Trace elements in human milk: correlation with blood levels, inter-element correlations and changes in concentration during the first month of lactation

Effect of lactation on the distribution of mineral elements in goat milk

The distribution of mineral elements in milk is crucial for their absorption and utilization, however, there has been limited attention given to the status of mineral elements in goat milk. In this study, goat milk was collected at 4 lactation periods (1-3, 90, 150, 240 d) and separated into 4 fractions (fat, casein, whey, and aqueous phase). The concentrations of Mg, Ca, Na, K, Zn, Fe, Cu, Mn, Co, Ni, Mo, and Cr in 4 fractions were analyzed using an inductively coupled plasma emission spectrometer. Our findings reveal that Ca, Zn, Fe, Cu, Mn, and Cr exhibit the highest levels in casein, while Mo demonstrates the highest content in whey. Additionally, Mg, Na, K, and Ni display the highest concentrations in the aqueous phase. Specifically, the contents of Ca, Cu and Fe in casein decrease from 1-3 to 150 d of lactation but increase from 150 to 240 d of lactation. Furthermore, the content of Mg in the aqueous phase decreases from 1-3 to 90 d of lactation but increases from 90 to 240 d of lactation. The content of Na and K in the aqueous phase decreases from 1-3 to 150 d of lactation. Notably, the content of Mo in whey increases from 1-3 to 150 d of lactation and decreases from 150 to 240 d. Our research contributes to the advancement of understanding the bioavailability of mineral elements in goat milk.

Breastmilk mineral composition among well-educated mothers from Central Poland - Associations with maternal dietary intake, dietary patterns and infant psychomotor development

BACKGROUND

Maternal dietary habits could affect breastmilk mineral composition, which may influence infant development. Mineral dietary intake or supplementation slightly affects its breastmilk concentration. However, the intake of selected food groups or dietary patterns that reflect diet complexity could have a greater impact. Hence, the aim of the study was to assess breastmilk mineral composition at one, three, and six months of lactation among mothers living in urban area of Central Poland, as well as the evaluate maternal dietary determinants and associations with infant anthropometric and psychomotor development.

METHODS

The study was conducted among 43 healthy and exclusively breastfeeding mothers. In the first, third, and sixth months of lactation, we collected breastmilk samples and assessed the concentration of Ca, P, Zn, Fe, Se, Ni, As, Pb, and Cd using the ICP-MS method. Maternal dietary habits were evaluated by a food frequency questionnaire in the first month of lactation, whereas in the third and sixth by the three-day food record. Based on the collected data adherence to the Polish-adapted Mediterranean (Pl-aMED; 1 month) and the DASH diet (Mellen's Index; 3 and 6 months) was assessed. In the third and sixth months of lactation infant anthropometric parameters and the sixth month of lactation psychomotor development were evaluated.

RESULTS

Breastmilk Se, Ni, As, Pb, and Cd levels were under the LOQ in all the breastmilk samples at all study visits. Median breastmilk mineral concentrations of Ca, P, Zn, and Fe in the first, third, and sixth months of lactation varied from 381.9 to 332.7 mg/L, 161.6 to 139.1 mg/L, 2.2 to 0.8 mg/L, and 0.26 to 0.17 mg/L, respectively. Maternal dietary intake and supplementation did not affect breastmilk Ca, P, Zn, and Fe. Pl-aMED scores were associated with breastmilk Ca (β = 0.489, 95% CI 0.180 - 0.799, p = 0.003) and Zn (β = 0.499, 95% CI 0.199 - 0.798, p = 0.002) in the first month of lactation, whereas no association with the DASH diet were observed in the third and sixth month of lactation. Breastmilk Fe in the third month was associated with infant motor development (β = 0.420, 95% CI 0.113 - 0.727, p = 0.009) in the sixth month of life, but no other associations with anthropometric or psychomotor development were observed. Moreover, we estimated that few infants meet their adequate intake (AI) requirements for P, Zn, and Fe.

CONCLUSION

Our study showed that maternal adherence to Pl-aMED is a significant predictor of breastmilk Ca and Zn in the first month of lactation, which may be especially important considering that more than 75% of infants had inadequate Zn intake. Moreover, we found that breastmilk Fe positively influenced infant motor development, despite the majority of infants having inadequate intake. On the other hand, no infant had deficiency symptoms, which emphasizes the necessity to evaluate of AI norms for infants.

Lactational Exposure of Human Infants to Metal (loid)s: A Comparison of Industrial and Urban Inhabitants in North of the Persian Gulf

In this study, postnatal metal (loid)s (MLs) exposure was compared between the petrochemical and gas area of Asaluyeh (PGA) and urban area of Kaki (UA) in Bushehr province, Iran. Two hundred human breast milk (BM) samples from the industrial and urban areas were analyzed for MLs using Inductivity Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Boron (B), copper (Cu), iron (Fe), and nickel (Ni) were found at the highest levels in both study areas. Adjusted multiple linear regression models revealed that the mean concentration of total MLs in BM samples collected from the PGA was statistically significantly greater than that of the UA (655.85 vs. 338.17 µg/L). Also, the mean concentrations of all detected MLs in BM samples collected from the PGA were statistically significantly higher than those collected from the UA. The hazard index (HI) of combined MLs in the PGA and UA illustrated non-cancer risk for infants. Lead (Pb) and chromium (Cr) in the PGA and Cr in the UA showed the risk of cancer. So it can be concluded that nursing infants from an industrial area are most at risk for MLs exposure during entire lactation course than those from an urban area.

Essential and non-essential element concentrations in human milk samples and the assessment of infants' exposure

As the data concerning element concentrations in human milk (HM) samples and their intake by infants are lacking in Poland, the present study aimed to explore this issue. The material consisted of HM samples obtained from 30 exclusively breastfeeding mothers during 4-6 weeks postpartum. Additionally, to identify the factors that may potentially affect HM composition, information regarding maternal data (anthropometry, body composition, and diet) was also collected. Maternal diet was assessed with two methods-a food frequency questionnaire and 3-day dietary records. In total, 18 essential and non-essential elements were determined. For the elements analysis, we used inductively coupled plasma quadrupole mass spectrometry. Most of the elements (n = 11, 61%) were detected in all HM samples. In all HM samples tin concentration was higher (5.67 ± 2.39 μg/L) than the usual range reported by the World Health Organization (~ 1.0 μg/L). HM cadmium content was positively associated with maternal salty snacks intake (r = 0.502, p = 0.005), arsenic with whole-grain products intake (r = 0.37, p = 0.043), and mercury concentration with fruits and seeds/nuts consumption (r = 0.424, p = 0.042 and r = 0.378, p = 0.039, respectively). Higher HM lead concentration was predicted by maternal age (95% CI [0.94-0.97]), intake of fish (95% CI [1.01-1.03]), and vegetables (95% CI [1.02-1.06]). The highest infants' intake was observed for copper (35.24 ± 12.48) and the lowest for arsenic (0.076 ± 0.102). Infants' exposure to lead was associated with maternal frequency consumption of canned fish (p = 0.0045). There is a need to perform further research on this topic to maximize the benefits of breastfeeding by minimizing maternal and infant exposure to potentially toxic elements.

