Dietary exposures to eight metallic contaminants of the Hong Kong adult population from a total diet study

Singapore's Total Diet Study (2021-2023): Study Design, Methodology, and Relevance to Ensuring Food Safety

A total diet study is often used to evaluate a population's baseline dietary exposure to chemical hazards from across the diet. In 2021-2023, Singapore carried out a TDS, and this article presents an overview of the study design and methodological selections in Singapore's TDS, as well as its relevance to ensuring food safety. A food consumption survey was conducted on Singapore citizens and permanent residents, where food consumption patterns of the Singapore population were identified. The selection of chemical hazards and foods for inclusion in Singapore's TDS, as well as principal considerations on sampling, food preparation, and analytical testing are discussed. Commonly consumed foods by the Singapore population in food categories such as grain and grain-based products, meat and meat products, fish and seafood, vegetables, fruits, milk and dairy products were included in this study, and mean concentrations of chemicals tested in each food category were reported, with food categories possessing higher levels identified. Future work will include dietary exposure assessments for the population and analysis of the contributions by food and cooking method.

A high spatial resolution dataset for methylmercury exposure in Guangdong-Hong Kong-Macao Greater Bay Area

Dietary methylmercury (MeHg) exposure increases the risk of many human diseases. The Guangdong-Hong Kong-Macao Greater Bay Area (GBA) is the world's most populous bay area and people there might suffer a high risk of dietary MeHg exposure. However, there lacks a time-series high spatial resolution dataset for dietary MeHg exposure in the GBA. This study constructs a high spatial resolution (1 km × 1 km) dataset for dietary MeHg exposure in the GBA during 2009-2019. It first constructs the dietary MeHg exposure inventory for each county/district of the GBA, based on MeHg concentrations of foods (i.e., rice and fish in this study) and per capita rice and fish intake. Subsequently, this study spatializes the dietary MeHg exposure inventory at 1 km × 1 km scale, using gridded data for food consumption expenditure as the proxy. This dataset can describe the spatially explicit hotspots, distribution patterns, and variation trend of dietary MeHg exposure in the GBA. This dataset can support spatially explicit evaluation of MeHg-related health risks in the GBA.

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.

Probabilistic Risk Assessment of Dietary Exposure to Cadmium in Residents of Guangzhou, China-Young Children Potentially at a Health Risk

Cadmium (Cd) and its compounds are hazardous environmental pollutants with renal toxicity and human carcinogenicity, with ingestion of contaminated foods representing the major mode of exposure. There have been a number of reports evaluating the Cd content in various foods; however, regarding the actual risk posed by dietary cadmium exposure, only a few reports are available in which single point evaluation (less accurate than multiple point evaluation) was employed. In this study, we used a margin of exposure (MOE) model and @RISK software (for multiple evaluation) to evaluate Cd-related health risk in the local Guangzhou residents at varying ages, through a comparison between the estimated monthly exposures and the provisional tolerable monthly intake (0.025 mg/kg body weight (b.w.)), based on the Cd contents in various food categories available locally (a total of 3964 food samples were collected from each of the 13 districts of Guangzhou between 2015 and 2019), which were determined by using inductively coupled plasma mass spectrometry. In this study, Cd was detected in 69.6% of the samples (averaged 0.120 mg/kg), and rice and its products, leafy vegetables, bivalves, and shrimp and crabs contributed most to Cd exposure (8.63, 3.18, 2.79, and 1.48 ng/kg b.w./day, respectively). The MOE values demonstrated the following tendency: the younger age group, the lower MOE, and its 95% confidence range for the (youngest) 3~6 year old group started from 0.92, indicating a health risk of young children, while that for the other age groups were all above 1.0. Our preliminary findings warrant further clarification using biomarker assays in the relevant population.

Results of the BfR MEAL Study: In Germany, mercury is mostly contained in fish and seafood while cadmium, lead, and nickel are present in a broad spectrum of foods

The BfR MEAL Study provides representative levels of substances in foods consumed in Germany. Mercury, cadmium, lead, and nickel are contaminants present in foods introduced by environmental and industrial processes. Levels of these elements were investigated in 356 foods. Foods were purchased representatively, prepared as consumed and pooled with similar foods before analysis. Highest mean levels of mercury were determined in fish and seafood, while high levels of cadmium, lead, and nickel were present in cocoa products and legumes, nuts, oilseeds, and spices. The sampling by region, season, and production type showed minor differences in element levels for specific foods, however no tendency over all foods or for some food groups was apparent. The data on mercury, cadmium, lead, and nickel provide a comprehensive basis for chronic dietary exposure assessment of the population in Germany. All levels found were below regulated maximum levels.

