Critical review of the safety assessment of titanium dioxide additives in food

Abstract

Nanomaterial engineering provides an important technological advance that offers substantial benefits for applications not only in the production and processing, but also in the packaging and storage of food. An expanding commercialization of nanomaterials as part of the modern diet will substantially increase their oral intake worldwide. While the risk of particle inhalation received much attention, gaps of knowledge exist regarding possible adverse health effects due to gastrointestinal exposure. This problem is highlighted by pigment-grade titanium dioxide (TiO2), which confers a white color and increased opacity with an optimal particle diameter of 200–300 nm. However, size distribution analyses showed that batches of food-grade TiO2 always comprise a nano-sized fraction as inevitable byproduct of the manufacturing processes. Submicron-sized TiO2 particles, in Europe listed as E 171, are widely used as a food additive although the relevant risk assessment has never been satisfactorily completed. For example, it is not possible to derive a safe daily intake of TiO2 from the available long-term feeding studies in rodents. Also, the use of TiO2 particles in the food sector leads to highest exposures in children, but only few studies address the vulnerability of this particular age group. Extrapolation of animal studies to humans is also problematic due to knowledge gaps as to local gastrointestinal effects of TiO2 particles, primarily on the mucosa and the gut-associated lymphoid system. Tissue distributions after oral administration of TiO2 differ from other exposure routes, thus limiting the relevance of data obtained from inhalation or parenteral injections. Such difficulties and uncertainties emerging in the retrospective assessment of TiO2 particles exemplify the need for a fit-to-purpose data requirement for the future evaluation of novel nano-sized or submicron-sized particles added deliberately to food.

Dietary Estimated Intake of Trace Elements: Risk Assessment in an Italian Population

“…Our results showed more than double intake compared with a previous study carried out in Japan and US (Reilly 2002;Shimbo et al 1996). Conversely, due to the large use in the most recent decades of titanium dioxide, many studies assessed its particular intake, showing intake levels approximately similar or slightly higher than our study (Bachler et al 2015;Heringa et al 2016;Rompelberg et al 2016;Weir et al 2012;Winkler et al 2018), also considering that most of them accounted the contribution from other sources like toothpaste that could not be considered in our study.…”

“…In addition, in food industry, titanium dioxide is used as food additive for whitening and brightening purpose in flour, confection, and other sweets products, and non-dairy milk products (European Food Safety Authority 2016a; Reilly 2002) as well as in other personal care products, e.g. toothpaste, cosmetics, or sunscreens (Rompelberg et al 2016;Weir et al 2012;Winkler et al 2018). Due to its wide-scale distribution in the environment, titanium is a frequent food contaminant, but at relatively low levels since it is poorly absorbed from soil (Reilly 2002).…”

Submicron Crystals of the Parkinson’s Disease Substantia nigra: Calcium Oxalate, Titanium Dioxide and Iron Oxide

“…Titanium compounds have no known role in human physiology, although implanted titanium alloys do produce erosion products found in the marrow [71] and result in measurable plasma-concentrations of titanium compounds. [72] Reviews of the toxicology of titanium focus, however, on ingested and inhaled white TiO2 pigment particles, [61,[73][74][75] widely used as white pigments in foods and medications. The ingested pigment particles pass into the bloodstream [76] and are transported to the human liver, [77] spleen [77] and pancreas [78].…”

Toxic effect of titanium dioxide nanoparticles on morphological characteristics of thymus

“…[1]. К пищевым продуктам с высоким содержанием НЧ TiO 2 относятся жевательные резинки и леденцы [2]. По данным просвечиваю щей электронной микроскопии около 36 % частиц в составе Е171 имеют размер меньше, чем 100 нм [3].…”