Presence and risks of nanosilica in food products

Abstract

This study uniquely describes all steps of the risk assessment process for the use of one specific nanomaterial (nanosilica) in food products. The aim was to identify gaps in essential knowledge and the difficulties and uncertainties associated with each of these steps. Several food products with added silica (E551) were analyzed for the presence, particle size and concentration of nanosilica particles, using experimental analytical data, and the intake of nanosilica via food was estimated. As no information is available on the absorption of nanosilica from the gastrointestinal tract, two scenarios for risk assessment were considered. The first scenario assumes that the silica is absorbed as dissolved silica, while the second scenario assumes that nanosilica particles themselves are absorbed from the gastrointestinal tract. For the first scenario no adverse effects are expected to occur. For the second scenario there are too many uncertainties to allow proper risk assessment. Therefore, it is recommended to prioritize research on how nanosilica is absorbed from the gastrointestinal tract.     

Novel insights into the risk assessment of the nanomaterial synthetic amorphous silica,additive E551, in food

Abstract

This study presents novel insights in the risk assessment of synthetic amorphous silica (SAS) in food. SAS is a nanostructured material consisting of aggregates and agglomerates of primary particles in the nanorange (<100?nm). Depending on the production process, SAS exists in four main forms, and each form comprises various types with different physicochemical characteristics. SAS is widely used in foods as additive E551. The novel insights from other studies relate to low gastrointestinal absorption of SAS that decreases with increasing dose, and the potential for accumulation in tissues with daily consumption. To accommodate these insights, we focused our risk assessment on internal exposure in the target organ (liver). Based on blood and tissue concentrations in time of two different SAS types that were orally and intravenously administered, a kinetic model is developed to estimate the silicon concentration in liver in (1) humans for average-to-worst-case dietary exposure at steady state and (2) rats and mice in key toxicity studies. The estimated liver concentration in humans is at a similar level as the measured or estimated liver concentrations in animal studies in which adverse effects were found. Hence, this assessment suggests that SAS in food may pose a health risk. Yet, for this risk assessment, we had to make assumptions and deal with several sources of uncertainty that make it difficult to draw firm conclusions. Recommendations to fill in the remaining data gaps are discussed. More insight in the health risk of SAS in food is warranted considering the wide applications and these findings.     

The impact of synthetic amorphous silica (E 551) on differentiated Caco-2 cells,a model for the human intestinal epithelium

For several decades, food-grade synthetic amorphous silica (SAS) have been used as a technological additive to reduce caking of food powders. Human exposure is thus inevitable and safety concerns are taken seriously. The toxicity of silica in general and SAS in particular has been studied extensively. Overall, there is little evidence that food-grade SAS pose any health risks to humans. However, from the available data it was often not clear which type of silica was used. Accordingly, the latest report of the European food safety authority requested additional toxicity data for well-characterised “real food-grade SAS”.To close this gap, we screened a panel of ten well-defined, food-grade SAS for potential adverse effects on differentiated Caco-2 cells. Precipitated and fumed SAS with low, intermediate and high specific surface area were included to determine structure-activity relationships.In a physiological dose-range up to 50 μg/ml and 48 h of incubation, none of the materials induced adverse effects on differentiated Caco-2 cells. This held true for endpoints of acute cytotoxicity as well as epithelial specific measures of barrier integrity. These results showed that despite considerable differences in production routes and material characteristics, food-relevant SAS did not elicit acute toxicity responses in intestinal epithelial cells.     

