DNA methylation changes in whole blood is associated with exposure to the environmental contaminants, mercury, lead, cadmium and bisphenol A, in women undergoing ovarian stimulation for IVF

Prenatal lead exposure is associated with decreased cord blood DNA methylation of the glycoprotein VI gene involved in platelet activation and thrombus formation

Early-life lead exposure impairs neurodevelopment and later exposure affects the cardiovascular system. Lead has been associated with reduced global 5-methylcytosine DNA methylation, suggesting that lead toxicity acts through epigenetic mechanisms. The objective of this study is to clarify how early-life lead exposure alters DNA methylation of specific genes, using an epigenomic approach. We measured lead concentrations in urine [gestational week (GW), 8] and erythrocytes (GW 14), using inductively coupled plasma mass spectrometry, for 127 pregnant mothers recruited in the MINIMat food and supplementation cohort in rural Bangladesh. Cord blood DNA methylation was analyzed with the Infinium HumanMethylation450K BeadChip, and top sites were validated by methylation-sensitive high-resolution melt curve analysis. Maternal urinary lead concentrations (divided into quartiles) showed significant (after adjustment for false discovery rate) inverse associations with methylation at nine CpGs. Three of these sites were in the 5'-end, including the promoter, of glycoprotein IV (GP6); cg18355337 (q = 0.029, β = -0.30), cg25818583 (q = 0.041, β = -0.18), and cg23796967 (q = 0.047, β = -0.17). The methylation in another CpG site in GP6 was close to significant (cg05374025, q = 0.057, β = - 0.23). The erythrocyte lead concentrations (divided into quartiles) were also inversely associated with CpG methylation in GP6, although this was not statistically significant after false discovery rate adjustments. Eight CpG sites in GP6 constituted a differentially methylated region in relation to urinary lead (P = 0.005, q = 0.48) and erythrocyte lead (P = 0.007, q = 0.46). In conclusion, we found that moderate prenatal lead exposure appears to epigenetically affect GP6, a key component of platelet aggregation and thrombus formation, suggesting a novel link between early lead exposure and cardiovascular disease later in life.

Toxicoepigenomics and cancer: implications for screening

Scientists have long considered genetics to be the key mechanism that alters gene expression because of exposure to the environment and toxic substances (toxicants). Recently, epigenetic mechanisms have emerged as an alternative explanation for alterations in gene expression resulting from such exposure. The fact that certain toxic substances that contribute to tumor development do not induce mutations probably results from underlying epigenetic mechanisms. The field of toxicoepigenomics emerged from the combination of epigenetics and classical toxicology. High-throughput technologies now enable evaluation of altered epigenomic profiling in response to toxins and environmental pollutants. Furthermore, differences in the epigenomic backgrounds of individuals may explain why, although whole populations are exposed to toxicants, only a few people in a population develop cancer. Metals in the environment and toxic substances not only alter DNA methylation patterns and histone modifications but also affect enzymes involved in posttranslational modifications of proteins and epigenetic regulation, and thereby contribute to carcinogenesis. This article describes different toxic substances and environmental pollutants that alter epigenetic profiling and discusses how this information can be used in screening populations at high risk of developing cancer. Research opportunities and challengers in the field also are discussed.

Placental transfer and concentrations of cadmium, mercury, lead, and selenium in mothers, newborns, and young children

There is an emerging hypothesis that exposure to cadmium (Cd), mercury (Hg), lead (Pb), and selenium (Se) in utero and early childhood could have long-term health consequences. However, there are sparse data on early life exposures to these elements in US populations, particularly in urban minority samples. This study measured levels of Cd, Hg, Pb, and Se in 50 paired maternal, umbilical cord, and postnatal blood samples from the Boston Birth Cohort (BBC). Maternal exposure to Cd, Hg, Pb, and Se was 100% detectable in red blood cells (RBCs), and there was a high degree of maternal-fetal transfer of Hg, Pb, and Se. In particular, we found that Hg levels in cord RBCs were 1.5 times higher than those found in the mothers. This study also investigated changes in concentrations of Cd, Hg, Pb, and Se during the first few years of life. We found decreased levels of Hg and Se but elevated Pb levels in early childhood. Finally, this study investigated the association between metal burden and preterm birth and low birthweight. We found significantly higher levels of Hg in maternal and cord plasma and RBCs in preterm or low birthweight births, compared with term or normal birthweight births. In conclusion, this study showed that maternal exposure to these elements was widespread in the BBC, and maternal-fetal transfer was a major source of early life exposure to Hg, Pb, and Se. Our results also suggest that RBCs are better than plasma at reflecting the trans-placental transfer of Hg, Pb, and Se from the mother to the fetus. Our study findings remain to be confirmed in larger studies, and the implications for early screening and interventions of preconception and pregnant mothers and newborns warrant further investigation.

