Can titanium dioxide (E171) in food disrupt your gut bacteria?

What's actually in it

Titanium dioxide (E171) is a white pigment used to brighten and whiten foods like candy, chewing gum, frosting, coffee creamer, and toothpaste. It's made of tiny particles, some small enough to count as nanoparticles. The EU banned E171 in food in 2022, but it's still allowed in the United States and many other countries.

What the research says

A 2026 study in J Appl Microbiol tested how titanium dioxide affects gut bacteria using a model of the human colon. The researchers found that E171 changed the metabolic activity of gut microbes and reduced the production of butyrate, a short-chain fatty acid that keeps the gut lining healthy.

Butyrate protects against inflammation, feeds the cells lining your intestines, and helps keep harmful bacteria in check. When butyrate drops, your gut becomes more vulnerable to damage and disease.

Check ingredient labels for titanium dioxide or E171. It's common in white-coated candies, powdered sugar donuts, and non-dairy creamers. Look for brands that use rice starch or calcium carbonate as whiteners instead.