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VigilNanos - Health risks of nanos in food

Health Risks of Nanos in Food

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Health Risks of Nanos in Food

By AVICENN Team – Last Modified January 2023

Reasons for concern about the ingestion of nanos

Studies have shown that nanomaterials can:

Titanium dioxide nanoparticles (E171)

The food additive E171, consisting of titanium dioxide particles (TiO2) (part of which in nano form), was banned in 2020 in France and in 2022 in Europe because of potential genotoxic effects (DNA damage). Many publications also reportdeleterious effects health related to the ingestion of TiO2 nanoparticles: risks for the liver, ovaries and testicles in humans, immune problems and precancerous lesions in the colon in rats, disturbances of the intestinal microbiota, inflammations and alterations of the intestinal barrier in animals as in humans, harmful effects for offspring in rodents, etc.

At the end of 2022, ANSES published its opinion on the risk assessment of the nanometric fraction of the food additive E171 which points to the lack of toxicological data available to carry out a complete assessment of the additive E171 and recommends limiting the uses and exposure of workers and consumers to nanomaterials, “by promoting the use of safe products, devoid of manufactured nanomaterials, and by limiting these uses to those ultimately considered to be duly justified and subject to a documented demonstration of the acceptability of the risk”.

Silica nanoparticles (E551)

Potentially adverse health effects associated with the ingestion of silica nanoparticles (SiO2 corresponds to the additive E551) have been highlighted for several years5See for example:
- Molecular mechanisms of cellular transformation induced by a silica nanoparticle in Bhas 42 cells, Thesis by Anais Kirsch, under the supervision of Hervé Schohn, Yves Guichard and Hélène Dubois-Pot Schneider, in preparation at the University of Lorraine, within the framework of Biology, health, environment, in partnership with the Center de Recherche in Automatic Nancy since May 12, 2017: see the comics e the video (both made in 2018)
- Amorphous Silica Particles Relevant in Food Industry Influence Cellular Growth and Associated Signaling Pathways in Human Gastric Carcinoma Cells, Wittig A et al., Nanomaterials (Basel), 13;7(1), January 2017
- Critical assessment of toxicological effects of ingested nanoparticles, McCracken C et al., About. Science: Nano, 3, 256-282, 2016
- Critical review of the safety assessment of nano-structured silica additives in food, Winkler HC et al., Journal of Nanobiotechnology, 14:44, June 2016
- Biodistribution, excretion, and toxicity of mesoporous silica nanoparticles after oral administration depend on their shape, Li L et al., Nanomedicine: Nanotechnology, Biology and Medicine, 11(8): 1915-1924, November 2015
-Toxicity, genotoxicity and proinflammatory effects of amorphous nanosilica in the human intestinal Caco-2 cell line, Tarantini A et al., in vitro toxicology, 29(2): 398-407, Mar 2015
- Novel insights into the risk assessment of the nanomaterial synthetic amorphous silica, additive E551, in food, van Kesteren PCE et al., Nanotoxicology 2014
, including dysfunctions of cell division and disturbances of cell trafficking6See in particular:
Risk assessment of nanomaterials for the general population and for the environment, Afsset (now ANSES), March 2010
-In vitro toxicity of amorphous silica nanoparticles in human colon carcinoma cells, Nanotoxicology, 7(3), May 2013
-Presence of nanosilica (E551) in commercial food products: TNF-mediated oxidative stress and altered cell cycle progression in human lung fibroblast cells, Cell Biology and ToxicologyFebruary 2014
-Sub-chronic toxicity study in rats orally exposed to nanostructured silica, Particle and Fiber Toxicology, 11:8, 2014
, as well as adverse effects on the liver7 See in particular:
-Silica nanoparticle-induced toxicity in mouse lung and liver imaged by electron microscopy, Fundamental Toxicological Sciences, 2(1): 19-23, 2015
-Novel insights into the risk assessment of the nanomaterial synthetic amorphous silica, additive E551, in food, van Kesteren PCE et al., Nanotoxicology 2014
; worrying considering that we absorb on average about 124 mg of nano-silica (E551) per day8cf. Silica nanoparticles in food, a risky diet?, OMNT, 20 April 2011; the article in French is no longer accessible today, but the source, in English, is still accessible: Presence and risks of nanosilica in food products, Dekkers et al., Nanotoxicology, 5(3): 393-405, 2011  ; in addition some nanosilica are more genotoxic at low doses than at high doses9See in particular:
– Results of the European program Nanogenotox on the genotoxicity of nanomaterials, presented in French at ANSES, during the Restitution of the national environmental and occupational health research program: Chemical substances and nanoparticles: models for the study of exposure and health effects: Participant's file et Slideshow, November 2013.
- 'Facilitating the safety evaluation of manufactured nanomaterials by characterizing their potential genotoxic hazard', Nanogenotox, 2013 and RISKS: Lessons from the Nanogenotox research program,, December 2013
- Documents presented at the meeting of the Risk Assessment and Research Office for the Netherlands Consumer Product Safety Authority (NVWA) in October 2013

