For his part, Kaminski argues most of the studies have been in animals, and any effects found were minuscule. He and his team also contested some of the findings in a 2019 study that found no evidence of increased inflammation or changes in the GI tract.

≥99.0

As early as sixty years ago, zinc sulphide was first thought of as a pigment for coloring India rubber and a patent for the process of its manufacture was issued in England. But it was not until twenty years later that zinc sulphide and its manufacture was seriously considered as a pigment for paint, and in 1874 a patent was issued for a process of manufacturing a white pigment, composed of zinc sulphide and barium sulphate, known as Charlton white, also as Orr's white enamel. This was followed in 1876 by a patent issued to a manufacturer named Griffith and the product, which was similar in character to Charlton white, was known as Griffith's patent zinc white. In 1879 another patent for a more novel process was obtained by Griffith & Cawley, the product made under this process proving the best of the series placed upon the market up to that date. After that time many new processes were patented, all, however, tending to the same object, that of producing a white pigment, composed of zinc sulphide and barium carbonate, the results, however, in many cases ending with failure.

In a review published in 2022 in the journal Archives of Toxicology, researchers found that the ingestion of E171 is a “a definite health risk for consumers and their progeny.” After reviewing dozens of in vivo, ex vivo and in vitro studies on the toxicity of E171, the researchers wrote that two facts must be noted: “First, reprotoxicity studies show that animals of both sexes are impacted by the toxicity of these nanoparticles, underlining the importance of conducting in vivo studies using both male and female animals. Second, human exposure begins in utero via maternal-fetal transfer and continues after birth by breastfeeding. Children are then chronically re-exposed due to their food preferences. To be relevant to the human in vivo situation, experimental studies should therefore consider nanoparticle exposure with respect to the age or life period of the studied population.”

The FDA's Code of Federal Regulations allows for the legal, regulated use of titanium dioxide in food products, under some restrictions.

Titanium dioxide is a widely used substance in various industries due to its versatility and unique properties. As a result, there are numerous manufacturers of titanium dioxide around the world, catering to the different needs of their customers.

Exposure to titanium dioxide in utero and in breastfeeding children

How pure TiO2 is extracted from titanium-containing molecules depends on the composition of the original mineral ores or feedstock. Two methods are used to manufacture pure TiO₂: a sulphate process and a chloride process.