Bisphenol-A: epigenetic reprogramming and effects on reproduction and behavior

Bisphenol A (BPA) is a synthetic compound used in the production of many polycarbonate plastics and epoxy resins. It is one of the most widely produced chemicals in the world today and is found in most canned goods, plastics, and even household dust. Exposure to BPA is almost universal: most people have measurable amounts of BPA in both urine and serum. BPA is similar in structure to estradiol and can bind to multiple targets both inside and outside the nucleus, in effect acting as an endocrine disruptor. Research on BPA exposure has accelerated in the past decade with findings suggesting that perinatal exposure to BPA can negatively impact both male and female reproduction, create alterations in behavior, and act as a carcinogen. BPA can have both short term and long term effects with the latter typically occurring through epigenetic mechanisms such as DNA methylation. This review will draw on both human and animal studies in an attempt to synthesize the literature and examine the effects of BPA exposure on reproduction, behavior, and carcinogenesis with a focus on the potential epigenetic mechanisms by which it acts.

Incorporating epigenetic data into the risk assessment process for the toxic metals arsenic, cadmium, chromium, lead, and mercury: strategies and challenges

Exposure to toxic metals poses a serious human health hazard based on ubiquitous environmental presence, the extent of exposure, and the toxicity and disease states associated with exposure. This global health issue warrants accurate and reliable models derived from the risk assessment process to predict disease risk in populations. There has been considerable interest recently in the impact of environmental toxicants such as toxic metals on the epigenome. Epigenetic modifications are alterations to an individual's genome without a change in the DNA sequence, and include, but are not limited to, three commonly studied alterations: DNA methylation, histone modification, and non-coding RNA expression. Given the role of epigenetic alterations in regulating gene and thus protein expression, there is the potential for the integration of toxic metal-induced epigenetic alterations as informative factors in the risk assessment process. In the present review, epigenetic alterations induced by five high priority toxic metals/metalloids are prioritized for analysis and their possible inclusion into the risk assessment process is discussed.

Ecogenetics of mercury: from genetic polymorphisms and epigenetics to risk assessment and decision-making

The risk assessment of mercury (Hg), in both humans and wildlife, is made challenging by great variability in exposure and health effects. Although disease risk arises following complex interactions between genetic ("nature") and environmental ("nurture") factors, most Hg studies thus far have focused solely on environmental factors. In recent years, ecogenetic-based studies have emerged and have started to document genetic and epigenetic factors that may indeed influence the toxicokinetics or toxicodynamics of Hg. The present study reviews these studies and discusses their utility in terms of Hg risk assessment, management, and policy and offers perspectives on fruitful areas for future research. In brief, epidemiological studies on populations exposed to inorganic Hg (e.g., dentists and miners) or methylmercury (e.g., fish consumers) are showing that polymorphisms in a number of environmentally responsive genes can explain variations in Hg biomarker values and health outcomes. Studies on mammals (wildlife, humans, rodents) are showing Hg exposures to be related to epigenetic marks such as DNA methylation. Such findings are beginning to increase understanding of the mechanisms of action of Hg, and in doing so they may help identify candidate biomarkers and pinpoint susceptible groups or life stages. Furthermore, they may help refine uncertainty factors and thus lead to more accurate risk assessments and improved decision-making.

A round robin approach to the analysis of bisphenol A (BPA) in human blood samples

BACKGROUND

Human exposure to bisphenol A (BPA) is ubiquitous, yet there are concerns about whether BPA can be measured in human blood. This Round Robin was designed to address this concern through three goals: 1) to identify collection materials, reagents and detection apparatuses that do not contribute BPA to serum; 2) to identify sensitive and precise methods to accurately measure unconjugated BPA (uBPA) and BPA-glucuronide (BPA-G), a metabolite, in serum; and 3) to evaluate whether inadvertent hydrolysis of BPA-G occurs during sample handling and processing.

