Testing commissioned by the environment group Friends of the Earth found nanoparticles in popular Australian infant formula products.
The group says the particles are both illegal in Australia and potentially dangerous. Friends of the Earth has called for a recall of all affected brands.
However, experts say there is no cause for alarm.
“Nanoparticles have become the latest boogeyman, despite nanoparticles occurring naturally,” says Dr Ian Musgrave, a senior lecturer in the Faculty of Medicine at the University of Adelaide.
He says infant formula is based on milk, which naturally contains calcium and phosphorus. One of the forms of calcium phosphate in milk is hydroxyapatite.
“So it is unsurprising that hydroxyapatite is found in dried infant formula which is predominantly dried milk powder,” says Dr Musgrave.
“Experiments with drying milk have found that nanometre-sized particles of calcium phosphate form naturally.”
He says the health effects of hydroxyapatite nanoparticles have been studied in animals with no toxicity at levels well above those present in milk.
“There are no significant public health implications for the finding small crystals of naturally occurring calcium phosphates in milk-based products,” he says.
Three of the seven samples tested by Friends of the Earth contained nano-hydroxyapatite particles.
Professor Ian Rae, an advisor to the United Nations Environment Program on chemicals in the environment, says the issue is what he calls a classical “nano scare”.
“The clue that the investigators are pushing an agenda is in their repeated use of the phrase ‘needle like’ to describe the crystals of hydroxyapatite,” he says.
“It’s a ‘dog whistle’ for ‘you will be feeding your babies sharp objects if you use these products’.
“The truth is that these particles are the natural form of hydroxyapatite and they dissolve easily in the acids of the digestive system.
“Moreover, the particles are extremely small — much smaller than the diameter of a human hair — and they make up a tiny proportion of the products.
“The use of all that analytical chemical firepower might serve to over-awe the non-expert reader. Anyone who understands them and can assess the numbers will just ask ‘so what?’.”
Andrew Bartholomaeus, a consultant toxicologist and former chief toxicologist for the Therapeutic Goods Administration, says calcium apatite is a human component of teeth and bones and small quantities of nanoparticulate deposits of this material can be found in normal human tissue.
“There is no evidence to indicate that nano dimensions of particulates are of themselves a risk to human health, and normal human breast milk is composed of a nano material (casein protein agglomerates),” he says.
He says small quantities of nanoparticulates are a normal aspect of the human diet and present no basis for concern.
“One would hope that Friends of the Earth have sufficient moral compass to not seek to exploit the natural concern of mothers for the health of their children to further their corporate objectives by scare mongering analytical findings of no especial significance,” he says.