Researchers studying dietary patterns report a possible link between tea consumption and high levels of forever chemicals known as PFAS, likely leeched from tea bags and bottles.
Researchers found high levels of pre- and polyfluoroalkyl (PFAS) contamination in participants who consumed processed meats, pork, hot dogs, and out-of-home foods.
The longitudinal study did not report causal links. Previous studies indicate most (97%) of PFAS in Americans accumulate through the water supply. The study was financed by the US National Institutes of Health (NIH) and was led by chemists at the Keck School of Medicine at the University of Southern California (USC). The results were published in the journal Environment International.
Dr. Jesse A. Goodrich is a population and public health sciences professor at the Keck School of Medicine and the study's senior author. He said the study is the first to examine how dietary factors are associated with changes in PFAS over time. "Looking at multiple time points gives us an idea of how changing people's diets might actually impact PFAS levels,” he said.
In response, the Tea & Herbal Association of Canada (THAC) posted a position statement on PFAS in Young Adults. “It is important to note that the study did not test any of the food and beverages consumed by the participants. Nor is there any indication of what format the food was consumed in. There is, therefore, no basis to draw an indisputable link between the consumption of the foods and beverages named and an increase in PFAS.
"Statements made by the study are inconclusive," writes THAC. The authors are unable to determine what the source of PFAS could be."
The study points to all possibilities, including the water used for the tea, the tea itself, and the packaging material. More research is needed to determine the source of PFAS, writes THAC.
Participants aged 17-22 answered questions about diet, including how frequently they consumed various foods and beverages. The nationally representative sample of 725 young multi-ethnic adults then gave blood samples tested for PFAS.
The concentrations of PFAS were highest in those who ate out frequently and those who drank tea and consumed processed foods. Eating food at home demonstrated the opposite. Every 200-gram increase in home-prepared food showed lower levels of PFOS (perfluorooctanesulfonic acid).
Those who reported higher tea consumption during the first visit had higher levels of PFSAs on the follow-up visit. A single additional serving of tea was linked to 24.8% higher levels of perfluoro- hexanesulphonic acid (PFHxS), 16.2% higher perfluoroheptanesulfonic acid (PFHpS), and 12.6% higher perfluorononanoic acid (PFNA).
Totals also rose among those who consumed processed meats.
Researchers expressed concern that even metabolically healthy foods such as tea can be contaminated with PFAS, which is known to harm human health.
Hailey Hampson, a PhD candidate at the University of Southern California, told Technology Networks, “Our primary hypothesis is based on a study published last year, which found that some tea bags contain PFAS. This study, conducted in India, tested 108 tea bag samples collected from the Indian market and found that 90% contained detectable PFAS concentrations.”
The research team is now testing popular tea brands in a follow-up study.
Hampson said, “We need more research on commercially available tea bags in the USA to determine the degree to which PFAS contamination in tea bags is an issue in the USA. Based on our findings and the findings from other researchers, we are currently performing a study to test for PFAS contamination in tea bags from the US market.”
A research paper published in 2019 calculated a single tea bag, when brewed in boiling water, releases up to 11.6 billion microplastics and 3.1 billion nanoplastics in a single cup. The plastics implicated were nylon and PET particles found at levels in tea “several magnitudes higher” than plastics in other foods. A 2021 study suggests that microwaving tea bags further amplifies the release of nanoparticles. Many brands have since switched to paper teabags.
Seafood, fruit, and vegetables, even the air you breathe, have been shown to contain microparticles of toxic polymers known to irritate lungs and cause headaches, asthma, and possibly cancers.