Having noticed vitro that silicon dioxide nanoparticles can cause inflammation in the gastrointestinal tract of mice (an attack on the immune defense of the digestive system), a team of Swiss researchers has  advocated less use of silica particles as a food additive10See Food additives: better appreciate the risk of nanoparticles, press release, 27 June 2017; In-vitro test to assess the risk of nanomaterials in food, Project led by Hanspeter Nägeli, from the Institute of Pharmacy and Veterinary Toxicology of the University of Zurich (Switzerland) between 2012-2015 and National research program NRP 64 – Opportunities and risks of nanomaterials – Results, conclusions and perspectives – final brochure, Swiss National Science Foundation, March 2017; MyD88-dependent pro-interleukin-1B induction in dendritic cells exposed to food-grade synthetic amorphous silica, Winckler HC et al., Particle and Fiber Toxicology, 14:21, June 2017.

La re-evaluation of silica as E551 (nano and non-nano), was adopted very late on the initial schedule, at the end of 2017, without it being possible to draw definitive conclusions concerning the safety or toxicity of this additive. A call for data was opened by EFSA between October 2018 and May 2020; In the absence of conclusive data, the current authorization of this food additive would be reviewed on the basis of the current scientific opinion of EFSA and the additive could be removed from the list of authorized additives of the European Union. (There will be no new call for additional data).

Since disturbing new studies have been published in scientific journals11See in particular:
Oral Toxicokinetics, Tissue Distribution, and 28-Day Oral Toxicity of Two Differently Manufactured Food Additive Silicon Dioxides, Yoo NK et al., Int J Mol Sci , 5;23(7):4023, 2022 Apr
- Gut microbiome and plasma metabolome changes in rats after oral gavage of nanoparticles: sensitive indicators of possible adverse health effects, Landsiede R et al., Particle and Fiber Toxicology, 19 (21) 2022
- Physiological and Behavioral Effects of SiO2 Nanoparticle Ingestion on Daphnia magna, Kim Y et al., Micromachinery (Basel), 12(9): 1105, September 2021
- Dietary nanoparticles alter the composition and function of the gut microbiota in mice at dose levels relevant for human exposure, Perez L et al., Food and Chemical Toxicology, 154, August 2021
- Particles in food additives: what are the effects on digestive health? Focus on the ANR PAIPITO project, Interview with Marie Carrière (CEA Grenoble), National Research Agency, June 7, 2021
- Oral intake of silica nanoparticles exacerbates intestinal inflammation, Ogawa T et al., Biochemical and Biophysical Research Communications, 534(1): 540-546, January 2021
- Impacts of foodborne inorganic nanoparticles on the gut microbiotaimmune axis: potential consequences for host health, Lamas B and Houdeau E, Particle and Fiber Toxicology, 17:19, 2020
- Hazard identification of pyrogenic synthetic amorphous silica (NM-203) after sub-chronic oral exposure in rat: a multitarget approach, Tassinari R et al., Food Chem Toxicol., 137:111168, 2020
- Toxicity to RAW264.7 Macrophages of Silica Nanoparticles and the E551 Food Additive, in Combination with Genotoxic Agents, Dussert F et al., Nanomaterials, MDPI, 10 (7): 1418, 2020: Silica nanoparticles are likely to carry genotoxic agents on their surface, which leads to aggravating their harmful effects on DNA
- Small silica nanoparticles transiently modulate the intestinal permeability by actin cytoskeleton disruption in both Caco-2 and Caco-2/HT29-MTX models, Horned R et al., Arch Toxicol, 94(4): 1191-1202, April 2020
- Chronic oral exposure to the food additive E551 (silica dioxide) blocks the induction of oral tolerance and predisposes to food intolerance in mice, Breyner NM et al. Francophone Nutrition DaysNovember 2019
- Chronic oral exposure to synthetic amorphous silica (NM-200) results in renal and liver lesions in mice, Boudard D et al., Kidney International Reports 2019
- Risk assessment of silica nanoparticles on liver injury in metabolic syndrome mice induced by fructose, Li J et al., Science of the Total Environment, 628–629: 366-374, July 2018: “Silica nanoparticles (SiNPs) aggravate liver injury in metabolic syndrome mice; SiNPs lead to mitochondrial injury in liver; SiNPs stimulate hepatic ROS generation; SiNPs lead to hepatic DNA damage »
- Silicon dioxide nanoparticle exposure affects small intestine function in an in vitro model, Guo Z et al, Nanotoxicology, April 2018: “SiO2 NP exposure significantly affected iron (Fe), zinc (Zn), glucose, and lipid nutrient absorption. Brush border membrane intestinal alkaline phosphatase (IAP) activity was increased in response to nano-SiO2. The barrier function of the intestinal epithelium (…) was significantly decreased in response to chronic exposure. Gene expression and oxidative stress formation analysis showed NP altered the expression levels of nutrient transport proteins, generated reactive oxygen species, and initiated pro-inflammatory signaling. SiO2 NP exposure damaged the brush border membrane by decreasing the number of intestinal microvilli, which decreased the surface area available for nutrient absorption. SiO2 NP exposure at physiologically relevant doses ultimately caused adverse outcomes in an in vitro model”
, which confirms the existence ofharmful effects of ingesting silica nanoparticles, especially on the liver, intestines and kidneys or the immune system.

