase (significant at 6 months) during this period (mg/mL): Day 1: 0.52±0.12; Day 28: 0.59±0.19; 6 months: 0.68±0.28. The concentration of Zn in the milk showed an opposite (decreasing) trend during the follow up: Day 1: 4.70±1.74mg/L; Day 28: 2.65±1.06; 6 months: 0.46±0.36. A significant negative correlation was established between serum and milk [Zn] at day 28 (R=-0.338; p=0.008), whereas a positive correlation was found at 6 months between these parameters (R=0.306; p=0.018). There was no significant correlation between [Zn] in the milk and serum and infants' body mass, mothers' age and mass at delivery. The level of Zn in the milk at 6 months of lactation is not sufficient to meet the recommended values. This implies that in Serbian population, Zn supplementation might be needed in the later phase of lactation.

The effect of the zinc concentration in breast milk on neonatal weight gain

The change in breast milk zinc (Zn) concentration in a feeding period during lactation may affect neonatal weight gain. The aim of this study was to determine how to change the Zn concentrations in breast milk during a feeding period in early and late lactation periods and identify the relationship between the differences in the Zn levels in breast milk during lactation and neonatal weight gain. Breast milk was collected in the early and late lactation periods with samples being obtained before (foremilk) and after (hindmilk) a feeding period. Then, we determined the Zn concentrations in the breast milk and measured the weight of the infants before and after the same feeding period. The study was composed of 37 newborns and their mothers. During the feeding period, the Zn concentrations in both the transitional and mature milk decreased significantly. During the lactation period, the Zn levels were markedly lower in only the hindmilk. The body weights of the infants both before and after feeding in the early lactation period were negatively correlated with the delta Zn concentration in the same period, but the delta body weights in the early lactation period were positively correlated with the Zn levels in the hindmilk in the same period. In addition, body weights before feeding in the late lactation period were also positively correlated with Zn levels in hindmilk in the early lactation period. This study suggests that the Zn concentrations in both the transitional and mature milk decreased, which suggests that changes in the Zn content of breast milk during lactation might play a role in the weight gain of healthy neonates.

Impact of ingredients on the elemental content of baby foods

The levels of the minerals: Ca, K, Mg, Na, P, and the trace elements: Cd, Cu, Fe, Mn, Ni, Pb, Se, Zn were determined in foods for 4-6, 7+ and 10+ months old babies in a brand available on the UK market. The mineral contents in the vegetarian meals for all the age groups were similar, in contrast, when compared to the non-vegetarian options, the Ca, Na and P levels were higher in the former. Both the trace elements and minerals levels in the 4-6months vegetarian meal were the lowest of all the products analysed. The Cu, Se and Zn levels in all the meals were comparable to those in mature human breast milk. Calculations of the following molar ratios: Zn:Cu, Fe:Zn, and Fe:Mn, pairs of elements that have been shown to interaction antagonistically, were higher in the vegetarian meals.

Assessment of Aflatoxin M1 and Heavy Metal Levels in Mothers Breast Milk in Famagusta, Cyprus

Breast milk contributes towards optimal nutrition for infants. However, studies showed that it can also contain different toxins and heavy metals, which reduce its health benefits. The aim of this study is to determine the level of contaminants such as aflatoxin M1 (AFM1), Pb, Cd, As, and Hg in breast milk samples from Famagusta, Cyprus. Correlations between moldy food consumption, smoking habits of the mothers, and contaminant levels in breast milk were also investigated. Breast milk samples from 50 lactating mothers in rural and urban areas of Famagusta District were analyzed for AFM1 by ELISA. Eighty percent of them were found to be contaminated with AFM1 with the mean measurement of 7.84 ± 1.72 ng/l. Socio-demographic status, moldy food consumption habits, and smoking status do not have any effect on the AFM1 levels observed in breast milk. Heavy metal levels in breast milk were examined by inductively coupled plasma mass spectrometry, and the mean measurements were1.19 ± 1.53 ppm for Pb, 0.73 ± 0.58 ppm for As, 0 ± 0.20 ppm for Hg, and 0.45 ± 0.23 ppm for Cd. This study indicates that the levels of these contaminants in breast milk samples obtained in Famagusta District are well within the acceptable levels. However, the presence of AFM1 and heavy metals still may pose risks for infant health.

