Titanium dioxide

Titanium dioxide (E171) is an inorganic white pigment used in food manufacturing to provide whiteness and opacity to products including chewing gum, confectionery, certain sauces, and powdered foods. Chemically it is dioxotitanium (TiO2, CAS 13463-67-7), one of the most chemically stable inorganic compounds known. Its high refractive index makes it exceptionally effective as a whitener at very low concentrations. In food, it is present as ultrafine particles, and the proportion of particles in the nanometre size range has been a central regulatory concern.

JECFA, the joint WHO/FAO expert committee on food additives, first set an ADI of "not specified" for titanium dioxide at its 13th meeting in 1969 and reaffirmed it at its 97th meeting in 2023. "Not specified" is JECFA's most reassuring category: the committee found no identifiable hazard at the levels used in food, largely because very little titanium dioxide is absorbed from the gut, so it did not consider a numerical limit necessary. EFSA reached the opposite conclusion in 2021: it concluded that titanium dioxide can no longer be considered safe as a food additive, primarily because genotoxicity concerns, particularly for the nanometre-sized particles, could not be excluded. The two bodies therefore disagree about the same substance, and that disagreement, rather than a lack of data at JECFA, is why this additive is controversial.

The European Union banned titanium dioxide as a food additive in August 2022 (EU Regulation 2022/63), following the 2021 EFSA scientific opinion. The ban affects all food categories in EU member states. The additive remains permitted in the United States, Japan, South Korea, and many other markets where regulatory bodies have not taken equivalent action. The EU ban represents one of the most significant food additive reversals in recent regulatory history and reflects application of the precautionary principle in response to persistent uncertainty about nanoparticle genotoxicity. Manufacturers exporting to EU markets must reformulate products containing E171.