Dietary Exposure of the Japanese General Population to Elements: Total Diet Study 2013-2018.

Some countries have conducted a total diet study (TDS) focused on the estimation of specific trace elements. Although some results of a Japanese TDS examining trace elements were published, there have been no reports of a nationwide TDS across Japan over a multi-year period to estimate the level of exposure to multiple elements. In the present study, a TDS using a market basket approach was performed to estimate the dietary exposure levels of the general population of Japan to 15 elements, including aluminum (Al), total arsenic (tAs), boron (B), barium (Ba), cadmium (Cd), cobalt (Co), chromium (Cr), total mercury (THg), molybdenum (Mo), nickel (Ni), lead (Pb), antimony (Sb), selenium (Se), tin (Sn), and uranium (U). Samples prepared in eight regions across Japan over a 6-year period were analyzed using validated methods. The robust mean exposure estimates for Al, tAs, B, Ba, Cd, Co, Cr, THg, Mo, Ni, Pb, Sb, Se, Sn, and U were 48, 4.2, 29, 8.6, 0.35, 0.17, 0.49, 0.14, 4.2, 2.8, 0.15, 0.022, 1.8, 0.10, and 0.021 µg/kg body weight/day, respectively. Although the variability in exposure estimates varied greatly from element to element, the relative standard deviations calculated from the robust means and robust standard deviations were ≤ 50% for all elements except Sn. Compared against the health-based guidance values, none of the robust and precise estimates obtained for the target elements would be associated with urgent health risk concern. In addition, the estimated exposure levels were generally in agreement with previously reported estimates, indicating that health risks associated with exposure to these elements have not changed markedly nationwide in Japan in recent years.

Probabilistic Estimation of Dietary Intake of Methylmercury from Fish in Japan.

Dietary intake of methylmercury from fish was estimated via Monte Carlo simulation using data for methylmercury concentrations in 210 fish samples and data regarding fish consumption extracted from the Japanese National Health and Nutrition Survey. The fish analyzed were classified into 5 groups according to categories used in the survey. The distribution of consumption of fish from each group was used without fitting to statistical distributions. A log-normal distribution was fitted to the distribution of methylmercury concentration in each fish group. Two random numbers that followed these distributions were generated, and a trial value was calculated by multiplying these random numbers. The trial value was divided by the body weight (50 kg) to arrive at an estimate of dietary methylmercury intake. A total of 100,000 Monte Carlo simulation iterations were performed. The estimated mean daily intake of methylmercury was 0.093 µg/kg body weight (bw)/day. This value is well below the tolerable daily intake of 0.292 µg/kg bw/day calculated from the tolerable weekly intake (2.0 µg/kg bw/week) established by the Food Safety Commission of Japan. The probability that the daily intake of methylmercury exceeds the tolerable daily intake was 7.6%. As there are no data regarding fish consumption for consecutive days, estimation of the weekly intake of methylmercury is a subject for future studies.

[Validation Procedure for a Multi-Element Analytical Method Aiming at Dietary Intake Estimation].

Total diet study (TDS) is a useful way to estimate the dietary intake of hazardous and chemical substances. Regarding the analysis performed in TDS, international guidelines published by the World Health Organization, recommend selecting and confirming the validity of suitable analytical methods to achieve the purpose of TDS. However, concrete procedures and/or approaches for confirming the validity of suitable methods have yet to be established. In the present study, we aimed to develop samples, referred to as SEMPs; Samples to estimate methods performance, that can be used to evaluate the performance of the analytical methods applied to the composite samples prepared in TDS. The concentrations of 14 kinds of elements, including hazardous substances such as arsenic, lead, and cadmium, in SEMPs were measured for use in the validation of a multi-element analytical method for estimating dietary intake. After examining the appropriate amount of relevant elements added to the samples, we established a performance evaluation procedure by repeatedly analyzing five fortified and non-fortified SEMPs each.

[Current Problems Associated with Overseas Health Products].