Health risk assessments of heavy metals and trace elements exposure in the breast milk of lactating mothers in the Northeastern Iran

Mother's breast milk is a natural and complete food for infants but can be a main source of exposure to toxic pollutants. These pollutants can negatively affect the health of the infant. Therefore, conducting biomonitoring surveys is essential to evaluate such health effects in toxicological research. This study aimed to estimate the probable health risks for infants exposed to essential and non-essential trace elements through breast milk ingestion. This descriptive-analytical, cross-sectional study was performed on 90 breastfeeding mothers referred to the health centers in Mashhad, Iran in January 2021. The health risk assessments (carcinogenic and non-carcinogenic risk) were estimated using chronic daily intake (CDI), hazard quotient (HQ), hazard index (HI), and lifetime carcinogenic risk (CR), which were recommended by the US Environmental Protection Agency (US EPA). The results of the HQ values of trace elements through ingestion exposure for arsenic (90%), copper (90%), zinc (40%), and iron (10%) exceeded the threshold of HQ, and arsenic (66.59%), copper (16.91%), and zinc (9.68%) and iron (4.57%) had the highest contribution to increasing the HI index. The average value of CR was 5. 08 × 10-3. Chromium and iron showed significant relationships (P<0.05) with education level and disease background in this study, and the concentration of chromium, iron, and zinc in the breast milk samples significantly changed during lactation stages (P<0.05). Overall, the risk of carcinogenicity through exposure to breast milk for infants was higher than the safety level of US EPA risk. Therefore, there could be a potential health risk of trace elements, particularly arsenic, copper, and zinc for infants in Mashhad, Iran through the consumption of mothers' breast milk. More efforts are required to control and reduce routes of receiving trace elements in breastfeeding mothers by the competent authorities.

Human health risk assessment of potentially toxic elements in the breast milk consumed by infants in Western Iran

This study aimed to assess the human health risk of some toxic metals/metalloids [lead (Pb), mercury (Hg), cadmium (Cd), nickel (Ni), chromium (Cr), and arsenic (As)] on infants via consumption of the breast milk of women living in urban areas of Kermanshah city, west of Iran. After collecting milk samples, the carcinogenic and non-carcinogenic risk assessment as well as uncertainty analysis of toxic metal levels were carried out. The order of concentration of heavy metals/metalloids in the breast milk samples was Cr (41.07 ± 23.19) > Ni (19.25 ± 11.81) > Pb (11.5 ± 4.48) > As (1.96 ± 2.04) > Cd (.72 ± 0.42) > Hg (0.31 ± 0.26). The results revealed that the levels of Cr and Pb in the breast milk samples were exceeded the World Health Organization (WHO) tolerable daily intake. In the breast milk samples a high levels of one of the trace elements As, Cd, Cr, Pb, and Ni were observed (over 73%) and in 40% of them the levels of Cr, Pb, Cd, As, and Ni were all above WHO tolerable daily intake. Moreover, the As-related point assessment of target risk factor (THQ) was higher than the allowable limit only for 1-month-old male neonates and 2-month-old female neonates (THQ > 1). In addition, Cr-related THQ scores were higher at all age and gender groups (THQ > 1). In conclusion, our findings suggest a potential risk of some metals for infants via the consumption of mothers' breast milk.

The impact of the 2019/2020 Australian landscape fires on infant feeding and contaminants in breast milk in women with asthma

BACKGROUND

The 2019/2020 Australian landscape fires (bushfires) resulted in prolonged extreme air pollution; little is known about the effects on breastfeeding women and their infants. This study aimed to examine the impact of prolonged landscape fires on infant feeding methods and assess the concentration of polycyclic aromatic hydrocarbons (PAHs) and elements in breast milk samples.

METHODS

From May - December 2020, women with asthma, who were feeding their infants during the fires, were recruited from an existing cohort. Data on infant feeding and maternal concern during the fires were retrospectively collected. Breast milk samples were collected from a sample of women during the fire period and compared with samples collected outside of the fire period for levels of 16 PAHs (gas chromatography coupled with mass spectrometry), and 20 elements (inductively coupled plasma-mass spectrometry).

RESULTS

One-hundred-and-two women who were feeding infants completed the survey, and 77 provided 92 breast milk samples. Two women reported concern about the impact of fire events on their infant feeding method, while four reported the events influenced their decision. PAHs were detected in 34% of samples collected during, versus no samples collected outside, the fire period (cross-sectional analysis); specifically, fluoranthene (median concentration 0.015 mg/kg) and pyrene (median concentration 0.008 mg/kg) were detected. Women whose samples contained fluoranthene and pyrene were exposed to higher levels of fire-related fine particulate matter and more fire days, versus women whose samples had no detectable fluoranthene and pyrene. Calcium, potassium, magnesium, sodium, sulphur, and copper were detected in all samples. No samples contained chromium, lead, nickel, barium, or aluminium. No statistically significant difference was observed in the concentration of elements between samples collected during the fire period versus outside the fire period.

CONCLUSIONS

Few women had concerns about the impact of fire events on infant feeding. Detection of fluoranthene and pyrene in breast milk samples was more likely during the 2019/2020 Australian fire period; however, levels detected were much lower than levels expected to be related to adverse health outcomes.

Evaluation of some toxic metals in breast milk samples with dietary and sociodemographic characteristics: a case study of Kermanshah, Western Iran

This study aimed to investigate the concentration of some toxic metals (gold (Au), cadmium (Cd), chromium (Cr), mercury (Hg), nickel (Ni), lead (Pb), tin (Sn), and vanadium (V)) and arsenic (As) in breast milk based on demographic characteristics and the diet of mothers. In this cross-sectional study, 100 lactating mothers from Kermanshah, Western Iran, were included. The mean age of the participants was 29.5 (ranging from 16 to 43 years) with a mean BMI of 26.9 (± 3.81) kg (range: 17.0-39.1). The results of the pairwise correlation coefficient of trace elements illustrated that correlation was mostly positive and weak to moderate. A few exceptions of strong correlations were Cr-Ni (r = 0.82), Au-As (r = 0.64), Cr-V (r = 0.64), and Ni-V (r = 0.58). Moreover, results indicated that BMI (p = 0.008), cooking oil (0.042), and potato intake (p = 0.010) affected the trace element levels significantly. The concentrations of V (p = 0.044), Sn (p = 0.036), Au (p < 0.001), and As (p < 0.001) in the breast milk of women was affected by the BMI. The results of univariate linear regression analysis showed that the concentration of Pb in the milk of mothers who use cosmetics was significant (p < 0.05). Since the lifestyle of lactating women, such as cosmetics usage can impact the content of some elements in breast milk, they should be educated in this part.

