For a mini-review published in the journal Particle and Fibre Technology in 2021, scientists wanted to evaluate whether Ti02 particles contributed to the development and/or exacerbation of irritable bowel disease, and whether they altered the four elements of intestinal barrier function: the intestinal microbiota, the immune system, the mucus layer, and the epithelium. The breakdown of these four elements can contribute to autoimmune, neurological, inflammatory, infectious, and metabolic diseases. Following their review, the researchers concluded: “Data indicate that TiO2 is able to alter the four compartments of IBF and to induce a low-grade intestinal inflammation associated or not with pre-neoplastic lesions.”
Prof. Maged Younes, Chair of EFSA’s expert Panel on Food Additives and Flavourings (FAF), wrote of the decision: “Taking into account all available scientific studies and data, the Panel concluded that titanium dioxide can no longer be considered safe as a food additive. A critical element in reaching this conclusion is that we could not exclude genotoxicity concerns after consumption of titanium dioxide particles. After oral ingestion, the absorption of titanium dioxide particles is low, however they can accumulate in the body.”
In the meantime, the chemical factories of Continental Europe, principally in Germany, Austria and Belgium, had taken hold of the novelty and under the collective name of lithopone or lithophone, by numerous processes, produced various grades of the pigment, branding the respective qualities as red seal, green seal, yellow seal, blue seal, etc., or selling them under some fancy name. Of this we shall speak later on. The crusade against the use of white lead in the various countries of Continental Europe, assisted the manufacturers, to a very great extent, in marketing their products, not only to industrial concerns, as has been the case in this country, until recently, but to the general painting trade. Up to 1889 the imports into this country were comparatively small. At that time one of the largest concerns manufacturing oilcloth and linoleum in the State of New Jersey began to import and use Charlton white. Shortly after that other oilcloth manufacturers followed suit, replacing zinc white with lithopone in the making of white tablecloth, etc., and later on abandoning the use of white lead in floor cloth and linoleum. This gave an impetus to several chemical concerns, that erected plants and began to manufacture the pigment. Competition among the manufacturers and the activity of the importers induced other industries to experiment with lithopone, and the shade cloth makers, who formerly used white lead chiefly, are now among the largest consumers. Makers of India rubber goods, implement makers and paint manufacturers are also consumers of great quantities, and the demand is very much on the increase, as the nature of the pigment is becoming better understood and its defects brought under control. Large quantities find their way into floor paints, machinery paints, implement paints and enamel paints, while the flat wall paints that have of late come into such extensive use owe their existence to the use of lithopone in their makeup.
In 2017, French researchers from the Institut National de la Recherche Agronomique (INRAE) were among the first to examine the effects of E171 nanoparticles on the body. They fed rats a dose of 10mg of E171 per kilogram of body weight per day, which was similar to human exposure in food. The research, which was published in Scientific Reports, showed that E171 was able to traverse the intestinal barrier, pass into the bloodstream, and reach other areas of the body in rats. Researchers also found a link between immune system disorders and the absorption of titanium dioxide nanoparticles.