Realistic Evaluation of Titanium Dioxide Nanoparticle Exposure in Chewing Gum

There is growing concern about the presence of nanoparticles (NPs) in titanium dioxide (TiO 2 ) as food additive (E171). To realistically estimate the number and the amount of TiO 2 NPs ingested with food, we applied a transmission electron microscopy method combined with inductively coupled plasma optical emission spectrometry. Different percentages of TiO 2 NPs (6–18%) were detected in E171 from various suppliers. In the eight chewing gums analyzed as food prototypes, TiO 2 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 TiO 2 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 TiO 2 NPs/kg b.w/day, raising important questions regarding their potential accumulation in the body, possibly causing long-term effects on consumers’ health.