Infants' dietary arsenic exposure during transition to solid food

Urinary concentrations of non-essential and essential elements during weaning in infants from the NELA cohort in Spain

Infancy is a period of continuous growth and development, where inadequate intake of essential elements and exposure to non-essential elements may have lifelong health consequences. Thus, the aim of this study is to evaluate the urine concentration of essential and non-essential elements as a proxy for internal exposure during the weaning period, from 3 to 18 months of age. The Nutrition in Early Life and Asthma (NELA) birth cohort generated the data for this study. Sociodemographic, dietary, and urine concentration of essential (Co, Cu, Mo, I, Fe, Mn, Se, Zn, and Ni) and non-essential elements (Al, V, As, Cd, Sb, Tl, and Pb) data were available for 490 participants at 3 months of age and 216 participants at 18 months of age. Paired urine samples at both time periods were available for 175 infants. At 3 months of age, exclusively breastfed infants had lower urine concentrations of Al, V, Fe, Co, Se, Sb, and Tl. Notably, the concentration of Mo had a median (IQR) of 0.60 (0.40-2.10) μg/L compared to a median (IQR) of 39.80 (25.00-56.40) μg/L observed in infants exclusively fed with formula. When we analyzed the change in urine elements concentrations between 3 and 18 months of age, we observed increased As (0.75 vs. 18.60 μg/L), Co (0.05 vs. 0.24 μg/L), Mo (1.98 vs. 50.0 μg/L), Pb (0.15 vs. 0.69 μg/L), Se (11.3 vs. 23.1 μg/L), Tl (0.02 vs. 0.11 μg/L), and V (0.05 vs. 0.11 μg/L). For Cu, lower urine concentrations were observed at 18 months of age in comparison with concentrations at 3 months (5.77 vs. 4.41 μg/L). Among the main food items identified as driving the changes in urine concentration between 3 and 18 months of age were white fish, rice and pasta, potato chips, custard, small blue fish, and legumes. Exclusively breastfed infants showed lower exposure to non-essential elements compared to those who were fed with a mixture or formula. With the introduction of solid foods, the exposure to some non-essential elements increased drastically, as in the case of As and Pb. In addition, exposure to the essential metal Mo also increased substantially with the introduction of solid food.

Effect of Adopting a Gluten-Free Diet on Exposure to Arsenic and Other Heavy Metals in Children With Celiac Disease: A Prospective Cohort Study

INTRODUCTION

Lifelong adherence to a gluten-free diet (GFD) is the primary treatment of celiac disease (CeD), a gluten-driven enteropathy. Concerns have been raised about increased exposure to arsenic from a GFD because rice, which naturally bioaccumulates arsenic, is commonly used as a substitute for gluten-containing grains such as wheat. We hypothesize that arsenic exposure increases in newly diagnosed children with CeD after they adopt a GFD.

METHODS

This is a single-center prospective longitudinal cohort study of children (age 2-18 years) with elevated celiac serology who underwent a diagnostic endoscopy before initiation of a GFD between January and May 2022. The primary outcome was change in urinary arsenic concentration between endoscopy and after 6 months on a GFD.

RESULTS

Of the 67 recruited participants, 50 had a biopsy diagnostic of CeD and were invited to continue the study. Thirty-five participants completed sample collection. Participants were from a middle-class, well-educated population that was predominantly White with presenting symptoms of abdominal pain (51%) and diarrhea (29%). After 6 months on a GFD, there was a significant increase in the median urinary arsenic concentration (3.3 µg/L vs 13.6 µg/L, P = 0.000004). In regression models, family history of CeD and Hispanic ethnicity were associated with having a higher urinary arsenic concentration after 6 months on a GFD.

DISCUSSION

Children with newly diagnosed CeD have increased arsenic exposure shortly after transitioning to a GFD. While the arsenic levels were well below acutely toxic concentrations, the clinical impact of chronic exposure to mildly elevated arsenic levels is unknown.

Dietary Intake and Exposure Assessment of Trace Elements in Infants' Diets: A Case Study in Kuwait

