Experts warn of hidden health risks in cups of tea

Tea is a cornerstone of British life, poured at breakfast, mid-morning, and often in the evening. It’s long been celebrated for its calming effects, digestive benefits, and ability to boost focus. But new research suggests that your daily cuppa may carry hidden health risks that many drinkers are unaware of.

A study by the University of Birmingham, published in Science of the Total Environment, tested over 150 popular hot and cold drinks and found that hot tea contained the highest levels of microplastics.

Professor Mohamed Abdallah, who led the research, explained that tea can contain up to 60 microplastic particles per litre—roughly 12 to 15 per cup.

By contrast, energy drinks contained an average of 25 MPs/L and soft drinks 17 MPs/L, suggesting that higher temperatures increase plastic particle release. Takeaway cups, often lined with plastic, further raise exposure, averaging 22 microplastic particles per cup compared with 14 in a glass mug, the Telegraph reported.

“Microplastics are tiny fragments created either from the breakdown of larger plastics or produced intentionally for certain products,” Prof Abdallah said.

“They are now found in water, food, air, and even human tissue.” While the full implications for human health remain under study, lab and animal research have linked microplastics to inflammation, hormonal disruption, and disturbances in the gut microbiome.

Tea bags themselves are a significant source. Since their invention in 1908, they have evolved from silk pouches to paper, nylon, and bioplastics. While convenient, these materials can shed microplastics when immersed in hot water.

To reduce risk, experts recommend loose-leaf tea or plastic-free paper bags and avoiding takeaway cups with plastic linings.

Another consideration is tannins, compounds that give tea its characteristic bitterness. Tannins can bind to non-heme iron found in plant-based foods, limiting absorption.

This is most relevant for vegetarians, vegans, and pregnant women. Strategies to reduce this effect include drinking tea between meals, pairing iron-rich foods with vitamin C, or limiting intake to three cups per day.

Despite these potential risks, tea remains a safe and enjoyable drink for most people when consumed thoughtfully.

Simple measures, such as choosing loose-leaf tea, avoiding plastic-lined cups, timing consumption, and moderating intake, can help Brits enjoy their beloved brew while minimising potential health risks.