Realistic Evaluation of Titanium Dioxide Nanoparticle Exposure in Chewing Gum

There is growing concern about the presence of nanoparticles (NPs) in titanium dioxide (TiO2) as food additive (E171). To realistically estimate the number and the amount of TiO2 NPs ingested with food, we applied a transmission electron microscopy method combined with inductively coupled plasma optical emission spectrometry. Different percentages of TiO2 NPs (6–18%) were detected in E171 from various suppliers. In the eight chewing gums analyzed as food prototypes, TiO2 NPs were absent in one sample and ranged 0.01–0.66 mg/gum, corresponding to 7–568 billion NPs/gum, in the other seven. We estimated that the mass-based TiO2 NPs ingested with chewing gums by the European population ranged from 0.28 to 112.40 μg/kg b.w./day, and children ingested more nanosized titanium than adolescents and adults. Although this level may appear negligible it corresponds to 0.1–84 billion TiO2 NPs/kg b.w/day, raising important questions regarding their potential accumulation in the body, possibly causing long-term effects ...