Different types of infant foods categorized as formulas, cereals, and purees imported from seven different countries and available on the Kuwaiti retail market were collected to determine the elemental content, including essential trace elements namely chromium (Cr), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), selenium (Se), and molybdenum (Mo); potentially toxic trace elements such as aluminum (Al), nickel (Ni), tin (Sn), antimony (Sb), and uranium (U); and toxic trace elements including arsenic (As), lead (Pb), cadmium (Cd), and mercury (Hg). The samples were analyzed using ICP-MS. An extensive literature search illustrated the uniqueness of this study since seven different essential elements, five different potentially toxic elements, and four different toxic trace elements were measured in a variety of infant foods; in addition, the different trace etlemental levels measured in the investigated infant foods were compared to the ones associated with the different infant foods types reported in the literature. The essential trace element concentrations detected in this study were implemented to calculate their total daily intake, where the calculated daily intake values were compared to their recommended dietary allowance (RDA) to assess the percentage total daily intake for the essential trace elements. Further, the calculated potentially toxic and toxic trace elements daily intake values were used to assess the potential health risks to infants incurred by consuming different infant foods by calculating the hazard quotient (HQ), while the margin of exposure (MOE) was calculated for the toxic ones only. It was concluded that infant formulas and foods should be added to the infant diet in addition to breast milk to meet specific nutritional needs. This study confirms that infants are exposed to toxic trace elements via diet, warranting careful attention to diet choices both to limit this exposure and to avert potentially hazardous adverse health effects to the infants. However, based on the calculated hazard quotients (HQs) and margin of exposures (MOEs), consuming breast milk in addition to almost all different types of infant foods is considered safe and unlikely to contribute to infants' non-cancerous health hazards.

Association between gestational arsenic exposure and infant physical development: a prospective cohort study

BACKGROUND

Arsenic pollution is widespread worldwide. The association between gestational arsenic exposure and adverse birth outcomes has been demonstrated in previous studies; however, few investigations have examined whether gestational arsenic exposure has adverse effects on infant growth and development after birth.

OBJECTIVE

Our study was designed to evaluate particular associations between gestational arsenic exposure during pregnancy and newborn birth size and to investigate whether these associations continue to affect infants after birth.

METHODS

An ongoing prospective cohort study of 1100 pregnant women was conducted at the Wuxi Maternity and Child Health Care Hospital. The total urinary arsenic concentrations in the 2nd and 3rd trimester were determined using atomic fluorescence spectrometry. The relationships between urinary arsenic concentration and foetal growth parameters (birth weight, head circumference, length, and ponderal index), SGA (Small for gestational age), and physical growth of infants within one year after birth were analysed.

RESULTS

Urinary arsenic concentration in the 3rd trimester was associated with an increased incidence of SGA [adjusted model: OR = 2.860 (95% CI: 1.168, 7.020), P = 0.021)]. Arsenic exposure in late pregnancy had an adverse effect on the physical development of infants before the age of 1 year, and there was an interaction effect with the sex of infants. The weight and length of boys at 6 and 12 months negatively correlated with maternal urinary arsenic levels during late pregnancy.

CONCLUSIONS

In addition to affecting foetal growth, exposure to arsenic in the 3rd trimester also negatively affected the growth of offspring within the first year of life.

Update of the risk assessment of inorganic arsenic in food

The European Commission asked EFSA to update its 2009 risk assessment on arsenic in food carrying out a hazard assessment of inorganic arsenic (iAs) and using the revised exposure assessment issued by EFSA in 2021. Epidemiological studies show that the chronic intake of iAs via diet and/or drinking water is associated with increased risk of several adverse outcomes including cancers of the skin, bladder and lung. The CONTAM Panel used the benchmark dose lower confidence limit based on a benchmark response (BMR) of 5% (relative increase of the background incidence after adjustment for confounders, BMDL05) of 0.06 μg iAs/kg bw per day obtained from a study on skin cancer as a Reference Point (RP). Inorganic As is a genotoxic carcinogen with additional epigenetic effects and the CONTAM Panel applied a margin of exposure (MOE) approach for the risk characterisation. In adults, the MOEs are low (range between 2 and 0.4 for mean consumers and between 0.9 and 0.2 at the 95th percentile exposure, respectively) and as such raise a health concern despite the uncertainties.

Epidemiological evidence for the effect of environmental heavy metal exposure on the immune system in children

Heavy metals exist widely in daily life, and exposure to heavy metals caused by environmental pollution has become a serious public health problem worldwide. Due to children's age-specific behavioral characteristics and imperfect physical function, the adverse health effects of heavy metals on children are much higher than in adults. Studies have found that heavy metal exposure is associated with low immune function in children. Although there are reviews describing the evidence for the adverse effects of heavy metal exposure on the immune system in children, the summary of evidence from epidemiological studies involving the level of immune molecules is not comprehensive. Therefore, this review summarizes the current epidemiological study on the effect of heavy metal exposure on childhood immune function from multiple perspectives, emphasizing its risks to the health of children's immune systems. It focuses on the effects of six heavy metals (lead (Pb), cadmium (Cd), arsenic (As), mercury (Hg), nickel (Ni), and manganese (Mn)) on children's innate immune cells, lymphocytes and their subpopulations, cytokines, total and specific immunoglobulins, and explores the immunotoxicological effects of heavy metals. The review finds that exposure to heavy metals, particularly Pb, Cd, As, and Hg, not only reduced lymphocyte numbers and suppressed adaptive immune responses in children, but also altered the innate immune response to impair the body's ability to fight pathogens. Epidemiological evidence suggests that heavy metal exposure alters cytokine levels and is associated with the development of inflammatory responses in children. Pb, As, and Hg exposure was associated with vaccination failure and decreased antibody titers, and increased risk of immune-related diseases in children by altering specific immunoglobulin levels. Cd, Ni and Mn showed activation effects on the immune response to childhood vaccination. Exposure age, sex, nutritional status, and co-exposure may influence the effects of heavy metals on immune function in children.