Infant exposure to trace elements in breast milk, infant formulas and complementary foods from southern China

Excessive intake of essential trace elements or exposure to potentially toxic elements above certain thresholds may cause adverse health effects in humans. To date, there is scarce evidence concerning Chinese infant exposure to trace elements and the associated risks. In this study, we collected 61 breast milk, 54 infant formula and 90 complementary food samples from southern China to investigate the levels of cobalt (Co), chromium (Cr), copper (Cu), selenium (Se), zinc (Zn), arsenic (As), cadmium (Cd), nickel (Ni) and lead (Pb). The concentrations of these elements in the breast milk samples ranged from under the limit of detection (<LOD)-0.65, <LOD-65.5, 107-1040, 6.17-27.9, 820-10,160, <LOD-2.96, <LOD-0.52, <LOD-230, and <LOD-19.1 μg/L, respectively. In infant formula samples, the concentrations of these elements ranged from 2.77 to 7.56, 27.5-205, 188-4321, 69.7-322, 40,793-84,405, 2.47-12.2, 0.15-3.57, <LOD-505 and 2.19-26.5 μg/kg, respectively, while the concentrations detected in complementary food samples ranged from <LOD-23.7, <LOD-224, <LOD-3705, <LOD-219, 15,335-100,905, <LOD-159, <LOD-66.6, <LOD-502 and <LOD-25.6 μg/kg, respectively. The results showed that the levels of Cr, Cu and Se in 14.8-55.6 % of the infant formula and complementary food samples were lower than the reference values set by Codex Alimentarius or Chinese National Standards, while the levels of Zn in commercial food samples exceeded the corresponding reference values in 9.3-27.8 % of cases; these results suggest a potential risk via the consumption of commercial infant foods. To the best of our knowledge, this is the first study that has comprehensively assessed whether exposure to trace elements via food intake poses potential health risks to Chinese infants.

The concentration and health risk of potentially toxic elements (PTEs) in the breast milk of mothers: a systematic review and meta-analysis

AIM

Breast milk is the best source of nutrition for a newborn during the first six months of his or her life. However there is a possibility that breast milk may contain pollutants such as metals. The current meta-analytic study assessed the concentration of potentially toxic elements (PTEs), including lead (Pb), cadmium (Cd), arsenic (As), Iron (Fe), Zinc (Zn), copper (Cu), and nickel (Ni), in mothers' milk.

METHOD

The literature studies regarding the concentrations of PTEs in the breast milk of mothers were collected from international databases such as PubMed, Scopus, Web of Science, and Embase. Afterward, the Total Target Hazard Quotient (TTHQ) by Monte Carlo Simulation (MCS) model was used to assess the non-carcinogenic risk.

RESULTS AND DISCUSSION

According to 42 of the 836 retrieved articles, the PTE concentrations in mother's milk were as follows: Cu (1.84 mg/kg) > Zn (1.80 mg/kg) > Fe (1.03 mg/kg) > Ni (0.60 mg/kg) > Pb (0.10 mg/kg) > As (0.15 mg/kg) ≈ Cd (0.15 mg/kg). Based on the containment type, the highest concentrations of As (2.80 mg/kg), Cd (0.07 mg/kg), and Pb (2.68 mg/kg) were related to Western Pacific Region (WPRO), European Region (EURO), and WPRO, respectively. In addition, for trace elements, Eastern Mediterranean Region (EMRO) was the region with the highest concentrations of Cu (3.56 mg/kg), Fe (2.78 mg/kg), Ni (3.13 mg/kg), and Zn (5.58 mg/kg) were related to Lastly, the non-carcinogenic risk assessment of the PTEs in breast milk indicated different risk patterns in various countries, and the calculated TTHQ level in infants was below 1.

CONCLUSION

Overall, human breast milk was generally safe for infants to consume and poses no risks to their health.

Contamination of breast milk with lead, mercury, arsenic, and cadmium in Iran: a systematic review and meta-analysis

Breast milk is a complete food for the development of the newborn, but it can also be an important route for environmental pollutants transmission to the infants. This study was aimed to evaluate the status of heavy metals including lead (Pb), mercury (Hg), cadmium (Cd) and arsenic (As) in the breast milk of Iranian mothers. The international databases including Scopus, PubMed, Web of Science and the Persian electronic databases including Scientific Information Database, IranMedex and Magiran were examined to find relevant articles published until July 2021. A total of 23 studies examined the levels of toxic metals in Iranian breast milk samples. According to the findings, the pooled average concentrations (µg/L) of Pb, Cd, Hg and As were 25.61, 2.40, 1.29 and 1.16, respectively. The concentration of Hg and Pb in colostrum milk was more than twice of mature milk. The Hg mean concentration in the breast milk of mothers with at least one amalgam-filled tooth was approximately three times that of mothers without amalgam-filled teeth. Risk assessment analysis indicated that the intake of Pb and Hg by infants through breastfeeding can be considered a health concern in Iran. It seems necessary to reduce the Pb exposure of pregnant and lactating women in Iran. However, more extensive studies are needed to clarify the toxic metals' exposure status of infants through breast milk in other parts of the country.

The risk estimation and assessment of heavy metal exposure by biomonitoring in the breast milk of mothers in the Cukurova Region, Turkey

Toxic heavy metals released into the environment through various industrial processes have potential adverse effects on the environment and human health. In order to reveal these adverse health effects, it is vital to carry out toxicological studies by performing biomonitoring. This study aimed to assess the level of Cr, As, Cd, Hg, and Pb in the breast milk samples of mothers in the Cukurova region, Turkey, and its association with health risk to infants. Ten-milliliter postpartum milk samples were collected from 34 breast-feeding mothers in the first 2 months of their postpartum period and living in the Cukurova region, Adana. The measurement of target heavy metals levels was performed by using inductively coupled plasma mass spectroscopy (ICP-MS). The average breast milk levels of Cr, As, Cd, Hg, and Pb were 8.25, 1.64, 0.37, 2.60, and 12.12 μg/L, respectively. Evaluation of breast milk samples for these toxic heavy metals revealed the high exposure level for Cr and As. However, the mothers who participated in the study were not occupationally exposed to these metals. This study showed that Cr, As, Cd, Hg, and Pb cross the placenta and blood-brain barrier prenatally and accumulate in breast milk postnatally.

Human Biomonitoring of Selected Hazardous Compounds in Portugal: Part I-Lessons Learned on Polycyclic Aromatic Hydrocarbons, Metals, Metalloids, and Pesticides

Human biomonitoring (HBM) data provide information on total exposure regardless of the route and sources of exposure. HBM studies have been applied to quantify human exposure to contaminants and environmental/occupational pollutants by determining the parent compounds, their metabolites or even their reaction products in biological matrices. HBM studies performed among the Portuguese population are disperse and limited. To overcome this knowledge gap, this review gathers, for the first time, the published Portuguese HBM information concerning polycyclic aromatic hydrocarbons (PAHs), metals, metalloids, and pesticides concentrations detected in the urine, serum, milk, hair, and nails of different groups of the Portuguese population. This integrative insight of available HBM data allows the analysis of the main determinants and patterns of exposure of the Portuguese population to these selected hazardous compounds, as well as assessment of the potential health risks. Identification of the main difficulties and challenges of HBM through analysis of the enrolled studies was also an aim. Ultimately, this study aimed to support national and European policies promoting human health and summarizes the most important outcomes and lessons learned through the HBM studies carried out in Portugal.

