Drinking tea is often praised for its health advantages, such as reducing the risk of heart disease and mitigating inflammation. However, a recent study from researchers at Northwestern University has unveiled another surprising benefit: the tea brewing process might actually help purify water.
According to research published in ACS Food Science & Technology, brewing tea can naturally absorb heavy metals, including lead and cadmium. The term “adsorb” describes how a solid can hold molecules in a thin film on its surface or within its inner structures.
Dr. Vinayak Dravid, the senior author of the study and a professor of Materials Science and Engineering at Northwestern University, noted in an email, “This is one of very few systematic studies that apply rational control, meaningful statistics, and a sophisticated approach typically reserved for nanotechnology to the seemingly simple process of tea brewing. There’s so little focus on its ability to capture contaminants, rather than just the act of releasing them.”
Interestingly, the study indicated that black tea leaves may be the most effective in removing metal contaminants from water. The researchers evaluated how the adsorption of heavy metals varied across different types of tea—black, green, oolong, white, chamomile, and rooibos—while also considering brewing methods and whether the tea was looseleaf or in different types of bags, like cotton, nylon, or biodegradable cellulose made from wood pulp.