Characterization and Quantification of Arsenic Species in Foodstuffs of Plant Origin by HPLC/ICP-MS

Arsenic is a well-known carcinogenic, mutagenic and toxic element and occurs in the environment both as inorganic arsenic (iAs) and organoarsenical compounds (oAsCs). Since the toxicity of arsenic compounds depends on their chemical form, the identification and determination of arsenic species are essential. Recently, the European Food Safety Authority, following the European Commission request, published a report on chronic dietary exposure to iAs and recommended the development and validation of analytical methods with adequate sensitivity and refined extraction procedures for this determination. Moreover, the authority called upon new arsenic speciation data for complex food matrices such as seaweeds, grains and grain-based products. Looking at this context, an optimized, sensitive and fast analytical method using high performance liquid chromatography followed by inductively coupled plasma-mass spectrometry (HPLC/ICP-MS) was developed for the determination of iAs (sum of arsenite-As^III and arsenate-As^V) and the most relevant oAsCs, arsenobetaine, dimethylarsinic acid and monomethylarsonic acid. The method was validated with satisfactory results in terms of linearity, sensitivity, selectivity, precision, recovery, uncertainty, ruggedness and matrix effect, and then successfully applied for the analysis of several matrices, i.e., processed and unprocessed cereal and cereal products, fruits, vegetables, legumes, seaweeds, nuts and seeds. The results obtained indicate that not only seaweed and rice matrices but also many cereals, legumes and plant-based foods for infants and young children contain significant concentrations of iAs and oAsCs. These findings contribute to the data collection necessary to assess the role of these matrices in the total arsenic exposure and if specific maximum limits have to be established.

Alterations in Microbial-Associated Fecal Metabolites in Relation to Arsenic Exposure Among Infants

In utero and early life exposure to inorganic arsenic (iAs) alters immune response in experimental animals and is associated with an increased risk of infant infections. iAs exposure is related to differences in the gut microbiota diversity, community structure, and the relative abundance of individual microbial taxa both in laboratory and human studies. Metabolomics permits a direct measure of molecular products of microbial and host metabolic processes. We conducted NMR metabolomics analysis on infant stool samples and quantified the relative concentrations of 34 known microbial-related metabolites. We examined these metabolites in relation to both in utero and infant log2 urinary total arsenic concentrations (utAs, the sum of iAs and iAs metabolites) collected at approximately 6 weeks of age using linear regression models, adjusted for infant sex, age at sample collection, type of delivery (vaginal vs. cesarean section), feeding mode (breast milk vs. any formula), and specific gravity. Increased fecal butyrate (b = 214.24), propionate (b = 518.33), cholate (b = 8.79), tryptophan (b= 14.23), asparagine (b = 28.80), isoleucine (b = 65.58), leucine (b = 95.91), malonate (b = 50.43), and uracil (b = 36.13), concentrations were associated with a doubling of infant utAs concentrations (p< 0.05). These associations were largely among infants who were formula fed. No clear associations were observed with maternal utAs and infant fecal metabolites. Metabolomic analyses of infant stool samples lend further evidence that the infant gut microbiota is sensitive to As exposure, and these effects may have functional consequences.

Consequences of Arsenic Contamination on Plants and Mycoremediation-Mediated Arsenic Stress Tolerance for Sustainable Agriculture

Arsenic contamination in water and soil is becoming a severe problem. It is toxic to the environment and human health. It is usually found in small quantities in rock, soil, air, and water which increase due to natural and anthropogenic activities. Arsenic exposure leads to several diseases such as vascular disease, including stroke, ischemic heart disease, and peripheral vascular disease, and also increases the risk of liver, lungs, kidneys, and bladder tumors. Arsenic leads to oxidative stress that causes an imbalance in the redox system. Mycoremediation approaches can potentially reduce the As level near the contaminated sites and are procuring popularity as being eco-friendly and cost-effective. Many fungi have specific metal-binding metallothionein proteins, which are used for immobilizing the As concentration from the soil, thereby removing the accumulated As in crops. Some fungi also have other mechanisms to reduce the As contamination, such as biosynthesis of glutathione, cell surface precipitation, bioaugmentation, biostimulation, biosorption, bioaccumulation, biovolatilization, methylation, and chelation of As. Arsenic-resistant fungi and recombinant yeast have a significant potential for better elimination of As from contaminated areas. This review discusses the relationship between As exposure, oxidative stress, and signaling pathways. We also explain how to overcome the detrimental effects of As contamination through mycoremediation, unraveling the mechanism of As-induced toxicity.

