Associations of environmental exposures to methylmercury and selenium with female infertility: A case-control study

Associations between follicular fluid trace elements and ovarian response during in vitro fertilization

INTRODUCTION

Exposure to trace elements has been associated with ovarian response in experimental studies. We conducted a hypothesis-generating study of associations between ovarian follicular fluid (FF) trace elements and measures of ovarian response among women using in vitro fertilization (IVF).

METHODS

We collected ovarian FF specimens from 56 women. We determined concentrations (μg/L) of 11 trace elements using inductively coupled plasma-tandem mass spectrometry. We estimated associations between women's FF trace elements per interquartile range difference, and measures of ovarian response using linear (peak estradiol (E2), baseline anti-mullerian hormone (AMH), and follicle stimulating hormone (FSH)) and negative binomial (baseline antral follicle count (AFC) and oocyte count) regression, adjusting for confounding factors. We used principal component analysis (PCA) to estimate the associations of the FF trace elements mixture. We also explored FF oxidative stress enzymes as causal mediators of the associations.

RESULTS

Higher FF cobalt was associated with greater peak E2 (mean difference = 351.48 pg/mL; 95%CI: 21.76, 724.71) and AFC (rate ratio = 1.14; 95%CI: 1.01, 1.28), and higher FF copper was associated with greater peak E2 (mean difference = 335.66 pg/mL; 95%CI: 81.77, 753.08) and oocyte count (rate ratio = 1.19; 95%CI: 1.02, 1.43). Higher FF mercury was also associated with greater peak E2 (mean difference = 410.70 pg/mL; 95%CI: 61.90, 883.39). Higher FF lead was associated with lesser AFC (rate ratio = 0.85; 95%CI: 0.73, 0.98). Using PCA, the mixture of Sr, Hg, and As was associated with higher peak estradiol, AFC, and oocyte count. FF glutathione peroxidase, paraoxonase, and arylesterase activities were inconsistent mediators of the associations, but the effect estimates were imprecise.

CONCLUSION

Our results suggest that essential and non-essential trace elements in FF were associated with ovarian response during IVF.

Exposure to potentially toxic elements (PTEs) and the risk of male infertility- A Systematic review and meta-analysis

BACKGROUND

Infertility has been defined as a failure to conceive for at least 12 months of regular unprotected sexual intercourse. The male factors are responsible for about 50 % of cases. Various factors such as endocrine, immunological, genetic, exposure to toxicants, and idiopathic factors are involved in male infertility. Recently, the role of PTEs in reproductive performance has been explored by various studies.

OBJECTIVES

Current systematic review and meta-analysis have been carried out to compile and statistically analyze the findings of relevant studies and reach some conclusion.

METHODOLOGY

A literature search was done according to the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines in three scientific literature databases; PubMed, Google Scholar, and Science Direct. Meta-analysis was performed using Review Manager 5.4 software. The study's protocol was registered in PROSPERO (CRD42023465776).

RESULTS

Meta-analysis of lead in the blood of infertile cases and healthy controls indicated a significant association with male infertility, observed standard mean difference (SMD) was 0.67 at 95 % confidence interval (CI) (0.07, 1.28), and p = 0.03. In the case of lead analysis in semen, the values are as follows: SMD = 1.19 at 95 % CI (0.42, 1.96) with p = 0.002. Significant association appears for cadmium in semen with SMD 0.92 at 95 % CI (0.54, 1.29) and p < 0.00001. No significant association was observed for arsenic, barium, and mercury in blood.

CONCLUSION

Most of the studies focus on the detection of PTE in semen samples followed by blood as sample type. Lead and cadmium exposure is significantly associated with male infertility. However, non-significant results for arsenic, barium, and mercury are observed.

Mercury, natural fertility and outcomes of assisted reproduction: A systematic review

The primary route of mercury exposure for the general population is through consumption of contaminated seafood. There is a biological basis for an adverse effect of mercury exposure on human fertility. The goal of this review was to evaluate the existing literature on the association between mercury and pregnancy, among men and women attempting to conceive with and without assisted reproductive technology (ART). Systematic searches were performed in PubMed, EMBASE, Scopus and Web of Science for papers published up to March 2023 with no early date restriction, only including studies with a biomarker measurement of mercury exposure. We identified 11 studies examining mercury and natural fertility and 12 studies examining mercury and outcomes of assisted reproduction (implantation or clinical pregnancy). The accumulated evidence provides some support for a null association between bodily mercury concentrations and natural fertility among women, however, a large proportion of studies did not report adjusted estimates or were extremely imprecise. The majority of studies of natural fertility were also cross-sectional in nature. There was no evidence for an inverse or null association between mercury and natural fertility among men, or mercury and ART outcomes among men or women. In spite of biological plausibility, the existing evidence includes studies that are imprecise and often conflicting and does not allow us to make definitive conclusions on the associations of mercury exposure with successful pregnancy. Additional, larger studies are warranted, especially among individuals with high concentrations of mercury exposure as these individuals may be underrepresented in the current literature.