The safety assessment of nanomaterials in reproductive developmental field

A diverse array of nanomaterials (NMs) such as amorphous nanosilica and carbon nanotubes have become widespread in use due to the development of nanotechnology. NMs are already being applied in universal fields because they have unique physicochemical properties. On the other hand, the increasing use of NMs has raised public concern about their potential risks to human health. In particular, recent reports indicated that carbon nanotubes induced mesothelioma-like lesions in mice, in a way similar to those induced by crocidolite asbestos. However, current knowledge of the potential risk of nanomaterials is considered insufficient. Because NMs have the potential to improve the quality of human life, it is essential to ensure the safety of NMs and provide information for designing NMs with safety. Especially, few studies have examined the effect of NMs on maintenance of pregnancy. Similar to the cases of thalidomide, a lot of evidence shows that fetuses are affected more than adults by a variety of environmental toxins because of physiological immaturity. Therefore it is essential to examine the effect of NMs on fetuses and pregnancies. Here we introduce the potential risk of amorphous nanosilica, most widely used NMs in food and the cosmetics field, to induce fetotoxicity and useful information for developing NMs with safety.     

The contribution of epidemiology.

Epidemiologic studies directly contribute data on risk (or benefit) in humans as the investigated species, and in the full food intake range normally encountered by humans. This paper starts with introducing the epidemiologic approach, followed by a discussion of perceived differences between toxicological and epidemiologic risk assessment. Areas of contribution of epidemiology to the risk assessment process are identified, and ideas for tailoring epidemiologic studies to the risk assessment procedures are suggested, dealing with data collection, analyses and reporting of both existing and new epidemiologic studies. The dietary habits and subsequent disease occurrence of over three million people are currently under observation worldwide in cohort studies, offering great potential for use in risk assessment. The use of biomarkers and data on genetic susceptibility are discussed. The paper describes a scheme to classify epidemiologic studies for use in risk assessment, and deals with combining evidence from multiple studies. Using a matrix approach, the potential contribution to each of the steps in the risk assessment process is evaluated for categories of food substances. The contribution to risk assessment of specific food substances depends on the quality of the exposure information. Strengths and weaknesses are summarized. It is concluded that epidemiology can contribute significantly to hazard identification, hazard characterisation and exposure assessment.     

Risk assessment of amorphous silicon dioxide nanoparticles in a glass cleaner formulation

Abstract

Since nanomaterials are a heterogeneous group of substances used in various applications, risk assessment needs to be done on a case-by-case basis. Here the authors assess the risk (hazard and exposure) of a glass cleaner with synthetic amorphous silicon dioxide (SAS) nanoparticles during production and consumer use (spray application). As the colloidal material used is similar to previously investigated SAS, the hazard profile was considered to be comparable. Overall, SAS has a low toxicity. Worker exposure was analysed to be well controlled. The particle size distribution indicated that the aerosol droplets were in a size range not expected to reach the alveoli. Predictive modelling was used to approximate external exposure concentrations. Consumer and environmental exposure were estimated conservatively and were not of concern. It was concluded based on the available weight-of-evidence that the production and application of the glass cleaner is safe for humans and the environment under intended use conditions.     

ICH Q3D新药制剂元素杂质评估及控制的要点解读

目的：药品中可能有多个来源的元素杂质,由于元素杂质不能给病人提供任何治疗益处,因而药品生产中元素杂质含量应被控制在可接受的限度内。国际人用药物注册技术协调会议（ICH）Q3D元素杂质指南是新药制剂元素杂质控制的质量指南,旨在为新药制剂和其赋形剂中元素杂质的定性和定量控制提供全球性方针。本文介绍Q3D元素杂质指南,对相关要点进行解读。方法：详细描述元素杂质指南的主要内容,侧重于对元素风险评估及设定制剂中各组分元素杂质的限度进行具体分析。根据《美国药典》39和《欧洲药典》9.0中相关金属元素杂质的通则,汇总这些指导性文件与ICH Q3D的不同之处。结果与结论：Q3D主要包括潜在元素杂质的安全性评价、类别、元素杂质的风险评估和控制、日允许暴露量（Permitted Daily Exposure,简称PDE）与浓度限度之间的转换。元素杂质的风险评估应考虑潜在元素杂质的来源和药物服用方式,将特定元素杂质水平与PDE进行比较,评价该元素在药品中存在的可能性。经风险评估需要进行控制的元素杂质,可以根据药物服用剂量和PDE用3种方法设定元素浓度限度,这有利于帮助药品生产企业通过风险评估来决定对哪些元素进行额外控制,从而有效保障药品质量。     