In recent years, consumer interest in health and health foods (e.g., dietary supplements) has increased, and the types of and market for health foods have also expanded rapidly. The safety of health foods is a significant concern in many countries. Numerous adverse events associated with the consumption of health foods have been reported. There are cases that have resulted in serious liver failure, renal failure, and death in other countries. These products may contain undeclared medical ingredients and toxic chemical compounds that are illegally and intentionally added or contain natural plant toxins. Products containing high levels of heavy metals have also been reported to cause such adverse events. Some products remain on the market, even after regulatory agencies alert consumers and issue warnings to their sellers. Moreover, because people can buy health foods from sources overseas via the Internet, adverse effects associated with the use of such products remain a concern. Two cases of adverse events were reported in Japanese individuals who purchased "OxyElite Pro" products imported privately. They are advertised as weight-loss and muscle-building products and have been associated with many cases of liver failure and hepatitis in the USA. In this paper, regulatory systems and adverse events associated with the use of health foods in other countries are discussed.

Genotoxicity assessment of 4-methylimidazole: regulatory perspectives.

4-Methylimidazole (4-MI) is formed as a result of the Maillard reaction process, and therefore is found in many foods and beverages. It is also found in soft drinks (i.e., cola) as a by-product in the production of some caramel colors. NTP bioassays revealed clear evidence of lung carcinogenicity of 4-MI in male and female mice, but not in rats and then IARC classified 4-MI as group 2B carcinogen. Genotoxicity studies with 4-MI were negative in the Ames tests and in the erythrocyte micronucleus tests with mice or rats. US California EPA (CEPA) evaluated the testing has not been adequately comprehensive to rule out a genotoxic mode of action; as target tissue of the carcinogenicity of 4-MI was lung, the lung should be used as a source tissue for in vitro metabolic activation system. Thus, CEPA defined the No Significant Risk Level (NSRL) for 10-5 lifetime risk level of cancer by 4-MI as 29 µg/day based on the non-threshold approach. As higher levels of 4-MI than the NSRL were identified in some kinds of cola, health concerns of 4-MI were drawn the attention. On the other hand, other regulatory bodies (e.g., European Food Safety Authority, EFSA) showed no concerns of 4-MI from the use of caramel colors in food. EFSA evaluated 4-MI is not genotoxic, so, non-observed adverse effect level of 4-MI was considered to be 80 mg/kg/day. In this paper, genotoxic assessments of 4-MI in different regulatory bodies are presented and the risk evaluation of 4-MI is discussed based on new genotoxicity data.

[Trends of plant toxin food poisonings during the past 50 years in Japan].

In the present study, we reviewed food poisoning data published by the Ministry of Health, Labour and Welfare of Japan from 1961 to 2010 in Japan to analyze the trends of plant toxin food poisonings (PTFPs). The annual number of incidents of PTFPs has gradually increased since 1995. PTFPs were predominantly caused by Datura spp., Veratrum spp. and Aconitum spp. Although PTFPs frequently occurred in April and May, poisonings caused by some plants occurred in all seasons, e.g. Datura spp. The major location of PTFPs was "at home", and most of the patients had accidentally harvested poisonous plants. During the past decade, the numbers of incidents of PTFPs caused by Veratrum spp., Narcissus spp., Solanum tuberosum and Alocasia odora were especially increased. Consumer advice to prevent PTFPs associated with certain plants that are cultivated in gardens and contain toxic substances is needed, because PTFPs caused by such plants are increasing. In addition, education of elementary school teachers and children about the potential risks of natural toxins in plants, particularly Solanum tuberosum, is desirable.

[Trends of food poisonings caused by natural toxins in Japan, 1989-2011].

In order to reduce the health risk associated with food poisonings caused by natural toxins, it is necessary to implement risk management strategies based on previous poisoning data and risk factors. In present study, we statistically analyzed natural toxin food poisoning (NTFP) data published by the Ministry of Health, Labour and Welfare from 1989 to 2010 in Japan and reviewed the trends of NTFP for each natural toxin hazard. Since 1989, the number of incidents of NTFP in each year has not been reduced. Prevention and control are needed to reduce the risk of NTFP. The major site for all hazards was "at home". This result suggested that consumer education is critically important to inform about NTFP occurrence, preventive measures and emergency treatments. Furthermore, countermeasures for NTFPs which have never occurred in the past in Japan should be considered, because of the increasing variety of imported foods and changes resulting from the inerease of sea temperature with global warming.

[Histamine food poisonings in Japan and other countries].