Use of human milk in the assessment of toxic metal exposure and essential element status in breastfeeding women and their infants in coastal Croatia

Pregnant and lactating women and infants are vulnerable population groups for adverse effects of toxic metals due to their high nutritional needs and the resultant increased gastrointestinal absorption of both, essential and toxic elements. Although breastfeeding is recommended for infants worldwide, as human milk is the best source of nutrients and other required bioactive factors, it is also a pathway of maternal excretion of toxic substances including toxic metals and thus a source of infant exposure. The aim of this research was to assess health risks in breastfeeding women in the coastal area of the Republic of Croatia and their infants (N=107) due to maternal exposure to Cd and Pb via cigarette smoking, and Hg via seafood and dental amalgam fillings, and their interaction with essential elements. Biological markers of exposure were the concentrations of main toxic metals Pb, Cd and Hg in maternal blood and three types of breast milk throughout lactation stages. Biological markers of effects were the levels of essential elements Ca, Fe, Cu, Zn and Se in maternal serum and breast milk. With regard to cigarette smoking as a source of exposure to Cd and Pb, there were effects of smoking on Cd concentration in blood and correlations between the smoking index and Cd concentrations in maternal blood (ρ=0.593; P<0.001) and mature milk (ρ=0.271; P=0.011) and Pb concentration in transitional milk (ρ=0.280; P=0.042). Regarding fish, we found correlations between weekly consumption frequency and total Hg concentrations in maternal blood (ρ=0.292; P=0.003) and mature milk (ρ=0.303; P=0.003). The number of dental amalgam fillings correlated with total Hg concentrations in colostrum (ρ=0.489; P=0.005) and transitional milk (ρ=0.309; P=0.018). As for the essential element status, only Se levels in maternal serum decreased by 10% in persons who continued smoking during pregnancy compared to non-smokers. In conclusion, the levels of main toxic metals Cd, Pb and Hg and essential elements Ca, Fe, Cu, Zn and Se in maternal blood and three types of breast milk samples in the studied area of coastal Croatia showed no risk of disrupted essential element levels with regard of toxic metal exposure in both breastfeeding women and their infants.

A randomized controlled trial on the effects of jujube fruit on the concentrations of some toxic trace elements in human milk

BACKGROUND

This study aims to investigate the concentrations of lead, cadmium, and arsenic in the human milk, and to assess the effect of jujube fruit consumption by lactating mothers in reducing the concentration of these heavy metals in their milk.

MATERIALS AND METHODS

This randomized controlled trial was conducted in 2014 among forty postpartum mothers in Isfahan, the second largest and polluted city in Iran. Mothers were randomized into two groups; the intervention group received 15 g/day of fresh jujube fruit, and the controls received routine care for 8 weeks.

RESULTS

In the beginning, the concentrations of lead, cadmium, and arsenic were high, without significant difference between groups. The mean (standard deviation) concentrations of lead, cadmium, and arsenic were 29.49 (16.6), 4.65 (3.51), and 1.23 (0.63) μg/L, respectively. The smoothed empirical distribution of environmental pollutants showed that in both groups the mean values and variance of toxic metals decreased after 8 weeks, with a sharper decline in the intervention group. Quantile regression analysis showed that in the intervention group, lead concentration decreased by 2.54 μg/L at the 90^th quintile, and cadmium decreased by 0.19 μg/Lat 75^th quintile; without significant change in arsenic level. The corresponding figures were not significant in the control group.

CONCLUSION

The concentrations of heavy metals were high in human milk, and the consumption of jujube fruit had some beneficial effects in reducing these harmful elements. Pregnant and lactating mothers should be advised to reduce their exposure to environmental pollutants, and consumption of some natural medicinal foods can be useful in reducing the concentration of pollutants in human milk. Because of numerous benefits of breast milk, in spite of the existence of some toxic trace elements, breastfeeding must be encouraged because such contaminants are also found in water and formula. The impact of the current findings on the primary prevention of chronic disease should be determined in future longitudinal studies.

The Nickel Concentration in Breast Milk during the First Month of Lactation in Yazd, Center of Iran

Breastfeeding plays an important role in the growth and development of breastfed infants, especially in the first 6 months of their lives. The present study was conducted to determine the nickel concentrations in breast milk of lactating women in Yazd, Iran. One hundred fifty volunteers were selected among nursing mothers referring to health centers in Yazd. In the first month of lactation, milk samples were collected three times, on days 3 to 5 (first), 16 (Second), and 30 (third) after delivery. Nickel concentration of the samples was measured by atomic absorption spectrophotometer. Demographic variables were collected through a questionnaire which was completed by mothers. The mean age of the study group was 27.40 ± 4.66 years. The mean nickel concentrations in breast milk at the first, second, and third samples were 47.3 ± 7.40, 49.9 ± 8.05, and 54.8 ± 7.38 μg/l, respectively. The concentration of nickel in the breast milk of more than 86 % of mothers was higher than the permissible range for it. There was no significant relationship between the mean value of nickel in breast milk and education, age, and job of mothers. High level of nickel in breast milk may be attributed to consumed food and drinking water containing nickel. Monitoring the nickel level in breast milk regularly is recommended.

