if you compare the levels—which went as high as 50,000 milligrams/killigrams per day— to what humans are actually exposed to, we're talking orders of magnitude. It was a huge amount, Norbert Kaminski, PhD, a professor of pharmacology & toxicology and director of the Center for Research on Ingredient Safety at Michigan State University told Health.

Research has shown that, when ingested as a food additive, titanium dioxide and its nanoparticles can impact, alter, and/or damage important protective bacteria in the gut, along with the metabolic pathways of gut bacteria.