METHODS

Four laboratories participated in this Round Robin. Laboratories screened materials to identify BPA contamination in collection and analysis materials. Serum was spiked with concentrations of uBPA and/or BPA-G ranging from 0.09-19.5 (uBPA) and 0.5-32 (BPA-G) ng/mL. Additional samples were preserved unspiked as 'environmental' samples. Blinded samples were provided to laboratories that used LC/MSMS to simultaneously quantify uBPA and BPA-G. To determine whether inadvertent hydrolysis of BPA metabolites occurred, samples spiked with only BPA-G were analyzed for the presence of uBPA. Finally, three laboratories compared direct and indirect methods of quantifying BPA-G.

RESULTS

We identified collection materials and reagents that did not introduce BPA contamination. In the blinded spiked sample analysis, all laboratories were able to distinguish low from high values of uBPA and BPA-G, for the whole spiked sample range and for those samples spiked with the three lowest concentrations (0.5-3.1 ng/ml). By completion of the Round Robin, three laboratories had verified methods for the analysis of uBPA and two verified for the analysis of BPA-G (verification determined by: 4 of 5 samples within 20% of spiked concentrations). In the analysis of BPA-G only spiked samples, all laboratories reported BPA-G was the majority of BPA detected (92.2 - 100%). Finally, laboratories were more likely to be verified using direct methods than indirect ones using enzymatic hydrolysis.

CONCLUSIONS

Sensitive and accurate methods for the direct quantification of uBPA and BPA-G were developed in multiple laboratories and can be used for the analysis of human serum samples. BPA contamination can be controlled during sample collection and inadvertent hydrolysis of BPA conjugates can be avoided during sample handling.

Early Life Origins of Metabolic Syndrome: The Role of Environmental Toxicants

Metabolic syndrome (MetS) affects more than 47 million people in the U.S. Even more alarming, MetS, once regarded as an "adult problem", has become increasingly common in children. To date, most related research and intervention efforts have occurred in the adult medicine arena, with limited understanding of the root causes and lengthy latency of MetS. This review highlights new science on the early life origins of MetS, with a particular focus on exposure to two groups of environmental toxicants: endocrine disrupting chemicals (EDCs) and metals during the prenatal and early postnatal periods, and their specific effects and important differences in the development of MetS. It also summarizes available data on epigenetic effects, including the role of EDCs in the androgen/estrogen pathways. Emerging evidence supports the link between exposures to environmental toxicants during early life and the development of MetS later in life. Additional research is needed to address important research gaps in this area, including prospective birth cohort studies to delineate temporal and dose-response relationships, important differences in the effects of various environmental toxicants and their joint effects on MetS, as well as epigenetic mechanisms underlying the effects of specific toxicants such as EDCs and metals.

Lead exposure disrupts global DNA methylation in human embryonic stem cells and alters their neuronal differentiation

Exposure to lead (Pb) during childhood can result in learning disabilities and behavioral problems. Although described in animal models, whether Pb exposure also alters neuronal differentiation in the developing brains of exposed children is unknown. Here, we investigated the effects of physiologically relevant concentrations of Pb (from 0.4 to 1.9μM) on the capacity of human embryonic stem cells (hESCs) to progress to a neuronal fate. We found that neither acute nor chronic exposure to Pb prevented hESCs from generating neural progenitor cells (NPCs). NPCs derived from hESCs chronically exposed to 1.9μM Pb throughout the neural differentiation process generated 2.5 times more TUJ1-positive neurons than those derived from control hESCs. Pb exposure of hESCs during the stage of neural rosette formation resulted in a significant decrease in the expression levels of the neural marker genes PAX6 and MSI1. Furthermore, the resulting NPCs differentiated into neurons with shorter neurites and less branching than control neurons, as assessed by Sholl analysis. DNA methylation studies of control, acutely treated hESCs and NPCs derived from chronically exposed hESCs using the Illumina HumanMethylation450 BeadChip demonstrated that Pb exposure induced changes in the methylation status of genes involved in neurogenetic signaling pathways. In summary, our study shows that exposure to Pb subtly alters the neuronal differentiation of exposed hESCs and that these changes could be partly mediated by modifications in the DNA methylation status of genes crucial to brain development.