Arsenic, lead, mercury and cadmium: Toxicity, levels in breast milk and the risks for breastfed infants

Metals are ubiquitous in nature, being found in all environmental compartments, and have a variety of applications in human activities. Metals are transferred by maternal blood to the fetus via the placenta, and exposure continues throughout life. For the general population, exposure comes mainly from water and food consumption, including breast milk. In this paper, we reviewed studies on the toxicity of arsenic, lead, mercury and cadmium, the toxic metals of most concern to human health, focusing on the potential risks to newborns and infants. A total of 75 studies published since 2000 reporting the levels of these metals in breast milk were reviewed. Lead was the metal most investigated in breast milk (43 studies), and for which the highest levels were reported (up to 1515µg/L). Arsenic was the least investigated (18 studies), with higher levels reported for breast milk (up to 149µg/L) collected in regions with high arsenic concentrations in water (>10µg/L). Data from 34 studies on mercury showed that levels in breast milk were generally higher in populations with high fish consumption, where it may be present mainly as MeHg. Cadmium levels in breast milk were the lowest, with means <2µg/L in most of the 29 studies reviewed. Results of risk assessments indicated that the intake of arsenic, lead and mercury by infants through breastfeeding can be considered a health concern in most regions of the world. Although the potential risks to infants are mostly outweighed by the benefits of breast milk consumption, it is essential that contaminants be continuously monitored, especially in the most critical regions, and that measures be implemented by health authorities to reduce exposure of newborns and infants to these metals, and thus avoid unnecessary health risks.

Cadmium Concentration in Mother's Blood, Milk, and Newborn's Blood and Its Correlation with Fatty Acids, Anthropometric Characteristics, and Mother's Smoking Status

The aim of this study was to determine cadmium concentration in mothers' blood, milk, and newborns' blood from Szczecin (Poland) as a result of environmental cadmium exposure and evaluate the correlation (1) between cadmium levels in analyzed matrices, (2) between cadmium and fatty acids in those matrices, and (3) between cadmium and some selected personal variables, such as anthropometric characteristics, mothers' smoking status, and fruit and fish consumption by mothers. The concentration of cadmium in whole blood and milk of mothers and in the umbilical cord blood of newborns was determined by atomic absorption spectrometry with graphite furnace atomization and Zeeman correction. The fatty acid concentrations were determined by gas chromatography in our previous study. The mean concentrations of cadmium in maternal blood, newborn's blood, and breast milk were 0.61 ± 0.62 μg/L, 0.05 ± 0.04 μg/L, and 0.11 ± 0.07 μg/L, respectively, and differed significantly between analyzed matrices. Cadmium concentrations in the umbilical cord blood were 15 % (range 0-83 %) of the concentration in maternal blood, whereas cadmium concentrations in breast milk constituted 35 % (range 3-142 %) of the concentration in mothers' blood. No correlation was found between cadmium levels in three analyzed matrices. The correlation analysis revealed significant low positive correlation between maternal blood cadmium concentrations and concentrations of elaidic, oleic, and cis-vaccenic acids in mothers' milk (correlation coefficients 0.30, 0.32, and 0.31, respectively). Mothers' blood cadmium correlated with mothers' age (r = -0.26, p = 0.03), maternal smoking before pregnancy (r = 0.55, p < 0.000), maternal smoking during pregnancy (r = 0.58, p < 0.000), and fruit consumption by mothers after delivery (r = -0.44, p = 0.003). Mothers' height was the only variable that correlated significantly with breast milk cadmium levels. Newborns' blood cadmium concentrations correlated significantly with mothers' height (r = 0.28, p = 0.02), newborns' birth weight (r = 0.26, p = 0.03), maternal smoking during pregnancy (r = 0.24, p = 0.048), and fish consumption by mothers after delivery (r = 0.37, p = 0.02). The concentrations of cadmium in Polish mother-newborn pairs are among the lowest in Europe and within the norms established by different institutions. The results of our study confirm the existence of effective partial barriers (such as the placenta and mammary gland) restricting cadmium passage from mother to newborn. The significant positive correlations between maternal blood Cd and concentrations of oleic, elaidic, and cis-vaccenic acids in breast milk might suggest the increased cadmium toxicity to infant, taking into consideration even low cadmium passage to milk. Maternal smoking during pregnancy increases both maternal and newborn's blood cadmium level. Promotion of nonsmoking among pregnant women could substantially reduce prenatal and neonatal exposure to cadmium. Moreover, the results of our study point to the need of establishing complex biomonitoring of cadmium in mother-infant pairs in order to better protect children from this toxic and carcinogenic metal exposure.

