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

Individualized support for breastfeeding in a case of elevated blood lead levels: A case report

Introduction

Lead is a known toxicant that affects all tissues in the body, most notably the brains of developing children. However, there are limited data on the dynamics of lead transfer via breastmilk and its short-term and long-term consequences. Much of the available data come from areas of the world where numerous sources of lead complicate our understanding of the effects of lead exposure via breast milk.

Case Presentation

We present trends in blood lead levels in a breastfeeding dyad, where the only source of lead exposure identified was prior to pregnancy, without other known ongoing lead exposures for the lactating parent or infant.

Discussion and Conclusions

In this case, all lead exposure in the infant was presumed to come from in utero transmission and breastfeeding; and infant blood lead levels varied significantly with initiation and interruption of breastfeeding. This case is discussed in the context of current models for predicting transfer of lead in breastmilk and highlights pathophysiologic considerations for understanding lead transfer in the breastfeeding dyad.

High arsenic contamination in the breast milk of mothers inhabiting the Gangetic plains of Bihar: a major health risk to infants

Groundwater arsenic poisoning has posed serious health hazards in the exposed population. The objective of the study is to evaluate the arsenic ingestion from breastmilk among pediatric population in Bihar. In the present study, the total women selected were n = 513. Out of which n = 378 women after consent provided their breastmilk for the study, n = 58 subjects were non-lactating but had some type of disease in them and n = 77 subjects denied for the breastmilk sample. Hence, they were selected for the women health study. In addition, urine samples from n = 184 infants' urine were collected for human arsenic exposure study. The study reveals that the arsenic content in the exposed women (in 55%) was significantly high in the breast milk against the WHO permissible limit 0.64 µg/L followed by their urine and blood samples as biological marker. Moreover, the child's urine also had arsenic content greater than the permissible limit (< 50 µg/L) in 67% of the studied children from the arsenic exposed regions. Concerningly, the rate at which arsenic is eliminated from an infant's body via urine in real time was only 50%. This arsenic exposure to young infants has caused potential risks and future health implications. Moreover, the arsenic content was also very high in the analyzed staple food samples such as rice, wheat and potato which is the major cause for arsenic contamination in breastmilk. The study advocates for prompt action to address the issue and implement stringent legislative measures in order to mitigate and eradicate this pressing problem that has implications for future generations.

Evaluating Heavy Metals in Human Breast Milk: a Cross-Sectional Study from Mining and Agricultural Areas in Northwestern Iran

This study aimed to assess the levels of heavy metals in the breast milk of women residing in the mining and agricultural areas of East Azerbaijan province in Iran. This cross-sectional study analyzed 68 lactating mothers from mining (n = 28) and agricultural (n = 40) areas of East Azerbaijan province in Iran between June 2022 and March 2023. The study used an Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) to measure the concentrations of heavy metals, including arsenic (As), chromium (Cr), copper (Cu), and iron (Fe). A semi-quantitative food frequency questionnaire (SQ-FFQ) was used to collect data on the dietary and sociodemographic characteristics of the mothers. Although the concentration of arsenic (As) was below the limit of detection (LOD), the mean concentrations of chromium (Cr), copper (Cu), and iron (Fe) were 1.11, 0.87, and 13.25 mg/L in agricultural areas and 0.83, 0.93, and 11.35 mg/L in mining areas, respectively. The concentrations of Cr (p < 0.001) and Fe (p = 0.019) were significantly higher in the breast milk of women residing in agricultural areas. However, the concentration of Cu was significantly higher (p = 0.085) in the breast milk of women living in mining areas. Additionally, lactation age had a significant effect on Cu levels (p = 0.015), with a negative coefficient of -0.011. The study indicates that the levels of heavy metals in breast milk can be influenced by the exposure to pesticides, fertilizers, volcanic soil, and disparities in access to post-natal care and iron supplements.

