title: Novel insights into the risk assessment of the nanomaterial synthetic amorphous silica, additive E551, in food.
abstract: This study presents novel insights in the risk assessment of synthetic amorphous silica (SAS) in food. SAS is a nanostructured material consisting of aggregates and agglomerates of primary particles in the nanorange (<100 nm). Depending on the production process, SAS exists in four main forms, and each form comprises various types with different physicochemical characteristics. SAS is widely used in foods as additive E551. The novel insights from other studies relate to low gastrointestinal absorption of SAS that decreases with increasing dose, and the potential for accumulation in tissues with daily consumption. To accommodate these insights, we focused our risk assessment on internal exposure in the target organ (liver). Based on blood and tissue concentrations in time of two different SAS types that were orally and intravenously administered, a kinetic model is developed to estimate the silicon concentration in liver in (1) humans for average-to-worst-case dietary exposure at steady state and (2) rats and mice in key toxicity studies. The estimated liver concentration in humans is at a similar level as the measured or estimated liver concentrations in animal studies in which adverse effects were found. Hence, this assessment suggests that SAS in food may pose a health risk. Yet, for this risk assessment, we had to make assumptions and deal with several sources of uncertainty that make it difficult to draw firm conclusions. Recommendations to fill in the remaining data gaps are discussed. More insight in the health risk of SAS in food is warranted considering the wide applications and these findings.
authors.affiliation: National Institute for Public Health and the Environment (RIVM) , Bilthoven , The Netherlands .
authors.forename: Petra C E
authors.initials: PC
authors.lastname: van Kesteren
authors.forename: Francesco
authors.initials: F
authors.lastname: Cubadda
authors.forename: Hans
authors.initials: H
authors.lastname: Bouwmeester
authors.forename: Jan C H
authors.initials: JC
authors.lastname: van Eijkeren
authors.forename: Susan
authors.initials: S
authors.lastname: Dekkers
authors.forename: Wim H
authors.initials: WH
authors.lastname: de Jong
authors.forename: Agnes G
authors.initials: AG
authors.lastname: Oomen
mesh_terms: D000818:Animals; D004781:Environmental Exposure; D005503:Food Additives / Q000493:pharmacokinetics / Q000633:toxicity*; D006801:Humans; D049329:Nanostructures / Q000633:toxicity*; D018570:Risk Assessment; D012822:Silicon Dioxide / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D005503:Food Additives; D012822:Silicon Dioxide
keywords: Absorption; accumulation; internal dose; kinetic modelling; synthetic amorphous silica