Nano-silver health risk?

Dietary supplements containing nano-silver could be harmful to health say Danish researchers who have shown that the small sized particles can penetrate cells and cause damage. Silver has an antibacterial effect and is used in food and cosmetics – nano-silver can be found in drinking bottles, plasters, toothbrushes, running socks and food packaging. It is also sold as a dietary supplement promising to have antibacterial, anti-flu and cancer-inhibitory effect. Although regulated in the UK, nano-silver is easy to find online. The Danish Veterinary and Food Administration are warning against taking dietary supplements in the wake of research from the University of Southern Denmark which suggests nano-silver could cause changes to cells. “Silver as a metal does not pose any danger, but when you break it down to nano-sizes, the particles become small enough to penetrate a cell wall,” said Professor Frank Kjeldsen and Thiago Verano-Braga. “If nano-silver enters a human cell, it can cause changes to the cell.” The pair studied human intestinal cells, as they considered these the most likely to come into contact with nano-silver ingested in food. “We can confirm that the nano-silver leads to the formation of harmful so-called free radicals in cells. We can also see that there are changes in the form and amount of proteins. This worries us,” they said. A number of diseases – including cancer, Alzheimer’s and Parkinson’s – are characterised by an overproduction of free radicals in cells. The research – published in ACS Nano – was conducted in human cells in the laboratory, and Kjelsen and Verano-Braga point out that they do not know how large a dose of nano-silver a person must be exposed to before these changes take place. “We don’t know how much is needed, so we cannot conclude that nano-silver can make you sick,” they say, “But we can say that we must be very cautious and worried when we see and overproduction of free radicals in human cells.” Insights into the Cellular Response Triggered by Silver Nanoparticles using Quantitative Proteomics