Concentrations and determinants of lead, mercury, cadmium, and arsenic in pooled donor breast milk in Spain

AIM

To measure concentrations of lead (Pb), mercury (Hg), cadmium (Cd), and arsenic (As) in longitudinally collected donor breast milk samples and to determine associated factors.

METHODS

Pb, Hg, Cd, and As concentrations were measured in 242 pooled breast milk samples from 83 donors to a Human Milk Bank in Spain, in 2015-2018, determining their association with the donors' sociodemographic profile, dietary and lifestyle habits, and post-partum time, among other factors, and with the nutritional characteristics of samples. Mixed-effect linear regression was used to identify predictors of Hg and As concentrations in breast milk and mixed-effect logistic regression to identify predictors of the presence of Pb and Cd.

RESULTS

As was the element most frequently detected in milk samples (97.1%), followed by Hg (81.2%), Pb (50.6%), and Cd (38.0%). Their median breast milk concentrations were 1.49 μg/L, 0.26 μg/L, 0.14 μg/L, and <0.04 μg/L, respectively. Concentrations of As were higher in breast milk from primiparous donors, while Hg was higher in donors with a greater intake of fatty fish and meat and lower in samples collected after a longer post-partum time and with higher lactose content. Detection of Pb was higher among multiparous donors, those gaining weight since before pregnancy, and ex-smokers and was lower in samples collected more recently and from donors with greater intake of red meat and eggs. Cd detection was higher for donors with university education and those with greater intake of fried and canned food and more frequent use of hand cream and was lower for donors with greater bread intake.

CONCLUSIONS

These findings reveal relatively high As concentrations, moderate Hg concentrations, and low Pb and Cd concentrations in pooled donor breast milk. Several factors including post-partum time, parity, smoking habit, and the intake of certain food items were associated with the metal content of milk samples.

Lead (Pb) and neurodevelopment: A review on exposure and biomarkers of effect (BDNF, HDL) and susceptibility

Lead (Pb) is a ubiquitous environmental pollutant and a potent toxic compound. Humans are exposed to Pb through inhalation, ingestion, and skin contact via food, water, tobacco smoke, air, dust, and soil. Pb accumulates in bones, brain, liver and kidney. Fetal exposure occurs via transplacental transmission. The most critical health effects are developmental neurotoxicity in infants and cardiovascular effects and nephrotoxicity in adults. Pb exposure has been steadily decreasing over the past decades, but there are few recent exposure data from the general European population; moreover, no safe Pb limit has been set. Sensitive biomarkers of exposure, effect and susceptibility, that reliably and timely indicate Pb-associated toxicity are required to assess human exposure-health relationships in a situation of low to moderate exposure. Therefore, a systematic literature review based on PubMed entries published before July 2019 that addressed Pb exposure and biomarkers of effect and susceptibility, neurodevelopmental toxicity, epigenetic modifications, and transcriptomics was conducted. Finally included were 58 original papers on Pb exposure and 17 studies on biomarkers. The biomarkers that are linked to Pb exposure and neurodevelopment were grouped into effect biomarkers (serum brain-derived neurotrophic factor (BDNF) and serum/saliva cortisol), susceptibility markers (epigenetic markers and gene sequence variants) and other biomarkers (serum high-density lipoprotein (HDL), maternal iron (Fe) and calcium (Ca) status). Serum BDNF and plasma HDL are potential candidates to be further validated as effect markers for routine use in HBM studies of Pb, complemented by markers of Fe and Ca status to also address nutritional interactions related to neurodevelopmental disorders. For several markers, a causal relationship with Pb-induced neurodevelopmental toxicity is likely. Results on BDNF are discussed in relation to Adverse Outcome Pathway (AOP) 13 ("Chronic binding of antagonist to N-methyl-D-aspartate receptors (NMDARs) during brain development induces impairment of learning and memory abilities") of the AOP-Wiki. Further studies are needed to validate sensitive, reliable, and timely effect biomarkers, especially for low to moderate Pb exposure scenarios.

Health Risk Assessments of Selected Trace Elements and Factors Associated with Their Levels in Human Breast Milk from Pretoria, South Africa

While breast milk is the recommended food for infants up to at least six months, exogenously derived compounds such as trace elements have been widely reported in human milk which may make it become toxic or a source of pollutants to the infants. Numerous short- and long-term health effects have been associated with high body-burdens of trace elements, which are amplified in infants. The current study determined the levels and possible contributing factors of six trace elements in breast milk of nursing mothers from a local hospital in Pretoria. Extraction of trace elements employed a digestion technique using perchloric and nitric acid in a ratio of 1:3, while Inductively Coupled Plasma-Membrane Spectrophotometry was used to identify and quantify their levels in breast milk. Concentrations of Cr and Mn were the highest in breast milk, with values ranging from 0.30 to 5.72 µg/L and 0.23 to 5.13 µg/L, respectively. Levels of Co, As, Pb and Cd ranged from Collapse

Key Words

• arsenic
• breast milk and passive smoking
• chromium
• manganese

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MESH Headings

• Environmental Pollutants
• Female
• Humans
• Milk, Human/chemistry
• Risk Assessment
• South Africa
• Trace Elements/analysis

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Grants Collapse

Affiliation(s)

Joshua O. Olowoyo Department of Biology, Sefako Makgatho Health Sciences University, P.O Box 139, Pretoria 0204, South Africa; (L.R.M.); (P.M.M.)
Linda R. Macheka
Phiona M. Mametja

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Heavy Metals and Trace Elements in Human Breast Milk from Industrial/Mining and Agricultural Zones of Southeastern Spain

Human breast milk is the most complete foodstuff for infants but can also be a potential source of exposure to toxic chemicals. The aim of this study was to assess the levels of metal pollution in the breast milk of women living in agricultural and industrial/mining areas of the Region of Murcia (Spain) that are well known for their cases of environmental pollution. Human milk samples were collected from 50 mothers and inorganic contaminants were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The mean or maximum concentrations of the different inorganic elements analyzed in breast milk, with the exception of manganese, exceeded the maximum limits established by the WHO and could constitute a high risk for pregnant mothers and their children. The breast milk of women living in the industrial/mining zone presented the highest levels of aluminum, zinc, arsenic, lead, mercury and nickel. On the contrary, the highest concentrations of manganese, chromium and iron were determined in the milk of women living in the agricultural zone. These results suggested and confirmed different profiles of environmental contamination of these areas.

Trace element levels in mature breast milk of recently lactating Japanese women

BACKGROUND

Many trace elements are essential for infant growth and development during early life. Their concentrations in breast milk vary depending on social and economic factors. Nonetheless, the present available values in Japan were derived from lactating mothers approximately 15 years ago.

METHODS

Healthy mothers who gave birth to a single infant after 37 weeks of gestation at Teikyo University Hospital were recruited between July 2016 and December 2017. They were encouraged to collect breast milk samples and a self-administered food frequency questionnaire at 1 and 3 months postpartum. Anthropometric data for the mothers and their infants were also collected. Overall, 79 subjects were analyzed after excluding subjects with inadequate data in the food frequency questionnaire, insufficient breast milk samples, and medication that could affect dietary intakes. Trace element concentrations were determined by inductively coupled plasma mass spectrometry, and their correlation with several factors were investigated.

