Titanium dioxide (E 171) and four new toxicity studies
What it found
Four new studies on titanium dioxide food additive E 171 showed some concerns but with uncertainties, and did not change the earlier EFSA safety opinion.
The studies included lab tests and animal work.
What they found
Animal and lab studies
Bettini study
The Bettini et al. (2017) study did not give enough reason to run a new cancer study. If useful information on how it works becomes available, this could be looked at again later.
Proquin lab findings
The new lab findings in the Proquin et al. (2017) study did not change the earlier EFSA conclusion on whether titanium dioxide can damage genes.
Guo engineered particles
The effects of engineered titanium dioxide tiny particles reported by Guo et al. (2017) were of uncertain biological significance. Their relevance for assessing the risk of the food additive E 171 was limited.
Studies in people and animals
Overall view
The four studies highlighted some concerns but with uncertainties. Their relevance for risk assessment was considered limited, and further research would be needed to lower the uncertainties.
Other findings
Heringa uncertainty
The risk assessment by Heringa et al. (2016) had significant uncertainty. It did not include a weight of evidence analysis of the whole database.
What the authors conclude
“the outcome of the four studies did not merit re-opening the existing opinion of EFSA related to the safety of TiO 2 (E 171) as a food additive”
Also in their conclusions
- They concluded that the outcome of the four studies did not merit re-opening the existing opinion of EFSA related to the safety of TiO 2 (E 171) as a food additive.
- They noted that three of the studies may be useful for hazard identification of TiO 2.
- They stated that further research would be needed to decrease the level of uncertainties.
How it was done
The European Commission asked EFSA to check whether four new studies on the possible toxicity of titanium dioxide (E 171) as a food additive would justify re-opening EFSA's existing safety opinion.
EFSA looked at four studies: Bettini et al. (2017), Proquin et al. (2017), Guo et al. (2017) and Heringa et al. (2016). The studies reported effects in lab tests and in live models, and one made many assumptions in its risk assessment.
What it can’t tell you
- We summarised it from the abstract only.
- The studies looked at lab tests and live models, so they cannot show what happens in people eating the additive.
- The findings had uncertainties, so they cannot show a clear cause and effect for health effects in people.
The paper
- Title
- Evaluation of four new studies on the potential toxicity of titanium dioxide used as a food additive (E 171)
- Type
- Scientific opinion of the European Food Safety Authority
- Evidence
- Studies in people · animals · lab
- Summarised from
- Abstract only
- Cite
- EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), Younes M, Aggett P, et al (2018). Evaluation of four new studies on the potential toxicity of titanium dioxide used as a food additive (E 171). EFSA journal. European Food Safety Authority. doi:10.2903/j.efsa.2018.5366Free full textPubMed 32625996DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error