STUDY: Tea Reduces Stroke Risk

Drinking green or oolong tea consistently is linked to a significantly lower risk of Ischaemic stroke due to reduced blood flow to the brain.

Ischaemic stroke occurs when oxygen-delivering arteries in the brain become partially or completely blocked reducing the blood flow to the brain. Previous research has suggested that tea or its components might reduce high blood pressure and other risk factors.

To ascertain the relationship between drinking tea and risk of ischaemic stroke, researchers studied the tea drinking habits of 838 Chinese men and women, aged around 70 years. Information on frequency and duration of tea drinking, quantity of dried tea leaves, and types of tea consumed, together with habitual diet and lifestyle characteristics, was obtained from participants using a questionnaire.

A slice of brain from the autopsy of a person who suffered an acute middle cerebral artery (MCA) stroke (Wikipedia)

Of all, 374 participants had a medically confirmed ischaemic stroke, and 464 (the "control" group) had no history of cardiovascular disease or medical conditions that raised their risk of stroke. The stroke group had a higher occurrence of elevated blood pressure, diabetes and smoking. The control group reported higher fruit and vegetable intake and a longer duration of tea drinking.

The researchers also took into account gender, body mass, level of education, lifelong physical activity, smoking, alcohol intake, the presence of high blood pressure, cholesterol level, diabetes, and diet.

Those who reported drinking at least one cup of tea per week for more than 30 years had a 60 percent lower risk of ischaemic stroke. Those who drank more than 2 cups of tea daily had about a 40 percent lower risk of such strokes. The risks were even lower in those who drank green or oolong tea, a traditional Chinese tea. Those who drank green or oolong tea had 72 and 79 percent lower risk for ischaemic stroke, respectively. Using more tea leaves was associated with a 73 percent reduced risk of stroke.

The above findings are consistent with previous research from Japan that drinking tea cuts stroke risk. However, further investigations are needed to ascertain whether tea consumption can enhance survival of stroke patients.