Impact of maternal nutrition on breast-milk composition: a systematic review

BACKGROUND

It is widely reported that maternal diet influences the nutritional composition of breast milk. The amount of variability in human milk attributable to diet remains mostly unknown. Most original studies that reported a dietary influence on breast-milk composition did not assess diet directly, did not quantify its association with milk composition, or both.

OBJECTIVE

To gather the quantitative evidence on this issue, we carried out a systematic PubMed and Medline search of articles published up to January 2015 and filtered the retrieved articles according to predefined criteria.

DESIGN

Only studies that provided quantitative information on both maternal diet and milk data, measured in individual healthy mothers of healthy term infants and based on an original observational or experimental design, were included. Exclusion criteria were a focus on supplements, transfer of toxic metals or other contaminants from diet to milk, or on marginally nourished women.

RESULTS

Thirty-six publications-including data on 1977 lactating women-that matched our criteria were identified. Seventeen studies investigated dietary effects on fatty acids in breast milk. The rest included studies that focused on a diverse spectrum of other nutritional properties of breast milk. The largest evidence, in terms of number of articles, for any link between maternal diet and a nutritive property of breast milk came from 3 studies that supported the link between fish consumption and high docosahexaenoic acid in breast milk and 2 studies that reported a positive correlation between dietary vitamin C and milk concentrations of this vitamin.

CONCLUSIONS

The available information on this topic is scarce and diversified. Most of the evidence currently used in clinical practice to make recommendations is limited to studies that only reported indirect associations.

Toxic effects of trace elements on newborns and their birth outcomes

Some trace elements are essential for newborns, their deficiency may cause abnormal biological functions, whereas excessive intakes due to environmental contamination may create adverse health effects. This study was conducted to measure the levels of selected trace elements in Chinese fish consumers by assessing their essentiality and toxicity via colostrum intake in newborns, and evaluated the effects of these trace elements on birth outcomes. Trace elements in umbilical cord serum and colostrum of the studied population were relatively high compared with other populations. The geometric means (GM) of estimated daily intake (EDI, mgday(-1)) of the trace elements were in the safe ranges for infant Dietary Reference Intakes (DRIs) recommended by the United States Food and Drug Administration (FDA). When using total dietary intake (TDI, mgkg(-1)bwday(-1)), zinc (Zn) (0.880mgkg(-1)bwday(-1)) and selenium (Se) (6.39×10(-3)mgkg(-1)bwday(-1)) were above the Reference Doses (RfD), set by the United States Environmental Protection Agency (EPA). Multivariable linear regression analyses showed that Se was negatively correlated with birth outcomes. Our findings suggested that overloading of trace elements due to environmental contamination may contribute to negative birth outcomes.

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.

Toxicological importance of human biomonitoring of metallic and metalloid elements in different biological samples

Human biomonitoring has become an important tool for the assessment of internal doses of metallic and metalloid elements. These elements are of great significance because of their toxic properties and wide distribution in environmental compartments. Although blood and urine are the most used and accepted matrices for human biomonitoring, other non-conventional samples (saliva, placenta, meconium, hair, nails, teeth, breast milk) may have practical advantages and would provide additional information on health risk. Nevertheless, the analysis of these compounds in biological matrices other than blood and urine has not yet been accepted as a useful tool for biomonitoring. The validation of analytical procedures is absolutely necessary for a proper implementation of non-conventional samples in biomonitoring programs. However, the lack of reliable and useful analytical methodologies to assess exposure to metallic elements, and the potential interference of external contamination and variation in biological features of non-conventional samples are important limitations for setting health-based reference values. The influence of potential confounding factors on metallic concentration should always be considered. More research is needed to ascertain whether or not non-conventional matrices offer definitive advantages over the traditional samples and to broaden the available database for establishing worldwide accepted reference values in non-exposed populations.

Real-time Detection of Trace Copper in Brain and Kidney of Fish for Medical Diagnosis

For the detection of trace copper to be used in medical diagnosis, a sensitive handmade carbon nanotube paste electrode (PE) was developed using voltammetry. Analytical optimized conditions were found at 0.05 V anodic peak current. In the same conditions, various common electrodes were compared using stripping voltammetry, and the PE was found to be more sharply sensitive than other common electrodes. At optimum conditions, the working ranges of 3~19 μgL⁻¹ were obtained. The relative standard deviation of 70.0 μgL⁻¹ was determined to be 0.117% (n = 15), and the detection limit (S/N) was found to be 0.6 μgL⁻¹ (9.4 × 10⁻⁹ M). The results were applied in detecting copper traces in the kidney and the brain cells of fish.