Contribution of gut bacteria to arsenic metabolism in the first year of life in a prospective birth cohort

Gut bacteria are at the interface of environmental exposures and their impact on human systems, and may alter host absorption, metabolism, and excretion of toxic chemicals. We investigated whether arsenic-metabolizing bacterial gene pathways related to urinary arsenic concentrations. In the New Hampshire Birth Cohort Study, urine and stool samples were obtained at six weeks (n = 186) and one year (n = 190) of age. Inorganic arsenic (iAs), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and arsenobetaine (AsB) were quantified in infant urine samples using high-performance liquid chromatography with inductively coupled plasma mass spectrometry. Total arsenic exposure (tAs) was summarized as Σ(iAs, MMA, DMA) and log2-transformed. Fecal microbial DNA underwent metagenomic sequencing and the relative abundance of bacterial gene pathways were grouped as KEGG Orthologies (KOs) using BioBakery algorithms. Arsenic metabolism KOs with >80% prevalence were log2-transformed and modeled continuously using linear regression, those with <10% were not evaluated and those with 10-80% prevalence were analyzed dichotomously (detect/non-detect) using logistic regression. In the first set of models, tAs was regressed against KO relative abundance or detection adjusting for age at sample collection and child's sex. Effect modification by delivery mode was assessed in stratified models. In the second set of models, the association between the relative abundance/detection of the KOs and arsenic speciation (%iAs, %MMA, %DMA) was quantified with linear regression. Urinary tAs was associated with the increased relative abundance/detection odds of several arsenic-related KOs, including K16509, an arsenate reductase transcriptional regulator, with stronger associations among six-week-olds than one-year-olds. K16509 was also associated with decreased %MMA and increased %DMA at six weeks and one year. Notably, many associations were stronger among operatively-delivered than vaginally-delivered infants. Our findings suggest associations between arsenic-metabolizing bacteria in the infant gut microbiome and urinary arsenic excretion.

Dietary Exposure to Toxic Elements and the Health of Young Children: Methodological Considerations and Data Needs

Concerns have been raised regarding toxic-element (arsenic, cadmium, lead, and mercury) contamination of commercially available infant foods around the world. Young children are vulnerable to the effects of toxic elements, based on higher absorption levels and potentially poorer detoxification capacities. Toxic-element exposures in early life exact high societal costs, but it is unclear how much dietary exposure to these elements contributes to adverse health outcomes. Well-designed epidemiological studies conducted in different geographical and socioeconomic contexts need to estimate dietary toxicant exposure in young children and to determine whether causal links exist between toxicants in children's diets and health outcomes. This commentary outlines the methodological considerations and data needs to advance such research.

Toxic metal exposures from infant diets: Risk prevention strategies for caregivers and health care professionals

Concerns are growing regarding the presence of toxic elements such as arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) in the ingredients and prepared foods for infants and young children. There are few clear, evidence-based, guidelines on the maximum tolerable limits of toxicants in foods and little understanding of toxicant exposure or adverse health effects attributable to dietary exposure. Caregivers are faced with the burden of making decisions about which foods to select, how often to feed them to their children, and what foods to limit. This article reviews the current literature and existing recommendations on dietary exposure to toxic elements in children under 2 years of age, and their health effects in early childhood-focusing on growth, neurodevelopment, and immune function. The article also outlines best practices for healthcare providers to address the concerns of toxic element exposure through the diet in young children. Several foods consistently appear in the literature as potential sources of toxic element exposure. Contaminated drinking and cooking water, including water used to prepare infant formula, could also be a major exposure source. In the absence of stronger evidence on effects of dietary modification, exclusive breastfeeding until six months of age, followed by a diverse diet are some strategies to reduce dietary toxic element exposure while ensuring an adequate and balanced nutrient intake. Healthcare providers can support families by sharing information and encouraging blood Pb testing, the only element for which such testing is currently recommended.

Dietary Exposure to Essential and Non-essential Elements During Infants' First Year of Life in the New Hampshire Birth Cohort Study

Even the low levels of non-essential elements exposure common in the US may have health consequences especially early in life. However, little is known about the infant's dynamic exposure to essential and non-essential elements. This study aims to evaluate exposure to essential and non-essential elements during infants' first year of life and to explore the association between the exposure and rice consumption. Paired urine samples from infants enrolled in the New Hampshire Birth Cohort Study (NHBCS) were collected at approximately 6 weeks (exclusively breastfed) and at 1 year of age after weaning (n = 187). A further independent subgroup of NHBCS infants with details about rice consumption at 1 year of age also was included (n = 147). Urinary concentrations of 8 essential (Co, Cr, Cu, Fe, Mn, Mo, Ni, and Se) and 9 non-essential (Al, As, Cd, Hg, Pb, Sb, Sn, V, and U) elements were determined as a measure of exposure. Several essential (Co, Fe, Mo, Ni, and Se) and non-essential (Al, As, Cd, Hg, Pb, Sb, Sn, and V) elements had higher concentrations at 1 year than at 6 weeks of age. The highest increases were for urinary As and Mo with median concentrations of 0.20 and 1.02 µg/L at 6 weeks and 2.31 and 45.36 µg/L at 1 year of age, respectively. At 1 year of age, As and Mo urine concentrations were related to rice consumption. Further efforts are necessary to minimize exposure to non-essential elements while retaining essential elements to protect and promote children's health.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12403-022-00489-x.

