TAINAN, Taiwan--Consumption of 120 ml/day or more of green or oolong tea for one year may protect against hypertension, according to a study published in the July 26 issue of the Archives of Internal Medicine (164, 14:1534-1540, 2004) (http://archinte.ama-assn.org).
Researchers examined the influence of long-term tea consumption on the risk of developing hypertension in 1,507 subjects (711 men and 796 women), 20 years or older, who had no history of hypertension. Six hundred (39.8 percent) of the subjects were habitual tea drinkers, defined by tea consumption of 120 ml/day or more for at least one year. Compared with non-habitual tea drinkers, the risk of developing hypertension decreased by 46 percent for those who drank 120 ml/day to 599 ml/day, and by 65 percent for those who drank 600 ml/day or more. Results were adjusted for age; sex; socioeconomic status; family history of hypertension; body mass index; waist-hip ratio; lifestyle factors including total physical activity, sodium intake, cigarette smoking, alcohol consumption and coffee drinking; and dietary factors including vegetable, fruit, unrefined grain, fish, milk, visible-fat food and deep-fried food intake. However, tea consumption for more than one year was not associated with additional reduction of hypertension risk.
The researchers concluded consumption of moderate-strength green or oolong tea at 120 ml/day or more for one year significantly reduces the risk of developing hypertension.