Bioaccumulation of Non-Essential Trace Elements Detected in Women's Follicular Fluid, Urine, and Plasma Is Associated with Poor Reproductive Outcomes following Single Euploid Embryo Transfer: A Pilot Study

This study aims to determine the association of non-essential trace elements present in follicular fluid, plasma, and urine with reproductive outcomes of women undergoing intracytoplasmic sperm injection (ICSI), preimplantation genetic testing for aneuploidies (PGT-A) and single frozen euploid embryo transfer (SET/FET). This single-center, prospective cohort study included sixty women undergoing ICSI with PGT-A and SET/FET between 2018 and 2019. Urine, plasma and follicular fluid samples were collected on the vaginal oocyte retrieval day to simultaneously quantify ten non-essential trace elements (i.e., Ba, Sr, Rb, Sn, Ti, Pb, Cd, Hg, Sb, and As). We found several associations between the levels of these non-essential trace elements and clinical IVF parameters. Specifically, the increased levels of barium in follicular fluid were negatively associated with ovarian function, pre-implantation development and embryo euploidy, while elevated strontium concentrations in this biofluid were negatively associated with impaired blastulation and embryo euploidy. Elevated plasma strontium levels were negatively associated with ovarian function, fertilization and blastulation. Enhanced presence of other trace elements in plasma (i.e., rubidium and arsenic) were associated with a diminished ovarian function and limited the number of recovered oocytes, mature oocytes and zygotes, respectively. Fully adjusted models suggested significantly lower odds of achieving a live birth when increased concentrations of barium and tin were found in urine.

Comparison between pollutants found in breast milk and infant formula in the last decade: A review

Since ancient times, breastfeeding has been the fundamental way of nurturing the newborn. The benefits of breast milk are widely known, as it is a source of essential nutrients and provides immunological protection, as well as developmental benefits, among others. However, when breastfeeding is not possible, infant formula is the most appropriate alternative. Its composition meets the nutritional requirements of the infant, and its quality is subject to strict control by the authorities. Nonetheless, the presence of different pollutants has been detected in both matrices. Thus, the aim of the present review is to make a comparison between the findings in both breast milk and infant formula in terms of contaminants in the last decade, in order to choose the most convenient option depending on the environmental conditions. For that, the emerging pollutants including metals, chemical compounds derived from heat treatment, pharmaceutical drugs, mycotoxins, pesticides, packaging materials, and other contaminants were described. While in breast milk the most concerning contaminants found were metals and pesticides, in infant formula pollutants such as metals, mycotoxins, and packaging materials were the most outstanding. In conclusion, the convenience of using a feeding diet based on breast milk or either infant formula depends on the maternal environmental circumstances. However, it is important to take into account the immunological benefits of the breast milk compared to the infant formula, and the possibility of using breast milk in combination with infant formula when the nutritional requirements are not fulfilled only with the intake of breast milk. Therefore, more attention should be paid in terms of analyzing these conditions in each case to be able to make a proper decision, as it will vary depending on the maternal and newborn environment.

An Overview of Essential Microelements and Common Metallic Nanoparticles and Their Effects on Male Fertility