Infant infections, respiratory symptoms, and allergy in relation to timing of rice cereal introduction in a United States cohort

Rice products marketed in the USA, including baby rice cereal, contain inorganic arsenic, a putative immunotoxin. We sought to determine whether the timing of introduction of rice cereal in the first year of life influences occurrence of infections, respiratory symptoms, and allergy. Among 572 infants from the New Hampshire Birth Cohort Study, we used generalized estimating equation, adjusted for maternal smoking during pregnancy, marital status, education attainment, pre-pregnancy body mass index, maternal age at enrollment, infant birth weight, and breastfeeding history. Among 572 infants, each month earlier of introduction to rice cereal was associated with increased risks of subsequent upper respiratory tract infections (relative risk, RR = 1.04; 95% CI: 1.00-1.09); lower respiratory tract infections (RR = 1.19; 95% CI: 1.02-1.39); acute respiratory symptoms including wheeze, difficulty breathing, and cough (RR = 1.10; 95% CI: 1.00-1.22); fever requiring a prescription medicine (RR = 1.22; 95% CI: 1.02-1.45) and allergy diagnosed by a physician (RR = 1.20; 95% CI: 1.06-1.36). No clear associations were observed with gastrointestinal symptoms. Our findings suggest that introduction of rice cereal earlier may influence infants' susceptibility to respiratory infections and allergy.

Prenatal exposure to arsenic and lung function in children from the New Hampshire Birth Cohort Study

Prenatal arsenic exposure is associated with an increased risk of lung cancer along with multiple non-carcinogenic outcomes, including respiratory diseases in arsenic-contaminated areas. Limited epidemiologic data exist on whether in utero arsenic exposure influences lung development and subsequent respiratory health. We investigated the association between gestational arsenic exposure and childhood lung function in the New Hampshire Birth Cohort Study. Urinary arsenic speciation including inorganic arsenic (iAs), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and arsenobetaine was measured in maternal urine samples collected during pregnancy and spirometry was performed in offspring at a median age of 7.4 years. Forced vital capacity (FVC), forced expiratory volume in the first second of exhalation (FEV1), and forced expiratory flow between 25% and 75% of FVC (FEF25-75) standardized z-scores were assessed in linear models as dependent variables with the log2-transformed summation of urinary arsenic species (ΣAs = iAs + MMA + DMA) corrected for specific gravity as an independent variable and with adjustment for maternal smoking status, children's age, sex and height. Among the 358 children in the study, a doubling of ΣAs was associated with a -0.08 (ß) decrease in FVC z-scores (95% confidence interval (CI) from -0.14 to -0.01) and -0.10 (ß) (95% CI from -0.18 to -0.02) decrease in FEV1 z-scores. The inverse association appeared stronger among those mothers with lower secondary methylation index (urinary DMA/MMA), especially among girls. No association was observed for FEF25-75 z-scores. Our results suggest that gestation arsenic exposure at levels relevant to the general US population during the vulnerable period of lung formation may adversely affect lung function in childhood.

Arsenic, Cadmium, Lead, and Mercury in Lactation Foods and Prenatal Vitamins: Potentially Avoidable Exposure for Breastfeeding Mothers and Infants

Background: Human milk is a biofluid that can contain heavy metals such as arsenic, cadmium, lead, and mercury. These toxins can adversely affect endocrine, respiratory, immune, and nervous systems. Infants may have higher dietary arsenic exposure than adults due to their more restricted diets and greater intake per unit body mass. We identified commonly purchased vitamins, lactation bars, and supplements, to measure the concentration of heavy metals. The goal of the study was to measure and determine if vitamins and lactation foods could be a source of exposure. Methods: We tested 9 popular vitamins and 16 lactation bars and supplements all marketed toward breastfeeding mothers to determine the presence of heavy metals. All vitamins, bars, and supplements were analyzed using inductively coupled plasma mass spectrometry, for the total concentration of arsenic, mercury, cadmium, and lead, with the lowest detection limit of 0.001 μg/L. Results: The majority of the samples had total arsenic levels below detectable quantities (detection limit of 1 part per trillion [0.001 μg/L]), one sample of syrup had a concentration of 0.112 ± 0.005, 0.132 ± 0.009, and 0.108 ± 0.010 μg of arsenic/g. We also tested nine popular prenatal vitamins for the amount of arsenic in one serving of vitamins per day and showed exposure to arsenic in one vitamin of 7.108 μg of arsenic/day. All lactation foods and vitamins tested had undetectable amounts of cadmium, mercury, and lead. Conclusion: Most of the vitamins and bars that were tested had below the detectable limit of arsenic, cadmium, lead, and mercury; we did find one vitamin and one rice syrup that had significantly higher levels. Our data suggest that it is highly feasible to manufacture vitamins and lactation foods and supplements with significantly lower concentrations of heavy metals.

