Tea is the world’s second most consumed beverage, behind only water in terms of consumption. While making tea with boiled tap water, residual chlorine in the water may react with the tea components to produce disinfection byproducts, which are harmful to the body (DBPs). Researchers publishing in Environmental Science & Technology tested 60 dibenzopyrenes (DBPs) in three kinds of tea and discovered that the levels in brewed tea were lower than those in tap water, which was surprising. However, they discovered a large number of DBPs that were previously unknown and whose health consequences were unclear.
Although disinfection is necessary to guarantee the safety of drinking water, it has a negative side effect: the development of DBP. It is estimated that tea contains about 500 components, including polyphenols and amino acids, as well as caffeine and other chemicals, which may react with chlorine to produce DBPs, some of which have been related to cancer and poor birth outcomes in epidemiological studies. In addition, DBPs may develop as a result of chemical interactions with chemicals found in tap water. Susan Richardson and colleagues intended to perform a thorough study in order to assess 60 known DBPs in three green and black teas that were popular in the United States at the time.
The researchers brewed the teas and then used gas chromatography-mass spectrometry to analyze the chemicals present in them. The levels of the 60 DBPs were greater in tap water than in the brewed teas, which is likely due to the fact that many of the compounds evaporated or were absorbed by tea leaves during the brewing process. However, just 4 percent of the total organic halogen (a measure of all halogen-containing DBPs) in tea was accounted for by the 60 known DBPs, suggesting that the vast majority of these compounds in tea are unknown. Tea has been linked to 15 of these chemicals, which are thought to develop when chlorine reacts with natural phenolic and polyphenolic precursors in the leaves. This is the first time any of these compounds have been discovered in a beverage. Although no “safe” levels have yet been established for the majority of DBPs, the researchers estimate that an average person would need to consume 18-55 cups of tea per day in order to exceed the limits set by the United States Environmental Protection Agency for those that are regulated, according to the study.
The National Science Foundation, the University of South Carolina, and the Chinese Scholarship Council provided support for the research conducted by the authors.