Titanium dioxide is one of the most widely used white pigments, often used to add whiteness and brightness to products. It is used in the production of paints, coatings, plastics and other products to provide a white color or opacity.

When E171 is part of a food product, it passes through the digestive system without causing harm because E171 combines with the other ingredients. 

The FDA has not updated its general guidance on safety assessments since 2007. Within that time, there has been a significant increase in research on the confluence of toxicology, nanotechnology and human health. The EU updates its guidance regularly with new science available to offer proper safety assessments, with its most recent update published in 2021.