Northwestern University study shows brewing tea removes lead, toxic metals from water

Researchers at Northwestern University have discovered another benefit for tea drinkers. A recent study revealed that brewing tea actually removes harmful and toxic metals such as cadmium and lead from the water. They have found that the heavy metal ions stick to the tea leaves and are trapped on them upon brewing. This means that the tea is safer to drink than the water used to make it!

The study published in ACS Food Science and Technology showed that the tea leaves acted as an absorbing filter for those heavy metals in the brewed water, with varying success depending on the type of tea, tea bag, and steeping time. The scientists found that the most effective combination of removing toxic metals through brewing would be to brew finely powdered black tea through a paper tea bag with a long steeping time.

The types of tea, tea bags, and seeping time impact how much metal can be removed from water.Photo credit: Canva

These toxic metals can appear within drinking water throughout the world, but primarily in developing nations where heavy industrial waste runoff contaminates nearby streams, rivers, and other bodies of water. It’s also not uncommon for lead and cadmium among other heavy metals to travel through traffic pollution, land on soil, and that soil runoff into drinking water sources. This can include private wells and water pumps. Exposure to these metals has been associated with health problems such as cardiovascular disease, cancer, hypertension, kidney disease, and many other issues. This is why water filtration is consistently advocated as a global initiative.

“We’re not suggesting that everyone starts using tea leaves as a water filter,” said Dr. Vinayak P. Dravid, the study’s senior author. “For this study, our goal was to measure tea’s ability to absorb heavy metals. By quantifying this effect, our work highlights the unrecognized potential for tea consumption to passively contribute to reduced heavy metal exposure in populations worldwide.”

Water filtration is still a need throughout the world.Photo credit: Canva

Dr. Dravid makes a valid point. According to Statisa, tea is the second most consumed beverage on the planet, just falling behind water. Its popularity as a drink is further cemented by having 6.7 million tonnes produced worldwide in 2022 alone and a projected market size of $134 billion by the end of 2025. While it’s not a replacement for water filtration, tea drinking would definitely limit additional exposure and consumption of harmful metals.

By those numbers, one can see that tea drinking is a worldwide human trait without borders and is steeped in history among numerous nations. While China is the largest producer of tea, England remains one of the largest consumers of it, with afternoon tea being a countrywide tradition. A traditional Japanese tea ceremony dates all the way back to the 9th century, with its roots in both Buddhist and Shinto religions.

Tea drinking is a staple in many different cultures throughout the world.Photo credit: Canva

Tea is also a staple in the United States. Per the Census, 159 million Americans are drinking tea on any given day. It is a part of American history as one of the first strikes towards independence from British colonial rule came in the form of the Boston Tea Party in 1773.

While it is not as effective as genuine water filtration as Dr. Dravid stated, it is still good to know that the most common beverage on the planet is one that can lessen exposure to harmful metals throughout the world, too.