Histamine food poisonings are allergy-like food poisonings caused by the ingestion of spoiled fish containing markedly elevated histamine levels. We examined histamine food poisonings in Japan from 1998 to 2008. In average 8 food poisonings and 150 cases were reported annually and there was no fatality case. In more than 80% of remaining food samples, histamine content exceeded 20 mg/100 g. These poisonings were caused by tuna, billfish (marlin) and mackerel, which contained higher level of histamine than other fishes in histamine food poisonings in Japan. Cooking methods of these fishes were mainly "broiled". We also studied histamine food poisonings in other countries. Tuna was the main fish in histamine food poisonings reported to Centers for the Disease Control and Prevention (CDC) in the US and Ozfoodnet in Australia from 2000 to 2006. In the US, histamine food poisonings were also caused by mahimahi and escolar fish. Our review will be useful for in taking measures to reduce risk of histamine food poisonings.

[Studies on the results of monitoring of veterinary drug residues in food products of animal origin in Japan and other countries].

The positive list system was introduced in Japan for agricultural chemicals such as pesticides, feed additives and veterinary drugs in May 2006. After this time, food containing residues of these chemicals exceeding MRLs, or the default tolerance (uniform limit: 0.01 ppm) cannot be marketed in Japan. The number of chemicals to be tested for imported food at the port increased remarkably. We studied on the results of monitoring of imported food for the residues of veterinary drugs and change in trend of violation after the enforcement of the system. The number of violation of the veterinary drugs in imported food increased largely, most of them were attributed to chloramphenicol and nitrofurans in seafood from Asian countries. Monitoring of the veterinary drugs in seafood in other countries such as EU, United States, United Kingdom and Australia were also studied.

A 13-week subchronic toxicity study of madder color in F344 rats.

A 13-week repeated oral dose toxicity study of madder color (MC), a natural food colorant extracted from the roots of Rubia tinctorum L., was performed using F344 rats. Five groups of animals, each consisting of 10 males and 10 females, were fed diet containing 0, 0.6, 1.2, 2.5 or 5.0% MC for 13 weeks. During the experiment, lower body weight was evident from the 2.5% dose. Hematologically, fluctuation in red blood cell (RBC) parameters suggestive of weak anemia (females), and slight increases of platelet counts (both sexes) and white blood cell (WBC) counts (males) were observed at higher doses. Serum biochemically, slight fluctuations were observed in many parameters, including increased total protein (TP), conjugated bilirubin, Ca, and inorganic phosphate, and decrease of the albumin/globulin (A/G) ratio in both sexes, with dose-dependence for TP and A/G from 0.6% in females. Histopathological changes were mainly observed in the renal proximal tubules, such as microvesicular vacuolar degeneration in the cortex and karyomegaly in the outer medulla involving both sexes, lesions being evident even with 0.6%. In the outer medulla, elevation of cell proliferation activity as assessed with proliferating cell nuclear antigen was observed in males from 2.5%. Severity of focal necrosis of hepatocytes was increased only in females at 5.0%, while the increased relative liver weight as with the increased conjugated bilirubin was evident in both sexes from 1.2%. The results thus suggest that MC exerts mild toxicity, targeting liver, kidneys, and possibly RBCs and WBCs, some renal changes being evident from 0.6% in diet, that is attributable to be the lowest-observed adverse effect level (305.8-309.2mg/kg body weight/day).

[Study on pesticides residue monitoring data in some countries of the world].

In May 2006, the positive list system for residues of pesticide and veterinary medicines in food was introduced in Japan. Under this system, the number of regulated pesticides remarkably increased. The information of food items and foods/origins combinations in which pesticides were frequently detected over the detection limits and/or exceeding MRL in the foreign pesticides residue monitoring are useful to achieve the Japanese pesticides residue monitoring programme more efficiently and effectively. We investigated pesticides residue monitoring data published by food safety authorities of North America, Europe and Oceania countries in their web sites. We focused food items and foods/origins combinations which Japan imported in large quantity. Most of pesticides residues detected in twelve food items were mainly fungicides and insecticides, and some residues level of their samples were exceeding the MRLs (maximum residue limits) established in Japan. Most of pesticides residues detected in European countries were also fungicides (e.g. maneb-group and procymidone) and insecticides (e.g. pirimiphos-methyl and malathion), but herbicides were less detected. We provided the collection of Web links to information sites of MRLs and the pesticides residue monitoring reports published by food safety authorities of other countries.