Numerous factors affect reproduction, including stress, diet, obesity, the use of stimulants, or exposure to toxins, along with heavy elements (lead, silver, cadmium, uranium, vanadium, mercury, arsenic). Metals, like other xenotoxins, can cause infertility through, e.g., impairment of endocrine function and gametogenesis or excess production of reactive oxygen species (ROS). The advancement of nanotechnology has created another hazard to human safety through exposure to metals in the form of nanomaterials (NMs). Nanoparticles (NPs) exhibit a specific ability to penetrate cell membranes and biological barriers in the human body. These ultra-fine particles (<100 nm) can enter the human body through the respiratory tract, food, skin, injection, or implantation. Once absorbed, NPs are transported to various organs through the blood or lymph. Absorbed NPs, thanks to ultrahigh reactivity compared to bulk materials in microscale size, disrupt the homeostasis of the body as a result of interaction with biological molecules such as DNA, lipids, and proteins; interfering with the functioning of cells, organs, and physiological systems; and leading to severe pathological dysfunctions. Over the past decades, much research has been performed on the reproductive effects of essential trace elements. The research hypothesis that disturbances in the metabolism of trace elements are one of the many causes of infertility has been unquestionably confirmed. This review examines the complex reproductive risks for men regarding the exposure to potentially harmless xenobiotics based on a series of 298 articles over the past 30 years. The research was conducted using PubMed, Web of Science, and Scopus databases searching for papers devoted to in vivo and in vitro studies related to the influence of essential elements (iron, selenium, manganese, cobalt, zinc, copper, and molybdenum) and widely used metallic NPs on male reproduction potential.

Relation between Selenium and Female Fertility: A Systematic Review

OBJECTIVE

 To analyze the influence of selenium in female fertility.

DATA SOURCE

 A search was performed in the following databases: MEDLINE, Web of Science, Scopus, SciELO, LILACS, MDPI, ScienceDirect, and Europe PMC. The descriptors selected were "selenium" AND "female" AND "fertility". The search interval was from 1996 to 2021.

STUDY SELECTION

 The evaluation was performed independently by two reviewers, and a third reviewer confirmed the inclusion of papers in case of divergence between the first two reviewers. Papers were selected after the title and abstract were read, and those that met the eligibility criteria had the full text read.

DATA COLLECTION

 The following data was extracted: author, year of publication, country, type of study, objective, method, sample size, follow-up period, patients' mean age, inclusion and exclusion criteria, and concentration of serum and capillary selenium. The data was organized in chronological order of paper publication.

DATA SYNTHESIS

 The number of papers identified totaled 3,800, out of which 7 were included in the systematic review. The studies indicated a positive correlation between serum selenium and antioxidant concentration in the follicular fluid, reduction in antithyroid antibodies, oocyte production and follicle number.

CONCLUSION

 Selenium supplementation is promising in women with this micronutrient deficiency to promote improvement of the reproductive efficiency and prevent damage to the pregnancy. Further studies on this theme are still required.

Comprehensive Review Regarding Mercury Poisoning and Its Complex Involvement in Alzheimer's Disease

Mercury (Hg) is considered one of the most widespread toxic environmental pollutants, which seems to have multiple effects on organisms even at low concentrations. It has a critical role in many health problems with harmful consequences, with Hg primarily targeting the brain and its components, such as the central nervous system (CNS). Hg exposure was associated with numerous CNS disorders that frequently trigger Alzheimer's disease (AD). Patients with AD have higher concentrations of Hg in blood and brain tissue. This paper aims to emphasize a correlation between Hg and AD based on the known literature in the occupational field. The outcome shows that all these concerning elements could get attributed to Hg. However, recent studies did not investigate the molecular level of Hg exposure in AD. The present review highlights the interactions between Hg and AD in neuronal degenerations, apoptosis, autophagy, oxidative stress (OS), mitochondrial malfunctions, gastrointestinal (GI) microflora, infertility and altering gene expression.

Mercury impairs human primary endometrial stromal cell function

Heavy metal exposures could compromise endometrial cells and decidualization. Although studies assessed mercury toxicity in cell lines, limited data are available on the concentration of mercury that induces damage in hEnSC, which could alter endometrial function. This research aims to study effects of mercury exposure on cell viability and functional features of hEnSC. Primary hEnSC were isolated from 23 endometrial biopsies obtained from healthy egg donors. After in vitro mercury exposure or control treatment of hEnSC, cell viability was evaluated via tetrazolium salt metabolism and oxidative stress was assessed by 2',7'-DCFDA assay. hEnSC were decidualized in vitro in the presence of mercury (0, 25, 50, 75, 250 and 350 nM). Decidualization was evaluated based on prolactin and IGFBP1 secretion and cytoskeletal rearrangement (F-actin staining). Cell proliferation and apoptosis were evaluated by Ki67 immunostaining and TUNEL assay. Mercury doses of 250 nM (p = 0.028) and 500 nM (p = 0.026) increased ROS production in hEnSC after 24 h. Cell viability significantly decreased after 48 h and 72 h (p = 0.032 and p = 0.016, respectively) of mercury exposure at 500 nM. After in vitro decidualization and mercury treatment, decidual hEnSC showed a dose-dependent decrease in prolactin and IGFBP1 secretion, particularly at 350 nM (p = 0.016). Cell proliferation was decreased in hEnSC treated with 350 nM mercury (p < 0.001); an increase in apoptosis followed a dose-dependent trend in non-decidual and decidual hEnSC. These findings support that mercury-induced damage could be due to an increase in ROS production.

