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.

When E171 isn’t combined with other ingredients and administered in water, some studies suggest that under these artificial conditions, E171 may be processed differently in the body resulting in some biological changes in experimental animals that are poorly understood.