Reference intervals of 24 trace elements in blood, plasma and erythrocytes for the Slovenian adult population

OBJECTIVES

The aim of the present study was to establish the population- and laboratory-specific reference intervals (RIs) for the Slovenian adult population for 24 trace elements (TEs) in blood, plasma and erythrocytes and to evaluate the impact of gender, age, seafood consumption, smoking habits and amalgam fillings on TEs levels.

METHODS

TEs (Mn, Co, Cu, Zn, Se and Mo, Li, Be, V, Cr, Ni, Ga, As, Rb, Sr, Ag, Cd, Sn, Cs, Au, Hg, Tl, Pb and U) were determined in 192 a priori selected blood donors (107 women and 85 men, aged 18-65 years), using inductively coupled plasma mass spectrometry (ICP-MS) with the Octopole Reaction System. Participants filled out a questionnaire, and RIs were established according to the Clinical and Laboratory Standards Institute (CLSI) guidelines for TEs.

RESULTS

Uniform RIs for non-essential and gender-specific for essential TEs in blood, plasma and erythrocytes were established. In our population, higher blood and plasma Cu, and erythrocyte Mn levels in women were found. In men, blood Zn, plasma Zn, Mn and Se, and erythrocyte Cu levels were higher. Zn levels were higher in 30-39 years age group. Pb and Sr increased with age. Smoking positively affected Cd, Pb, Cs and Rb; seafood consumption increased As, Hg and Zn; and amalgam increased Hg, Ag and Cu levels.

CONCLUSIONS

Essential TEs were inside recommended levels, and the non-essential ones were far below critical levels. Established RIs will provide an important foundation for clinical diagnostics, safety erythrocyte transfusions assessment, toxicology and epidemiological studies.

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.

Accumulation characteristics of metals in human breast milk and association with dietary intake in northeastern China

The trace elements present in breast milk play a vital role in the growth and development of infants. Nevertheless, numerous studies have reported the presence of toxic metal contamination in breast milk from various countries and regions, which poses potential risks to breastfed infants. This article aimed to investigate the characteristics of trace elements in breast milk and explore the relationship between breast milk and diet in Dalian, a coastal city in northeastern China. Breast milk samples and representative local food samples were collected from Dalian for research. The results revealed that 57 % of breast milk samples significantly exceeded the WHO safety limit (0.6 μg/L) for arsenic, with a measured mean value of 0.96 μg/L. Moreover, the levels of chromium (mean value: 2.63 μg/L) in 34 % of breast milk samples exceed the WHO recommended safety level (chromium: 1.5 μg/L). Aquatic foods accounted for 60 % to 90 % of the total intake of arsenic, cadmium, vanadium, mercury, and lead. The Spearman correlation analysis demonstrated strong positive correlations among breast milk metal elements, including copper-zinc (r = 0.68) and nickel‑chromium (r = 0.89). Furthermore, the food-to-milk accumulation factors (FMAF) of strontium, nickel, arsenic, vanadium, cadmium, and mercury were relatively low (median values <0.005). While the FMAF values for chromium and lead were higher, with median values of 0.038 and 0.07, respectively. The results indicated potential risks of the toxic metal arsenic in breast milk from Dalian, China for breastfed infants. Therefore, continuous monitoring of breast milk for toxic metals and foodborne contamination is necessary.

Involvement of Nrf2 Signaling in Lead-induced Toxicity

Nuclear factor erythroid 2-related factor 2 (Nrf2) is used as one of the main protective factors against various pathological processes, as it regulates cells resistant to oxidation. Several studies have extensively explored the relationship between environmental exposure to heavy metals, particularly lead (Pb), and the development of various human diseases. These metals have been reported to be able to, directly and indirectly, induce the production of reactive oxygen species (ROS) and cause oxidative stress in various organs. Since Nrf2 signaling is important in maintaining redox status, it has a dual role depending on the specific biological context. On the one hand, Nrf2 provides a protective mechanism against metal-induced toxicity; on the other hand, it can induce metalinduced carcinogenesis upon prolonged exposure and activation. Therefore, the aim of this review was to summarize the latest knowledge on the functional interrelation between toxic metals, such as Pb and Nrf2 signaling.

