Green tea takes on poison

Dioxin, a carcinogenic by-product of many combustion processes, is ubiquitous throughout the environment, including in the food people eat. One way to protect against this contaminant could rely on natural plant compounds that short-circuit dioxin’s toxicity. A new study finds that green tea contains several such agents and suggests that other dietary staples might offer protection against dioxin.

Several antioxidants in green tea leaves have the potential to block dioxin’s effect on its docking point within cells. Chief among these is epigallocatechin gallate (EGCG). In the new study, Hitoshi Ashida of Kobe (Japan) University and his colleagues assess the potency of 20 different green tea compounds, including EGCG, in blocking dioxin.

The team in Japan found six compounds similar to EGCG strength in defusing dioxin—three slightly more potent and the others slightly less potent. None of these compounds has more than a minuscule concentration in tea; however, several of them are abundant in other foods.

Among the three stronger compounds, the antioxidant quercetin is plentiful in green apples. Kale and spinach are rich in the three slightly weaker alternatives to EGCG—chlorophyll-a, chlorophyll-b and lutein. For people who don’t like these leafy vegetables, Department of Agriculture scientists have been breeding high-lutein carrots and potatoes. The researchers report their results in the May 5 Journal of Agricultural and Food Science.

Janet Raloff is the Editor, Digital of Science News Explores, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer, specializing in toxicology. To her never-ending surprise, her daughter became a toxicologist.

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