Development of a screening system for the detection of chemically induced DNA methylation alterations in a zebrafish liver cell line

Early molecular events with correlation to disease, such as aberrant DNA methylation, emphasize the importance of DNA methylation as a potential environmental biomarker. Currently, little is known regarding how various environmental contaminants and mixtures alter DNA methylation in aquatic organisms, and testing is both time- and labor-consuming. Therefore, the potential of an in vitro screening method was evaluated by exposing zebrafish liver cells (ZF-L) for 96 h to the nonmutagenic model substance 5'-azacytidine (AZA), as well as a selection of environmental pollutants such as sodium arsenite (NAS), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 17α-ethinylestradiol (EE2), and diethylstilbestrol (DES). Six single genes with reported and anticipated importance in cancer were selected for analysis. Methylation of gene promoter areas was monitored by bisulfite conversion and high-resolution melt (HRM) analysis after exposure to sublethal concentrations of the test compounds. Subsequently, results were validated with direct bisulfite sequencing. Exposure of ZF-L cells to 0.5 μM AZA for 96 h led to hypomethylation of genes with both low and high basal methylation indicating similarity to mechanism of action in mammals. Further, NAS, EE2, and DES were shown to induce significant alterations in methylation, whereas TCDD did not. It was concluded that cell line exposure in combination with HRM may provide an initial contaminant screening assay by quantifying DNA methylation alterations with high throughput capacity. In addition, the rapid determination of effects following contaminant exposure with this in vitro system points to the possibility for new in vivo applications to be useful for environmental monitoring.

Environmental exposure to lead (Pb) and variations in its susceptibility

Based on exposure frequency and intrinsic toxicity, lead (Pb) ranks one of the highest priority toxic materials. Continuous regulation of environmental Pb exposure has contributed to dramatically diminished exposure levels of Pb, for example, blood level of Pb. However, the safety level of Pb is not established, as low-level exposure to Pb still shows severe toxicity in high susceptible population and late onset of some diseases from early exposure. In the present study, we focused on food-borne Pb exposure and found broad variations in Pb exposure levels via food among countries. In addition, there are genetic or ethnical variations in Pb-targeted and protective genes. Moreover, various epigenetic alterations were induced by Pb poisoning. Therefore, we suggest a systemic approach including governmental (public) and individual prevention from Pb exposure with continuous biological monitoring and genetic or epigenetic consideration.

LINE-1 hypomethylation in spermatozoa is associated with Bisphenol A exposure

Bisphenol A (BPA) is an endocrine disruptor with potentially harmful effects on humans. However, epigenetic mechanisms that modulate the effects of BPA remain unclear. Methylation of long interspersed nucleotide elements (LINE-1) is a marker of genome-wide methylation status. This study aims to examine whether BPA exposure was associated with LINE-1 methylation changes in men. Male factory workers in Hunan, China (N = 149) were studied, 77 with BPA exposure in workplace (BPA-exposed group) and 72 without BPA exposure in workplace (control group). Pre-shift and post-shift urine samples were collected from the BPA-exposed group and spot urine samples were collected from the control group. Urine samples were assessed for BPA. In addition, blood and semen samples were collected from both groups for LINE-1 methylation analysis. In multivariate analysis adjusted for age, education, smoking habits and alcohol consumption, sperm LINE-1 methylation level was significantly lower in BPA exposed workers (p < 0.001) compared to that in the unexposed workers. Linear regression analysis also showed that log-transformed urine BPA levels were inversely associated with sperm LINE-1 methylation (p < 0.0001), but not peripheral blood cell LINE-1 methylation. Moreover, the association between urine BPA level and semen quality was not attenuated after adjustments for LINE-1 level. In summary, the observed independent relationship between BPA exposure and LINE-1 methylation may have public health implications on reproductive health in men because of ubiquitous exposure to BPA.

Real-time methylomic aberrations during initiation and progression of induced human mammary epithelial cell tumorigenesis

AIM

Neoplastic transformation provides one of the few existing opportunities to analyze molecular changes in real time during the initiation and progression of breast cancer.

MATERIALS & METHODS

Human mammary epithelial cells underwent neoplastic reprogramming, generating one line of semitransformed, premalignant cells and two separate, temporal lines of fully transformed human mammary epithelial cells (THMECs). An Illumina Infinium HumanMethylation27 BeadChip was used to analyze DNA methylation alterations in 27,578 CpG loci at three consecutive time points over an 80-day (d) transformation period.

RESULTS

The mean β value for semitransformed human mammary epithelial cells CpG loci (0.245) was much greater than for either THMEC-40d (0.055) or THMEC-80d (0.066), indicating a large loss of methylation after neoplastic induction. In addition, 54% of CpG loci were hypermethylated during the THMEC-40d to THMEC-80d transition. We observed that the CpG loci exhibiting DNA methylation changes during early oncogenesis were enriched for biological functions like cellular movement; this was distinctly different than in the later, more progressive stages of the transformation process enriched for processes involving differentiation.