The toxicological mode of action and the safety of synthetic amorphous silica-a nanostructured material

Synthetic amorphous silica (SAS), in the form of pyrogenic (fumed), precipitated, gel or colloidal SAS, has been used in a wide variety of industrial and consumer applications including food, cosmetics and pharmaceutical products for many decades. Based on extensive physico-chemical, ecotoxicology, toxicology, safety and epidemiology data, no environmental or health risks have been associated with these materials if produced and used under current hygiene standards and use recommendations. With internal structures in the nanoscale size range, pyrogenic, precipitated and gel SAS are typical examples of nanostructured materials as recently defined by the International Organisation for Standardisation (ISO). The manufacturing process of these SAS materials leads to aggregates of strongly (covalently) bonded or fused primary particles. Weak interaction forces (van der Waals interactions, hydrogen bonding, physical adhesion) between aggregates lead to the formation of micrometre (μm)-sized agglomerates. Typically, isolated nanoparticles do not occur. In contrast, colloidal SAS dispersions may contain isolated primary particles in the nano-size range which can be considered nano-objects. The size of the primary particle resulted in the materials often being considered as "nanosilica" and in the inclusion of SAS in research programmes on nanomaterials. The biological activity of SAS can be related to the particle shape and surface characteristics interfacing with the biological milieu rather than to particle size. SAS adsorbs to cellular surfaces and can affect membrane structures and integrity. Toxicity is linked to mechanisms of interactions with outer and inner cell membranes, signalling responses, and vesicle trafficking pathways. Interaction with membranes may induce the release of endosomal substances, reactive oxygen species, cytokines and chemokines and thus induce inflammatory responses. None of the SAS forms, including colloidal nano-sized particles, were shown to bioaccumulate and all disappear within a short time from living organisms by physiological excretion mechanisms with some indications that the smaller the particle size, the faster the clearance is. Therefore, despite the new nomenclature designating SAS a nanomaterial, none of the recent available data gives any evidence for a novel, hitherto unknown mechanism of toxicity that may raise concerns with regard to human health or environmental risks. Taken together, commercial SAS forms (including colloidal silicon dioxide and surface-treated SAS) are not new nanomaterials with unknown properties, but are well-studied materials that have been in use for decades.     

Prediction of lapse from associations between smoking and situational antecedents assessed by ecological momentary assessment

Smoking is associated with particular moods and activities, but it is not known whether there are individual differences in these associations and whether these differences are associated with success in smoking cessation. We assessed such associations using ecological momentary assessment: real-world, real-time data, collected by palm-top computer. Two hundred and fourteen smokers participating in a smoking cessation study provided data during ad lib smoking at baseline. Participants recorded moods and activities each time they smoked and, for comparison, at randomly selected non-smoking occasions. Situational associations with smoking were captured by examining the associations between smoking and antecedents considered relevant to lapse risk: negative affect (NA), arousal, socializing with others, the presence of others smoking, and consumption of coffee and alcohol. The associations varied across participants, confirming individual differences in situational smoking associations. Survival analyses revealed that only the NA pattern predicted first lapse. The effect was only seen in EMA assessments of NA smoking, and was not captured by questionnaire measures of negative affect smoking, which did not predict lapse risk. Moreover, the effect was not mediated by nicotine dependence.     