Low-level exposure to lead, mercury, arsenic, and cadmium, and blood pressure among 8-17-year-old participants of the 2009-2016 National Health and Nutrition Examination Survey

BACKGROUND

Dysregulation of systolic, diastolic blood pressure (SBP, DBP), and pulse pressure (PP) in children may predict elevated blood pressure (BP) in adulthood. Toxicant exposure is widely studied as a risk factor for high BP in adults, but not in children. We assessed the joint associations between lead (Pb), mercury (Hg), arsenic (As), and cadmium (Cd) exposure and SBP, DBP, and PP among 8-17 year-old participants (n = 1642) of the 2009-2016 National Health and Nutrition Examination Survey (NHANES).

METHODS

Participants with at least two BP measures were included. Urinary As and Cd were adjusted for urinary creatinine concentrations. Blood Pb, Hg, and urinary As, Cd were natural log-transformed. Bayesian Kernel Machine Regression (BKMR) analyses were conducted to assess the associations between the toxicant mixture and BP measures. Multivariable regression models assessed the associations between individual toxicants, and the four toxicants simultaneously with each of the outcomes. Interactions with sodium intake were tested.

RESULTS

Exposure to all toxicants was low, with median (5%, 95%) level: Pb, 0.57 (0.26, 1.60) μg/dL; Hg, 0.37 (0.19, 2.12) μg/L; As, 5.61 (1.37, 33.2) μg/g creatinine, Cd, 0.06 (0.03, 0.23) μg/g creatinine. Toxicant mixture showed a statistically significant, inverse association with DBP, but not other BP measures. Linear regressions revealed no association between toxicants, individually or together, and BP measures. No evidence of interaction of sodium intake with any of the toxicants was observed.

CONCLUSIONS

In a nationally representative sample of 8-17 year-olds, we found suggestive inverse association of the mixture of low-level Pb, Hg, As, and Cd, with DBP. Longitudinal studies with multiple toxicants are needed to understand the interactive effects of toxicants on children's BP.

Chronic dietary exposure to inorganic arsenic

Following an official request to EFSA from the European Commission, EFSA assessed the chronic dietary exposure to inorganic arsenic (iAs) in the European population. A total of 13,608 analytical results on iAs were considered in the current assessment (7,623 corresponding to drinking water and 5,985 to different types of food). Samples were collected across Europe between 2013 and 2018. The highest mean dietary exposure estimates at the lower bound (LB) were in toddlers (0.30 μg/kg body weight (bw) per day), and in both infants and toddlers (0.61 μg/kg bw per day) at the upper bound (UB). At the 95th percentile, the highest exposure estimates (LB-UB) were 0.58 and 1.20 μg/kg bw per day in toddlers and infants, respectively. In general, UB estimates were two to three times higher than LB estimates. The mean dietary exposure estimates (LB) were overall below the range of benchmark dose lower confidence limit (BMDL 01) values of 0.3-8 μg/kg bw per day established by the EFSA Panel on Contaminants in the Food Chain in 2009. However, for the 95th percentile dietary exposure (LB), the maximum estimates for infants, toddlers and other children were within this range of BMDL 01 values. Across the different age classes, the main contributors to the dietary exposure to iAs (LB) were 'Rice', 'Rice-based products', 'Grains and grain-based products (no rice)' and 'Drinking water'. Different ad hoc exposure scenarios (e.g. consumption of rice-based formulae) showed dietary exposure estimates in average and for high consumers close to or within the range of BMDL 01 values. The main uncertainties associated with the dietary exposure estimations refer to the impact of using the substitution method to treat the left-censored data (LB-UB differences), to the lack of information (consumption and occurrence) on some iAs-containing ingredients in specific food groups, and to the effect of food preparation on the iAs levels. Recommendations were addressed to improve future dietary exposure assessments to iAs.