Breastmilk cadmium levels and estimated infant exposure: a multicenter study of associated factors in a resource-limited country

BACKGROUND

Despite the undisputed benefits of breastfeeding, infants might become exposed to xenobiotics that could be excreted into breast milk following maternal exposure. This study was conducted to assess breastmilk cadmium levels among lactating women in Palestine, a resource-limited country. Estimated daily intake (EDI) of cadmium via breastmilk was also calculated and predictors of high breastmilk cadmium levels and high infant exposure via breastmilk were identified.

METHODS

This multicenter study was conducted using a descriptive-analytical design. The lactating women were recruited from different maternity and public health clinics in all regions of Palestine. Demographic variables and exposure to sources of cadmium were collected in an interviewer-administered questionnaire. Foremilk samples (about 5 mL) were collected in polyethylene tubes using the hand-expression technique. The breast milk samples were collected in the period between December 2020 and March 2021. A pre-validated method using inductively coupled plasma mass spectrometry (ICP-MS) was used to quantify breastmilk cadmium levels. EDI values were calculated from the quantified breastmilk cadmium levels.

RESULTS

Breastmilk samples were obtained from 256 lactating women. The mean breastmilk cadmium level was 0.34 (SD: 0.33) μg / L and the mean EDI of cadmium via breastmilk was 0.059 (SD: 0.058) µg / kg per body weight / day. Breastmilk cadmium levels were quantified in 92.6% of the breastmilk samples. Of the breastmilk samples, 13 (5.1%) had cadmium levels above those reported as "normal" by the World Health Organization (WHO). Multiple linear regression showed that higher breastmilk cadmium levels and higher EDI were predicted by being a smoker, living in a refugee camp, living close to an industrial area, living close to disposal of wastes, living close to paint shops, living in a house with peeling / chipping paint, frequent use of cosmetics, frequent use of hair dyes, and not using vitamins.

CONCLUSION

The breastmilk cadmium levels and infant exposure were predicted by maternal exposure to sources of cadmium. The findings reported in this study are valuable to antenatal and postnatal healthcare service providers. More studies are needed to plan and implement measures to reduce breastmilk cadmium levels and infants' exposure to cadmium via breastmilk.

Ascorbic acid attenuates cadmium-induced myocardial hypertrophy and cardiomyocyte injury through Nrf2 signaling pathways comparable to resveratrol

Chronic cadmium (Cd) exposure severely affects the structural integrity of the heart, leading to cardiovascular disease. This study investigates the protective role of ascorbic acid (AA) and resveratrol (Res) in cellular defense against Cd-induced cardiomyocyte damage and myocardial hypertrophy in H9c2 cardiomyocytes. Experimental results showed that AA and Res treatment significantly increased cell viability, reduced ROS production, attenuated lipid peroxidation, and increased antioxidant enzyme activity in Cd-induced H9c2 cells. AA and Res decreased the mitochondrial membrane permeability and protected the cells from Cd induced cardiomyocyte damage. This also suppressed the pathological hypertrophic response triggered by Cd, which increased the cell size of cardiomyocytes. Gene expression studies revealed that cells treated with AA and Res decreased the expression of hypertrophic genes ANP (two-fold), BNP (one-fold) and β- MHC (two-fold) compared to Cd exposed cells. AA and Res promoted the nuclear translocation of Nrf2 and increased the expression of antioxidant genes (HO-1, NQO1, SOD and CAT) during Cd mediated myocardial hypertrophy. This study proves that AA and Res play a significant role in improving Nrf2 signaling, thereby reversing stress-induced injury, and facilitating the regression of myocardial hypertrophy.

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.