(Silica manufacturers have tried to defend their product by attacking one of these studies, published in 2019; the researchers in question have in turn responded, still in the same journal, by dismantling point by point the criticisms highlighted by silica manufacturers12The original article was by Boudard D et al. : Chronic oral exposure to synthetic amorphous silica (NM-200) results in renal and liver lesions in mice, Boudard D et al., Kidney International Reports, 2019. The letter to the editor from representatives of manufacturers (or users) of silica (the Association of Synthetic Amorphous Silica Producers (ASASP), PQ Corporation, Wacker Chemie AG, Evonik Resource Efficiency GmbH, Grace Europe Holding GmbH, Solvay, and Pittsburgh Plate Glass Company) was sent in November 2019. The researchers response was sent in December 2019. Both were published on the website of KI Reports the 10 March 2020.).

Silver nanoparticles (E174)

Turnkey silver nanoparticles are present in theE174 additive but also in antibacterial food wraps or containers ; however, silver nanoparticles injected into the blood of rats have been found as far as the liver, at the level of the nucleus of the hepatocytes, and alter the cells of this vital organ13See Effects of Silver Nanoparticles on the Liver and Hepatocytes in vitro, Gaiser BK et al., Toxicol. Science. 2012.

Another study showed that silver nanoparticles administered orally to mice damaged epithelial cells as well as intestinal glands rodents and led to a decrease in their weight14cf. Toxic effects of repeated oral exposure of silver nanoparticles on small intestine mucosa of mice, Toxicology Mechanisms and Methods, 23(3), March 2013;; a disturbance of the intestinal flora was also observed in zebrafish fed with food containing silver nanoparticles15cf. Ingestion of metal-nanoparticle contaminated food disrupts endogenous microbiota in zebrafish (Danio rerio), environmental pollution, 174, March 2013, as well as in mice16Dietary silver nanoparticles can disturb the gut microbiota in mice, Van den Brule S et al., Particle and fiber toxicology, 13, 2016 (see the summary and analysis in French here: Effects of silver nanoparticles on bacterial communities, Varnish L., Scientific watch bulletin, n°32, October 2017).

It has also been demonstrated that theingestion of silver nanoparticles causes permanent genome alterations in mice and could therefore lead to cancer17Oral ingestion of silver nanoparticles induces genomic instability and DNA damage in multiple tissues, Nanotoxicology 2014
See also: Exposure to silver nanoparticles induces size- and dose-dependent oxidative stress and cytotoxicity in human colon carcinoma cells, in vitro toxicology, 28(7), 1280-1289, October 2014
, etc. Other concordant results have recently been published, also showing negative effects silver nanoparticles in the kidneys on rats18See for example:
- Oral subchronic exposure to silver nanoparticles causes renal damage through apoptotic impairment and necrotic cell death, Rui Deng et al., Nanotoxicology, 11(5): 671-686, 2017
- Comparative toxicity of silicon dioxide, silver and iron oxide nanoparticles after repeated oral administration to rats, Journal of Applied Toxicology, 35(6): 681–693, Jun 2015

Zinc oxide nanoparticles (ZnO)

Zinc oxide nanoparticles present on the inside coating of food cans find their way into food and may cause poorer nutrient absorption and greater gut permeability, transferring unwanted compounds into the blood19See in particular:
- ZnO nanoparticles affect intestinal function in an in vitro model, Moreno-Olivas F et al., Food Function., 9: 1475-1491, 2018; see the summary in French here: Canned foods could harm our digestion, Top Health, April 10, 2018 and there canned foods interfere with digestion,Bio in the spotlight, April 12, 2018.

