The FDA first approved the use of titanium dioxide in food in 1966, following its 1960 removal (along with the removal of other color additives) from the agency's original Generally Recognized as Safe list. In 1977, titanium dioxide joined the list of color additives that are exempt from certification, which means titanium dioxide doesn't have to be listed on the packaging of every product it's used in, Faber noted.

In general, nanoparticles have been shown to accumulate in the body, particularly in organs in the gastrointestinal tract, along with the liver, spleen, and capillaries of the lungs.