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.”

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 plas

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 Amelia 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."

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. Overall, this trial has delivered a message of hope that we can actively reduce plastic chemical levels in our bodies but this is linked to significant changes in the way we produce and package our food.”

This study was funded by The Minderoo Foundation and sponsored by The University of Western Australia.