Nanotechnology provides many opportunities for improvement in the food industry. These include intelligent packaging with sensors to detect when food has gone bad, longer shelf lives due to antibacterial packaging, not to mention nano food additives with various benefits. Some of these benefits are better nutrient delivery using nanoencapsulation [i], and improving flavors, texture, and colors of the foods. Nevertheless, the safety of novel food products must also be addressed.
Why use nano food additives?
When you shrink the size of something, you increase the surface area to volume ratio, meaning that there is a larger area that can interact with its surroundings; thus giving you more flavor for fewer amounts of ingredients. This for example allows the use of less table salt in processed foods which could help reduce harmful overconsumption. Furthermore, nanosized additives can be used to change the texture or appearance of food. [ii]
Another benefit is the encapsulation of different nutrients such as vitamins, antioxidants, and proteins to control when and where they are released to the body [i]. Better vitamin delivery can have a huge positive impact. When eating non-encapsulated vitamins, a large amount does not make it to the parts of our bodies that need them. This is due to them being affected by the acidic environment of the stomach. 690 million people in the world suffer from undernutrition and far more from malnutrition [iii], so nano-encapsulation can help tackle an important issue.
While the positive benefits speak highly in favor of nanotechnology in food, there is a flip side to the coin.
Are nano additives safe?
The nature of nanoparticles can vary greatly based on size, shape, composition, aggregation state, and electrical charge. This means that risk assessment is necessary on a case-by-case basis. In general, what makes nanoparticles risky is their small size, which makes them both more reactive and allows them to pass through biological boundaries such as cell membranes. If they are bio-accumulating this, in the worst case, could lead to cellular dysfunction. [iv]
To give an example: some inorganic nanoparticles, such as zinc oxide (ZnO), which could be used as a source of zinc in supplements and functional foods, are considered bad in large amounts as they can cause an excess of reactive oxidative species (ROS) [ii]. ROS have important bodily functions, but can be bad in large amounts. One solution could be to ensure a proper balance in the food by adding dietary antioxidants [iv].
Another example of an inorganic nano food additive is titanium dioxide (TiO2) which is used as a colorant in for instance chewing gum. There is a size distribution when adding particles, so even when aiming for the optimal particle size of 100-300 nm (above the nanoscale), smaller particles are added as well [ii]. Whether they are toxic or not may depend on the specific form in which they are added.
In general, there seems to be a bigger concern about inorganic nanoparticles over organic nanoparticles with the main reason being that organic ones are often completely digested. However, more research is needed into both types of particles to establish their toxicity [ii]. Luckily, regulations are in place in many countries to ensure the safety of consumers.
What are the regulations?
In the EU, EFSA (European Food Safety Authority) is the one to issue guidelines about what can be added to food products. Nanosized additives in food fall into the category of novel foods which must undergo a safety assessment and be approved before they can be traded in the EU. Additionally, food contact materials such as plastic packaging are regulated to be safe for consumers [v]. Packaging would for example not be allowed if unsafe chemicals or nanoparticles leak into the food.
One concern with regulating this is that nano-sized particles are particularly hard to detect. It could therefore be possible for dishonest companies to avoid regulations by not informing about the nano additives. Advancements in sensing technologies could be one of the solutions to ensure rules are being adhered to. Another thing that would help could be larger transparency about the production process of food using nano additives.
Nanotechnology is a rapidly growing field, and its effects on our every-day life are numerous. On one hand, it advances many fields – improving lives and addressing global issues such as hunger and malnutrition. On the other hand, it may have unforeseeable consequences if we are not careful. These can however be addressed by regulation and proper information to consumers. Otherwise, there is a danger that a bad case of unregulated use of nano food additives not representing the whole spectrum could mitigate the positive aspects and give nano food additives a bad reputation. Luckily, at least in the EU, the regulation on novel food products is strict to ensure consumer safety.
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[i] María Ximena et al., Nanoencapsulation: A New Trend in Food Engineering Processing. 2009. Accessed at https://link.springer.com/article/10.1007/s12393-009-9012-6
[ii] David Julian McClements & Hang Xiao, Is nano safe in foods? Establishing the factors impacting the gastrointestinal fate and toxicity of organic and inorganic food-grade nanoparticles, 2017, Accessed at https://www.nature.com/articles/s41538-017-0005-1
[iii] Global Hunger Index, https://www.globalhungerindex.org/
[iv] Benedette Cuffari, Nanotechnology in Food, accessed at https://www.azonano.com/article.aspx?ArticleID=4069
[v] European Union Observatory for Nanomaterials, Food, accessed at https://euon.echa.europa.eu/food