[Study on usage of pesticides in various countries].

Usage of pesticides in food items in export countries was studied, focusing items which Japan imports in large quantity. Japan has imported field crops such as wheat, corn and soy bean, and also grapefruit in large quantity on a weight base, mainly from United States, Australia and Canada. While, Japan has imported various kinds of vegetables in which China had the largest share. We collected usage data of pesticides for 44 food items of 17 countries of 2004. Pesticides which were used frequently (usage rank within top ten in each item/country) were dichlorvos, carbofuran, chlorpyrifos, dimethoate (insecticides), mancozeb, carbendazim, thiophanate-methyl, chlorthalonil (fungicides), glyphosate, 2,4-D, paraquat, acetochlor (herbicides). Carbendazim, thiophanate-methyl, acetochlor and dichlorvos were mainly used in China. Dithiocarbamates are used frequently in various food items in various countries, and also frequently detected in monitoring in foreign countries. Some pesticides such as bisultap, monosultap, etaboxam and triazmate were used only in certain countries, and available information on toxicity or analytical method was very limited. Some of pesticides described above have not been analyzed in the pesticide residue monitoring in Japan before 2005,however, many of them are subjects of analysis for import food after 2006 with the enforcement of positivelist system for residues of pesticide and veterinary medicines in food in Japan.

[Development of the databases for ADI (acceptable daily intake) and relevant information on food additives, pesticides and veterinary drugs].

Databases for ADI (Acceptable Daily Intake) and relevant information on food additives, pesticides and veterinary drugs were developed. The databases we developed are easily accessible on the web, and contain ADIs, latest evaluation year, classification and use, as well as synonym and CAS registry number. The databases are designed to be easily updated by researchers as ADI and relevant information are updated or added without delay. The database for food additives has already provided from the homepage of NIHS, and the access log of the web site was 1325/month in December 2005 and 2179/month in March 2006.

Methacarn fixation for genomic DNA analysis in microdissected cells.

We have found methacarn, a non-crosslinking protein-precipitating fixative, to be useful for the analysis of DNA from microdissected specimens of wax-embedded tissue. In this chapter, we present the procedure regarding genomic DNA analysis in methacarn-fixed wax-embedded microdissected rat tissue. Using nested polymerase chain reaction (PCR), and a rapid extraction procedure, fragments of DNA up to 2.8 kb in size can be amplified from a 1 x 1 mm area of a 10-microm-thick tissue section. Target fragments of about 500 bp can be amplified from a single cell, but 10-20 cells are necessary for practical detection by nested PCR. Although tissue staining with hematoxylin and eosin inhibits the PCR, amplification of about 500-bp fragments is successful with 150-270 cells by single-step PCR. Immunostaining results in a substantial decrease of yield and degradation of extracted DNA. However, even after immunostaining, fragments of about 180 bp can be amplified with 150-270 cells by single-step PCR. These features demonstrate the suitability of methacarn-fixed wax-embedded tissue for practical genomic DNA analysis in terms of tissue handling, extraction efficiency, and satisfactory PCR results.

Limited tumor-initiating activity of phenylethyl isothiocyanate by promotion with sodium L-ascorbate in a rat two-stage urinary bladder carcinogenesis model.

Initiation activity of phenylethyl isothiocyanate (PEITC) was examined in a two-stage urinary bladder carcinogenesis model. Male 6-week-old Fischer 344 rats were fed diet containing 0.1% PEITC for 12 or 24 weeks, with or without subsequent administration of 5% sodium l-ascorbate (Na-AsA) in diet until week 48, or for the entire experimental period. After 12 weeks of PEITC-treatment, both simple hyperplasia and papillary or nodular (PN) hyperplasia had developed in all animals, but the majority of these lesions had disappeared at week 48, irrespective of the Na-AsA-treatment. The same lesions after 24 weeks of PEITC-treatment had progressed to dysplasia and carcinoma, in a small number of cases by week 48 (6% in incidence for each lesion), but enhancement by the Na-AsA-treatment was evident only with simple hyperplasias (from 56 to 100% in incidence) and PN hyperplasias (from 19 to 56%). The results suggest a limited initiation activity of PEITC with induction of irreversible lesions by 24 weeks of exposure.