Evaluation of exposure to chemical substances through foods - Exposure to pesticides, heavy metals, dioxins, acrylamide and food additives in Japan

For the risk management of chemical substances in foods, evaluating the exposure to chemical substances is essential. The Ministry of Health, Labour and Welfare (MHLW) continuously performs total diet studies to estimate the average Japanese dietary intake of various chemical substances, such as pesticides, heavy metals, dioxins, food additives, etc. In many of the studies, the National Institute of Health Sciences, especially the Division of Foods plays a central role. In this mini-review, the results of several recent total diet studies are described. The Total Diet Study of Food Contaminants which began in 1977 has found that the intake of banned pesticides is very low compared with the acceptable daily intake (ADI). However, the dietary intake of Cd is high, and was 52% of the Provisional Tolerable Weekly Intake in 2002. The average daily intake of dioxins [polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar-polychlorinated biphenyls (PCBs)] was 1.49 pgTEQ/kg in 2002, which is lower than the tolerable daily intake (TDI) value of 4 pgTEQ/kg/day. Total diet study samples from the Kansai area demonstrated a reduction in dioxin intake between 1977 and 2002. The daily dietary intake of acrylamide was estimated to be several scores of micrograms per person. Although the daily intake of most food additives was much lower than ADI, the intake of nitrate exceeded ADI when estimated by the market basket method. The contribution of food additives was low and most of the intake was attributed to nitrate in vegetables. These data form the basis for risk management performed by the MHLW.