Brewing tea reduces heavy metals in drinking water, study reveals

In a recent study conducted by researchers at Northwestern University in the United States, scientists discovered that preparing tea could play a role in filtering out harmful heavy metals from drinking water. The research indicates that the brewing process can significantly reduce the presence of toxic metals, such as lead and cadmium, which are known contaminants in some water supplies. This discovery adds a new dimension to the health benefits associated with tea consumption, which has been linked to various positive health outcomes in populations with high tea intake. The study assessed several types of tea, including black, green, oolong, white, chamomile, and rooibos, to determine their effectiveness in reducing metal content. It was found that tea leaves naturally adsorb heavy metals on their surfaces during the brewing process. Specifically, the researchers estimated that brewing a typical cup of tea, for about three to five minutes, could reduce lead content by approximately 15%. A longer brewing time may further enhance this effect, indicating that preparation methods can influence the level of contamination reduction. Researchers noted that finely ground leaves, especially from black tea, were more effective at removing metal ions when compared to whole leaves. This is attributed to the larger surface area that ground tea leaves present. The study also investigated different types of tea bags, revealing that cellulose tea bags absorbed significantly more contaminants than cotton or nylon bags. These findings highlight the importance of both the type of tea and the materials used in brewing. Benjamin Shindel, the first author of the study, remarked on the potential broader implications of this research, suggesting that increased tea consumption within populations might lead to a reduction in health issues associated with heavy metal exposure, such as heart disease and stroke. Vinayak P. Dravid, the senior author of the study, stated that the goal was to quantify tea's ability to adsorb heavy metals, emphasizing its potential as a passive contributor to reduced exposure to these dangerous contaminants. The study's results were published in the journal ACS Food Science & Technology, providing a foundation for further exploration into the health benefits of tea and its role in mitigating toxic metal exposure.