Priority persistent contaminants in people dwelling in critical areas of Campania Region, Italy (SEBIOREC biomonitoring study)

To investigate if protracted living in degraded environments of the Caserta and Naples provinces (Campania Region, Italy) had an impact on exposure of local people, highly toxic persistent contaminants were measured in blood, blood serum, and human milk of a large number of healthy donors. Sampling was carried out from 2008 to 2009. Blood was collected from over 850 20-64-year old donors; by pooling, 84 blood and 84 serum samples were obtained. Milk was donated by 52 mothers: specimens were pooled into six samples. Polychlorodibenzodioxins (PCDDs), polychlorodibenzofurans (PCDFs), and polychlorobiphenyls (PCBs, dioxin-like (DL) and non-dioxin-like (Σ6PCBs)), arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) were measured in serum (organic biomarkers) and blood (metals); these chemicals and polybromobiphenyl ethers (Σ9PBDEs) were analyzed in milk. PCDD+PCDF, DL-PCB, TEQTOT, and Σ6PCB concentration ranges (medians) in serum were 6.26-23.1 (12.4), 3.42-31.7 (11.5), 10.0-52.8 (23.9) pgTEQ97/g fat, and 55.5-647 (219) ng/g fat, respectively, while in milk concentration ranges were 5.99-8.77, 4.02-6.15, 10.0-14.2 pgTEQ97/g fat, and 48.7-74.2 ng/g fat. Likewise, As, Cd, Hg, and Pb findings in blood spanned 2.34-13.4 (5.83), 0.180-0.930 (0.475), 1.09-7.60 (2.60), 10.2-55.9 (28.8) μg/L, respectively; only Pb could be measured in milk (2.78-5.99 μg/L). Σ9PBDE levels in milk samples were 0.965-6.05 ng/g fat. Biomarkers' concentrations were found to be compatible with their current values in European countries and in Italy, and consistent with an exposure primarily determined by consumption of commercial food from the large distribution system. Based on relatively higher biomarker values within the hematic biomonitoring database, the following municipalities were flagged as possibly deserving attention for health-oriented interventions: Brusciano and Caivano (As), Giugliano (Hg), Pianura (PCDDs+PCDFs), and Qualiano-Villaricca (As, Hg). The analysis of samples' qualitative variability indicated that biomarker composition was sensitive at municipality level, a feature that can potentially drive interventions for future local risk assessment and/or management measures.

Concentration profiles of metals in breast milk, drinking water, and soil: relationship between matrices

The concentrations of Cd, Cr, Cu, Hg, Mn, Ni, Pb, Sn, and Zn were determined in breast milk of women living in Conceição das Alagoas, Minas Gerais, Brazil. The potential relationships between metal levels in samples of breast milk, drinking water, and soils collected in the study area were also established. Metal levels in breast milk, except Cr, were lower in comparison to WHO reference concentrations. Zinc was the predominant element in breast milk and drinking water samples, with a median level of 46.2 and 82.2 μg · L(-1), respectively. Soils presented a different pattern of metal concentrations with respect to those found in breast milk and drinking water, Chromium showed the highest median levels (148 mg · kg(-1)), while a certain predominance of Zn and Cu was also observed (47.0 and 43.0 mg · kg(-1), respectively). Similar profiles were observed when comparing metal concentrations in drinking water and breast milk (chi-square χ(2) = 14.36; p < 0.05). In contrast, breast milk-soil and drinking water-soil metal concentration profiles showed significant differences (χ(2) = 635.05 and χ(2) = 721.78, respectively; p < 0.05). These results indicate that drinking water is an important exposure pathway for metals to newborns through breast milk. Further studies should be aimed at assessing the body burdens of metals in that population and at evaluating the potential relationships in the concentrations in biological and environmental matrices as well as at estimating the contribution of dietary intake of metals. In addition, the presence of other chemical pollutants in breast milk should be also studied in order to assess the combined newborn exposure to other contaminants.