Differences between children and adults: implications for risk assessment at California EPA

The California legislature enacted a law requiring the California Environmental Protection Agency (Cal/EPA) Office of Environmental Health Hazard Assessment (OEHHA) to evaluate whether our risk assessment methodologies are adequately protective of infants and children. In addition both OEHHA and the California Air Resources Board must examine whether the Ambient Air Quality Standards set for criteria air pollutants and the health values developed for air toxics are adequately protective of infants and children. We have initiated a program to look at potential differences in response to toxicants between children and adults. We are evaluating this issue from the perspective of exposure differences as well as toxicokinetic and toxicodynamic differences between children and adults. Data on specific chemicals are rather limited. As a result, we will be pooling information to determine whether there are generic differences between children and adults that may be applicable to risk assessment in general or to risk assessment of specific classes of compounds. This paper discusses the rationale for approaching the issue of determining whether our risk assessment methods are adequate for infants and children and includes a discussion of some of the available information on both qualitative and quantitative differences in response to toxicants between children and adults or immature and mature laboratory animals. We provide examples of differences between children and adults in absorption, metabolism, and excretion of toxicants as well as qualitative differences in toxic response.     

Consumer exposures to laser printer-emitted engineered nanoparticles: A case study of life-cycle implications from nano-enabled products

Abstract

It is well established that printers emit nanoparticles during their operation. To-date, however, the physicochemical and toxicological characterization of “real world” printer-emitted nanoparticles (PEPs) remains incomplete, hampering proper risk assessment efforts. Here, we investigate our earlier hypothesis that engineered nanomaterials (ENMs) are used in toners and ENMs are released during printing (consumer use). Furthermore, we conduct a detailed physicochemical and morphological characterization of PEPs in support of ongoing toxicological assessment. A comprehensive suite of state of the art analytical methods and tools was employed for the physicochemical and morphological characterization of 11 toners widely utilized in printers from major printer manufacturers and their PEPs. We confirmed that a number of ENMs incorporated into toner formulations (e.g. silica, alumina, titania, iron oxide, zinc oxide, copper oxide, cerium oxide, carbon black among others) and released into the air during printing. All evaluated toners contained large amounts of organic carbon (OC, 42–89%), metals/metal oxides (1–33%), and some elemental carbon (EC, 0.33–12%). The PEPs possess a composition similar to that of toner and contained 50–90% OC, 0.001–0.5% EC and 1–3% metals. While the chemistry of the PEPs generally reflected that of their toners, considerable differences are documented indicative of potential transformations taking place during consumer use (printing). We conclude that: (i) Routine incorporation of ENMs in toners classifies them as nano-enabled products (NEPs); (ii) These ENMs become airborne during printing; (iii) The chemistry of PEPs is complex and it reflects that of the toner and paper. This work highlights the importance of understanding life-cycle (LC) nano-EHS implications of NEPs and assessing real world exposures and associated toxicological properties rather than focusing on “raw” materials used in the synthesis of an NEP.     

State of the art in benefit-risk analysis: Food and nutrition

Benefit-risk assessment in food and nutrition is relatively new. It weighs the beneficial and adverse effects that a food (component) may have, in order to facilitate more informed management decisions regarding public health issues. It is rooted in the recognition that good food and nutrition can improve health and that some risk may be acceptable if benefit is expected to outweigh it. This paper presents an overview of current concepts and practices in benefit-risk analysis for food and nutrition. It aims to facilitate scientists and policy makers in performing, interpreting and evaluating benefit-risk assessments.Historically, the assessments of risks and benefits have been separate processes. Risk assessment is mainly addressed by toxicology, as demanded by regulation. It traditionally assumes that a maximum safe dose can be determined from experimental studies (usually in animals) and that applying appropriate uncertainty factors then defines the ‘safe’ intake for human populations. There is a minor role for other research traditions in risk assessment, such as epidemiology, which quantifies associations between determinants and health effects in humans. These effects can be both adverse and beneficial. Benefit assessment is newly developing in regulatory terms, but has been the subject of research for a long time within nutrition and epidemiology. The exact scope is yet to be defined. Reductions in risk can be termed benefits, but also states rising above ‘the average health’ are explored as benefits. In nutrition, current interest is in ‘optimal’ intake; from a population perspective, but also from a more individualised perspective.In current approaches to combine benefit and risk assessment, benefit assessment mirrors the traditional risk assessment paradigm of hazard identification, hazard characterization, exposure assessment and risk characterization. Benefit-risk comparison can be qualitative and quantitative. In a quantitative comparison, benefits and risks are expressed in a common currency, for which the input may be deterministic or (increasingly more) probabilistic. A tiered approach is advocated, as this allows for transparency, an early stop in the analysis and interim interaction with the decision-maker. A general problem in the disciplines underlying benefit-risk assessment is that good dose-response data, i.e. at relevant intake levels and suitable for the target population, are scarce.It is concluded that, provided it is clearly explained, benefit-risk assessment is a valuable approach to systematically show current knowledge and its gaps and to transparently provide the best possible science-based answer to complicated questions with a large potential impact on public health.     