Essentiality of Trace Elements in Pregnancy, Fertility, and Gynecologic Cancers-A State-of-the-Art Review

Gynecological neoplasms pose a serious threat to women's health. It is estimated that in 2020, there were nearly 1.3 million new cases worldwide, from which almost 50% ended in death. The most commonly diagnosed are cervical and endometrial cancers; when it comes to infertility, it affects ~48.5 million couples worldwide and the number is continually rising. Ageing of the population, environmental factors such as dietary habits, environmental pollutants and increasing prevalence of risk factors may affect the reproductive potential in women. Therefore, in order to identify potential risk factors for these issues, attention has been drawn to trace elements. Trace mineral imbalances can be caused by a variety of causes, starting with hereditary diseases, finishing with an incorrect diet or exposure to polluted air or water. In this review, we aimed to summarize the current knowledge regarding trace elements imbalances in the case of gynecologic cancers as well as female fertility and during pregnancy.

Can Nutrition Help in the Treatment of Infertility?

Infertility is defined as the inability to conceive after 12 months of unprotected intercourse or six months for women aged 35 years or older. The physical, emotional, psychological, and financial statuses of infertile couples are tremendously affected especially after undergoing diagnostic and/or curative treatments. Human fertility is influenced by multiple factors including female or male, and modifiable or non-modifiable factors. There is growing evidence that nutri-tion may play an important role in adjusting fertility-related outcomes in both men and women. The objective of our study was to summarize the latest data on nutritional factors (specific food groups, nutrients, and nutritional supplements) that have an impact on female or male sexual and reproductive function. PubMed and Google Scholar platforms were used to collect appropriate articles for the review using several combinations of keywords (infertility, diet, dietary supplements, antioxidants, and beverages). Adherence to a healthy dietary pattern favoring fish, poultry, whole grains, fruits, vegetables, and healthy fats, was related to better fertility in both genders. Despite the multifactorial etiology of sexual infertility, nutrition may affect the sexual/reproductive function in both women and men.

Prenatal exposure to mercury and precocious puberty: a prospective birth cohort study

STUDY QUESTION

Is in utero exposure to mercury associated with the risk of precocious puberty?

SUMMARY ANSWER

Prenatal exposure to high levels of mercury was associated with increased risk of precocious puberty, which was strengthened by concomitant maternal cardiometabolic conditions and adverse birth outcomes.

WHAT IS KNOWN ALREADY

The developing fetus is sensitive to mercury, a well-known endocrine disruptor which impacts the endocrine and reproductive system.

STUDY DESIGN, SIZE, DURATION

This study included 1512 mother-child pairs from the Boston Birth Cohort, a longitudinal cohort which recruited at birth and followed prospectively up to 21 years of age.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Mother-child pairs, from a predominantly urban minority population, were enrolled from 2002 to 2013. Prenatal exposure was assessed by maternal mercury concentration in red blood cells (RBCs) collected at 1-3 days after delivery. Precocious puberty was defined based on International Classification of Disease codes. Cox proportional hazards models were applied to the association between maternal mercury concentrations and the risk of precocious puberty.

MAIN RESULTS AND THE ROLE OF CHANCE

The median (interquartile range) of maternal mercury concentrations among children with and without precocious puberty were 3.4 (1.9-4.6) µg/l and 2.0 (1.0-3.7) µg/l, respectively. Compared to those in the lowest tertile for mercury, the highest tertile was associated with increased risk of precocious puberty, with an adjusted hazard ratio (HR) of 2.41, 95% CI: 1.16-5.03. In addition, concomitant maternal cardiometabolic conditions and adverse birth outcomes strengthened the effects of mercury on the risk of precocious puberty. The highest risk of precocious puberty was observed among children who had adverse birth outcomes and whose mothers had high RBC-mercury concentrations along with cardiometabolic conditions, with an HR of 4.76 (95% CI: 1.66-13.60) compared to children with favorable profiles of all three risk factors.

