June 1, 2025

expert reaction to a conference abstract looking at the effect of nanoplastic consumption on metabolism and liver function in mice

A conference abstract presented at NUTRITION 2025 looks at the effect of nanoplastic consumption on metabolism and liver function in mice. 

Prof Oliver Jones, Professor of Chemistry, RMIT University, said:

“While we only have the press release and abstract to go on, the keywords are ‘in mice’. Mice are not mini-humans; we can’t assume the result would automatically translate to humans.

“The methods are not clear, but it seems the mice were given 60 mg/kg per day of a solution that was 10% polystyrene (so 6 mg/kg of plastic per kg of body weight per day). It is equivalent to an 80 kg human eating half a gram of plastic per day. This is just not a realistic dose [see 1]. A recent independent review suggests that we ingest only 0.0000006 g of plastic per day [2]. Even then, they likely pass straight out again as the gut wall is relatively thick and well-regulated in humans.

“The mice were also force-fed this diet directly into the stomach for 6-7 weeks before the biochemical analysis was performed. If I were force-fed almost 0.5 grams of plastic a day for 6-7 weeks, I expect I would have some sort of metabolic response, but that would not necessarily be bad in itself, and in any case, this just isn’t what happens in real life.  

“The researchers only used one plastic, polystyrene, which is far from the most common plastic found in the environment. However, it is readily available and is often used in such studies, even if it is not the best plastic to use.

“Another issue is that the type of mouse (C57/B6J) used may have problems with glucose metabolism under normal circumstances anyway [3]. Metabolic analyses also only give you an idea of what was happening at the single point in time the sample was taken. We don’t know if the metabolic changes were permanent or went back to normal later.

“The World Health Organisation (WHO) says there is no clear evidence that microplastics pose a threat to human health. Now, this is not the same as saying they are safe, it simply means they feel there is no proof they pose a risk, despite the numerous papers published on microplastics each year. 

“I don’t think this study is helpful for human risk assessment. It uses unrealistically high amounts of a plastic, which is not the major type found in the environment, fed to a type of mouse prone to glucose issues, in an unrealistic manner.”

References:

1. Green, H. (2022) Are You Eating a Credit Card Every Week? https://www.youtube.com/watch?v=2Ntp6BqhSng accessed 29/05/25
2. Mohamed Nor N.H., Kooi M., Diepens N.J. & Koelmans A.A. (2021) Lifetime Accumulation of Microplastic in Children and Adults. Environmental Science & Technology 55, 5084-96. https://pubs.acs.org/doi/10.1021/acs.est.0c07384
3. Freeman H.C., Hugill A., Dear N.T., Ashcroft F.M. & Cox R.D. (2006) Deletion of nicotinamide nucleotide transhydrogenase: a new quantitive trait locus accounting for glucose intolerance in C57BL/6J mice. Diabetes 55, 2153-6.https://diabetesjournals.org/diabetes/article/55/7/2153/14138/Deletion-of-Nicotinamide-Nucleotide”

‘Adverse Effects of Nanoplastics Administration on the Metabolic Profile and Glucose Control in Mice’ is a conference abstract which was presented by Amy Parkhurst at NUTRITION 2025. The embargo lifted at 21:45 UK Time, Sunday 1^st June 2025.

Declared interests

Prof Oliver Jones: “I am a professor of chemistry at RMIT University in Melbourne. I don’t have any conflicts of interest to declare. However, I do conduct research into environmental pollution, such as microplastics. Sixteen years ago, I worked on a toxicology project funded by the UK Food Standards Agency.”