Cerium dioxide (CeO2) nanocomposites

They can cause a impaired metabolism20See "Oxide nanoparticles: what toxicity on intestinal cells?" », CEA-iBEB work carried out as part of the ANR AgingNanoTroph project, January 3, 2013.

Nano cellulose?

In addition to the health repercussions of ingesting nanoparticles, it should be noted that environmental risks are also poorly understood and of concern.

Many scientific uncertainties

Much is still unknown today about the repercussions that the ingestion of nanomaterials can have on human health. Oral nanoparticle toxicity studies are rare and many may have had methodological weaknesses that make it difficult to use their results. The experimental conditions still poorly reflect the way consumers are exposed; the nanomaterials considered are often synthesized in the laboratory and therefore different from the nanomaterials (and nanomaterial residues) that consumers actually ingest. Furthermore, the physico-chemical characteristics nanoparticles tested and their interactions with the food matrix are insufficiently documented. Nevertheless, progress has recently been underway, thanks to improvements in researcher practices, tools and protocols.

The complexity of assessing the risks associated with the ingestion of nanomaterials

One of the problems that is likely to persist, however, relates to the great complexity of the risk assessment related to the ingestion of nanomaterials : the toxicity of nanoparticles differs according to their physico-chemical characteristics (size, shape, degree of agglomeration, etc.). However, these characteristics are very variable according to the nanomaterials and can evolve throughout their life cycle :

  • depending on the conditions under which the nanomaterials are synthesized, stored, possibly coated;
  • by the transformations they undergo during cooking and the preparation of dishes or in the digestive tract21Mammalian gastrointestinal tract parameters modulating the integrity, surface properties, and absorption of food-relevant nanomaterials, Bellmann S et al., WIREs Nanomed Nanobiotechnol. 2015 (for example in contact with the acid medium of the stomach, etc.)
  • during interactions with the packaging and/or with the other ingredients and chemical substances with which the nanomaterials are found mixed (before then during ingestion and digestion); one can fear, for example, a “cocktail effect” with certain other synthetic molecules22Nanomaterials, combined with other substances, could become (more) dangerous? Toxicologists often work by isolating substances, which makes it impossible to establish the interaction effects of a plurality of substances entering the body..

The risk assessment must also take into account:

Since 2009, a broad consensus on the need to strengthen research on the risks associated with ingested nanos

In 2009, the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) convened a meeting of experts on the impact of nanotechnology on food safety: the investigation report which resulted from it, published in 2011, lists the research needs to better assess the risks in the field. 

Since 2009, ANSES has called for improving knowledge of the dangers and consumer exposure to nanomaterials. In October 2016, ANSES was contacted by its supervisory ministries to study the risks associated with nanoparticles in food, and more specifically:

  • carry out a detailed study of the agri-food sector with regard to the use of nanos in food,
  • prioritize the substances and/or finished products of interest according to relevant criteria determined during the expert appraisal,
  • carry out a review of the available data (toxicological effects and exposure data)
  • and depending on their availability, study the feasibility of a health risk assessment for certain products.

A "working group" ("WG nano food") composed of independent experts was set up in 2017. The first results of the expertise, initially expected by the end of 201726Response to question N° 85181 from MP Yves Daniel, Ministry of Social Affairs, Health and Women's Rights, October 2016; See as well ANSES is calling for applications from scientific experts to set up a "Nanos & Food" working group (WG), ANSES, January 2017, were published in mid-2020 in a report identifying food products containing (or likely to contain) nanomaterials27See ANSES, Nanomaterials in food products; Collective expert reportMay 2020.
In 2021, ANSES published a second report: a specific guide to assess the health risks of nanomaterials in food complementary to investigation report on the same subject published a few months earlier by the EFSA.

At the end of 2022, ANSES published its opinion and report on the risk assessment of the nanometric fraction of the food additive E171 which points to the lack of toxicological data available to carry out a complete assessment of the additive E171 and recommends limiting the uses and exposure of workers and consumers to nanomaterials, “by promoting the use of safe products, devoid of manufactured nanomaterials, and by limiting these uses to those ultimately considered to be duly justified and subject to a documented demonstration of the acceptability of the risk”.

Notwithstanding the broad consensus on the need to strengthen research on the risks associated with ingested nanomaterials, which is still limited today.

