Food and drink manufacturers use nanoparticles in and on their products for many reasons.
In packaging, they can provide strength, control how much air gets in and out, and keep unwanted microbes at bay.
As additives to food and drinks, they can prevent caking, deliver nutrients and prevent bacterial growth.
“Consumers might absorb some of these materials through their skin, and inhale and ingest them. What does not get digested is passed in urine and faeces to the sewage system,” explained US-based lead researcher Robert Reed.
To understand hazards associated with nanoparticles, researchers tested the effects of eight commercial drinks containing nano-size metal or metal-like particles on human intestinal cells in the lab.
The drinks changed the normal organisation and decreased the number of microvilli, finger-like projections on the cells that help digest food.
“In humans, if such an effect occurs as the drinks pass through the gastrointestinal tract, these materials could lead to poor digestion or diarrhoea,” Reed noted.
The analysis of sewage waste containing these particles suggested that much of the nanomaterials are likely making their way back into surface water, potentially causing health problems for aquatic life.
The report on dietary supplement drinks containing nanoparticles was published in the journal ACS Sustainable Chemistry and Engineering. (ians)