The pros and cons of nanofoods
Nanotechnology has the potential to improve the foods we eat, making them tastier, healthier and more nutritious. Yet little is known about how nanoparticles behave in the body, or what kind of toxic effects they could have. Hermann Stamm works on this issue for the European Commission's Joint Research Centre (JRC); he gave a presentation on the topic of nanofoods at the American Association for the Advancement of Science (AAAS) Annual Meeting in Chicago, US. Before travelling to the event, Dr Stamm spoke to CORDIS News about how nanotechnology is used in the food industry, what the risks are, and what research is needed. Citing food industry experts, he explained that foods containing artificial nanomaterials are not on sale in Europe, although they are available over the Internet. Nanotechnology can be used to enhance the flavour and texture of foods, to reduce fat content, or to encapsulate nutrients such as vitamins to ensure they do not degrade during a product's shelf life. In addition to this, nanomaterials can be used to make packaging that keeps the product inside fresher for longer. Intelligent food packaging incorporating nanosensors could even provide consumers with information on the state of the food inside. However, adding nanomaterials to food is not without risks. 'One knows that due to their small size, nanomaterials can overcome barriers like the epithelium in the gut and get into the blood stream,' said Dr Stamm. 'They can then reach secondary target organs and accumulate there.' We already know that ultra-fine particles from diesel engines can get into the lungs, and a number of studies have found a link between these and cardiovascular diseases. Studies in animals have also confirmed that nanoparticles are able to get through the gut wall. Dr Stamm was involved in an EFSA (European Food Safety Authority) group that recently released a draft opinion on nanotechnologies in food and feed. They found that current approaches to risk assessment can be applied to nanomaterials, but warned that data on the non-nano versions of substances cannot be extrapolated to the nano-versions. This is because the small size of nanoparticles allows them to move around the body in a different way to larger particles, while their high surface area increases their reactivity. For this reason, risk assessments should be carried out on a case-by-case basis. According to Dr Stamm, much more research is needed to understand how nanoparticles move around the body, and what tests should be carried out to determine their toxicity. For example, little is known about how they are absorbed by, distributed around and excreted from the body, the EFSA draft opinion notes. 'You also have to characterise the materials very well, so that you know why the nanomaterial is potentially more toxic than other materials,' Dr Stamm added. Another difficulty is caused by the lack of a clear definition of nanotechnology or nanomaterials. 'In food you have natural nanomaterials,' commented Dr Stamm. 'Homogenised milk has a nanostructure of 100nm sized droplets in it.' Any definition would have to avoid confusion with natural nano-scaled materials.