The French environmental organization Agir pour l’Environment is calling for four food products to be removed from the market, because they contain undeclared engineered nanoparticles. The call comes after the organization found nanoparticles of Titanium Dioxide and Silicon Dioxide in the products – additives they claim should be listed as nanoparticles on the ingredient labels, and were not.
Details are sparse about what tests were carries out by the organization and what the results were – especially what the size distribution of the particles was, which is essential for evaluating compliance with EU food label regulations. Most of the information available comes from coverage in a FoodNavigator.com article.
European Union food label regulations require that if 50% or more of the particles in a powdered food additive are smaller than 100 nm, the ingredient should be identified with the postfix (nano) on the label.
Titanium dioxide (TiO2) and Silicon dioxide (SiO2) have been used as food ingredients for many years. TiO2 (additive E171 in the EU) is used as a pigment to create white or brightly colored foods, or to increase opacity. Because it depends on being highly opaque to visible light, the additive is typically manufactured with an average particle diameter of around 200 nm – 300 nm (although there is some variation around this). However, because all powders have a range of particle sizes, there is inevitably a small number of particles smaller than 100 nm in TiO2 food additives.
SiO2 is used as an anti-caking agent in foods, to prevent products like powdered spices from clogging together, and ensuring they flow smoothly when used. A widely used food-grade form of SiO2 is fumed silica (additive E551 in the EU). This is made in a hot flame which produces particles of around 20 nm in diameter. These fuse together while being made into much larger agglomerates. It’s a process that’s been used to make the material since the 1940’s.
Like food-grade TiO2, fumed silica added to foods will contain some particles smaller than 100 nm. However, in this case, it’s much harder to tell whether these will be a small or a larger percentage of the total number of particles.
Despite both of these materials being used widely in food products for many years (thousands – probably tens of thousands – of food products use them), there is no evidence for them being associated with adverse health effects. However, increasing interest into the potential health impacts of nanoparticles more generally has raised questions around whether they are as safe as assumed.
Laboratory research has suggested that, under very specific conditions (like high concentrations and isolated cells), both nanoscale TiO2 and SiO2 can cause harm to cells. But translating this research to real-world uses and potential risks is not straight forward.
Both TiO2 and SiO2 are known to be pretty safe materials in the body – they don’t do much at all once there. However, current research is suggesting that nanoscale particles of the materials might be a little less safe. The differences are small though, and depend on how and where safety is evaluated (for instance, whether the particles are in a pristine cell culture, or in the harsh acidic environment of your stomach, as well as how much material is used).
And it’s worth remembering that our bodies have evolved over millions of years to handle being exposed to small quantities of nanoparticles quite well.
While it would be foolish to assume there aren’t “unknown unknowns” here, and that ingredients that have seemingly been used safely for years by hundreds of millions of people are not as safe as we thought, current research does not at this point indicate that there are significant risks from using TiO2 and SiO2 in food.
This doesn’t mean we should stop doing research into their safety – just in case. But it does mean we probably need to be very cautious about speculating about possible risks where there isn’t strong evidence.
What about identifying these as “nano” on food labels though?
In the case of fumed silica, this is clearly intentionally designed and manufactured as a nanomaterial – even if many of the final aggregated particles are larger than 100 nm. As such, there is an argument for identifying it as (nano) on food ingredient labels. However, it may not technically make the cut for the EU definition of nanomaterial if the majority of aggregates are above 100 nm – that’s information that isn’t readily available at this point.
Food grade TiO2 is a little more complex, as intentionally making it nanosize would make it less useful – the particles have to be large enough to reflect visible light well. Here, it’s hard to justify using the (nano) label, unless there is direct evidence of powders being used with most of the particles being below 100 nm in diameter.
At the end of the day, whether to label or not comes down to policy, and the desire and right of consumers to know what’s in their products. But at this point, there’s little to indicate that the TiO2 and SiO2 being used in foods at the quantities they’re being used in, present a health risks – whether labeled or not.
Image: SiO2 is often used as an anti caking agent in spices like chili powder.