Comparative study of heavy metals in dried and fluid milk in Peshawar by atomic absorption spectrophotometry

Various essential and toxic heavy metals (Ca, Mg, Cu, Zn, Fe, Mn, Pb, Cd, Cr, and Ni) contents in various types of dried (infant formula and powdered) and fluid (fresh and processed) cow milk were assessed by atomic absorption spectrophotometry. The milk samples were collected from local markets of different parts of Peshawar city, Pakistan. Heavy metal concentrations varied significantly depending upon the type of milk. The heavy metal concentrations in most of the samples were within normal and permissible ranges. It was observed that the samples contained considerable amounts of calcium, while magnesium levels were well above the required levels. The results also revealed that copper levels were slightly lower than the permissible limits. The concentration of zinc in dried milk samples was greater than the values for the liquid milk types. Infant milk formulae had higher iron levels as compared to other milk samples because of the added constituents. Significant differences were observed in the mean values of manganese and cadmium in different types of milk. The toxic metals were within the acceptable limits and did not show significant levels leading to toxicity.

Arsenic, cadmium, lead, and aluminium concentrations in human milk at early stages of lactation

BACKGROUND

Human milk is considered to be the best nutrition for all infants because it provides the optimal source of nutritional, immunological, developmental, psychological, economic, practical, and environmental benefits in both the short and long terms. To the best of our knowledge, few studies in Taiwan have examined the toxicant levels in breast milk and associated factors.

METHODS

The research was carried out over a 6-month period. Forty-five healthy lactating women, who delivered full-term newborns at our maternity ward, were recruited, and all participants had been living in coastal urban areas of mid-Taiwan for at least 3 years. One hundred and eighty human milk samples were collected on four occasions, which were classified into four lactation stages as follows: colostrums, transitional milk, early mature milk, and mature milk.

RESULTS

We found that lead, cadmium, aluminium, and arsenic concentrations were the highest in colostrums: 13.22 ± 3.58 ng/mL, 1.37 ± 0.94 ng/mL, 56.45 ± 22.77 ng/mL, and 1.50 ± 1.50 ng/mL, respectively. The results of lead, cadmium, aluminium, and arsenic determination in human milk samples demonstrated a trend of decline of microelement concentrations with advancing stages of lactation. We found that the infants of smoking mothers were exposed to more cadmium than infants of nonsmoking mothers (p < 0.05).

CONCLUSION

According to our findings, frequent routine sampling of breast milk is worthwhile. Prevention strategies including behavior modification and education on proper nutrition should be provided to women who are at high risk of toxicant exposure. In summary, breastfeeding is still generally encouraged and recommended.

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.

Breast milk lead and cadmium levels in suburban areas of Nanjing, China

OBJECTIVE

To evaluate levels of lead (Pb) and cadmium (Cd) in the breast milk in the second postpartum month, to investigate the relationship between Pb/Cd levels in breast milk and some sociodemographic parameters, and to explore whether these levels affect the infants' physical status or the mothers' psychological status (postpartum depression).

METHODS

A cross-sectional study was conducted between November 2009 and December 2010. Altogether 170 healthy mothers were enrolled from Nanjing Maternity and Child Health Care Hospital. The inclusion criteria were: voluntary to participate in this study, healthy, with no chronic disease, breastfeeding in the second postpartum month, living in a suburban but not non-industrial area of Nanjing, and not occupationally exposed to toxic metals. All the mothers completed a questionnaire and were evaluated based on the Edinburgh Postpartum Depression Scale (EPDS) to identify the risk of postpartum depression. Pb and Cd levels in breast milk were determined by inductively coupled plasma mass spectroscopy. The infants of these mothers were examined for their z scores of weight for age, length for age, head circumference for age, and body mass index for age.

RESULTS

The median breast milk levels of Pb and Cd were 40.6 μg/L and 0.67 μg/L, respectively. In 164 (96.5%) of the 170 samples, Pb levels were higher than the limit reported by the World Health Organization (> 5 μg/L). Breast milk Cd level was > 1 μg/L in 54 (31.8%) mothers. The mothers with a history of anemia had a higher breast milk Pb level than those without a history of anemia (41.1 μg/L vs. 37.9 μg/L, P = 0.050). The median breast milk Cd level in those who were active and passive smokers during pregnancy was significantly higher than that in non-smokers (0.88 μg/L vs. 0.00 μg/L, P = 0.025). The breast milk Cd level in the mothers not taking iron and vitamin supplements for 2 months postpartum was higher than in those taking the supplements (iron supplement: 0.74 μg/L vs. 0.00 μg/L, P = 0.025; vitamin supplement: 0.78 μg/L vs. 0.00 μg/L, P = 0.005). Breast milk Cd level at the second postpartum month was negatively correlated with the z scores of head circumference (r = - 0.248, P = 0.042) and weight for age at birth (r =- 0.241, P = 0.024) in girls. No correlation was found between the breast milk Pb/Cd levels and the EPDS scores.