LIMITATIONS, REASONS FOR CAUTION

Precocious puberty was defined based on medical records, not on a direct assessment, which may have led to underdiagnosis and the inability to make a subclassification. The study included a predominately urban, low-income, minority population and as such our findings may not be widely generalizable.

WIDER IMPLICATIONS OF THE FINDINGS

Prenatal Hg exposure was associated with an increased risk of precocious puberty. This risk was strengthened by concomitant maternal cardiometabolic conditions during pregnancy and adverse birth outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the NIH/National Institute of Environmental Health Sciences, NIH/Eunice Kennedy Shriver National Institute of Child Health and Human Development and the Health Resources and Services Administration of the U.S. Department of Health and Human Services. The authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Sexual and reproductive health in riverine communities: integrative review

OBJECTIVE

To analyze the scientific evidence available on the sexual and reproductive health of riverine communities.

METHOD

Integrative review, conducted on the databases LILACS, MEDLINE; WEB OF SCIENCE and SCOPUS, including publications in Portuguese, English or Spanish, without an initial time limit and published until 2018.

RESULTS

11 studies were selected. The studies included are from the period 1993-2017. The results originated four analytical categories: sexual component, which gathered findings about sexually transmitted infections; reproductive component, which included family planning/fertility control, abortion and problems with pregnancy; environmental component, which presented issues with environmental contaminants and its reproductive implications; and the sociocultural component, which discussed gender, beliefs and social indicators.

CONCLUSION

In this review, studies with a quantitative approach, from a female point of view and a biological perspective predominated. No study investigated the meanings and representations of SRH for the riverine communities. In addition, the findings show little evidence of thoughts and practices of people living in riverine communities regarding SRH issues, providing limited evidence.

Ecotoxicity Risk of Low-Dose Methylmercury Exposure to Caenorhabditis elegans: Multigenerational Toxicity and Population Discrepancy

Methylmercury (MeHg) is a common organic form of mercury in water, which has been linked to several forms of biological toxicity. However, studies on the ecotoxicity risk of long-term exposure to low-dose MeHg are insufficient for the assessment of environmental safety. In the present study, the effects of MeHg on multiple generations (P0-F3) and population of Caenorhabditis elegans were investigated under long-term, low-dose exposure. We investigated the multigenerational toxicity of MeHg by analyzing reproductive and developmental indicators. According to our results, exposure to 100 nM MeHg had little effect on the parental generation (P0) but caused serious reproductive toxicity in the offspring (F1-F3), and the effect of MeHg was aggravated with each passing generation. The genes related to apoptosis and DNA damage were upregulated in the F3 generation. Pearson correlation analysis showed that the changes in these genes were closely related to the apoptosis of gonadal cells. Furthermore, chronic exposure to MeHg (from 100 to 1000 nM group) caused a sharp decline in population size and triggered the "bag of worms" phenotype. Genes related to vulvar development were downregulated in the F3 generation after treatment with 100 nM MeHg. These data suggest that long-term low-dose MeHg exposure adversely affected C. elegans and its offspring and triggered multigenerational toxicity and population discrepancy.

Associations of toxic and essential trace elements in serum, follicular fluid, and seminal plasma with In vitro fertilization outcomes

Toxic and essential trace elements are associated with human fertility. However, limited studies have been conducted on the relationship between trace elements and in vitro fertilization (IVF) outcomes in the Chinese population. In this exploratory study, 103 couples who underwent IVF/intracytoplasmic sperm injection (ICSI) treatment in our reproductive center were recruited. Serum and follicular fluid (FF) samples and seminal plasma samples were collected from the female and male partners, respectively, on the day of oocyte retrieval. Concentrations of chromium (Cr), nickel (Ni), arsenic (As), selenium (Se), cadmium (Cd), and lead (Pb) in the specimens were measured by inductively coupled plasma-mass spectrometry. Generalized linear models were used to evaluate the associations of toxic and essential trace element levels with the intermediate parameters and outcomes of IVF at both the sex-specific and couple levels. The Cr level in the serum of the female partners was inversely associated with the count of mature oocytes retrieved (p for trend = 0.033). In terms of embryo development, As concentrations in female serum and FF were inversely associated with the probabilities to obtain good-quality cleavage embryos (p for trend < 0.01). There were significant correlations between follicular Se concentrations and seminal As concentrations and higher quality cleavage embryos (p for trend < 0.01). Moreover, a positive correlation was observed between the female serum Se concentrations and blastocyst formation (p for trend = 0.031). In contrast, a higher follicular Se level was negatively correlated with embryo development at the blastocyst stage (p for trend < 0.01). Regarding the clinical outcomes, a positive association of Se levels in seminal plasma and a negative association of follicular Cd levels was observed with the probabilities of pregnancy (p for trend = 0.006 and 0.035, respectively) and live birth (p for trend = 0.014 and 0.027, respectively). The results indicate that exposure to toxic elements (Cr, As and Cd) is associated with intermediate parameters and outcomes of IVF. Furthermore, male Se exposure may be related to better pregnancy outcomes.

