Drinking tea or coffee may be linked to a lower risk of stroke and dementia, a large study has found.
The new research, published in the Public Library of Science (PLOS) journal, followed 365,000 people aged between 50 and 74 for more than 10 years.
At the start the participants, who were involved in the UK Biobank study, self-reported how much coffee and tea they drank. Over the research period, 5,079 of them developed dementia and 10,053 went on to have at least one stroke.
Scientists found that people who had two to three cups of coffee or three to five cups of tea a day, or a combination of four to six cups of coffee and tea, had the lowest risk of stroke or dementia.
Those who drank two to three cups of coffee and two to three cups of tea daily had a 32 per cent lower risk of stroke and a 28 per cent lower risk of dementia compared with those who did not drink tea or coffee.
The study, conducted by the Tianjin Medical University, China, showed that drinking coffee alone or in combination with tea may also be linked to lower risk of post-stroke dementia.
“Our findings suggested that moderate consumption of coffee and tea separately or in combination were associated with lower risk of stroke and dementia,” the authors wrote.
“The main limitations were that coffee and tea intake was self-reported at baseline and may not reflect long-term consumption patterns, unmeasured confounders in observational studies may result in biased effect estimates, and UK Biobank participants are not representative of the whole UK population.”
In the UK stroke remains the largest cause of disability and the fourth biggest killer, causing around 38,000 deaths each year.
Coffee contains over 1,000 different chemical compounds some of which may reduce the risk of stroke. It has been shown to lower blood pressure, protect cells from damage due to free radicals, lower LDL cholesterol and improve blood flow.
A separate study, published in the American Heart Association journal Stroke, found that Japanese stroke survivors who drank at least seven cups of green tea daily had a lower risk of death from any cause by 62 per cent compared to non-tea drinkers.
