Arsenic (As) is an ubiquitous element frequently present in food items. Human health risks related to its dietary intake are not linked to total As intake, but depend on the chemical form (speciation) in which As is taken up. Hence normative legislation should preferably be speciation-based in the case of As. To assess the risks associated to dietary As intake, the knowledge of the internal exposure to different As-species is necessary, and this can only be determined if speciation changes during food preparation and food digestion are known. The BIOTRAs project aimed at incorporating these changes and knowledge about As-species bioaccessibility and bioavailability into the risk assessment of dietary As intake in Belgium.
Different food items were analysed before and after preparation to determine the effect of preparation on As concentrations and speciation. The prepared food samples were subjected to a sequential in vitro digestion system (Unified Barge Method). To mimic colon digestion, the intestinal digests were incubated with colon suspension sampled from the SHIME reactor. The bioaccessible fraction was collected by centrifuging the small intestine- or colon digests. Apparent permeability values of As and its species from the digested food matrices were obtained by means of the Caco-2 cell system. From these data, human intestinal absorption values were derived (bioavailability). To perform As in- and uptake calculations, different food consumption scenario’s were elaborated based on the Belgian Food consumption survey and literature data. To evaluate the risk of inorganic As (iAs) in- and uptake, margins-of-exposure were calculated.
An increasing consumption of typical iAs sources (e.g. rice, hijiki seaweed) increases the intake of iAs, although cooking these food items in an excess water mitigates the increase. The calculated systemic uptake of iAs for a usual Belgian consumption pattern is calculated as 7 µg/d. A high consumption of selected food items leads maximally to a doubling of the iAs intake. Ethnic groups with a rice-based diet have a 25- to 100-times higher uptake of iAs than the average Belgian population, depending on the consumed amount of rice and its preparation method. No health risks due to iAs intake or uptake are expected for the general Belgian population. A long-term ethnical rice-based diet is discouraged for people with an increased risk for lung cancer such as smokers.
Acknowledgement - This study was funded by the Belgian Federal Public Service of Health, Food Chain Safety and Environment (Project RT-11/6247 BIOTRAs).
