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First, let's understand exactly what a nanoparticle is
Nanoparticles are tiny objects that range in size from about 100 nm down to about 1 nm (1 nm is 1 billionths of a metre). They are similar in size to small molecules, and far too small to see with a microscope. Nanoparticles exist in the natural world and are also created as a result of human activities.
Owing to their submicroscopic size, they have unique material characteristics, and manufactured nanoparticles may find practical applications in a variety of areas, including medicine, engineering, catalysis, and environmental remediation. Working with nanoparticles is called nanotechnology. Source: Britannica Online, News-medical.net.
So what are the health implications of this new development?
Nanoparticles typically have at least one dimension that measures less than 100 nanometres and they can be as minute as a single nanometer.
To put the scale of these objects into perspective: a nanometer is equivalent to a billionth of a metre and a human hair has a diameter of around 80 000 nanometres.
At this sub-microscopic scale even ordinary substances take on some rather unusual properties that have led to a variety of practical applications in areas from biology and medicine to electronics and materials engineering.
Nanoparticles are already contained in hundreds of consumer products and have been used in treating brain tumours, delivering medicines to the precise location in the body where they are needed, cleansing polluted water and manufacturing anti-microbial, odour-resistant socks and underwear.
Read: Nanoparticles may kill cancer cells
Increasingly, they are also found in food, both intentionally and by accident.
The Nanotechproject database lists food items for sale in the US which contain nanoparticles of some sort. Examples include rice and soy milk, chocolate and cheese to which trace amounts of nanometer-scale titanium dioxide particles have been added as an artificial colour enhancer.
Another pathway through which nanoparticles are suspected to be entering the human food chain is through enhanced packaging materials. Silicate or clay nanoparticles embedded in plastic packaging provide a barrier to gasses and moisture, keeping food dryer and making it less likely to spoil. Anti-bacterial nanosilver is used in packaging plastics, storage containers and a variety of kitchen and tableware.
While the manufacturers argue that these products go through rigorous tests which show that no detectable quantities of nanoparticles leak from the packaging material into the food it contains, a number of recent medical research articles suggest otherwise, indicating that silver and copper nanoparticles can, in fact, migrate from plastic packaging to food under normal storage conditions.
But what are the health risks, if any?
While many companies are investing heavily in the technology – the global nanotech industry as a whole is currently worth over US$20 billion annually and is expected to grow to nearly US$50 billion by 2017 according to Nanotechnology market research– surprisingly little is known about the potential human health implications of food laced with nanoparticles.
Read: Nanotechnology
Although US labeling regulations do not require nanoparticles to be listed as ingredients in either packaging or food, the country’s Food and Drug Administration has acknowledged that they may present certain health risks. Well-controlled research on possible human health implications has been limited, but animal studies suggest that nanoparticles may be toxic to the immune system, kidneys and liver.
Recent scientific papers have highlighted the occupational health risks associated with exposure to nanoparticles in the workplace, and have shown that the types of nanoparticles used as drug delivery systems in medicine can lead to brain tumours in rats.
The South African Nanotechnology Initiative brings together scientists and engineers from universities, research institutions and industry to foster home-grown progress in nanoscience and nanotechnology.
Read more:
Nanoparticles may adversely affect environment
Nanoparticles - pills of the future