CONCLUSION

Considering the high levels of Pb and Cd in breast milk in this study, breast milk monitoring programs are necessary.

Metals and trace element concentrations in breast milk of first time healthy mothers: a biological monitoring study

BACKGROUND

Breast milk is the best source of nutrition for the newborn infant. However, since all infants cannot be breast-fed, there is a need for background data for setting adequate daily intakes. Previously, concentration data on major essential elements and some toxic elements in breast milk, based on different analytical techniques, have been published. There is no recent study on a large number of metals and trace elements in breast milk, using a sensitive analytical method for determination of low element concentrations.

METHODS

Breast milk concentrations of 32 metals and elements in early lactation (days 14-21) were determined in a random sample of first time Swedish mothers (n = 60) using inductively coupled plasma mass spectrometry (ICPMS).

RESULTS

There were small inter-individual concentration variations in the macroelements Ca, K, Mg, P and S, and striking similarities across studies and over time, supporting a tight regulation of these elements in breast milk. Large inter-individual and over time differences were detected for Na concentrations, which may reflect an increase in salt consumption in Swedish women. Large inter-individual differences were also detected for the microelements Co, Cr, Mn and Mo, and the toxic metals As, Cd, Pb, Sb and V. Arsenic and B were positively correlated with fish consumption, indicating influence of maternal intake on breast milk concentrations. Observed differences in breast milk element concentrations across studies and over time could be attributed to the timing of sampling and a general decline over time of lactation (Cu, Fe, Mo, Zn), a possible lack of regulation of certain elements in breast milk (As, B, Co, Mn, Se) and time trends in environmental exposure (Pb), or in some cases to differences in analytical performance (Cr, Fe).

CONCLUSIONS

This study provides reliable updated information on a number of metals and elements in breast milk, of which some have not previously been reported.

Determination of mercury, cadmium and lead in human milk in Iran

Breast milk contains both essential and nonessential trace elements. Mercury, cadmium and lead are nonessential, potentially toxic heavy metals with hematotoxic, neurotoxic and nephrotoxic properties even at very low concentrations. The objectives of this study were to determine the concentrations of mercury, cadmium and lead in the breast milk of healthy lactating women who were living in Isfahan, Iran. Concentrations of mercury, cadmium and lead were determined by graphite furnace atomic absorption spectrometry in 37 milk samples from healthy lactating women collected on first to sixth postpartum week. Accuracy of the analysis was checked by various methods including the use of reference material. The mean ± SD of the concentrations of mercury, cadmium and lead in human milk were 0.92 ± 0.54 μg/L (range 0.0–2.07 μg/L), 1.92 ± 1.04 μg/L (range 0.45–5.87 μg/L) and 7.11 ± 3.96 μg/L (range 3.06–19.47 μg/L), respectively. The results of this study showed that the concentrations of mercury, lead and cadmium in the milk samples from lactating women in Isfahan were high, which makes a major public health hazard for the inhabitants, especially neonatal and children, of the industrial locations. The results of the present study indicate a need for establishing safe intake values of heavy metals in human milk.

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.

Mercury, lead and cadmium in human milk in relation to diet, lifestyle habits and sociodemographic variables in Madrid (Spain)

BACKGROUND

Although breastfeeding is the ideal way of nurturing infants, it can be a source of exposure to toxicants. This study reports the concentration of Hg, Pb and Cd in breast milk from a sample of women drawn from the general population of the Madrid Region, and explores the association between metal levels and socio-demographic factors, lifestyle habits, diet and environmental exposures, including tobacco smoke, exposure at home and occupational exposures.

METHODS

Breast milk was obtained from 100 women (20 mL) at around the third week postpartum. Pb, Cd and Hg levels were determined using Atomic Absorption Spectrometry. Metal levels were log-transformed due to non-normal distribution. Their association with the variables collected by questionnaire was assessed using linear regression models. Separate models were fitted for Hg, Pb and Cd, using univariate linear regression in a first step. Secondly, multivariate linear regression models were adjusted introducing potential confounders specific for each metal. Finally, a test for trend was performed in order to evaluate possible dose-response relationships between metal levels and changes in variables categories.

RESULTS

Geometric mean Hg, Pb and Cd content in milk were 0.53 μg L(-1), 15.56 μg L(-1), and 1.31 μg L(-1), respectively. Decreases in Hg levels in older women and in those with a previous history of pregnancies and lactations suggested clearance of this metal over lifetime, though differences were not statistically significant, probably due to limited sample size. Lead concentrations increased with greater exposure to motor vehicle traffic and higher potato consumption. Increased Cd levels were associated with type of lactation and tended to increase with tobacco smoking.

