Tea and Strokes

Gallotannin, a substance found in green tea, is up to 100 times more powerful than comparable existing medicines in preventing brain damage after stroke. It is the overactivation of a normal DNA repair system (the PARP/PARG system), that causes cells to die after stroke. The PARP/PARG system is activated by the release of cell-damaging oxygen radicals (oxidative stress), and when cells become overexcited by various toxins. Gallotannin acts by blocking the PARP/PARG system and is 100 times more effective than antioxidants at neutralising oxidative stress. It is also effective at blocking brain cell death from chemicals that normally overexcite the cells. The researchers also found comparable results from Nobotanin B, derived from the Brazilian glory bush (Proceedings of the National Academy of Sciences 2001;98:12227).

Macular degeneration is the leading cause of blindness for the over-65's in the US. A large study by the Eye Disease Case-Control Study Group has found that a high intake of carotenoids (found most abundantly in yellow vegetables such as carrots and squash) lowers the risk of developing macular degeneration. In a separate study on 552 Dutch men, it has been found that the consumption of large quantities of black tea (more than 4.7 cups a day), and other foods containing flavonoids (fruit and vegetables), could help to reduce the risk of strokes. Previous studies have linked flavonoids to protection against heart attacks. Flavonoids are also found in red wine and green tea, both of which seem to offer protection against heart disease. Finally a new study suggests that a substance in watercress may lower the risk of lung cancer in smokers. The study - presented at a seminar held by the American Cancer Society - found evidence that the substance blocks a chemical pathway from tobacco smoke to lung cancer.