Titanium dioxide particles in immune cells of the gut
What it found
In human gut tissue and in mice fed titanium dioxide, the particles built up in immune cells of the small intestine's Peyer's patches, but the authors found no sign that this triggered inflammation in the mice.
What they found
Studies in people
Human gut cells
In human tissue, titanium dioxide was found in immune cells in the subepithelial dome of Peyer's patches and occasionally in the lamina propria. These cells often contained many particles.
Animal and lab studies
Mouse model match
Mice fed titanium dioxide had similar particle build-up in the same Peyer's patch cells as humans, with comparable amounts per cell. The rest of the villous mucosa had no particles.
Cell types targeted
The particles went specifically into LysoMac and LysoDC immune cells in the Peyer's patches, which already carry the PD-L1 marker. The number of these cells and their markers did not change with titanium dioxide.
No inflammation signal
In mice, long-term titanium dioxide in the diet did not increase any of 92 inflammation-related proteins in the ileum. When mice were also given Salmonella, the particles did not boost the inflammatory response.
Salmonella effect
Salmonella infection caused the titanium dioxide-loaded cells to move deeper into the Peyer's patch and some particles appeared in the villous lamina propria. This matched the distribution seen in human tissue.
What the authors conclude
“Immunocompetent cells that accumulate fgTiO 2 in vivo are now identified and we demonstrate a mouse model that finally enables human-relevant risk assessments of ingested, bio-persistent (nano)particles.”
Also in their conclusions
- They conclude that food-grade titanium dioxide is taken up by specific immune cells in the Peyer's patches of the small intestine, in both humans and mice.
- They state that in wild-type mice, titanium dioxide did not initiate or augment inflammatory signalling in the ileum, despite the particles accumulating in immune cells.
- They suggest that this mouse model can now be used for human-relevant risk assessment of ingested titanium dioxide and other persistent particles.
How it was done
The authors wanted to find out which cells in the gut take up food-grade titanium dioxide, because until now the only known cells that store it were thought to be inactive. They also wanted to see whether the particles could start or worsen inflammation.
They looked at human small intestine tissue from nine people and fed mice a diet with titanium dioxide for 16 to 18 weeks. Some mice were also given a Salmonella infection to see if the particles changed the immune response.
What it can’t tell you
- The study looked at the small intestine, so it cannot show what titanium dioxide does in the large intestine or elsewhere in the body.
- The mouse experiments used healthy, wild-type animals, so the results may not apply to people with conditions like Crohn's disease or certain gene variants.
- The findings on inflammation are from mice, and it is not known if the same is true in people.
Who paid
- Funding
- Funded by RCUK | Medical Research Council (MRC) (from the PubMed record).
- Conflicts
- Competing interests: J.W. states that after completing the presented work as University of Cambridge Herchel-Smith Fellow, he subsequently undertook employment with the pharmaceutical company, GlaxoSmithKline. A.D., J.R., M.M., S.R., H.D.S., R.E.H., A.F., A.B.D.S., C.A.P.B., S.M., Å.V.K., J.D.S., N.C.R., D.O., R.J., P.M., A.P.B., P.R. and J.J.P. declare no competing interests.
- Authors work at
- University of Cambridge, UK; Massey University, New Zealand; Grasslands Research Centre, New Zealand
The paper
- Title
- Immunocompetent cell targeting by food-additive titanium dioxide
- Type
- Study
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Wills JW, Dabrowska A, Robertson J, et al (2025). Immunocompetent cell targeting by food-additive titanium dioxide. Nature communications. doi:10.1038/s41467-025-60248-9Free full textPubMed 40615368DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error