CONCLUSIONS

Surveillance for the presence of heavy metals in human milk is needed. Smoking and dietary habits are the main factors linked to heavy metal levels in breast milk. Our results reinforce the need to strengthen national food safety programs and to further promote avoidance of unhealthy behaviors such as smoking during pregnancy.

Breast milk lead and cadmium levels from suburban areas of Ankara

The objectives of this study were (1) to evaluate levels of lead (Pb) and cadmium (Cd) in the breast milk at 2 months postpartum, (2) to investigate the relationship between Pb and Cd levels in breast milk and some sociodemographic parameters and (3) to detect whether these levels have any influence on the infant's physical status or on postpartum depression in the mothers. Pb and Cd levels in breast milk were determined by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The median breast milk concentrations of Pb and Cd were 20.59 and 0.67 μg/l, respectively. In 125 (87%) of 144 samples, Pb levels were higher than the limit in breast milk reported by the World Health Organization (WHO) (> 5 μg/l). Breast milk Cd levels were > 1 μg/l in 52 (36%) mothers. The mothers with a history of anemia at any time had higher breast milk Pb levels than those without a history of anemia (21.1 versus 17.9 μg/l; p=0.0052). The median breast milk Cd levels in active and passive smokers during pregnancy were significantly higher than in non-smokers (0.89, 0.00 μg/l, respectively; p=0.023). The breast milk Cd levels of the mothers who did not use iron and vitamin supplements for 2 months postpartum were found to be higher than in those who did use the supplements (iron: 0.73, 0.00 μg/l, p=0.023; vitamin: 0.78, 0.00 μg/l, p=0.004, respectively). Breast milk Cd levels at the 2nd month were correlated negatively with the z scores of head circumference and the weight for age at birth (r=-0.257, p=0.041 and r=-0.251, p=0.026, respectively) in girls. We found no correlation between the breast milk Pb and Cd levels and the Edinburgh Postpartum Depression Scale scores. Breast milk monitoring programs should be conducted that have tested considerable numbers of women over time in view of the high levels of Pb in breast milk in this study.

Lead levels in human milk and children's health risk: a systematic review

Lead (Pb), a naturally-occurring element and industrially-produced metal, is highly toxic to children, causing intellectual and behavioral deficits, hyperactivity, fine motor function deficits, decreased intelligence quotient, alteration of hand-eye coordination, and problems in reaction time. Children's exposure to Pb occurs mainly through ingestion of contaminated food, water and soil. Few discussions have been held on the magnitude and potential risk associated with exposure from the consumption of breast milk. Hence, this research was designed to systematically review the scientific literature on published epidemiologic studies, with an emphasis on the study designs and analytical procedures used for Pb assessment in breast milk. From a total of 112 selected articles published since the 1980s, 11 met the inclusion criteria. A review of the data indicated that Pb levels varied from 0.15 to 6.1 microg L(-1) in mature milk samples, from 0.48 to 14.6 microg L(-1) in colostrum samples, and were non-detectable in some samples. The milk/blood ratio, which estimates the mean efficiency transfer of lead from blood to milk, varied between 0.01 and 0.48. The heterogeneity of methods revealed by our assessment of published studies underscores the need for harmonization of study designs and sample collection and analysis protocols to reflect specific exposure scenarios. Human milk seems to be one of the relevant biological matrices for use as a biomarker for assessing children's health risk to Pb poisoning.

Iron concentrations in breast milk and selected maternal factors of human milk bank donors

The aim of this study was to evaluate the relationship between iron concentration in mature breast milk and characteristics of 136 donors of a Brazilian milk bank. Iron, vitamin A, zinc, and copper concentrations were assessed in human milk and maternal blood. Data were collected on maternal anthropometrics, obstetric, socioeconomic, demographic, and lifestyle factors. Iron, zinc, and copper in milk and zinc and copper in blood were detected by spectrophotometry. Vitamin A in milk and blood was determined by high-performance liquid chromatography. Hemoglobin was measured by electronic counting and serum iron and ferritin by colorimetry and chemoluminescence, respectively. Transferrin and ceruloplasmin were determined by nephelometry. According to multivariate linear regression analysis, iron in milk was positively associated with vitamin A in milk and with smoking but negatively associated with timing of breast milk donation (P < .001). These results indicate that iron concentration in milk of Brazilian donors may be influenced by nutritional factors and smoking.