Nanosilver fad poses 'serious risk to health'

Online retailers are selling drinks and tablets containing silver nanoparticles, claiming the products boost health by killing off harmful bacteria.

The revolutionary particles are being safely and effectively used in bandages and other external treatments, but experts fear internal use could lead to a build-up inside the body, causing brain damage, liver dysfunction and blood diseases.

'Medicines' containing the nanosilver particles – so tiny that 800 would fit side by side on a human hair – are being sold for as little as 4 online as an alternative to antibiotics. The tablets, drinks and eyedrops are claimed to combat everything from coughs and colds to conjunctivitis.

Nanotechnology, the engineering of tiny particles, has boomed in recent years as scientists find uses in a variety of areas, including medicine, electronics and optics.

Nanosilver is the most widely used of the new particles because silver is naturally toxic to most living things, especially bacteria. Millions of the particles can be created from a gram of the metal – and collectively these have a much greater surface area with which to kill off bugs.

The nano-material's anti-bacterial quality is exploited in a range of products, from medical bandages that prevent wounds from becoming infected to socks that stop feet from smelling and stain-resistant ties.

Online pharmaceutical retailers, both in the UK and United States, have latched on to nanosilver, in one case claiming their products are tasteless and safe to use even on small children, and recommending that people gargle it, drink it, spray it on sore throats or dropper it into eyes and ears.

One seller, UK Colloidal Silver, tells customers a lack of nanosilver in the body causes "many ailments" of modern times, and claims that epidemics such as severe acute respiratory syndrome and bird flu could have been prevented by its widespread use.

The website, which claims to carry out continual research on the product, although not by medical professionals, sells 500ml bottles of "colloidal" silver – nanoparticles of the metal dissolved in water – for 19.95.

Online natural health store Higher Nature sells 15ml of colloidal silver solution in spray bottles for 7.20, and claims it "tastes like water, and is safe, even on small children".

But scientists emphasise there is no clinical research into the ingestion of nanosilver, and Scottish nano-technologists were shocked when they found out about the widespread use of such products.

Professor Vicki Stone of Napier University, who was researching the effects of nanoparticles on the body, was recommended nanosilver by her hairdresser.

Her colleague, Professor Ken Donaldson, said: "She was alarmed to hear this woman and her mother were drinking nanosilver almost every day, even though we knew very little about its effect, positive or negative.

"We bought some nanosilver samples from the internet and found that some had very high levels of toxicity. Others were not even silver, and the particles were not nano-sized, but as there is no regulation, people were selling them anyway."

Donaldson, chairman of respiratory toxicology at the University of Edinburgh, said: "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."

A 2005 study by Dr Max Fung of the University of California suggested that taking nanosilver could cause argyria, a condition that turns the skin bluish-grey, and high doses could lead to comas and anaemia.

Dr Ken Lawton, of the Royal College of General Practitioners, said: "I am very concerned that patients are taking an untried and untested product, particularly a metal, because there is evidence they accumulate and will target organs like the liver, the brain and bone marrow."

But a spokesman for UK Colloidal Silver said: "If we had reason to believe that the mineral solution we sell is in any way hazardous to health, we would not sell it.

"This product is being sold at present in the USA and the Food and Drug Administration has not sought to prevent or restrict its sale on the basis of public health concerns."

A spokesman for Higher Nature admitted they used nanoparticles but said: "We use ionic silver, which has a relationship to the water molecule. That keeps the silver safe."

'Magic spray'

Alexa Bentley, 59, a semi-retired property consultant from north London, has used colloidal silver for 13 years.

She drinks it, gives it to her daughter, feeds it to her eight pet dogs and sprays her whole house with it. "It's magic spray," she said. "I take it whenever I'm starting to feel ill, and now I hardly ever get a cold."

Bentley heard about colloidal silver through a friend who had used it on her dog. She said: "The vet was about to operate on the dog because antibiotics had failed to clear up an infection, but they put colloidal silver on and it cleared up literally overnight.

"I got really interested when I had an ulcer in my mouth. I sprayed the stuff in my mouth and the next morning it was gone. It's comforting at first, and then it repairs. It's completely natural.

"We started using it and I sprayed it on everything that moved. My daughter, who was seven, called it magic spray, and we now drink the solution whenever we feel unwell."

There is little scientific information on colloidal silver's safety or effectiveness, but Bentley said: "It's 100% safe, as long as you take it in moderation. I have been doing it for 13 years, so it can't be that wrong. All these natural remedies are safer than the drugs we get from the doctors, and my experience is it works. I have never had side-effects."