Research has shown that, when ingested as a food additive, titanium dioxide and its nanoparticles can impact, alter, and/or damage important protective bacteria in the gut, along with the metabolic pathways of gut bacteria.

Matthew Wright, chair of the authority's working group on titanium dioxide, noted that the evidence for general toxic effects was not conclusive, but that the panel couldn't rule out genotoxicity entirely. There were also some current data limitations and the assessment could not establish a safe level for daily intake of the food additive, he stated.