RESULTS

Trace element concentrations were widely distributed as previously reported. Median concentrations of Cr, Mn, Fe, Cu, Zn, Se, and Mo were 0.8, 0.8, 98, 50, 272, 2.2, and 0.7 µg/dL at 1 month postpartum and 0.6, 0.7, 55, 33, 177, 2.1, and 0.7 µg/dL at 3 months postpartum, respectively. There were no correlations between trace element concentrations and either mothers' intakes or infants' growth. In contrast, there were significant correlations between several trace elements and macronutrients in addition to inter-element correlations among almost all trace elements.

CONCLUSIONS

Trace element concentrations in mature breast milk were determined from recently lactating mothers in Japan.

Lead concentrations in breast milk of Moroccan nursing mothers and associated factors of exposure: CONTAMILK STUDY

The aim of CONTAMILK study was to estimate levels of contamination of breast milk (BM) of Moroccan nursing mothers by some xenobiotics including, lead (Pb), to identify associated factors of exposure and to determine the daily intake of newborns. Lead concentrations were determined in 70 samples of colostrum by ICPMS and a structured questionnaire was filled during milk collection to report participants' data. The median lead concentration was 908 μg/L (range 1.38-515,39 μg/L) and in 79 % of samples, levels were higher than the normal range reported by the World Health Organization (WHO) in BM (2-5 μg/L). Indeed, preterm delivery, frequency of use of cosmetic powders and lipsticks were significantly associated with the level of lead in BM. The estimated daily intake was greater than the tolerable daily intake (TDI) of the European food safety authority (0.5 μg/kg/day) for 39 babies and 6 babies according to the WHO (3.6 μg/kg/day).

The need to study human milk as a biological system

Critical advancement is needed in the study of human milk as a biological system that intersects and interacts with myriad internal (maternal biology) and external (diet, environment, infections) factors and its plethora of influences on the developing infant. Human-milk composition and its resulting biological function is more than the sum of its parts. Our failure to fully understand this biology in a large part contributes to why the duration of exclusive breastfeeding remains an unsettled science (if not policy). Our current understanding of human-milk composition and its individual components and their functions fails to fully recognize the importance of the chronobiology and systems biology of human milk in the context of milk synthesis, optimal timing and duration of feeding, and period of lactation. The overly simplistic, but common, approach to analyzing single, mostly nutritive components of human milk is insufficient to understand the contribution of either individual components or the matrix within which they exist to both maternal and child health. There is a need for a shift in the conceptual approach to studying human milk to improve strategies and interventions to support better lactation, breastfeeding, and the full range of infant feeding practices, particularly for women and infants living in undernourished and infectious environments. Recent technological advances have led to a rising movement towards advancing the science of human-milk biology. Herein, we describe the rationale and critical need for unveiling the multifunctionality of the various nutritional, nonnutritional, immune, and biological signaling pathways of the components in human milk that drive system development and maturation, growth, and development in the very early postnatal period of life. We provide a vision and conceptual framework for a research strategy and agenda to change the field of human-milk biology with implications for global policy, innovation, and interventions.

Human Milk Microbiota in an Indigenous Population Is Associated with Maternal Factors, Stage of Lactation, and Breastfeeding Practices

BACKGROUND

Human milk contains a diverse community of bacteria that are modified by maternal factors, but whether these or other factors are similar in developing countries has not been explored. Our objective was to determine whether the milk microbiota was modified by maternal age, BMI, parity, lactation stage, subclinical mastitis (SCM), and breastfeeding practices in the first 6 mo of lactation in an indigenous population from Guatemala.

METHODS

For this cross-sectional study, Mam-Mayan indigenous mothers nursing infants aged <6 mo were recruited. Unilateral human milk samples were collected (n = 86) and processed for 16S rRNA sequencing at the genus level. Microbial diversity and relative abundance were compared with maternal factors [age, BMI, parity, stage of lactation, SCM, and 3 breastfeeding practices (exclusive, predominant, mixed)] obtained through questionnaires.

RESULTS

Streptococcus was the most abundant genus (33.8%), followed by Pseudomonas (18.7%) and Sphingobium (10.7%) but relative abundance was associated with maternal factors. First, Lactobacillus and Streptococcus were more abundant in early lactation whereas the common oral (Leptotrichia) and environmental (Comamonas) bacteria were more abundant in established lactation. Second, Streptococcus,Lactobacillus,Lactococcus,Leuconostoc, and Micrococcus had a higher abundance in multiparous mothers compared with primiparous mothers. Third, a more diverse microbiota characterized by a higher abundance of lactic acid bacteria (Lactobacillus,Leuconostoc, and Lactococcus), Leucobacter, and Micrococcus was found in mothers with a healthy BMI. Finally, distinct microbial communities differed by stage of lactation and by exclusive, predominant, or mixed breastfeeding practices.

CONCLUSION

Milk bacterial communities in an indigenous community were associated with maternal factors. Higher microbial diversity was supported by having a healthy BMI, the absence of SCM, and by breastfeeding. Interestingly, breastfeeding practices when assessed by lactation stage were associated with distinct microbiota profiles.

Patterns and Determinants of Essential and Toxic Elements in Chinese Women at Mid-Pregnancy, Late Pregnancy, and Lactation

Maternal status of essential and toxic elements affects the health of the mother, developing fetus, or breastfeeding infant. However, few studies have examined the patterns of these elements and their determinants in pregnant or lactating women. Plasma samples of 1211 healthy mid-pregnant, late pregnant, and lactating women enrolled in coastland, lakeland, and inland areas of China from May–July 2014, were analyzed for concentrations of 15 elements, using inductively coupled plasma mass spectrometry. The adjusted median concentrations of elements varied by physiologic stage and region. Lactating versus pregnant women showed higher concentrations of Zn, Cr, Mo, Ni, Sb, Cd and Pb, but lower concentrations of Cu, I, Al and Hg. In pregnant women, the concentrations of Fe, Zn, I, Mo, Ni, Al, Hg and Cd were higher in mid- versus late-pregnancy. Overall, the highest concentrations were observed in Zn, I, Mn, Al, and Pb in coastland, in Hg in lakeland, and in Fe in inland area. Element concentrations varied by maternal age, pre-pregnancy BMI, education, parity, delivery mode, feeding practice, and intakes of aquatic products and mutton. In conclusion, essential and toxic elements coexisted in pregnant and lactating women, and their concentrations varied by physiologic stages, regions, maternal socio-demographic characteristics and dietary factors.

Estimating daily intakes of manganese due to breast milk, infant formulas, or young child nutritional beverages in the United States and France: Comparison to sufficiency and toxicity thresholds

BACKGROUND

Although manganese (Mn) is an essential nutrient, recent research has revealed that excess Mn in early childhood may have adverse effects on neurodevelopment.

METHODS

We estimated daily total Mn intake due to breast milk at average body weights by reviewing reported concentrations of breast milk Mn and measurements of body weight and breast milk intake at 3 weeks, 4.25 months, 7 months, and 18 months. We compared these figures to the Mn content measured in 44 infant, follow-up, and toddler formulas purchased in the United States and France. We calculated Mn content of formula products made with ultra-trace elemental analysis grade water (0 μg Mn/L) and with water containing 250 μg Mn/L, a concentration which is relatively high but less than the World Health Organization Health-based value of 400 μg Mn/L or the United States Environmental Protection Agency Health Advisory of 350 μg Mn/L.