Children exposure to inorganic and organic arsenic metabolites: A cohort study in Northeast Italy

The aim of this study was to provide urinary levels of total arsenic (TAs) and As species as arsenobetaine (AsB), arsenocholine (AsC), inorganic As (i.e., [As(III)+As(V)]), methylarsonic acid (MMA) and dimethylarsinic acid (DMA) in 7 year-old-children (n = 200) enrolled in the Northern Adriatic Cohort II (NACII), a prospective cohort in a coastal area of Northeast Italy. TAs was determined by sector field-inductively coupled plasma mass spectrometry (SF-ICP-MS) and AsB, AsC, As(III), As(V), MMA and DMA by ion chromatography coupled to ICP-MS (IC-ICP-MS). The geometric mean (GM) for TAs was 12.9 μg/L and for [iAs + MMA + DMA] was 4.26 μg/L. The species AsB (GM of 5.09 μg/L) and DMA (GM of 3.20 μg/L) had the greatest percentage contribution to TAs levels; a greater percentage contribution from AsB is seen at TAs >10 μg/L and from DMA at TAs <10 μg/L. Urinary [iAs + MMA] levels were positively associated with [iAs + MMA + DMA] and DMA with AsB levels. Fish, shellfish and crustaceans consumption increased the AsB and TAs levels, while rice intake, mothers' education level and selenium (Se) concentration influenced the DMA concentration. Children have a high capacity to metabolize and detoxify the iAs because of the higher secondary methylation index (ratio DMA/MMA) with respect to primary methylation index (ratio MMA/iAs). In addition, the median level of [iAs + MMA + DMA] in the whole population of children was lower than the Biomonitoring Equivalent (BE) value for non-cancer endpoints. Also the Margin of Safety (MOS) value based on the population median was greater than 1, thus the exposure to the toxicologically relevant As species was not likely to be of concern.

CRM rapid response approach for the certification of arsenic species and toxic trace elements in baby cereal coarse rice flour certified reference material BARI-1

With recently legislated maximum levels of inorganic arsenic (iAs) in white and brown rice in Canada, the regulatory bodies are evaluating the need for regulation of As levels in infant food products. Rice is a major part of infants' diet, and therefore, the presence of As in this staple food causes concerns. So far, the scientific community was lacking suitable certified reference material (CRM) which could be used to assess the accuracy of developed analytical methods for As speciation in infants' food products. As a result, we have developed BARI-1, a baby cereal coarse rice flour reference material which was certified for total arsenic (0.248 ± 0.018 mg kg^-1), cadmium (0.0134 ± 0.0014 mg kg^-1), mercury (0.0026 ± 0.0003 mg kg^-1), lead (0.0064 ± 0.0016 mg kg^-1), inorganic As (0.113 ± 0.016 mg kg^-1) and dimethylarsinic acid (DMA) (0.115 ± 0.010 mg kg^-1), and reference value for monomethylarsonic acid (MMA) (0.0045 ± 0.0008 mg kg^-1) was reported. We also observed trace amounts of an unknown As compound, with chromatographic retention time close to DMA. Participating laboratories were allowed to use their in-house-validated extraction and/or digestion methods, and the detection of total metals was done by ICP-MS whereas HPLC-ICP-MS was used for As speciation. Despite the diversity in sample preparation and quantitation methods, reported values were in good agreement. For iAs measurement, the comparison between hydride generation ICP-MS and HPLC-ICP-MS found iAs overestimation with the former method, possibly due to interference from DMA. The certification was accomplished with a CRM rapid response approach in collaborative, focused effort completing the CRM development in few months instead of the typical multiyear project. This approach allowed to respond to measurement needs in a timely fashion. Graphical abstract.

Masking Phosphate with Rare-Earth Elements Enables Selective Detection of Arsenate by Dipycolylamine-ZnII Chemosensor

Functional reassessment of the phosphate-specific chemosensors revealed their potential as arsenate detectors. A series of dipicolylamine (Dpa)-ZnII chemosensors were screened, among which acridine Dpa-ZnII chemosensor showed the highest capability in sensing arsenate. The presence of excess ZnII improved sensitivity and strengthened the binding between acridine Dpa-ZnII complex to arsenate as well as phosphate. However, due to their response to phosphate, these sensors are not suited for arsenate detection when phosphate is also present. This study demonstrated for the first time that rare-earth elements could effectively mask phosphate, allowing the specific fluorescence detection of arsenate in phosphate-arsenate coexisting systems. In addition, detection of arsenate contamination in the real river water samples and soil samples was performed to prove its practical use. This sensor was further employed for the visualization of arsenate and phosphate uptake in vegetables and flowering plants for the first time, as well as in the evaluation of a potent inhibitor of arsenate/phosphate uptake.

Dietary determinants of inorganic arsenic exposure in the Strong Heart Family Study

BACKGROUND

Chronic exposure to inorganic arsenic (iAs) in the US occurs mainly through drinking water and diet. Although American Indian (AI) populations have elevated urinary arsenic concentrations compared to the general US population, dietary sources of arsenic exposure in AI populations are not well characterized.