Interactive effects of maternal exposure to chemical fertilizer and socio-economic status on the risk of low birth weight

Background

Maternal exposure to chemical fertilizer and disadvantaged maternal socio-economic status (SES) have been found to associate with increased risk of low birth weight (LBW). However, whether the two factors would interact to elevate the risk of LBW remains unknown. The present study aimed to explore the interactive effects of maternal exposure to chemical fertilizer during pregnancy and low SES on the risk of term LBW (tLBW).

Methods

In this population-based case–control study, 179 tLBW cases (birthweight < 2500 g and gestational age ≥ 37 weeks) and 204 controls (birthweight ≥ 2500 g and gestational age ≥ 37 weeks) were chosen from the Perinatal Health Care Surveillance System of Pingding County, Shanxi Province, China between 2007 and 2012. Data on basic socio-demographic, dietary and lifestyle characteristics and environmental exposure were directly extracted from the system. Maternal exposure to chemical fertilizer was measured at both household level and village level. Household-level exposure was indicated by household chemical fertilizer use in farming during pregnancy and the data was collected by trained healthcare workers after the selection of cases and controls in 2013. Village-level exposure was indicated by annual amount of village chemical fertilizer consumption per acre and the data came from the Annals of National Economics Statistics of Pingding County in 2010. Interactions between maternal exposure to chemical fertilizer and SES were assessed in logistic regressions using relative excess risk due to interaction (RERI), which indicates an additive interaction if larger than 0.

Results

The combination of low maternal SES and high exposure to village-level chemical fertilizer consumption was associated with increased risk of tLBW (aOR = 2.62, 95%CI: 1.44 ~ 4.77); The combination of low maternal SES and exposure to household chemical fertilizer use was associated with elevated risk of tLBW (aOR = 2.18, 95%CI: 1.24 ~ 3.83). Additive interactions were detected between high exposure to village-level chemical fertilizer consumption and low maternal SES (RERI:1.79, P < 0.001) and between exposure to household chemical fertilizer use and low maternal SES (RERI:0.77, P < 0.05).

Conclusions

Our study suggested negative impacts of potential agricultural pollutants on adverse pregnancy outcomes, especially in disadvantaged socio-economic populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13604-z.

The Role of PKC in Regulating NMDARs in Aluminum-Induced Learning and Memory Impairment in Rats

Aluminum is a widespread environmental neurotoxicant that can induce Alzheimer's disease (AD)-like damage, such as neuronal injury and impairment of learning and memory. Several studies have shown that aluminum could reduce the synaptic plasticity, but its molecular mechanism remains unclear. In this study, rats were treated with aluminum maltol (Al(mal)3) to establish a toxic animal model and PMA was used to interfere with the expression of PKC. The Morris water maze and open field test were used to investigate the behavioral changes of the rats. Western blotting and RT-PCR were used to detect the expression levels of NMDAR subunits, PKC and CaMKII. The results showed that Al(mal)3 damaged learning and memory function and reduced anxiety in rats. During this process, the expression of PKC was downregulated and it inhibited the expression of NMDARs through the phosphorylation of CaMKII.

Leaching and In Vivo Bioavailability of Antimony in PET Bottled Beverages

Antimony (Sb) may leach from polyethylene terephthalate (PET) materials into bottled water under improper storage conditions, particularly at high temperatures, leading to potential Sb chronic exposure and adverse health effects. However, Sb leaching may be promoted by various beverage constituents, which has received limited attention to date. In addition, few studies have considered Sb bioavailability in beverages and the influence of the beverage matrix on Sb bioavailability. In this study, PET-bottled beverages (n = 50) covering six categories (namely, carbonated, fruit juices, tea, sports, protein, and coffee beverages) were explored. Antimony leaching was assessed following the incubation of beverages at 60 °C for 7 days, which resulted in Sb concentrations 1.10-10.9 times greater than concentrations observed pre-incubation. Although regulatory standards vary internationally, a total of 21 beverages exceeded the Japanese Sb drinking water standard of 2 μg/L (up to 4.08 ± 0.11 μg/L) following incubation at 60 °C. pH significantly influenced Sb leaching (r = -0.38, p = 0.007) with beverages displaying lower pH (e.g., carbonated drinks) exhibiting higher Sb concentrations. An in vivo mouse model, using the liver as the biological endpoint, was adopted to assess Sb relative bioavailability (RBA) in bottled beverages. Sb RBA ranged from 1.97-58.7% with coffee beverages exhibiting the lowest Sb RBA (1.97-13.7%) and protein drinks the highest (41.1-58.7%). Linear regression revealed that Sb RBA in beverages was negatively influenced by Fe (r = -0.69, p = 0.02) and P (r = -0.73, p = 0.01) concentrations but positively correlated with tartaric acid (r = 0.59, p = 0.02). When an exposure assessment was undertaken using data generated in this study, carbonated and protein-rich beverages exhibited a higher exposure risk due to elevated Sb leaching and high Sb RBA compared to other beverage categories.