Evidence for a manifold role of selenium in infertility

This review aimed to assess the evidence from observational and interventional studies in humans and animals regarding the role of selenium (Se) in male and female infertility. As oxidative stress can seriously impair male, and possibly also female, reproductive functions, it can be speculated that the antioxidant properties of Se could constitute one of the pathways by which this element is involved in fertility. Specifically, there are strong indications that Se influences the growth, maturation, and replication of oocytes, though the precise mechanisms have not as yet been fully elucidated. Given that it is not clear at present which tissue sample (blood, serum, seminal plasma, sperm, or follicular fluid) renders the most accurate picture of Se concentration in terms of its role in reproduction, the data are still insufficient to recommend routine assessment of Se status in men and women seeking fertility. Nevertheless, the existing evidence, despite being of limited quantity and somewhat low quality, suggests that Se supplementation (< 200 μg/d) is possibly beneficial in men through its improvement of sperm motility. Well-designed, randomized control studies are needed to reveal the seemingly diverse protective/positive role of Se supplementation in men and women seeking fertility treatment.

Elevated blood mercury level has a non-linear association with infertility in U.S. women: Data from the NHANES 2013-2016

Mercury is a ubiquitous toxic heavy metal associated with an increased risk of female infertility; however, the evidence supporting this is limited and controversial. We aimed to explore the relationship between the total blood mercury and infertility in 1796 selected participants from the National Health and Nutrition Examination Survey (NHANES) (2013-2016). We found no significant association between mercury and infertility based on a fully-adjusted model (OR 1.04; 95 % CI 0.91, 1.19), and the results remained robust in a series of sensitive analysis. However, a non-linear relationship was detected. By a two-piecewise linear regression model and recursive algorithm, we identified an inflection point of 5.278 μg/L, when blood mercury was >5.278 μg/L, a 1-unit increase in mercury (log2) was associated with 157 % greater adjusted odds of infertility (OR 2.57; 95 % CI 1.12, 5.87). Our findings provide new insights to advance the research of the link between mercury and infertility.

Mercury exposure and its effects on fertility and pregnancy outcome

Mercury (Hg), a highly toxic environmental pollutant, shows harmfulness which still represents a big concern for human health, including hazards to fertility and pregnancy outcome. Research has shown that Hg could induce impairments in the reproductive function, cellular deformation of the Leydig cells and the seminiferous tubules, and testicular degeneration as well as abnormal menstrual cycles. Some studies investigated spontaneous abortion and complicated fertility outcome due to occupational Hg exposure. Moreover, there is a relation between inhaled Hg vapour and reproductive outcome. This MiniReview evaluates the hypothesis that exposure to Hg may increase the risk of reduced fertility, spontaneous abortion and congenital deficits or abnormalities.

The impact of environmental pollution on the quality of mother's milk

Breastfeeding is a gold standard of neonate nutrition because human milk contains a lot of essential compounds crucial for proper development of a child. However, milk is also a biofluid which can contain environmental pollution, which can have effects on immune system and consequently on the various body organs. Polychlorinated biphenyls are organic pollutants which have been detected in human milk. They have lipophilic properties, so they can penetrate to fatty milk and ultimately to neonate digestive track. Another problem of interest is the presence in milk of heavy metals-arsenic, lead, cadmium, and mercury-as these compounds can lead to disorders in production of cytokines, which are important immunomodulators. The toxicants cause stimulation or suppression of this compounds. This can lead to health problems in children as allergy, disorders in the endocrine system, end even neurodevelopment delay and disorder. Consequently, correlations between pollutants and bioactive components in milk should be investigated. This article provides an overview of environmental pollutants found in human milk as well as of the consequences of cytokine disorder correlated with presence of heavy metals. Graphical abstract.