Food-grade titanium dioxide exposure between age groups and in global regions: a systematic review and meta-analysis

Food-grade titanium dioxide (TiO₂), also known as food additive E171, is widely used for its opacifying and coloring properties in food, feed, and pharmaceuticals. Despite its ban in food within the European Union (EU), TiO₂ remains prevalent globally amidst safety debates. This study conducted a systematic search and meta-analysis to assess oral TiO₂ intake across different age groups in the EU, North America, and East Asia. Analyzing ten studies, we found that mean oral TiO₂ intake ranged from 0.045 to 10.5 mg/kg body weight (bw)/day, with the lowest exposures in East Asia and a lifelong weighted average TiO₂ exposure of 1.43 mg/kg_bw/day. Higher TiO₂ exposures were observed in children compared to adults, with Standardized Mean Differences (SMD) of 1.05 (general comparison) and 2.15 (ages 3-9 vs. 18-64 years). This discrepancy diminishes with age as adolescents (10-17 years) exposures approach adult levels (SMD = 0.49). The heightened TiO₂ exposure in children may be due to lower body weight and higher consumption of TiO₂-containing products. Regional disparities in exposure levels reflect dietary habits and legislative standards. Given concerns over TiO₂'s potential health impacts and regulatory differences, this study provides a comprehensive review to assist in refined health risk assessments.