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Food particles with bite

19 April 2012

Nanotechnology is all the rage. It is used in medicine, cosmetics and food to name but a few areas. You have probably consumed many nanoparticles today. The problem with that is that there are significant concerns about how nanoparticles affect your health and now a new study has shown that those concerns are well founded.

Nanoparticles are used in literally hundreds of products on supermarket shelves and billions of nanoparticles are consumed by humans every day. They are used to add nutrients to food and enhance flavours and colours. Nanocomposites are used to minimise the leakage of carbon dioxide out of glass bottles and silver nanoparticles are used to kill bacteria in plastic food packaging. Before we look at what the latest study it might be a good idea to remind ourselves what we are talking about.

Nanotechnology involves manipulating matter at the nanoscale generally defined as 100 nanometers or less. At such a small scale, the chemical and physical properties of particles change compared to their normal-scale counterparts. Their size also makes them more likely to pass through biological membranes, circulate through the body, and enter cells. There is concern about nanoparticles in the human body because we don’t really know how they will behave. That is, we are beginning to learn how they will behave and the latest study does not deliver good news.

This study tested polystyrene nanoparticles which are used in food additives meaning they are widely distributed and consumed. The researchers tested both short and long term exposure to these nanoparticles in both live chickens and in human gut intestinal cells in the laboratory. Chickens were used in the study as absorb iron into their body in similar ways to humans and this study was focussing on iron absorption.

The results showed that high intensity short term exposure to the nanoparticles blocked iron absorption. In the long term however, the nanoparticles caused intestinal cell structures to change leading to a compensatory increase in iron absorption.

What this highlights is that barely detectable levels of these undeclared substances could potentially impact absorption of a whole range of nutrients or even medications. You should not be fooled by appearances, these tiny particles can have huge effects.