idw – Informationsdienst Wissenschaft

Nachrichten, Termine, Experten

Grafik: idw-Logo
Grafik: idw-Logo

idw - Informationsdienst
Wissenschaft

Science Video Project
idw-Abo

idw-News App:

AppStore

Google Play Store



Instanz:
Teilen: 
27.06.2017 08:45

Nano particles as food additives: improving risk assessment

Media - Abteilung Kommunikation
Schweizerischer Nationalfonds SNF

    The anticaking agent E551 silicon dioxide, or silica, has been used widely in the food industry over the past 50 years, and was long thought to be quite safe. Now, however, researchers working on the National Research Programme “Opportunities and Risks of Nanomaterials” have discovered that these nanoparticles can affect the immune system of the digestive tract.

    It ensures that dry foods such as instant soup, instant coffee and spice powder retain good flow properties. “Synthetic amorphous silica”, the ultrafine powder which is obtained from quartz and bears the E number E551, has been used for around a century with no apparent cause for concern. “Previously it was assumed that these nanoparticles are completely inert,” explains Hanspeter Nägeli from the Institute for Pharmacology and Toxicology at the University of Zurich.

    Awakening the self-defence mechanism

    Now, however, Nägeli and his colleagues working on the National Research Programme “Opportunities and Risks of Nanomaterials” (NRP 64) have found out that these particles are capable of activating certain immune cells. “We have demonstrated that inactive dendritic cells are stimulated in response to contact with nanosilica, triggering a reaction similar in nature to an inflammation,” says Nägeli. Their findings (*) are piquing interest, since dendritic cells have a key role to play in the immune system of the gut: They maintain a dynamic balance between peace and war, or defence and tolerance reactions. Dendritic cells are significantly involved in the immune system’s fight against toxins and pathogens. Moreover, they coordinate the body’s favourable response to food components or agents of normal gut flora.
    As the researchers have shown in test with mouse cell cultures, dendritic cells ingest nanosilica into their cell interior. In doing so, they are awakened from their slumber, and start to discharge a signal molecule that causes an inflammation. The researchers do not know whether such processes might cause the immunological balance of the human gut to tend towards increased defence responses. Nevertheless, their findings could explain the observation that inflammatory gut illnesses seem to spread when more people consume instant products.

    “It is not a case of triggering fear. Inflammatory gut illnesses are dependent on a range of factors,” says Nägeli. The presence of nanosilica in food is no more than a small piece in the large jigsaw puzzle that makes up these complex illnesses. Nägeli does believe his findings should make us more careful about how we use these particles in food, however. “Their mass use needs to be rethought,” write the researchers in their article.

    Improving risk evaluation

    In a further publication (**) Nägeli directs criticism towards the current safety assessment of nanosilica. “The toxicology analyses list no immunological criteria.” In addition, tests involving the addition of particles to rat food have shown liver damage in the highest dosages, although this was not taken into account in the risk evaluation. While no link with nanosilica has apparently been proven, one cannot be excluded, given current knowledge. “For this reason, we ask a principle of caution to be exercised, and for the tolerance level in food to be reexamined,” says Nägeli.

    The research was conducted at the University of Zurich and in collaboration with EMPA, ETH Zurich and Bavarian Nordic.

    (*) H.C. Winkler et al.: MyD88-dependent pro-interleukin-1ß induction in dendritic cells exposed to food-grade synthetic amorphous silica. Particle and Fibre Toxicology (2017). doi: 10.1186/s12989-017-0202-8

    (**) H.C. Winkler, M. Suter and H. Naegeli: Critical review of the safety assessment of nano-structured silica additives in food. Journal of Nanobiotechnology (2016),
    doi: 10.1186/s12951-016-0189-6

    (Available online or via email: com@snf.ch)


    Contact
    Prof. Hanspeter Nägeli
    Institute of Veterinary Pharmacology and Toxicology
    Vetsuisse Faculty
    Winterthurerstrasse 260
    CH-8057 Zurich
    Phone: +41 44 635 87 63
    E-mail: hanspeter.naegeli@vetpharm.uzh.ch

    ‘Opportunities and Risks of Nanomaterials’ (NRP 64).

    The Swiss National Science Foundation was commissioned by the Federal Council to run the National Research Programme ‘Opportunities and Risks of Nanomaterials’ (NRP 64). Its goal was to bridge the gaps in our current knowledge of nanomaterials with regard to their manufacture, use and disposal. The overall final recommendations of NFP 64 have been published in summary reports in April 2017.


    Weitere Informationen:

    http://www.nfp64.ch/en
    http://www.nfp64.ch/SiteCollectionDocuments/Final_Brochure_NRP64_E.pdf 'Final brochure'
    http://www.nfp64.ch/SiteCollectionDocuments/White-Paper-NFP64-E.pdf 'White Paper'


    Bilder

    Merkmale dieser Pressemitteilung:
    Journalisten
    Chemie, Ernährung / Gesundheit / Pflege
    überregional
    Forschungsergebnisse, Forschungsprojekte
    Englisch


     

    Hilfe

    Die Suche / Erweiterte Suche im idw-Archiv
    Verknüpfungen

    Sie können Suchbegriffe mit und, oder und / oder nicht verknüpfen, z. B. Philo nicht logie.

    Klammern

    Verknüpfungen können Sie mit Klammern voneinander trennen, z. B. (Philo nicht logie) oder (Psycho und logie).

    Wortgruppen

    Zusammenhängende Worte werden als Wortgruppe gesucht, wenn Sie sie in Anführungsstriche setzen, z. B. „Bundesrepublik Deutschland“.

    Auswahlkriterien

    Die Erweiterte Suche können Sie auch nutzen, ohne Suchbegriffe einzugeben. Sie orientiert sich dann an den Kriterien, die Sie ausgewählt haben (z. B. nach dem Land oder dem Sachgebiet).

    Haben Sie in einer Kategorie kein Kriterium ausgewählt, wird die gesamte Kategorie durchsucht (z.B. alle Sachgebiete oder alle Länder).