Some cultures serve a cup of tea with every meal. Recently, researchers at Northwestern University discovered that tea can filter out some of the heavy metals. As well as being tasty, a cup of tea now seems to have another small health benefit.

The picture shows an SEM image of a tea leaf. While researching heavy metal filtration, the Northwestern team looked at different components of tea making. They compared different types of tea, bags, temperatures and brewing times to see which method was best at absorbing heavy metals.   

The cup of tea that contained the least amount of heavy metals was tea that had been steeped for 24 hours at room temperature. The long steeping time appeared to be the most effective in absorbing lead and cadmium from the water: the tea leaves were able to remove up to 15% of the lead. When it comes to tea bags, the cellulose-based ones are the most effective at absorbing heavy metals, regardless of the type of tea in the bag. An additional benefit is that these bags do not leave microplastics behind, whereas a nylon bag might.   

In some countries, these findings may explain why there are fewer health problems associated with heavy metal intake. 

1_3_300x

Beeld: Vinayak P. David Group/Northwestern University

SEM image of a black tea leaf, 300x magnified. The wrinkled surface of fully oxidised black tea leaves increases the surface area available for adsorption of metals.

Onderwerpen