BDNF rs 6265 polymorphism and COMT rs 4680 polymorphism in deficit schizophrenia in Polish sample

BackgroundDeficit schizophrenia (DS) is distinguished from the group of schizophrenic psychoses based on the presence of primary negative symptoms. It differs from nondeficit (NDS) forms of schizophrenia in dimensions such as risk factors, family history, course of illness and neurobiological differences. The aim of the study was assessment of a potential association of the investigated polymorphisms of the brain-derived neurotrophic factor (BDNF) and catechol-O-methyltransferase (COMT) genes with the deficit syndrome in schizophrenia.MethodsAcohort of 200 patients with schizophrenia (81 DS and 119 NDS subjects) and a group of 100 control subjects matched for ethnicity, sex and age were recruited. Somatic and psychometric assessment were conducted as well as structured interview about the influence of adverse biological, family and social factors. Genetic analysis of the BDNF (Val66Met) rs6265 and the COMT (Val158Met) rs4680 polymorphisms was performed.ResultsWe found significant differences between DS and NDS in rs4680 COMTgenotype distribution: more homozygous Val/Val were found (31 vs. 17%) in the NDS compared to the DS subgroup. No associations were found between the investigated polymorphisms of the BDNF gene and the presence of schizophrenia either in DS and NDS subgroups.ConclusionThe analysis of the COMT rs4680 polymorphism in the present DS and NDS study shows that some genetic factors may be relevant in analyzing the reasons for the differentiation of schizophrenic subtypes.     

Hazard identification of cis/trans-zearalenone through the looking-glass

Among the food-related health issues, the presence of contaminants has a prominent role, due to the wide range of exogenous compounds that can occur in food commodities and to their large differences in structure and biological activity. A comprehensive assessment of the related risk is thus actually demanding in terms of time and facilities involved. In this context, the use of computational strategies can be an effective choice for supporting the hazard identification procedure at the early stage. In this work, we focused on the food contaminant zearalenone by comparing the trans and cis isomers, respectively the well-known mycoestrogen and its still largely understudied isomer. We estimated the possible effects exerted by human metabolism on the xenoestrogenicity of cis-ZEN by using a validated in silico strategy based on docking simulations and rescoring procedures. Similarly, the exploitation of the most promising enzymatic detoxifying routes designed for trans-ZEN – which relies on the enzyme lactono hydrolase from Clonostachys rosea – has been assessed for the cis-isomer as well. Our results showed that both isomers can act as functional analogues with respect to xenoestrogenic activity, and several cis-ZEN metabolites with high biological potential have been identified. On the contrary, in spite of the high degree of structural analogy, the cis isomer showed a pattern of interaction with the degrading enzyme in stark contrast with that observed for trans-ZEN. For these reasons, the outcomes presented herein strongly support the inclusion of cis-ZEN in further studies of occurrence, metabolism and bioactivity assessment, and suggest the need for a dedicated handling for the cis isomer in risk assessment studies.     

