THE ESSENTIAL
- New work confirms that some tea bags made with plastic can release astronomical amounts of plastic particles per milliliter of hot drink.
- In this study, the researchers found that mucus-producing intestinal cells showed greater absorption of these particles, and that the latter were able to penetrate the cell nucleus that houses our genetic material.
- To reduce your risk of exposure to these particles, it is advisable to prefer loose teas or those packaged in cotton or paper bags.
Food packaging is a major source of contamination of the body by microplastics, i.e. plastic fragments smaller than 5 millimeters. In 2019, a study from Canadian McGill University alerted us to the astronomical quantity of these particles released when a single plastic tea bag was brewed: up to 11.6 billion microplastics and 3.1 billion nanoplastics! At this stage, researchers did not yet know what the risks were for our body. Five years later, the results of new research are worrying: it seems that these particles can penetrate our intestinal cells to reach our bloodstream and thus spread throughout our body… The results of the work were published in November 2024 in the review Chemosphere.
Plastic tea bag: up to 1.2 billion particles released per milliliter
The work of researchers from the Mutagenesis group at the Department of Genetics and Microbiology at the Autonomous University of Barcelona (UAB) was carried out using tea bags made from nylon-6 polymers, polypropylene and cellulose. The three types of sachets were purchased online (Amazon and AliExpress) or at a local supermarket.
“We have succeeded in innovatively characterizing pollutants with a set of cutting-edge techniques, which constitutes a very important tool for advancing research into their possible impacts on human health.”, said Alba Garcia, a researcher at UAB. Thus, the experiments carried out show that:
- polypropylene releases approximately 1.2 billion particles per milliliter, with an average size of 136.7 nanometers;
- cellulose releases approximately 135 million particles per milliliter, with an average size of 244 nanometers;
- nylon-6 releases 8.18 million particles per milliliter, with an average size of 138.4 nanometers.
Interactions with human intestinal cells discovered
The researchers then stained these particles and exposed them to different types of human intestinal cells to study their interaction and possible cellular internalization.
The result: mucus-producing intestinal cells showed the highest uptake of micro- and nanoplastics, with particles capable of penetrating the cell nucleus that houses our genetic material.
New research into the potential health impacts of chronic exposure to these particles is now essential to learn more.
According to the authors, standardized test methods should also be urgently developed to assess contamination by these particles in all foods in plastic packaging. They also want regulatory policies to be put in place to mitigate this contamination. “As the use of plastic in food packaging continues to increase, tackling MNPL contamination is critical [micro/nanoplastiques, ndrl] to ensure food safety and protect public health”, insist the researchers.
Tea, herbal tea: should we stop drinking herbal teas?
If researchers cannot yet identify the health consequences of such ingestion of plastics, caution remains in order! But rest assured, there are many ways to enjoy these hot drinks while reducing your risk of exposure. At best, you should prefer loose tea and herbal tea, to be infused directly in a teapot, using an infuser mug or a stainless steel infuser. And for fans of tea bags, choose those made from natural cotton muslin or paper without glue or staples.
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