Microplastics in the Body: A Cause for Concern?

In the 1960s, a group of scientists made a strange discovery; they found small pieces of plastic inside the stomachs of the albatrosses. Over subsequent decades, more and more research would link the rising levels of marine plastic pollution with the discovery of plastics inside the bodies of various fish and seabirds.  

The term “microplastic” appeared for the first time in 2004, in a seminal paper examining how marine plastic breaks down in the ocean to form microscopically small granular and fibrous fragments that can accumulate in marine habitats. In the past two decades, these microplastics have turned up everywhere – from the depths of the Mariana Trench to the most remote reaches of the Arctic. 

Today, researchers are looking at microplastics much closer to home – inside our bodies.  

A flurry of recent papers has found microplastics inside human organs, brain tissue, breast milk and in the blood. Concurrently, scientists have been hard at work attempting to decipher whether the presence of these plastics in our bodies may be linked to serious adverse health effects.   

Microplastics and your body 

High production volume polymers were first identified and quantified in human blood samples in 2022, in a paper published in Environment International. Conducted by Dutch researchers from the Vrije Universiteit Amsterdam and the Amsterdam University Medical Center, the study aimed to develop a robust and sensitive analytical method for measuring plastic particles measuring ≥700 nm in blood samples. 

The resulting double-shot pyrolysis-gas chromatography-mass spectrometry (DS-Py-GC-MS) technique was then used on blood samples donated by 22 healthy volunteers, finding a mean concentration of 1.6 µg/ml plastic particles in human blood. Polyethylene terephthalate (PET), polyethylene and various polystyrenes were the most widely seen plastic types, making this study the first to identify high production volume polymers in human blood. 

“Despite the low sample numbers and low concentrations detected, the analytical methods used are very robust and these data therefore unequivocally evidence the presence of microplastics and/ or nanoplastics in blood samples,” commented Dr. Alice Horton, an anthropogenic contaminants scientist at the National Oceanography Centre, in a statement to the Science Media Centre shortly following the paper’s publication. “This is a concerning finding given that particles of this size have been demonstrated in the lab to cause inflammation and cell damage under experimental conditions.” 

While it is believed that the primary route of human exposure to microplastics is through ingesting contaminated food and water, very small microplastics and nanoplastics come with a risk that they might be inhaled and distributed deep into the lungs. 

A 2022 study led by researchers at the University of Hull found that, of the 13 human lung tissue samples they analyzed using micro–Fourier transform infrared (μFTIR) spectrometry, 39 different types of microplastic were found across 11 samples. Additionally, some level of microplastic contamination was found in all regions of the lung, with the lower lung generally carrying the greatest microplastic load. 

“Before it’s possible to comment with any certainty of the physical and chemical toxicity of inhaled microplastics we need to understand what we are being exposed to ‒ sound particle characterization ‒ and establish where these particles are ending up,” Prof. Kevin Thomas, director of the Queensland Alliance for Environmental Health Sciences at the University of Queensland, previously told Technology Networks. 

“In vitro studies suggest that these [airborne] particles can induce inflammatory responses and oxidative stress in lung tissues, but I would question whether the model microplastics used are representative of what we are being exposed to,” he cautioned. 

Microplastics and your brain 

In early 2025, a study published in Nature Medicine reported having found evidence that microplastics can accumulate inside the human brain, as well as in the liver and kidneys. 

The main focus of the study lay in using Py-GC-MS to study various post-mortem frontal cortex brain samples, provided by forensic pathologists from 2016 and 2024 autopsy specimens. 

Additional analysis using attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy with energy-dispersive spectroscopy were also performed. 

The study found microplastics in the liver, kidney and brain samples, concluding that there appeared to be an increasing trend in microplastic concentrations in the brain and liver between 2016 and 2024. Brain samples belonging to people with dementia tended to exhibit a greater microplastic presence, however the study highlights that due to its experimental design, this cannot be interpreted as a causal link – only associative.   

“I can see this paper getting a lot of attention due to its scary-sounding title, but I’d urge caution. Before we get headlines like ‘Our brains are now made of plastics,’ we need to step back and look at how this study was conducted and what that might mean for the results,” commented Prof. Oliver Jones, a professor of chemistry at RMIT University, in a statement to the Science Media Centre.  

“The main analytical method used in this study was Py-GC-MS. This method can give false results when used to measure plastics because fats (which the brain is mainly made of) give the same pyrolysis products as polyethylene (the main plastic reported). The authors did try to address this concern, but I am not certain they were able to account for everything,” Jones pointed out. “Overall, the work is interesting, but the low sample numbers and potential analytical issues mean that care should be taken when interpreting the results.” 

The shortcomings of the Py-GC-MS technique is something that Dr. Matthew Campen, lead author of the Nature Medicine study, is very aware of. Speaking to Technology Networks shortly after the article appeared in pre-print, Campen cautioned that Py-GC-MS is not a “settled science” and acknowledged that questions remain over the specificity of the technique for assessing polymers. 

“Many chemists and health scientists around the planet are currently working to optimize this approach to ensure that we have confidence in this technique,” Campen told Technology Networks.  

“Py-GC-MS assesses the total mass concentration of plastics – that is in µg/g. This does not tell us much about the size, but when we consider linking chemicals to health effects, we always use mass concentration,” he added. 

Microplastics and your health 

The majority of microplastic research to date has focused on developing better methods for the detection, identification and continued monitoring of these plastics in the environment. There are comparatively fewer studies investigating the potential health effects of microplastic exposure and accumulation in humans.  

Studies in mice have suggested that the ingestion of microplastics can cause changes in the intestinal microbiome, resulting in gastrointestinal issues including abdominal pain, bloating and changes to bowel habits. Microplastic exposure in mice has also been linked to increased oxidative stress and cognitive dysfunction. 

Studies using human cell lines have also indicated potential adverse effects. Experiments with human lung and respiratory cell lines have shown associations between exposure to nanoplastics and mitochondrial damage, as well as autophagic cell death.  

While these types of studies do indicate potential harms, the common refrain of most published literature examining the effects of microplastics on the human body is that more research is still needed before any firm conclusions can be drawn.  

A recent literature review, published in Environment & Health, found that although current toxicity research appears to show links between exposure and intestinal injuries, “almost all the studies on the toxicity of microplastics use experimental models, and the harm to the human body is still unclear,” the paper stated. 

This broadly aligns with the findings of a 2022 report from the World Health Organization, which concluded that “the available data do not allow firm conclusions on the risks to human health of inhalation or ingestion of [nano- and microplastics (NMP)], but, as NMP are part of the [particulate matter (PM)] mixture, the health impacts will not exceed those of PM.” However, the report also takes care to note that its findings “do not, however, imply that exposure to NMP is ‘safe’, as concluded by some stakeholders.” 

While scientists continue to unravel the potential health effects of microplastics on our bodies, others are searching for solutions to the growing microplastics problem – whether that be through developing better microplastic remediation technologies or creating new fully-biodegradable plant-based plastics that won’t leave any pesky microplastics behind.