The food additive silicon dioxide (E 551), widely used in industrial foods and food supplements, may promote the development of coeliac disease, an autoimmune disorder linked to the ingestion of gluten. Evidence emerges from an ‘in vivo’ preclinical study (Lamas et al., 2024), published in Environmental Health Perspectives. (1)
Silicon dioxide, an often ‘invisible’ additive
Silicon dioxide is a powder composed of non-soluble nanoparticles (smaller than 100 nanometres, nm). It is used as an anti-caking additive in dry or powdered foods such as soups, spices, baby food, cereal-based foods, soluble coffees, ginseng coffee, chocolate products etc., as we have seen. (2)
On the label it is indicated among the ingredients by the name (silicon dioxide) and/or E 551. It may, however, escape this identification if it is used as a processing aid, i.e. useful for the production process, like other additives, enzymes and further substances, which we have reported on. (3,4)
Even when used as a food adjuvant, explains INRAE, the E 551 is ‘however present in the final product. Humans are therefore exposed daily and at low doses to E551 through the diet‘.
Nanomaterials and genotoxicity
The nanometric form is what brings titanium dioxide into common with other suspect additives, such as titanium dioxide (E 171), the white dye widely used for decades in gums, candies, supplements and packaged foods. After repeated warnings from the scientific community about its toxicity, it was finally banned in 2022 because it is genotoxic, i.e. capable of damaging DNA. (5) But it remains in toothpastes and medicines. (6)
‘Titanium dioxide is a material composed of insoluble particles, which are poorly absorbed by the intestine, but are eliminated very slowly. It accumulates in various organs, especially the liver and spleen. It has the ability to produce effects on the central nervous system, i.e. to act as a neurotoxic. In addition, it has inflammatory effects, on the immune system, and induces changes in the colon and rectum that can develop into cancer over time.
However, the decisive aspect in the evaluation (by EFSA, ed.) was genotoxicity‘, Francesco Cubadda, coordinator of the working group on the safety assessment of nanotechnologies in the food sector at the Istituto Superiore di Sanità (ISS) and expert involved in the assessment of titanium dioxide at EFSA, explained to GIFT – Great Italian Food Trade. (7)
Silicon dioxide (E 551) and celiac disease, the ‘in vivo’ study
At the end of the treatment from INRAE (Institut national de la recherche agronomique), working under a mandate from the French Ministries of Research and Agriculture, in collaboration with McMaster University in Canada explored the effect of silicon dioxide on tolerance to orally taken food proteins.
Tolerance is an innate function that blocks inflammatory immune reactions when the body takes in food proteins. A deficit in this function triggers a food allergy (to peanuts, cow’s milk, fish, shellfish, eggs, etc.) or an intolerance, even a chronic one, such as coeliac disease.
The ‘in vivo’ study was conducted by feeding food with a dose of silicon dioxide (E 551) to guinea pigs (mice) every day for three months, in an amount consistent with the average daily exposure of European consumers as estimated by EFSA (0,8 to 74,2 mg/kg bw in the general population and up to 160 mg/kg bw in infants).
Research outcome
At the end of the treatment, the researchers observed in the guinea pigs a reduction in tolerance to food proteins as well as a state of intestinal inflammation demonstrating food intolerance.
‘Our study provides evidence that chronic exposure to SiO2 (silicon dioxide, ed.), a common food additive in the human diet, can disrupt gut immune homeostasis and initiate the loss of OT and Th1 immunity to food antigens,’ the study authors explain.
Food exposure to silicon dioxide therefore increases the risk of developing celiac disease (chronic gluten intolerance) in genetically predisposed individuals, as well as aggravating the inflammatory signs characteristic of this chronic disease.
Provisional conclusions
Human and animal studies have already shown that silicon dioxide nanoparticles – following ingestion – breach the intestinal mucosa and can:
– interact with immune cells and
– alter their response in the lymphoid tissue associated with the intestine, in the blood and in the organs (liver, spleen, kidneys).
The research under review confirms the serious toxicity to the additive (or processing aid) E 551, highlighting its role in increasing the risk of increasingly common endemic diseases such as celiac disease and food allergies.
Food security crisis
‘The emerging risk on the food safety of silicon dioxide must be addressed and managed promptly by the European Commission‘, explains lawyer Dario Dongo, founder of GIFT as well candidate in the European elections of 6-9 June 2024 with the #PaceEarthDignity movement.
‘The European Commission must now ask EFSA for an urgent re-evaluation of its 2018 opinion – where the safety assessment of this substance was conditioned by a significant lack of data (8) – and immediately adopt the necessary transitional measures to protect public health‘.
Marta Strinati
Footnotes
(1) Bruno Lamas, Natalia Martins Breyner, Yann Malaisé, Mark Wulczynski, Heather J. Galipeau, Eric Gaultier, Christel Cartier, Elena F. Verdu, and Eric Houdeau. Evaluating the Effects of Chronic Oral Exposure to the Food Additive Silicon Dioxide on Oral Tolerance Induction and Food Sensitivities in Mice. Environmental Health Perspectives. 21.2.24. Volume 132, Issue 2. https://doi.org/10.1289/EHP12758
(2) Marta Strinati. Silicon dioxide, additive at risk still in use. GIFT (Great Italian Food Trade). 20.5.21
(3) Marta Strinati. Technological adjuvants, the additives that the label is silent on. GIFT (Great Italian Food Trade). 31.1.22
(4) Dario Dongo. Too much salt, anti-caking agents and microplastics. GIFT (Great Italian Food Trade). 28.1.24
(5) Dario Dongo. Titanium dioxide in food and supplements, stop from 7.2.22. GIFT (Great Italian Food Trade). 21.1.22
(6) Marta Strinati. New study on the risks of titanium dioxide present in toothpastes and medicines. GIFT (Great Italian Food Trade). 10.8.23
(7) Marta Strinati. Stop to titanium dioxide, interview with Francesco Cubadda, ISS expert. GIFT (Great Italian Food Trade). 8.5.21
(8) EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS). Re-evaluation of silicon dioxide (E 551) as a food additive. EFSA Journal. 17 January 2018 https://doi.org/10.2903/j.efsa.2018.5088
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".
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