Brewing tea helps remove heavy metals like lead and cadmium by naturally filtering them out of the water, according to the latest research.
During a study conducted by Northwestern University researchers in the United States, a variety of teas, including black, green, oolong, white, chamomile and rooibos, were tested to examine the effects of different tea types, brewing methods and tea formats on heavy metal absorption, according to a statement issued by the ACS Food Science & Technology journal a day before its publication on Tuesday.
The researchers created water solutions with known amounts of metals like lead, chromium, copper, zinc and cadmium, then heated them near boiling. They added tea leaves and let them steep for different lengths of time. After steeping, they measured the remaining metals in the water to calculate how much was removed.
The researchers estimated that brewing a typical cup of tea can remove about 15% of lead from water, with longer steeping resulting in more metal removal.
While the results vary based on factors like steeping time, tea bag type and the water-to-tea ratio, brewing tea can remove a noteworthy amount of lead from water, with potential public health benefits, according to the study.
"You could crush up all kinds of materials to get a similar metal-remediating effect, but that wouldn't necessarily be practical. With tea, people don't need to do anything extra. Just put the leaves in your water and steep them, and they naturally remove metals," said Benjamin Shindel, the study's author.
He also noted that while nylon tea bags release microplastics, most tea bags today are made from natural materials like cellulose, which may release harmless fiber particles.
"Across a population, if people drink an extra cup of tea per day, maybe over time, we'd see declines in illnesses that are closely correlated with exposure to heavy metals," Shindel added.