Pending conclusive evaluations, the marketing of food products containing nanoparticles continues

In the meantime, consumers therefore continue to ingest nanoparticles of titanium dioxide, silica, silver, etc., most often without knowing it, lack of application by the industry of the labeling obligation !

En presenting his guide to risk assessment of nanos in food (2021) as well as his opinion and report on the risk assessment of the nanometric fraction of the food additive E171 (2022), ANSES recalled "the need to limit the exposure of workers, consumers and the environment to nanomaterials" and recommend “to favor safe products, devoid of these substances”.

Certainly, the additive E171 containing titanium dioxide nanoparticles has been banned in food in France in 2020 and in the European Union in 2022, but it remains authorized for the moment in medicines and cosmetics (or, in toothpaste or lipsticks and lip balms for example, it is likely to be ingested ).

Given the dangers, calls for caution and the precautionary principle 

Government recommendations on nanos in food

In front of many uncertainties concerning the risks of nanos in food, many public or para-public organizations have issued recommendations concerning the use of nanomaterials or nanotechnologies in the food sector28See in particular the numerous reports from the public authorities listed in our bibliography. Among the most comprehensive reports is theOpinion on the ethical issues of nanotechnology in the agri-food sector of the Commission de l'éthique en science et en technologie du Québec published in 2011, with nine concrete recommendations that give a good overview of the recommendations issued by various actors in other frameworks, with the advantage of being relatively well articulated here and almost complete..

These recommendations can be schematically summarized as follows:

  • carry out a scientific and technological watch on nanotechnological applications in the food industry and the associated risks;
  • deepen research on risks ;
  • inform the public;
  • consult the population;
  • develop the interministerial exchange of information on the state of scientific knowledge on risks;
  • to allow the public evaluation of the innocuity and the legal framework of the products concerned;
  • demand transparency from manufacturers andlabeling of the products concerned.

NGOs have called for a moratorium on nanos in food for years

Among the NGOs that have spoken out against the use of nanomaterials in everyday consumer products29See among 51 actors' notebooks organizations that took a stand during the national public debate on nanotechnology of 2009-2010., various NGOs30See in particular the NGO reports listed in our bibliography specifically called for a moratorium on the use of nanomaterials in food, including:

Consumers unwilling to play guinea pigs

In a general context where consumers are increasingly suspicious of industrial food32See for example Food: faced with doubts, Internet users organize themselves, The World, April 15, 2013, consumer reluctance and distrust of nanoparticles in food are growing. In general, consumers expect more transparency and do not want to be “nano-food guinea pigs”33Nanotechnologies: all nano-food guinea pigs?, Basta!, January 14, 2010, which they already are, reluctantly, since our food already contains nanomaterials – and not only “virtual” nano objects like those used at INRA for the study mentioned above carried out in 2011.

Since 2016, the petition "Stop nanoparticles on our plates!" » launched by Agir pour l'Environnement, demanding a moratorium on nanoparticles in common food products, collected more than 52 signatures.

In 2011, INRA researchers concluded that"in situations of uncertainty and controversy, decision-makers should pay particular attention to participatory or deliberative modes of communication". THE'Citizen Science association has been campaigning in this regard for several years for the establishment of citizens' conventions whose recommendations should be taken into account by the authorities.

The INRA researchers add that "this communication must be accompanied by a strong policy guaranteeing the safety of nano-foods in a context of mistrust among European consumers". It remains to be determined who should bear the cost of such a security policy aimed at reassuring the population about applications whose benefits have yet to be proven and of which the agri-food industry and certain research laboratories seem to be the main beneficiaries, more than consumers: is it the taxpayers to pay or the companies hoping to profit from their commercialization ?

A remark, a question? This sheet produced by AVICENN is intended to be supplemented and updated. Please feel free to contribute.

The next nano appointments

“Nano and Health” dialogue committee (ANSES, Maisons-Alfort)
Dialogue Committee
  • 14th meeting of the “nano and health” dialogue committee
  • Organizer: ANSES
  • Website :
Nanomaterials, how to identify them more efficiently? (LNE, Paris)
  • Technical Day
  • Organizer: National Metrology and Testing Laboratory (LNE)
  • On the agenda: identification of nanomaterials, recent technological innovations in terms of particle size characterization, areas for progress to be considered 
  • Upcoming program
  • Website :…
NanoSafe conference 2023 (CEA, Grenoble)
  • 8th International Conference on Health Issues for a Responsible Approach to Nanomaterials
  • June 5-9, 2023
  • Organizer: Commissariat for Atomic Energy and Alternative Energies (CEA)
  • Website :…  

Sheet initially created in May 2013

Notes & references

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