CONCLUSION

The timing of major methylomic changes may be important in directing the cell toward a more cancerous phenotype. In addition, gene-specific hypermethylation appears to silence developmentally related genes, leading to dedifferentiation.

Bisphenol A and human health: a review of the literature

There is growing evidence that bisphenol A (BPA) may adversely affect humans. BPA is an endocrine disruptor that has been shown to be harmful in laboratory animal studies. Until recently, there were relatively few epidemiological studies examining the relationship between BPA and health effects in humans. However, in the last year, the number of these studies has more than doubled. A comprehensive literature search found 91 studies linking BPA to human health; 53 published within the last year. This review outlines this body of literature, showing associations between BPA exposure and adverse perinatal, childhood, and adult health outcomes, including reproductive and developmental effects, metabolic disease, and other health effects. These studies encompass both prenatal and postnatal exposures, and include several study designs and population types. While it is difficult to make causal links with epidemiological studies, the growing human literature correlating environmental BPA exposure to adverse effects in humans, along with laboratory studies in many species including primates, provides increasing support that environmental BPA exposure can be harmful to humans, especially in regards to behavioral and other effects in children.

Epigenetics of early-life lead exposure and effects on brain development

The epigenetic machinery plays a pivotal role in the control of many of the body's key cellular functions. It modulates an array of pliable mechanisms that are readily and durably modified by intracellular or extracellular factors. In the fast-moving field of neuroepigenetics, it is emerging that faulty epigenetic gene regulation can have dramatic consequences on the developing CNS that can last a lifetime and perhaps even affect future generations. Mounting evidence suggests that environmental factors can impact the developing brain through these epigenetic mechanisms and this report reviews and examines the epigenetic effects of one of the most common neurotoxic pollutants of our environment, which is believed to have no safe level of exposure during human development: lead.

Effects of methylmercury on epigenetic markers in three model species: mink, chicken and yellow perch

We previously reported that methylmercury (MeHg) exposure is associated with DNA hypomethylation in the brain stem of male polar bears. Here, we conveniently use archived tissues obtained from controlled laboratory exposure studies to look for evidence that MeHg can disrupt DNA methylation across taxa. Brain (cerebrum) tissues from MeHg-exposed mink (Neovison vison), chicken (Gallus gallus) and yellow perch (Perca flavescens) were analyzed for total Hg levels and global DNA methylation. Tissues from chicken and mink, but not perch, were also analyzed for DNA methyltransferase (DNMT) activity. In mink we observed significant reductions in global DNA methylation in an environmentally-relevant dietary exposure group (1 ppm MeHg), but not in a higher group (2 ppm MeHg). DNMT activity was significantly reduced in all treatment groups. In chicken or yellow perch, no statistically significant effects of MeHg were observed. Dose-dependent trends were observed in the chicken data but the direction of the change was not consistent between the two endpoints. Our results suggest that MeHg can be epigenetically active in that it has the capacity to affect DNA methylation in mammals. The variability in results across species may suggest inter-taxa differences in epigenetic responses to MeHg, or may be related to differences among the exposure scenarios used as animals were exposed to MeHg through different routes (dietary, egg injection), for different periods of time (19-89 days) and at different life stages (embryonic, juvenile, adult).

Mercury biomarkers and DNA methylation among Michigan dental professionals

Modification of the epigenome may be a mechanism underlying toxicity and disease following chemical exposure. Animal and human data suggest that mercury (Hg) impacts DNA methylation. We hypothesize that methylmercury and inorganic Hg exposures from fish consumption and dental amalgams, respectively, may be associated with altered DNA methylation at global repetitive elements (long interspersed elements, LINE-1) and candidate genes related to epigenetic processes (DNMT1) and protection against Hg toxicity (SEPW1, SEPP1). Dental professionals were recruited at Michigan Dental Association (MDA) meetings in 2009 and 2010. Subjects (n=131) provided survey data (e.g. exposure sources, demographics) and biological samples for Hg measurement and epigenetic analysis. Total Hg was quantified via atomic absorption spectrophotometry in hair and urine, indicative of methylmercury and inorganic Hg exposures, respectively. Global repetitive and candidate gene methylation was quantified via pyrosequencing of bisulfite converted DNA isolated from buccal mucosa. Hair Hg (geometric mean (95% CI): 0.37 (0.31-0.44) µg/g) and urine Hg (0.70 (0.60-0.83) µg/L) were associated with sources of exposure (fish consumption and dental amalgams, respectively). Multivariable linear regression revealed a trend of SEPP1 hypomethylation with increasing hair Hg levels, and this was significant (P<0.05) among males. The trend remained when excluding non-dentists. No significant relationships between urine Hg and DNA methylation were observed. Thus, in a limited cohort, we identified an association between methylmercury exposure and hypomethylation of a potentially labile region of the genome (SEPP1 promoter), and this relationship was gender specific.