Cadmium, lead and mercury in the blood of psoriatic and vitiligo patients and their possible associations with dietary habits

BACKGROUND

Psoriasis and vitiligo are common, autoimmune skin diseases, their etiology is still unclear. The relationship between environmental factors including diet and various skin diseases has been studied. The general mechanism of cadmium (Cd), lead (Pb) and mercury (Hg) toxicity is through the production of reactive oxygen species which are known to play a role in etiopathogenesis of skin disorders.

OBJECTIVE

The aim of this study was to estimate the influence of dietary habits on the concentration of Cd, Pb and Hg in the peripheral blood samples of patients with psoriasis and vitiligo.

METHODS

In this case-control study, sixty patients with psoriasis, fifty patients with vitiligo and fifty eight healthy people were examined. Blood levels of Cd, Pb and Hg were determined by atomic absorption spectrometry. Food-frequency questionnaires were implemented to collect the dietary data.

RESULTS

Significant differences (p < 0.05) of Cd levels were found between women and men with psoriasis and women and men in the control group. The concentration of Pb was significantly higher among vitiligo patients (50.04 ± 26.54 μg/L) than in healthy controls (36.04 ± 27.35 μg/L). Significantly lower ratio of Se/Pb, Zn/Pb and Cu/Pb was found among psoriatic men. Significantly (p < 0.05) lower values of Se/Hg ratio were observed among vitiligo patients compared to controls.

CONCLUSIONS

The elevated levels of toxic elements could increase oxidative stress which may partly contribute to inflammation in the pathogenesis of psoriasis and vitiligo, which requires further research. Analysis of the influence of frequent consumption of food products on toxic metals concentration showed that the dietary habits have impact on the content of examined toxic metals in the blood of patients. The obtained results may be useful for composing the diet and could be helpful in prevention of psoriasis and vitiligo.

Maternal Diet During Pregnancy and Blood Cadmium Concentrations in an Observational Cohort of British Women

Few studies have investigated the extent to which diet predicts body Cd concentrations among women of reproductive age, and pregnant women in particular. The aim of this study was to examine diet as a predictor of blood Cd concentrations in pregnant women participating in the UK Avon Longitudinal Study of Parents and Children (ALSPAC). Whole blood samples were analysed for Cd (median 0.26 (IQR 0.14–0.54) µg/L). Dietary pattern scores were derived from principal components analysis of data from a food frequency questionnaire. Associations between dietary pattern scores and foods/food groups with blood Cd ≥ median value were identified using adjusted logistic regression (n = 2169 complete cases). A health conscious dietary pattern was associated with a reduced likelihood of B-Cd ≥0.26 µg/l (OR 0.56 (95% CI 0.39–0.81)). There were similarly reduced likelihoods for all leafy green and green vegetables (0.72 (0.56–0.92) when consumed ≥4 times/week vs ≤1 to ≥3 times/week) and with all meats (0.66 (0.46–0.95) when consumed ≥4 times/week vs ≤ once in 2 weeks). Sensitivity analysis excluding smokers showed similar results. The evidence from this study provides continued support for a healthy and varied diet in pregnancy, incorporating foods from all food groups in accordance with national recommendations, without the need for specific guidance.

Fish from a polluted lake (Lake Chivero, Zimbabwe): a food safety issue of concern

Objectives

A study to determine food safety hazard status of fish products from Lake Chivero was conducted in selected high density suburbs of Harare. Lake water and fish were tested for E. coli O157:H7, total bacterial, fungal counts, mercury (Hg) and aflatoxin B1 (AFB1) to determine contamination levels and assessing human health hazard exposure.

Materials and Methods

Membrane filtration method was used to determine E. coli O157:H7 viable counts using CHROM agar. Plate count and Potato dextrose agar were used for determination of total viable bacterial and fungal counts. Concentrations of Hg and AFB1 in fish and water were determined by Atomic Absorption Spectrophotometer and High Performance Liquid Chromatography-Mass Spectrometry. A questionnaire survey was conducted on 136 adult fish consumers to determine the fish consumption patterns to assess hazard exposure against international standards.

