New article by William Dudefoi on "Impact of food grande and nano-TiO2 particles on a human intestinal community" in Food and Chemical Toxicology.

Abstract : Titanium dioxide (TiO2) nanoparticles (NPs) are used as an additive (E171 or INS171) in foods such as gum, candy and puddings. To address concerns about the potential hazardous effects of ingested NPs, the toxicity of these food-grade NPs was investigated with a defined model intestinal bacterial community. Each titania preparation (food-grade TiO2 formulations, E171-1 and E171-6a) was tested at concentra- tions equivalent to those found in the human intestine after sampling 1e2 pieces of gum or candy (100 e250 ppm). At the low concentrations used, neither the TiO2 food additives nor control TiO2 NPs had an impact on gas production and only a minor effect on fatty acids profiles (C16:00, C18:00, 15:1 w5c, 18:1 w9c and 18:1 w9c, p < 0.05). DNA profiles and phylogenetic distributions confirmed limited effects on the bacterial community, with a modest decrease in the relative abundance of the dominant Bacteroides ovatus in favor of Clostridium cocleatum ( 13% and þ14% respectively, p < 0.05). Such minor shifts in the treated consortia suggest that food grade and nano-TiO2 particles do not have a major effect on human gut microbiota when tested in vitro at relevant low concentrations. However, the cumulative effects of chronic TiO2 NP ingestion remain to be tested. 

https://doi.org/10.1016/j.fct.2017.05.050