New research casts doubt on on previous assumptions about how ingredients in green tea work to promote health. Green tea has long been known to have health benefits. In particular, it contains catechins called ECG and EGCG that are said to prolong life. These two substances belong to the group of polyphenols. They are considered antioxidants, which means they counteract or prevent oxidative stress in the body caused by aggressive free radicals of oxygen. Until now, researchers have assumed that the catechins neutralize these free radicals and thus prevent damage to cells or DNA. One source of oxygen free radicals is metabolism; for example, when the mitochondria—the powerhouses of the cell—are working to produce energy. In the new study in the journal Aging, the researchers show that these polyphenols from green tea initially increase oxidative stress in the short term, but that this has the subsequent effect of increasing the defensive capabilities of …