Results

Significant levels of microbial contamination above international standards in both fish and water were recorded. Mean E. coli O157:H7 counts were 106 ± 10 (cfu/cm2) in fish and 52 ± 14 (cfu/100ml) in water. Mean Log10 TBC were 8.98 ± 0.26 (cfu/cm2) in fish and 9.05 ± 0.05 (cfu/ml) in water. Mean Log10 TFC were 4.83 ± 0.02 (cfu/cm2) in fish and 4.56 ± 0.03 (cfu/ml) in water. Hg and AFB1 were 0.018 (µg/kg) and 0.025 (µg/kg) in fish and 0.008 (µg/kg) and 0.005 (µg/kg) in water, both with a hazard quotient (HQ) <1 using CODEX STAN 193-1995 of 2015.

Conclusion

Fish and water are contaminated with E. coli O157:H7, contain bacterial and fungal loads above international food safety guidance levels. Fish were caught already contaminated with pathogens together with toxigenic Hg and carcinogenic AFB1 although their concentration levels are within international food safety toxicological levels. Levels of Hg and AFB1 in water were almost double that of fish, implying bio-accumulation occurred in fish. Thus, fish consumers are exposed to food safety hazards and are at risk of contracting foodborne illnesses from consuming contaminated fish.

Dietary Lead Exposure and Associated Health Risks in Guangzhou, China

Lead exposure is associated with a wide range of adverse effects on human health. The principal exposure route in the general population is through the diet. In this study, we estimate the dietary lead intake and associated health risks among the residents of Guangzhou, China. Data on lead concentrations were derived from the food safety risk monitoring system, which included 6339 samples from 27 food categories collected in 2014–2017. Food consumption data were taken from a 2011 dietary survey of 2960 Guangzhou residents from 998 households. Dietary lead intake was estimated by age group (3–6, 7–17, 18–59, and ≥60 years), and relevant health risks were assessed using the margin of exposure (MOE) method. The mean and 95th percentiles (P95) of dietary lead intake were respectively 0.7466 and 2.4525 μg/kg body weight per day for preschool children aged 3–6 years; 0.4739 and 1.5522 μg/kg bw/day for school children aged 7–17 years; 0.3759 and 1.1832 μg/kg bw/day for adults aged 18–59 years; and 0.4031 and 1.3589 μg/kg bw/day for adults aged ≥60 years. The MOE value was less than 1 for preschool children at the mean exposure level and for all age groups at the P95 exposure level. Rice and its products, leafy vegetables, and wheat flour and its products were found to be the primary food sources of lead exposure. Our findings suggest that the health risk from dietary lead exposure is low for Guangzhou residents overall, but that young children and consumers of certain foods may be at increased risk. Continued efforts are needed to reduce the dietary lead exposure in Guangzhou.

Dietary Cadmium Intake and Sources in the US

Cadmium (Cd) is a toxic heavy metal that can contribute to numerous diseases as well as increased mortality. Diet is the primary source of Cd exposure for most individuals, yet little is known about the foods and food groups that contribute most substantially to dietary Cd intake in the US. Therefore, the objective of this study was to estimate dietary Cd intake and identify major food sources of Cd in the US population and among subgroups of the population. Individuals aged 2 years and older from the National Health and Nutrition Examination Survey (NHANES) 2007⁻2012 were included in this study (n = 12,523). Cd intakes were estimated from two days of 24-h dietary recalls by matching intake data with the Cd database of the Food and Drug Administration (FDA)'s Total Diet Study 2006 through 2013. The average dietary Cd consumption in the population was 4.63 μg/day, or 0.54 μg/kg body weight/week, which is 22% of the tolerable weekly intake (TWI) of 2.5 μg/kg body weight/week. Greater daily Cd intakes were observed in older adults, males, those with higher income, higher education, or higher body mass index. The highest Cd intakes on a body weight basis were observed in children 10 years and younger (38% of TWI), underweight individuals (38% of TWI), and alcohol non-consumers (24% of TWI). The food groups that contributed most to Cd intake were cereals and bread (34%), leafy vegetables (20%), potatoes (11%), legumes and nuts (7%), and stem/root vegetables (6%). The foods that contributed most to total Cd intake were lettuce (14%), spaghetti (8%), bread (7%), and potatoes (6%). Lettuce was the major Cd source for Caucasians and Blacks, whereas tortillas were the top source for Hispanics, and rice was the top contributor among other ethnic subgroups including Asians. This study provides important information on the dietary Cd exposure of Americans, and identifies the groups with the greatest dietary Cd exposure as well as the major sources of dietary Cd among sociodemographic subgroups.