RESULTS

Estimated mean daily Mn intake from breast milk ranged from 1.2 μg Mn/kg/day (3 weeks) to 0.16 μg Mn/kg/day (18 months), with the highest intakes at the youngest age stage we considered, 3 weeks. Estimated daily Mn intake from formula products reconstituted with 0 μg Mn/L water ranged from 130 μg Mn/kg/day (3 weeks) to 4.8 μg Mn/kg/day (18 months) with the highest intakes at 3 weeks. Formula products provided 28-520 times greater than the mean daily intake of Mn from breast milk for the 4 age stages that we considered. Estimated daily Mn intake from formula products reconstituted with water containing 250 μg Mn/L ranged from 12 μg Mn/kg/day to 170 μg Mn/kg/day, which exceeds the United States Environmental Protection Agency Reference Dose of 140 μg Mn/kg/day for adults.

CONCLUSIONS

Mn deficiency is highly unlikely with exclusive breast milk or infant formula feeding, but established tolerable daily intake levels for Mn may be surpassed by some of these products when following labeled instructions.

Total metal content and chemical speciation analysis of iron, copper, zinc and iodine in human breast milk using high-performance liquid chromatography separation and inductively coupled plasma mass spectrometry detection

The aim of this research was to quantify essential trace elements (iron, copper, zinc and iodine) and establish their speciation in human milk. Both the element and the species are important in new-born nutrition. Colostrum, and transitional and mature milks (25) were collected from 18 mothers of pre-term or full-term infants. Concentrations of the target elements were determined using ICP-MS. For speciation, HPLC coupled to ICP-MS was employed. Total contents of the micronutrients varied in mothers of pre-term (Fe = 0.997, Cu = 0.506, Zn = 4.15 and I = 0.458 mg L^-1) and mothers of full-term (Fe = 0.733, Cu = 0.234, Zn = 2.91 and I = 0.255 mg L^-1) infants. Fe, Cu and Zn were associated with biomolecules with high molecular mass compounds, such as immunoglobulins, albumin and lactoferrin whilst iodine was only found as iodide.

Systematic Review of the Literature of Factors Affecting the Exposure and the Levels of Lead in Human Breast Milk

Human milk may sometimes contain chemical contaminants, which could have adverse effects on neonates or nursing infants. Lead (Pb) is of considerable interest due to its toxicity and occurrence. Furthermore, it has been suggested that human milk is a significant potential source of lead exposure to nursing infants. A systematic literature search in PubMed, Science Direct, and Google Scholar databases was performed to identify relevant studies, published in English until 2017, that investigated and explored common factors affecting the level of lead in human milk among lactating women around the world. Forty-nine papers were rated and explored the effect of one or several factors on the level of lead in human milk from 28 countries and carried out over a wide time frame from 1983 to 2017 and through Europe, Asia, America, and Africa, reviewing more than 5,000 subjects. Place of residence, maternal age, stage of lactation, smoking habits, maternal dietary intakes, and parity were the mostly assessed factors among the studies and considered as the main factors affecting Pb levels in BM. Other factors were not studied well enough and considered minor because few surveys evaluated their impacts. However, the literature findings are very controversial.

Inhibiting the copper efflux system in microbes as a novel approach for developing antibiotics

Five out of six people receive at least one antibiotic prescription per year. However, the ever-expanding use of antibiotics in medicine, agriculture, and food production has accelerated the evolution of antibiotic-resistant bacteria, which, in turn, made the development of novel antibiotics based on new molecular targets a priority in medicinal chemistry. One way of possibly combatting resistant bacterial infections is by inhibiting the copper transporters in prokaryotic cells. Copper is a key element within all living cells, but it can be toxic in excess. Both eukaryotic and prokaryotic cells have developed distinct copper regulation systems to prevent its toxicity. Therefore, selectively targeting the prokaryotic copper regulation system might be an initial step in developing next-generation antibiotics. One such system is the Gram-negative bacterial CusCFBA efflux system. CusB is a key protein in this system and was previously reported to play an important role in opening the channel for efflux via significant structural changes upon copper binding while also controlling the assembly and disassembly process of the entire channel. In this study, we aimed to develop novel peptide copper channel blockers, designed by in silico calculations based on the structure of CusB. Using a combination of magnetic resonance spectroscopy and various biochemical methods, we found a lead peptide that promotes copper-induced cell toxicity. Targeting copper transport in bacteria has not yet been pursued as an antibiotic mechanism of action. Thus, our study lays the foundation for discovering novel antibiotics.

A prophylactic multi-strain probiotic treatment to reduce the absorption of toxic elements: In-vitro study and biomonitoring of breast milk and infant stools

Potential exposure to toxic elements initially occurs during gestation and after birth via breast milk, which is the principal source of nutrients for infants during the first months of life. In this study, we evaluated whether maternal oral supplementation with a multi-strain probiotic product can protect infants from exposure to arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) via breast milk. In-vitro studies of the bacterial strains present in this probiotic product showed a high bacterial tolerance for As, Cd, Hg, and Pb, and good binding capacity for Cd, Hg, and Pb (72%, 81%, and 64%, respectively) within 1 h of contact. We evaluated concentrations (5 mg L^-1 for Cd and Pb, and 2 mg L^-1 for Hg) that largely exceeded the provisional tolerable weekly intake of these toxic elements via food or water applicable for human consumption. Changes in the levels of these elements in breast milk and newborn stools were evaluated in the control (orally supplemented with placebo) and experimental (orally supplemented with probiotic) groups at birth (t0), 15 days (t15), and 30 days (t30) after delivery. Elemental analysis of breast milk did not show significant differences between the control and experimental groups at different stages of lactation; however, stool samples obtained from newborns of mothers supplemented with the probiotic product showed that Cd levels were significantly reduced (by 26%) at t15 compared with the levels of the controls. Our data did not show an association between concentration of toxic elements in breast milk and that in newborn stools. Indeed, the concentration of Cd, Hg, and Pb in breast milk decreased during the lactation period, whereas the levels of these elements in newborn stools were stable over time. Although our in-vitro data indicate that the consortium of these probiotic strains can absorb toxic compounds, this study was limited by its small sample size and potential uncontrolled confounding effects, such as maternal diet and lifestyle. Therefore, we could not confirm whether prophylactic use of this probiotic product can reduce the absorption of toxic elements. The risk assessment in the studied population evidenced a margin of exposure (MOE) of 1, or between 1 and 10 for Pb, and lower than 50 for As. This poses a potential risk for breastfed infants, indicating that interventions aimed to avoid breastfeeding-related health risks remain a major challenge in public health.

Dietary Manganese Exposure in the Adult Population in Germany-What Does it Mean in Relation to Health Risks?

