SAFENANO editor Bryony Ross points to an article in Saturday’s Scotsman newspaper on the potential health risks associated with silver nanoparticles contained in over-the-counter health products. The article is in my view a fair representation of expert opinion on the subject.
Silver is a powerful antibacterial agent that has been used for many centuries. In nanoparticle form silver shows promise as a post-operative wound healing treatment, and as an antibacterial agent in paints for hospitals and other sensitive environments. At the same time, however, we are seeing unsubstantiated claims for nanosilver being made by the same commercial interests that have for years been selling colloidal silver in the form of tablets, drinks and eyedrops marketed as alternatives to antibiotics.
One of my reports for Nanomaterials News has been ripped off by Californian snake-oil merchant Lloyd Wright and used to help market his colloidal silver preparation. I have still to decide whether to sue for copyright theft.
The market for consumer products containing antibacterial silver is largely unregulated, and this is of concern to scientists and health professionals. Silver is toxic to biological cells, and dose is critical if the metal or its compounds are to be used as medicine. Yet many of the currently available commercial products contain potentially toxic levels of silver, and the way in which people use the formulations as a tonic is bound to cause problems.
Edinburgh University toxicologist Ken Donaldson spells it out:
“There are entire textbooks written on the toxicity of metals and you don’t want to disturb the balance in your body. There are studies where animals have been fed nanosilver and you can detect the harmful effects on their weight and general health.
“I would like to see how these products are testing themselves and claiming to be safe for children. The same dose of silver would be diluted less in a child because they have less body water.”
And how do the purveyors of over-the-counter silver-based medicines respond to such criticism? Here is a spokesman for the dietary supplements retailer “Higher Nature”:
“We use ionic silver, which has a relationship to the water molecule. That keeps the silver safe.”
A “relationship to the water molecule”? Oh sweet Lord preserve us!
Scientists actively involved in promoting nanotechnology are calling for more research into the health and safety aspects of this new science, and for the market in consumer products that contain engineered nanomaterials to be regulated. Progress is being made on this front, but not fast enough given the increasing numbers of nanotech products on the market.