Association between dietary cadmium intake and early gastric cancer risk in a Korean population: a case-control study

PURPOSE

Foods such as grains and vegetables are the dominant sources of exposure to cadmium, which has been classified as a carcinogen by various public health agencies. Cadmium exposure is a growing concern due to its associations with numerous harmful health effects, including gastric cancer risk. The objective of this study was to investigate the association of dietary cadmium intake and the consumption of cadmium-contributing foods with early gastric cancer risk.

METHODS

A case-control study including 1245 subjects (cases, 415; controls, 830) was conducted in Korea. The dietary cadmium intake and the consumption of cadmium-contributing foods were assessed using a semi-quantitative food frequency questionnaire.

RESULTS

After adjustment for covariates, the gastric cancer risk was increased for participants in the highest tertile of cadmium intake [odds ratios (ORs) 1.33, 95% confidence intervals (95% CIs) 0.94-1.88], but there was no significance. Both female (ORs 2.71, 95% CIs 1.37-5.36) and male (ORs 1.63, 95% CIs 1.07-2.50) participants in the highest tertile of rice consumption had a higher gastric cancer risk than did those in the lowest tertile. Men in the highest tertile of crab consumption had a gastric cancer risk 2.23 times greater than that of men in the lowest tertile (ORs 2.23, 95% CIs 1.21-4.13), but a difference was not seen in women.

CONCLUSIONS

Future studies examining the causal effects of dietary cadmium intake and the consumption of cadmium-contributing foods on early gastric cancer risk in large-scale prospective cohorts are recommended.

What do we know about exposure of Iranians to cadmium? Findings from a systematic review

Cadmium is an important environmental contaminant. High consumption of chemical fertilizers and industrial activities in recent decades has caused people to be worried about exposure to cadmium. There is no policy for environmental and biological monitoring of exposure to cadmium in the general population in Iran. This study was aimed to review cadmium content in consuming foods and biological samples in Iran, systematically. We developed a comprehensive search strategy and used it to search on Web of Science, Scopus, Science Direct, and Scientific Information Database until 28 December 2016. The totals of 285 articles were identified and finally 31 original papers were selected. Cadmium contamination was found in Iranian food groups such as rice, cereal and legumes, canned tuna fish, vegetables, fruit juice, and egg. This study showed that cadmium amount in 75% of the consumed rice samples (domestic and imported) was higher than the maximum limits approved by institute of standards and industrial research of Iran. Lettuce samples in Yazd were recorded the highest concentration of cadmium compared to other studies. In addition, high amount of cadmium was observed in the blood of the general population. Regarding the cadmium contamination in food and blood samples in Iran, policies must be adopted to reduce exposure to cadmium through different matrices as much as possible.

Heavy Metal Dietary Intake and Potential Health Risks for University Hostel Students

The study was conducted to determine the residual concentration of Cd, Pb, Asand Hg in some foodstuffs served to university students living at hostels of Beni-Suef University (BSU), Egypt, and to estimate the dietary intake of such metals, as well as to assess the potential health risks associated with the consumption of such foods. Therefore, a total of 200 samples, 50 each of, soft cheese, UHT milk, raw broiler carcasses and canned tuna, were periodically collected from university hostels of BSU and examined for the residual levels of these metals using atomic absorption spectrophotometer. The obtained results revealed that the mean residual levels of Cd in soft cheese, UHT milk, broiler's meat and canned tuna samples were 0.37, 0.26, 0.089 and 0.093 mg/kg, respectively, while those of Pb were 0.187, 0.20, 0.181 and 0.164 mg/kg, respectively. Regarding As, they were 0.196, 0.24, 0.14 and 0.201 mg/kg, respectively, and Hg mean residual concentration accounted for 0.05, 0.05, 0.117 and 0.235 mg/kg, respectively. Some of the examined food samples had heavy metals' concentrations above the international standards. The total weekly dietary intakes of Cd, Pb, As and Hg were 4.99, 5.38, 4.77 and 2.76 μg/kg bw/week, respectively, that were comparable to the provisional tolerable weekly intake recommended by the Joint Expert Committee on Food Additives (JECFA). The total target hazard quotient (TTHQ) of broiler's meat was over 1 (1.686), thus indicating possible health risks in contrast to the TTHQs of other foodstuffs that were below one.