The role of the food matrix and gastrointestinal tract in the assessment of biological properties of ingested engineered nanomaterials (iENMs): State of the science and knowledge gaps

Abstract

Many foods contain appreciable levels of engineered nanomaterials (ENMs) (diameter < 100 nm) that may be either intentionally or unintentionally added. These ENMs vary considerably in their compositions, dimensions, morphologies, physicochemical properties, and biological responses. From a toxicological point of view, it is often convenient to classify ingested ENMs (iENMs) as being either inorganic (such as TiO2, SiO2, Fe2O3, or Ag) or organic (such as lipid, protein, or carbohydrate), since the former tend to be indigestible and the latter are generally digestible. At present there is a relatively poor understanding of how different types of iENMs behave within the human gastrointestinal tract (GIT), and how the food matrix and biopolymers transform their physico-chemical properties and influence their gastrointestinal fate. This lack of knowledge confounds an understanding of their potential harmful effects on human health. The purpose of this article is to review our current understanding of the GIT fate of iENMs, and to highlight gaps where further research is urgently needed in assessing potential risks and toxicological implications of iENMs. In particular, a strong emphasis is given to the development of standardized screening methods that can be used to rapidly and accurately assess the toxicological properties of iENMs.

Is nano safe in foods? Establishing the factors impacting the gastrointestinal fate and toxicity of organic and inorganic food-grade nanoparticles

“…6,109 Foodborne inorganic NPs are consumed as part of a food or beverage that may contain a variety of molecular and colloidal species that can interact with food nanoparticles and alter their biological fate. These interactions may occur within the food itself, or during the passage of the food nanoparticles through the GIT.…”

Synthesis and Physicochemical Transformations of Size‐Sorted Graphene Oxide during Simulated Digestion and Its Toxicological Assessment against an In Vitro Model of the Human Intestinal Epithelium

“…It has already been shown that certain ENMs have the capacity to alter the bioavailability of nutrients [59] while others may increase the bioavailability of noxious agents, like pesticides. [57] In addition, food matrix effects have been shown to modulate the bioactivity of ENMs, [32,35] and the gut microbiome and proteome of animals is known to be sensitive to the presence of chemically active particulates. [28,29,60] Therefore, we plan to apply the methods developed here to interrogate the physicochemical transformations, toxicological assessment, and effect on gut microbiome and proteome of GO in the presence of more complex food models.…”

“…These alterations include biodissolution, [33] biomolecular corona formation, [34] and morphological changes, like agglomeration. [35] In the case of anisotropic, carbonaceous, soft materials like GO, the technical challenges are ever so harder to overcome and could partially explain the scarcity in available literature.…”

A 72‐h exposure study with eastern oysters (Crassostrea virginica) and the nanomaterial graphene oxide

“…Organic matter in the water column serves as an adsorption phase for graphene oxide. Ingested particles could also undergo transformation in the digestive tracts of these organisms (McClements et al 2016) and may further affect FIGURE 6: Total protein levels in gill and digestive gland tissues of graphene oxide-exposed oysters. In addition, organic material (feces and pseudofeces) from shelled mollusks could increase particle association in the water column.…”

“…In natural environments, and as seen in our studies, nanomaterial aggregates can reach micron size ranges (Wong et al 2010;Sanchs et al 2015) that are preferred as food by bivalves and other coastal organisms. Ingested particles could also undergo transformation in the digestive tracts of these organisms (McClements et al 2016) and may further affect FIGURE 6: Total protein levels in gill and digestive gland tissues of graphene oxide-exposed oysters. Different letters indicate significant difference between concentrations; no letter indicates no difference.…”