Silicon dioxide, risk additive still in use


Silicon dioxide is a food additive approved as an anti-caking agent. And it is a nanomaterial, such as titanium dioxide dye (E171), whose toxicity EFSA recently re-evaluated. (1) Scientific studies reveal emerging public health risks. Yet, it is still widely found in foods, as we shall see.

Silicon dioxide, emerging risks

The European Food Safety Authority’s last opinion on silicon dioxide was in 2018. On that occasion, the lack of expertise on the impact of nanoscale particles added in food convinced the EFSA expert panel to acquit the additive. (2)

However, the scientific community has made great strides in nanomaterials research. With reference to added silicon dioxide in food, it showed adverse health effects very similar to those associated with the ingestion of titanium dioxide.

A review of its safety is therefore expected, with the adoption of appropriate criteria-guidelines for nanospecific risk assessment, with the support of experts specializing in nanomaterials. ISS researcher Francesco Cubadda expressed this view when explaining the EFSA opinion of 6.5.21 on titanium dioxide. (3)

Silicon dioxide and other nanomaterials, toxicity studies

Studies on titanium dioxide toxicity are growing in number and clearly indicate the negative impact on health. Recent research by Mexican researchers, for example, confirmed the serious adverse effects that had already emerged and were related to the consumption of food additives containing nanometer-sized particles (1-100 nm). Namely, titanium dioxide (E171), iron oxides and hydroxides (E172), silver (E174) and gold (E175), used as coloring agents, and silicon dioxide (E551), used as an anti-caking agent.

Oral consumption of such additives is associated with gastrotoxicity, hepatotoxicity and alterations in the gut microbiota, the researchers explain. Who add: ‘Although no studies have been conducted on the use of these food additives to assess neurotoxicity or alterations in animal behavior, their non-food nanometer counterparts have been associated with stress, depression, cognitive and eating disorders as signs of alterations in animal behavior.’ (4)

Silicon dioxide, where it is found

Silicon dioxide is also listed on food labels as E551. It is used as an anti-caking agent in many food categories.

It is easily found, for example, in dietary supplements, ginseng coffee capsules, broth powder, even in a rabbit meat preparation, as the photo gallery shows.

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1) Marta Strinati. EFSA: white titanium dioxide dye is carcinogenic. GIFT(Great Italian Food Trade), 7.5.21

2) EFSA’s scientific opinion on silicon dioxide was adopted in late 2017 and published in 2018. V.

3) Marta Strinati. Stop titanium dioxide, interview with Francesco Cubadda, ISS expert. GIFT(Great Italian Food Trade), 8.5.21

4) Medina-Reyes EI, Rodríguez-Ibarra C, Déciga-Alcaraz A, Díaz-Urbina D, Chirino YI, Pedraza-Chaverri J. Food additives containing nanoparticles induce gastrotoxicity, hepatotoxicity and alterations in animal behavior: The unknown role of oxidative stress. Food Chem Toxicol. 2020 Dec;146:111814. doi: 10.1016/j.fct.2020.111814. Epub 2020 Oct 15. PMID: 33068655.

Marta Strinati

Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".