Green Tea Chemical Best for New Plaques

An antioxidant found in green tea called epigallocatechin gallate (EGCG) has been shown to block blood vessel plaques, but now, findings from an animal study indicate that EGCG only works against developing plaques not against ones that have been around for a while.

An antioxidant found in green tea called epigallocatechin gallate (EGCG) has been shown to block blood vessel plaques, but now, findings from an animal study indicate that EGCG only works against developing plaques not against ones that have been around for a while. These results may help explain why antioxidants haven’t proven very effective in studies of patients with established plaques. “Most animal experiments evaluating the effects of antioxidants are started when the animals are young, while (human) trials typically enroll adult patients with varying stages of plaques,” lead author Dr. Kuang-Yuh Chyu, from Cedars-Sinai Medical Center in Los Angeles, said in a statement. “This discrepancy supports speculation that antioxidant treatment affects early but not later stages of plaque development.” In the new study, Chyu’s team evaluated the effects of EGCG in mice with high cholesterol levels. New and old plaques were assessed after 21 and 42 days of treatment. The researchers’ findings are published in Circulation: Journal of the American Heart Association. Compared with animals treated with an inactive solution, EGCG-treated mice showed a reduction in the size of developing plaques, but not established ones. Our findings “reinforce the theory that intervention (with antioxidants) is effective in early but not late stages of (plaque) development,” Chyu noted. (Source: Circulation: Reuters Health News: May 2004.)