This is just one of the negative effects of the food additive, which is found in everything from chewing gum to bread.
What is titanium dioxide?
Titanium dioxide is generally recognised as safe by the U.S. Food and Drug Administration, and ingestion is nearly unavoidable.
"Titanium oxide is a common food additive and people have been eating a lot of it for a long time - don't worry, it won't kill you! - but we were interested in some of the subtle effects, and we think people should know about them," said Biomedical Engineering Assistant Professor Gretchen Mahler, one of the researchers
The compound is an inert and insoluble material that is commonly used for white pigmentation in paints, paper and plastics. It is also an active ingredient in mineral-based sunscreens for pigmentation to block ultraviolet light.
The effects of titanium dioxide
Researchers exposed a small intestinal cell culture model to the physiological equivalent of a meal's worth of titanium oxide nanoparticles - 30 nanometers across - over four hours (acute exposure), or three meal's worth over five days (chronic exposure).
Acute exposures did not have much effect, but chronic exposure diminished the absorptive projections on the surface of intestinal cells called microvilli. With fewer microvilli, the following occurred:
- The intestinal barrier was weakened
- Metabolism slowed
- Some nutrients - iron, zinc, and fatty acids, specifically - were more difficult to absorb
- Enzyme functions were negatively affected
- Inflammation signals increased