Challenges to developing countries after joining WTO: risk assessment of chemicals in food

FAO/WHO encourages member countries to develop national food control measures based on risk assessment in order to assure proper protection level to consumers and facilitate fair trade. This is particularly important for developing countries as WTO members because it is clearly stated in the Sanitary and Phytosanitary Measures (SPS) Agreement that: (a) SPS measures should be based on risk assessment techniques developed by relevant international organizations; and (b) Codex standards which is based on risk assessment are regarded as the international norm in trade dispute settlement. When conducting risk assessment on food chemicals (including additives and contaminants) in developing countries, in most cases it is not necessary to conduct their own hazard characterization because the ADIs or PTWIs of food chemicals developed by international expert groups (e.g. JECFA) are universally applicable and also developing countries do not have the resources to repeat those expensive toxicological studies. On the other hand, it is necessary to conduct exposure assessment in developing countries because exposure to food chemicals varies from country to country. This is not only crucial in setting national standards, but also very important for developing countries to participate in the process of developing Codex standards. In addition to food standard development, risk assessment is also useful in setting up priorities in imported food inspection and evaluating the success of various food safety control measures.     

Genotoxicity evaluation of nanosized titanium dioxide,synthetic amorphous silica and multi-walled carbon nanotubes in human lymphocytes

Toxicological characterization of manufactured nanomaterials (NMs) is essential for safety assessment, while keeping pace with innovation from their development and application in consumer products. The specific physicochemical properties of NMs, including size and morphology, might influence their toxicity and have impact on human health. The present work aimed to evaluate the genotoxicity of nanosized titanium dioxide (TiO₂), synthetic amorphous silica (SAS) and multiwalled carbon nanotubes (MWCNTs), in human lymphocytes. The morphology and size of those NMs were characterized by transmission electron microscopy, while the hydrodynamic particle size-distributions were determined by dynamic light scattering. Using a standardized procedure to ensure the dispersion of the NMs and the cytokinesis-block micronucleus assay (without metabolic activation), we observed significant increases in the frequencies of micronucleated binucleated cells (MNBCs) for some TiO₂ NMs and for two MWCNTs, although no clear dose–response relationships could be disclosed. In contrast, all forms of SAS analyzed in this study were unable to induce micronuclei. The present findings increase the weight of evidence towards a genotoxic effect of some forms of TiO₂ and some MWCNTs. Regarding safety assessment, the differential genotoxicity observed for closely related NMs highlights the importance of investigating the toxic potential of each NM individually, instead of assuming a common mechanism and equal genotoxic effects for a set of similar NMs.     

Comparison of pharmacists’ scoring of fall risk to other fall risk assessments

ObjectivesGiven their professional education and participation within the health care system, pharmacists are ideal candidates to assess drug-associated fall risk for patients. The purpose of this investigation was to determine whether pharmacists can quantitatively differentiate individuals who reported falling within the previous year (fallers) from those who do not (nonfallers), and to compare the pharmacists' evaluation with 2 recently published fall risk assessments.DesignCross-sectional design of pharmacists’ assessments of fall risk.Setting and participantsThis is a cross-sectional study where 6 licensed pharmacists evaluated patient records from Wave 1 of the National Social Life, Health and Aging Project dataset using generic drug list (drug counts), age, and body mass index to generate a Pharmacist Risk Score (PRS) based on these variables. Pharmacists were allowed to use drug information resources and were provided with a simple 5-point scale to assist them in scoring patients.Outcome measuresThe main outcome measure of this study was a comparison of the following fall risk assessments (PRS, drug counts, Medication-Based Index of Physical Function, Quantitative Drug Index, and Timed Up and Go [TUG]) capacity to differentiate fallers from nonfallers.ResultsEach fall risk assessment was highly correlated (P < 0.001) with the number of reported falls. Drug-associated fall risk assessments were highly correlated (P < 0.001) with each other, but not with TUG. Each fall risk assessment differentiated fallers from nonfallers based on logistic regression (P ≤ 0.001). Receiver operating characteristic (ROC) curve analysis was significant (P ≤ 0.002) for each assessment. The comparison of ROC area under the curve for the fall risk assessments found no significant difference between the PRS and other assessments.ConclusionFall risk assessment by pharmacists was comparable with other fall risk assessments in distinguishing fallers from nonfallers.