title: Westernized diets lower arsenic gastrointestinal bioaccessibility but increase microbial arsenic speciation changes in the colon.
abstract: Arsenic (As) is an important contaminant present in food and water. Several studies have indicated that the occurrence of As based skin lesions is significantly different when root and gourd rich diets are consumed compared to meat rich diets. Additionally, urinary As speciation from orally exposed individuals appears to depend on the composition of the diet. These observations imply that diet composition can affect both the bioavailable As fraction as the As speciation in the body. In this study, we used the in vitro gastrointestinal method (IVG) to evaluate how an Asian type diet (fiber rich) and a Western type diet (fat and protein rich), differ in their capability to release inorganic As (iAs(V)) and dimethyl arsinate (DMA(V)) from a rice matrix following gastrointestinal digestion. Moreover, we used a validated dynamic gut simulator to investigate whether diet background affects As metabolism by gut microbiota in a colon environment. An Asian diet background resulted in a larger As bioaccessibility (81.2%) than a Western diet background (63.4%). On the other hand, incubation of As contaminated rice with human colon microbiota in the presence of a Western type diet resulted in a larger amount of hazardous As species - monomethyl arsonite and monomethylmonothio arsonate - to be formed after 48 h. The permeability of these As species (60.5% and 50.5% resp.) across a Caco-2 cell line was significantly higher compared to iAs(V) and DMA(V) (46.5% and 28% resp.). We conclude that dietary background is a crucial parameter to incorporate when predicting bioavailability with bioaccessibility measurements and when assessing health risks from As following oral exposure.
authors.affiliation: Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Alava
authors.affiliation: Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
authors.forename: Gijs
authors.initials: G
authors.lastname: Du Laing
authors.affiliation: Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
authors.forename: Filip
authors.initials: F
authors.lastname: Tack
authors.affiliation: Laboratory of experimental cancer research, Department of Radiation Oncology and Experimental Cancer Research, Faculty of medicine and health sciences, Ghent, Belgium.
authors.forename: Tine
authors.initials: T
authors.lastname: De Ryck
authors.affiliation: Laboratory of experimental cancer research, Department of Radiation Oncology and Experimental Cancer Research, Faculty of medicine and health sciences, Ghent, Belgium.
authors.forename: Tom
authors.initials: T
authors.lastname: Van De Wiele
mesh_terms: D001151:Arsenic / Q000737:chemistry* / Q000378:metabolism* / Q000493:pharmacokinetics; D001152:Arsenicals / Q000737:chemistry / Q000378:metabolism* / Q000493:pharmacokinetics; D001682:Biological Availability; D018938:Caco-2 Cells; D003106:Colon / Q000378:metabolism* / Q000382:microbiology; D004032:Diet; D059305:Diet, High-Fat; D006801:Humans; D064307:Microbiota / Q000502:physiology*
chemical_list: D001152:Arsenicals; D001151:Arsenic
keywords: Arsenic; Asian diet; Presystemic metabolism; Simulator of human gastrointestinal microbial ecosystem; Speciation; Western diet