Manganese is both an essential nutrient and a potential neurotoxicant. Therefore, the question arises whether the dietary manganese intake in the German population is on the low or high side. Results from a pilot total diet study in Germany presented here reveal that the average dietary manganese intake in the general population in Germany aged 14-80 years is about 2.8 mg day^-1 for a person of 70 kg body weight. This exposure level is within the intake range of 2-5 mg per person and day as recommended by the societies for nutrition in Germany, Austria, and Switzerland. No information on the dietary exposure of children in Germany can be provided so far. Although reliable information on health effects related to oral manganese exposure is limited, there is no indication from the literature that these dietary intake levels are associated with adverse health effects either by manganese deficiency or excess. However, there is limited evidence that manganese taken up as a highly bioavailable bolus, for example, uptake via drinking water or food supplements, could pose a potential risk to human health-particularly in certain subpopulations-when certain intake amounts, which are currently not well defined, are exceeded.

Evaluation of Essential and Toxic Elements in Amniotic Fluid and Maternal Serum at Birth

The objective of this study was to determine the concentration and the reference ranges of essential and toxic elements in amniotic fluid (AF) and maternal serum (MS) at birth. This study was conducted among 175 healthy pregnant Caucasian European women aged 18-42. AF and maternal blood samples were collected during delivery. An inductively coupled plasma mass spectrometry (ICP-MS) technique was used to determine the levels of Mg, Co, Cu, Zn, Sr, Cd, Ba, Pb, U, Ca, Cr, Al, Mn, V, Fe, As, Se and Sb in AF and MS. The range of reference values was calculated for all analyzed elements in the serum and AF. The mean concentrations of elements, except Pb, were generally higher in MS than in AF. Multiple regression analysis showed that the maternal/newborn body mass (MBM/NBM) ratio was a strong negative predictor (among maternal age and gravidity) of Mg concentration in amniotic fluid. In the serum, MBN/NBM ratio was a strong positive predictor of Cu concentration. Moreover, regression analysis showed that maternal age was an independent positive predictor of the Se level in maternal serum. The reference value ranges of 18 essential and toxic elements were established in AF and MS among a population of healthy pregnant Polish women at delivery. The level of Mg, Co, Cu, Ca and Se in AF and MS can be determined by maternal age and MBM/NBM ratio. These results can be useful in counseling individuals with pregnancies affected by exposure to one of the parameters under investigation.

Elemental metabolomics

Elemental metabolomics is quantification and characterization of total concentration of chemical elements in biological samples and monitoring of their changes. Recent advances in inductively coupled plasma mass spectrometry have enabled simultaneous measurement of concentrations of > 70 elements in biological samples. In living organisms, elements interact and compete with each other for absorption and molecular interactions. They also interact with proteins and nucleotide sequences. These interactions modulate enzymatic activities and are critical for many molecular and cellular functions. Testing for concentration of > 40 elements in blood, other bodily fluids and tissues is now in routine use in advanced medical laboratories. In this article, we define the basic concepts of elemental metabolomics, summarize standards and workflows, and propose minimum information for reporting the results of an elemental metabolomics experiment. Major statistical and informatics tools for elemental metabolomics are reviewed, and examples of applications are discussed. Elemental metabolomics is emerging as an important new technology with applications in medical diagnostics, nutrition, agriculture, food science, environmental science and multiplicity of other areas.

Exposure to heavy metals released to the environment through breastfeeding: A probabilistic risk estimation

Toxic heavy metals released into the environment through various anthropogenic activities, raising concerns over their potential adverse effects on human health and the environment. Biological monitoring studies are of great value in toxicological research for estimation of such health effects. The aim of this study was to evaluate the concentrations of lead (Pb), arsenic (As), and chromium (Cr) in the breast milk of urban mothers in Hamadan city, Iran and the accompanying health risk to infants. A total of 100 lactating mothers were recruited from public health care centers in Hamadan city and breast milk samples were collected at 2, 6, 8, and 12 months postpartum. Inductively coupled plasma mass spectroscopy (ICP-MS) has been used to measure target heavy metal concentrations. The median breast milk concentrations of Pb, As, and Cr were 41.90, 0.50, and 3.95 μg/L, respectively. The highest levels of Pb were observed after two months of delivery (with the mean of 96.69 μg/L and median of 45.70 μg/L). Up to 94% of the breast milk samples exceeded the WHO limit suggested for lead contamination of breast milk (<5 μg/L). The breast milk As and Cr contents were above the limit of detection (LOD) in 19% and 76% of samples, respectively. Unacceptable non-cancer health risk levels or hazard quotient (HQ) were found for Pb and As in 61% and 10% of the samples, respectively. Nevertheless, HQ from Cr was <1.0 for 100% of breastfeeding infants. Finally, our results indicated that there may be a potential risk of toxic metals, especially lead, for infants in Hamadan via the consumption of mothers' breast milk.

Impact of delivery mode on the levels of essential trace elements in breast milk

Aim: This study investigated whether the parturition mode (vaginal or cesarean [C-] section) affects breast milk concentrations of four essential trace elements (iron, copper, zinc, and manganese).Methods: Women giving birth at seven hospitals in seven different regions of China were enrolled in the study. Each participant provided breast milk, collected on postpartum day 3-5, for determination of iron, copper, zinc, and manganese concentrations. Breast milk concentrations of the subject trace elements were compared between women giving birth vaginally or via C-section.Results: Of the 1243 women enrolled in the study, 617 (49.6%) gave birth via the vaginal route and 626 (50.4%) delivered via C-section. The mean milk concentrations of iron, copper, zinc, and manganese in the milk of women delivering via the vaginal route were higher than those in the milk of women delivering via C-section; only the copper concentration differences were statistically significant, after adjusting for confounding factors (p = .023).Conclusion: Delivery mode impacts breast milk concentrations of essential trace elements, with vaginal delivery being associated with higher essential trace element concentrations than C-sections.

Analysis of aluminum, minerals and trace elements in the milk samples from lactating mothers in Hamadan, Iran

The present cross-sectional study is aimed at analyzing the breast milk of lactating mothers in Hamadan, Iran for aluminum and several minerals and trace elements. Ten governmental health care centers were utilized to facilitate collection of breast milk samples. The breast milk samples were collected at 1, 2, 6, 7, and 12 months postpartum from one hundred healthy lactating women, who delivered full-term newborns. Detection of sodium (Na), zinc (Zn), calcium (Ca), iron (Fe), copper (Cu), magnesium (Mg) and aluminum (Al) levels was conducted with the use of Inductively Coupled Plasma Mass Spectrometry (ICP-MS). This method has shown high accuracy, precision, sensitivity, and linearity for the wide range of concentrations. The accumulated data were not normally distributed; thus, the non-parametric Mann-Whitney U test was used in the statistical analysis of the results. Mean concentrations of Fe, Zn, Cu, Ca, Mg, and Na were 0.75, 1.38, 0.35, 255, 34.58, and 155.72 μg/mL, respectively. The mean level of Al, a well-known neurotoxic metal, was determined to be an alarming 0.191 μg/mL. Moreover, 95% of participants contained very harmful concentrations of Al in their milk. This study also revealed Zn deficiency in about 50% of milk samples. Further investigation is needed to elucidate sources of exposure and factors that may influence maternal and fetal exposure to aluminum.

