A recent study by the University of Southern Denmark revealed that nanosilver, which is normally present in dietary supplements, cosmetics and food packaging, can infiltrate human cells and can cause damages to human health.

Researchers said that since silver has an antibacterial, anti-flu and cancer-inhibatory effect, the food and cosmetic industries coat their products with silver nanoparticles. Nano-silver can be found in drinking bottles, cosmetics, band aids, toothbrushes, running socks, refrigerators, washing machines and food packagings. Previous studies found that nano-silver is effective against low blood counts and bad skin.

"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. If nano-silver enters a human cell, it can cause changes in the cell", Associate Professor Frank Kjeldsen and PhD Thiago Verano-Braga, Department of Biochemistry and Molecular Biology said in a press release.

For the study, the researchers analysed human intestinal cells as they are considered more likely to be exposed to nano-silver through food ingestion. Kjeldsen and Verano-Braga said that the study was conducted on human cells in a laboratory and not on living beings.

The researchers found that nano-silver triggers the formation of harmful, free radicals in cells. It also caused changes in the shape and quantity of proteins. The researchers said that the overproduction of free radicals in cells leads to cancer and neurological diseases like Alzheimer's and Parkinson's.

However, they said that they haven't yet determined the quantity of nano-silver that activates cellular changes in human body.

"We don't know how much is needed, so we cannot conclude that nano-silver can make you sick. But we can say that we must be very cautious and worried when we see an overproduction of free radicals in human cells", they say.

Søren Langkilde from the Danish Veterinary and Food Administration to the Danish Broadcasting Corporation (DR) discourages public from consuming dietary supplements with nano-silver.

The finding is published in the journal ACS Nano.