Tea, known for its multiple health benefits, adds a new attribute to its list: the ability to act as a natural filter to remove heavy metals from water, such as lead.
A recent study has revealed that tea leaves can significantly contribute to purifying drinking water, adding a positive environmental impact to its global popularity.
US researchers analyzed different varieties of tea, such as green, black, oolong, white, chamomile, and rooibos, exposing them to water contaminated with metals like lead, chromium, copper, zinc, and cadmium. By infusing them at 85 °C, they observed the leaves’ capacity to absorb these metals.
According to data published in the journal ACS Food Science & Technology, a cup of tea could eliminate approximately 15% of the lead content in drinking water, reducing health risks such as brain and kidney damage caused by high lead exposure.
The secret lies in the properties of the leaves
Benjamin Shindel, a doctoral student at Northwestern University and lead author of the study, highlighted that tea leaves have a vast active surface, ideal for absorbing metals while releasing aromatic compounds into the water. This process is efficient and practical, as it does not require additional steps. “With tea, simply infusing the leaves is enough to naturally remove metals,” Shindel assures.
The study also revealed that grinding the leaves enhances their effectiveness by increasing the contact surface, with black tea being slightly more effective than other varieties. Furthermore, extending the infusion time, even overnight as in the case of iced tea, maximizes the removal of heavy metals.
Tea bags and their impact on the process
Tea bags also influence the purification process. According to the researchers, bags made of cellulose, derived from wood pulp, are the most effective at trapping metal ions.
However, materials like nylon or cotton showed minimal effectiveness, in addition to presenting environmental issues such as the release of microplastics.
A new reason to drink tea daily
Besides its traditional benefits, such as improving cardiovascular health and offering protective effects against neurodegenerative diseases, tea could become a key tool in reducing population-level exposure to heavy metals.
“If more people incorporate an additional cup of tea into their daily routine, we could see a decrease in diseases associated with exposure to these contaminants,” Shindel concludes.
*With information from Euronews
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