Trace Element Concentrations in Beef Cattle Related to the Breed Aptitude

Animal feed has traditionally been supplemented with trace elements at dietary concentrations well above physiological needs. However, environmental concerns have led to calls for better adjustment of mineral supplementation to actual physiological needs and, in this context, consideration of breed-related differences in trace element requirements. The aim of this study was to analyze trace element concentrations in the main breeds used for intensive beef production in northern Spain (Holstein-Friesian [HF], Galician Blonde [GB], and GB × HF cross). Samples of blood, internal organs, and muscle were obtained at slaughter from 10 HF, GB, and GB × HF cross calves in the same feedlot. Overall, trace element concentrations in serum and internal organs were within adequate ranges and did not differ between those of breeds, suggesting that trace mineral supplementation was adequate in all groups. The only exception to this was copper, and hepatic copper concentrations were above adequate levels in all calves. This was particularly evident in the HF calves, and the maximum recommended level for human consumption was exceeded in 90% of these animals. Copper, iron, manganese, selenium, and zinc concentrations in muscle were significantly higher in the HF than those in the GB calves, with intermediate values for the crosses. These breed-related differences in trace element concentrations in the muscle may be related to lower muscle mass and/or higher hepatic activity in the HF (dairy) calves than in GB (beef) calves. As meat is an essential source of highly available trace elements in human diets, breed-related differences in trace element concentrations in meat deserve further investigation.

Optimization and validation of a fast digestion method for the determination of major and trace elements in breast milk by ICP-MS

Breast milk guarantees all the nutrients required by infants during their first few months of life and remains the most important food source for their health and growth. However, the mother may transfer potentially toxic chemicals to the suckling infant through breastfeeding. The aim of this study was to optimize and validate a fast method for the determination of a total content of 34 elements (Al, As, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, Sb, Se, Si, Sn, Sr, Te, Ti, Tl, U, V, and Zn) in liquid and lyophilized breast milk. The samples were subjected to HNO₃:H₂O₂ (2:1) digestion in an open vessel heated in a water bath (WBD; 80 °C) and subsequently analysed by quadrupole inductively coupled plasma mass spectrometry equipped with a collision-reaction interface. The performance of the proposed method was evaluated in terms of selectivity, detection and quantification limits, linearity, accuracy, and robustness by using standard reference materials and filed samples of breast milk. Compared to microwave-assisted acid digestion, the proposed open vessel digestion allows a significant reduction in treatment time and sample manipulation, while maintaining a similar analytical performance. Masses of 0.5 g of breast milk were efficiently digested with the WBD treatment allowing a residual carbon content lower than 60 mg L^-1 and a residual acidity lower than 0.87 mol L^-1 in final digested samples. Thus, it shows great potential for application to routine analysis. The method provides satisfactory detection limits and good performance (trueness and recovery percentages 80-111%; coefficient of variation <10%; and relative repeatability <15%) and allows a high sample throughput for multi-elemental determination in human biomonitoring studies.

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.

Evaluation of Mineral Concentrations in Maternal Serum Before and After Birth and in Newborn Cord Blood Postpartum-Preliminary Study

The mineral levels in maternal serum change during pregnancy and may be correlated with those of newborn cord blood. The aim of this study was to evaluate the concentrations of calcium (Ca), magnesium (Mg), zinc (Zn), iron (Fe), and copper (Cu) in maternal blood before and after delivery and in umbilical cord vein and artery serum. The study was carried out in 64 Caucasian pregnant women who delivered in a district hospital in Greater Poland region, aged 28.1 ± 5.4 years, with a mean gestational age of 39.2 ± 1.3 weeks. Blood samples were taken from women 2-8 h before delivery and immediately after childbirth. The umbilical cord artery and vein blood of newborns was obtained immediately after childbirth. The levels of minerals in serum were determined by flame atomic absorption spectrometry. A significant drop in the concentrations of Mg (17.71 ± 1.51 vs 17.07 ± 1.61 μg/ml; p < 0.007), Fe (1.08 ± 0.46 vs 0.82 ± 0.35 μg/ml; p < 0.0004), and Zn (0.63 ± 0.17 vs 0.46 ± 0.16; p < 0.0001) in maternal serum was found after delivery. Moreover, higher levels of Ca, Fe, and Zn and lower levels of Cu were observed in the umbilical vein (Ca: 102.80 ± 7.80 μg/ml; p < 0.0001, Fe: 1.96 ± 0.43 μg/ml; p < 0.0001, Zn: 0.65 ± 0.16 μg/ml; p < 0.0001, Cu: 0.36 ± 0.09 μg/ml; p < 0.0001) and in the umbilical artery cord blood (Ca: 98.07 ± 8.18 μg/ml; p < 0.0001, Fe: 1.63 ± 0.30 μg/ml; p < 0.0001, Zn: 0.65 ± 0.15 μg/ml; p < 0.0001, and Cu: 0.36 ± 0.10 μg/ml; p < 0.0001) compared to the maternal serum (Ca: 85.05 ± 10.76 μg/ml, Fe: 0.82 ± 0.35 μg/ml, Zn: 0.46 ± 0.16 μg/ml, and Cu: 1.90 ± 0.35 μg/ml). Fe levels in the cord artery serum negatively correlated with blood loss during delivery (R = -0.48; p = 0.01), while the Ca concentration in the maternal serum after birth decreased with the age of the women (R = -0.25; p = 0.03). In conclusion, it seems that the process of birth alters the mineral levels in pregnant women's blood. Moreover, it was found that blood loss and the age of the mother are associated with mineral concentrations in the maternal serum and cord artery blood.

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.

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.

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.

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.

Bio-accumulation of some heavy metals in blood serum of residents in Isfahan and Shiraz, Iran

In this study, some heavy metal (Cd, Pb, Ni, Fe, Co, Cr, Mn, Cu, and Zn) concentrations were measured in the blood serum samples of 25 patients who suffered from the multiple sclerosis (MS) disease living in two industrial regions of Isfahan, Iran, using inductively coupled plasma (ICP) instrument. Also, blood serum levels of heavy metals in 25 healthy people of Isfahan and 25 healthy people of Shiraz were analyzed as controls. In industrial regions, some of the heavy metals were also measured in the soils and food crop samples (wheat, rice, and onion). The results showed that the blood serum levels of Cd, Co, Ni, and Pb of MS patients (0.032, 0.56, 1.60, and 2.90 μg L(-1), respectively) were significantly higher than those of healthy people. These values exceeded the permissible ranges that are 0.08-0.50, 0.14-1.0, and 0.80-2.50 μg L(-1) for the Co, Ni, and Pb, respectively. The mean concentrations of Fe and Zn in the blood serum of MS patients (529 and 547 μg L(-1)) were significantly lower than those in the healthy people and also less than the acceptable ranges (700-1700 and 660-1100 μg L(-1), respectively). The target hazard quotients of Pb (2.23) and Cd (1.25) via wheat and Pb (1.34) via rice consumption were higher than one. Therefore, it is proposed that consumption of local contaminated food crops may have drastically increased the concentrations of heavy metals in the human blood serum of inhabitants of industrial regions.