METHODS

We evaluated food frequency questionnaires to determine the major dietary sources of urinary arsenic concentrations (measured as the sum of arsenite, arsenate, monomethylarsonate, and dimethylarsinate, ΣAs) for 1727 AI participants in the Strong Heart Family Study (SHFS). We compared geometric mean ratios (GMRs) of urinary ΣAs for an interquartile range (IQR) increase in reported food group consumption. Exploratory analyses were stratified by gender and study center.

RESULTS

In fully adjusted generalized estimating equation models, the percent increase (95% confidence interval) of urinary ΣAs per increase in reported food consumption corresponding to the IQR was 13% (5%, 21%) for organ meat, 8% (4%, 13%) for rice, 7% (2%, 13%) for processed meat, and 4% (1%, 7%) for non-alcoholic drinks. In analyses stratified by study center, the association with organ meat was only observed in North/South Dakota. Consumption of red meat [percent increase -7% (-11%, -3%)] and fries and chips [-6% (-10%, -2%)] was inversely associated with urinary ΣAs.

CONCLUSIONS

Organ meat, processed meat, rice, and non-alcoholic drinks contribute to ΣAs exposure in the SHFS population. Organ meat is a unique source of ΣAs exposure for North and South Dakota participants and may reflect local food consumption. Further studies should comprehensively evaluate drinking water arsenic in SHFS communities and determine the relative contribution of diet and drinking water to total arsenic exposure.

Arsenic in cooked rice foods: Assessing health risks and mitigation options

Human exposure to arsenic (As) through the consumption of rice (Oryza sativa L.) is a worldwide health concern. In this paper, we evaluated the major causes for high inorganic As levels in cooked rice foods, and the potential of post-harvesting and cooking options for decreasing inorganic As content in cooked rice, focusing particularly on As endemic areas. The key factors for high As concentration in cooked rice in As endemic areas are: (1) rice cultivation on As-contaminated paddy soils; (2) use of raw rice grains which exceed 200 μg kg^-1 of inorganic As to cook rice; and (3) use of As-contaminated water for cooking rice. In vitro and in vivo methods can provide useful information regarding the bioaccessibility of As in the gastrointestinal tract. Urinary levels of As can also be used as a valid measure of As exposure in humans. Polishing of raw rice grains has been found to be a method to decrease total As content in cooked rice. Sequential washing of raw rice grains and use of an excess volume of water for cooking also decrease As content in cooked rice. The major concern with those methods (i.e. polishing of raw rice, sequential washing of raw rice, and use of excess volume of water for cooking rice) is the decreased nutrient content in the cooked rice. Cooking rice in percolating water has recently gained significant attention as a way to decrease As content in cooked rice. Introducing and promoting rainwater harvesting systems in As endemic areas may be a sustainable way of reducing the use of As-contaminated water for cooking purposes. In conclusion, post-harvesting methods and changes in cooking practices could reduce As content in cooked rice to a greater extent. Research gaps and directions for future studies in relation to different post-harvesting and cooking practices, and rainwater harvesting systems are also discussed in this review.

Clinical Aspects of Thickeners for Pediatric Gastroesophageal Reflux and Oropharyngeal Dysphagia

PURPOSE OF REVIEW

The purpose of this review is to discuss current knowledge and recent findings regarding clinical aspects of thickeners for pediatric gastroesophageal reflux and oropharyngeal dysphagia. We review evidence for thickener efficacy, discuss types of thickeners, practical considerations when using various thickeners, and risks and benefits of thickener use in pediatrics.

RECENT FINDINGS

Thickeners are effective in decreasing regurgitation and improving swallowing mechanics and can often be used empirically for the treatment of infants and young children. Adverse effects have been reported, but with careful consideration of appropriate thickener types, desired thickening consistency, and follow-up in collaboration with feeding specialists, most patients have symptomatic improvements. Thickeners are typically well tolerated and with few side effects, but close follow-up is needed to make sure patients tolerate thickeners and have adequate symptom improvement.

Opportunities and Challenges for Dietary Arsenic Intervention

The diet is emerging as the dominant source of arsenic exposure for most of the U.S. population. Despite this, limited regulatory efforts have been aimed at mitigating exposure, and the role of diet in arsenic exposure and disease processes remains understudied. In this brief, we discuss the evidence linking dietary arsenic intake to human disease and discuss challenges associated with exposure characterization and efforts to quantify risks. In light of these challenges, and in recognition of the potential longer-term process of establishing regulation, we introduce a framework for shorter-term interventions that employs a field-to-plate food supply chain model to identify monitoring, intervention, and communication opportunities as part of a multisector, multiagency, science-informed, public health systems approach to mitigation of dietary arsenic exposure. Such an approach is dependent on coordination across commodity producers, the food industry, nongovernmental organizations, health professionals, researchers, and the regulatory community. https://doi.org/10.1289/EHP3997.