The most significant uncertainty identified by the EU experts was the concern that TiO₂ particles may have genotoxic effects. Genotoxicity refers to the ability of a chemical to directly damage genetic material within a cell (DNA), which may lead to cancer in certain situations. Although the experts did not conclude that TiO₂ particles in E171 are genotoxic, they could not rule out the concern that they might be.

Other experts say there is simply no conclusive evidence at this point that titanium dioxide is damaging to humans after ingesting. Kaminski in particular said the research studies cite health hazards that were found by using high doses of the product, which you would not normally see in food.

Titanium dioxide is a mineral that’s used as a white coloring in a variety of products, including sunscreens, cosmetics, paints, and plastics. The pigment grade is also known as titanium white, pigment white 6, or CI 77891; it's the whitest and brightest of all known pigments.