Titanium dioxide can form several different shapes, which have different properties. Some shapes can be converted to nanomaterials. Micronized TiO2 (also called “nano” or “nanoparticles”) was introduced in the early 1990s.Nanotechnology and micronization both refer to the practice of creating very small particles sizes of a given material. “Nanoparticles” usually refers to particles smaller than 100 nanometers; a nanometer is 1/1 billionth of a meter. At these small sizes, and at low concentrations, titanium dioxide appears transparent, allowing for effective sunscreens that do not appear white.

Because of their small size, nanoparticles may have unique physical and chemical properties. These properties may cause them to interact with living systems differently than larger materials with the same chemical composition (also known as bulk materials).

JECFA also evaluated estimates of dietary exposure to titanium dioxide, estimating the maximum 95^th percentile of exposure to be 10 mg/kg BW per day. Overall, considering the low oral absorption of titanium dioxide as a food additive, the committee reaffirmed the ADI “not specified” that was established at the 13^th meeting.

“Unlike some other chemicals used in food, titanium dioxide has no nutritive, preservative, or food safety function—its use is purely cosmetic,” said CSPI principal scientist for additives and supplements, Thomas Galligan. “The prospect of titanium dioxide nanoparticles damaging DNA is concerning enough for us to recommend consumers avoid foods that have it.” 

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