Influence of developmental lead exposure on expression of DNA methyltransferases and methyl cytosine-binding proteins in hippocampus

Developmental exposure to lead (Pb) has adverse effects on cognitive functioning and behavior that can persist into adulthood. Exposures that occur during fetal or early life periods may produce changes in brain related to physiological re-programming from an epigenetic influence such as altered DNA methylation status. Since DNA methylation is regulated by DNA methyltransferases and methyl cytosine-binding proteins, this study assessed the extent to which developmental Pb exposure might affect expression of these proteins in the hippocampus. Long Evans dams were fed chow with or without added Pb acetate (0, 150, 375, 750 ppm) prior to breeding and remained on the same diet through weaning (perinatal exposure group). Other animals were exposed to the same doses of Pb but exposure started on postnatal day 1 and continued through weaning (early postnatal exposure group). All animals were euthanized on day 55 and hippocampi were removed. Western blot analyses showed significant effects of Pb exposure on DNMT1, DNMT3a, and MeCP2 expression, with effects often seen at the lowest level of exposure and modified by sex and developmental window of Pb exposure. These data suggest potential epigenetic effects of developmental Pb exposure on DNA methylation mediated at least in part through dysregulation of methyltransferases.

Fluoroquinolone toxicity symptoms in a patient presenting with low back pain

Fluoroquinolone medications have been shown to contribute to tendinopathies, cardiotoxicity, and neurotoxicity. Low back pain is a common musculoskeletal condition for which chiropractic treatment is most often sought. This case report details a patient presenting with low back pain and a history of fluoroquinolone toxicity. The patient was initially treated with chiropractic manipulation, which increased her symptoms. She was then referred to an osteopathic physician who treated the patient with intravenous antioxidants and amino acids, an elimination diet, and probiotic supplementation. Within 4 months of therapy, the patient reported a decrease in pain, a resolution of her dizziness, shortness of breath, panic attacks, tachycardia, and blurred vision. After an additional 8 weeks of antioxidant therapy, she reported further reductions in pain and improved disability. People susceptible to fluoroquinolone toxicity may present with common musculoskeletal symptoms. A past medical history and medication history may help to identify this population of patients. People presenting with fluoroquinolone toxicity may have unidentified contributing factors that predispose them to this anomaly. This patient reported improvements in pain and disability following antioxidant amino acid therapy for a total of 6 months. The natural history of fluoroquinolone toxicity is unknown and may account for the observed improvements.

Environmental toxicants--induced epigenetic alterations and their reversers

Epigenetics has been emphasized in the postgenome era to clarify obscure health risks of environmental toxicants including endocrine disrupting chemicals (EDCs). In addition, mixed exposure in real life can modify health consequences of the toxicants. Particularly, some nutritional and dietary materials modify individual susceptibility through changes in the epigenome. Therefore, we focused on some environmental toxicants that induce epigenetic alterations, and introduced chemopreventive materials to reverse the toxicants-induced epigenetic alterations. Methodologically, we used global and specific DNA methylation as epigenetic end points and searched epigenetic modulators in food. We reviewed various epigenetic end points induced by environmental toxicants including alcohol, asbestos, nanomaterials, benzene, EDCs, metals, and ionizing radiation. The epigenetic end points can be summarized into global hypomethylation and specific hypermethylation at diverse tumor suppress genes. Exposure timing, dose, sex, or organ specificity should be considered to use the epigenetic end points as biomarkers for exposure to the epimutagenic toxicants. Particularly, neonatal exposure to the epimutagens can influence their future adult health because of characteristics of the epimutagens, which disrupt epigenetic regulation in imprinting, organogenesis, development, etc. Considering interaction between epimutagenic toxicants and their reversers in food, we suggest that multiple exposures to them can alleviate or mask epigenetic toxicity in real life. Our present review provides useful information to find new end points of environmental toxicants and to prevention from environment-related diseases.