A clinical trial investigating levels of plastic chemicals in the human body has found that a low plastic diet could be a fast and effective way to reduce exposure.
The University of Western Australia researchers on the Plastic Exposure Reduction Transforms Health (PERTH) Trial spent the past three years measuring exposure to plastic chemicals in adults across Perth in Western Australia.
Results published in Nature Medicine showed by minimising plastic touchpoints including food processing materials, food packaging, kitchenware and using personal care items low in plastic chemicals, the levels of these chemicals in the human body could be reduced in seven days.
Principal investigator and senior author Clinical Professor Michaela Lucas, from UWA's Medical School, said while other research had focused on the potential harms of micro and nanoplastics, research on the health effects of plastic-associated chemicals – which can account for up to 70 per cent of the weight of plastics – was equally critical.
"We investigated two major types of plastic chemicals, bisphenols and phthalates, both of which can interfere with endocrine or hormonal functions in our body and have been linked to infertility and cardiometabolic disease," Professor Lucas said.
"Our results showed strictly adhering to a diet of food which has not touched plastic, whether that is during production or packaging, can reduce plastic chemicals in our body in as little as a week. If this also carries major health benefits is something that's currently under further investigation."
More than 16,000 chemicals such as BPA, BPS and phthalates are commonly used in the manufacture of plastic for food and beverage packaging, kitchen utensils, cling film, plastic food and drink containers and personal care products, among many other items.
The trial team included dieticians, doctors, nurses, statisticians and biologists who analysed urine, blood and nasal samples, behavioural questionnaires and socio-demographic data from 211 healthy adults.
They found 100 per cent of participants showed high levels of plastic chemicals in their bodies, with each participant recording at least six different chemical types on any given day.
Co-first author Dr Amelia Harray said by assessing people's exposure to plastics in their diet, environment and lifestyle, while measuring plastic chemical levels in their urine, the research team identified that highly processed, packaged and canned foods and beverages were significant contributors.
From the original study, 60 individuals were selected to be part of a randomised controlled trial involving a low plastic diet and lifestyle intervention and divided into five groups to test the effectiveness of replacing food and beverages, kitchenware and personal care products with low plastic alternatives.
At the end of the seven-day intervention all trial groups showed a decrease in urinary plastic chemical levels, compared to the control group.
Co-first author Dr Andrew Lucas said by altering a participant's lifestyle to include the consumption of low plastic food, prepared with low plastic kitchenware and the use of low plastic personal care products, phthalates decreased by more than 44 per cent and bisphenols (such as, BPA and BPS) by more than 50 per cent.
Dr Harray said the team went to incredible lengths to ensure plastic and other sources of plastic chemicals, such as silicones and cans, were removed from the food supply chain.
"Our dietitians worked with over 100 farmers and food producers to educate and transform their food handling processes and packaging to reduce plastic exposure from paddock to plate," Dr Harray said.
"Participants had access to any type of food they would usually consume – pasta, salads, meats, butter, chocolate, fruit and snacks – which allowed energy intake to remain the same.
"By delivering participants low plastic food and providing them with plastic-free kitchenware, such as stainless-steel pots, pans, kettles, toasters and wooden chopping boards, we showed changing what you eat and how you prepare food could reduce plastic chemicals in the body."
Professor Lucas said we don't yet know what a 'safe' level of plastic in the body might be and more research was needed.
"We do know that plastic chemicals are harmful to humans, and the health burden has and will increase over time unless we intervene," she said.
"This trial has delivered a message of hope that we can actively reduce plastic chemical levels in our bodies but is linked to significant changes in the way we produce and package our food."
Dr Lucas said the high prevalence of BPS in healthy participants as an alternate chemical used to replace BPA should ring warning bells for food standards regulators as it is becoming clear these replacements are likely to cause similar harms.
John Hartman, CEO of Minderoo Foundation which funds the PERTH Trial, said the findings from the trial were deeply concerning.
"Researchers detected plastic chemicals in every single participant. This means Western Australians are being exposed to a pervasive chemical mixture originating from plastics throughout daily life," Mr Hartman said.
"We know this chemical mixture is harmful. If we keep relying on fossil fuel made plastic, we lock future generations into serious health harms.
"Minderoo is investing in a future where the materials we use every day don't come at the cost of our health or our environment.
"By backing the scientists and entrepreneurs developing safe alternatives, we are turning breakthrough technologies into commercially viable solutions at scale, creating a new generation of safe materials."
The next PERTH Trial study will investigate the effects of plastic chemical exposure on fertility.
Image top: Dr Andrew Lucas, Professor Michaela Lucas and Dr Amelia Harray.
