After oral ingestion, the absorption of titanium dioxide particles is low, however they can accumulate in the body, Maged Younes, chair of the European Food Safety Authority's expert Panel on Food Additives and Flavourings, said in a May 2021 statement.

Nowadays, the use of nanoparticles in pharmaceutical and cosmetic products has increased. In the last case, nano-sized components are used without proper characterization of their effects, leading to unwanted and dangerous consequences for the users [1,2].

Magnesium can be made by several methods (Fig. 1), but the most common method of manufacture is by the electrolytic process, as for example the electrolysis of magnesium chloride.

Mexican researchers sought to evaluate the effects of E171 across a span of conditions in mice, including its influence on behavior, along with the effects on the colon and liver. The research, published in 2020 in the journal Food and Chemical Toxicology, showed that E171 promoted anxiety and induced adenomas, or noncancerous tumors, in the colon. They also found that E171 heightened goblet cells hypertrophy and hyperplasia, which is typically seen in asthma patients and triggered by smoking or external pollutants and toxins. They also noted mucins overexpression in the mice, which can be linked to cancer cell formation. 

Though the regulated use of titanium dioxide in food products is legal in the U.S. and Canada, it's banned in some other countries, notably throughout Europe. In May 2021, the European Food Safety Authority announced that titanium dioxide can no longer be considered safe as a food additive.