Coffee and tea may help reduce rates of stroke and dementia

Drinking coffee or tea may be linked to a lower risk of stroke and dementia, research suggests. At least two cups of tea or coffee are needed to see an effect, said the study, published in the journal Plos Medicine on Tuesday.

The research project, carried out by researchers at Tianjin Medical University in China, included 365,682 participants from the UK Biobank study.

“Our findings suggested that moderate consumption of coffee and tea separately or in combination were associated with lower risk of stroke and dementia,” the study authors wrote.

People who drank 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 incidence of stroke or dementia, the researchers found.

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 research, led by Yuan Zhang, further suggests that the intake of coffee alone or in combination with tea is associated with a lower risk of post-stroke dementia. Researchers studied the 365,682 participants between 2006 and 2010 and followed them until 2020.

At the start, participants self-reported how much coffee and tea they drank. Over the study period, 5,079 participants developed dementia and 10,053 experienced at least one stroke. However, the scientists pointed out that the UK Biobank reflects a relatively healthy sample in relation to the general population, which could restrict the ability to generalise.

In addition, few people in the study developed dementia or stroke, which could make it difficult to extrapolate rates accurately for larger populations.

Finally, while it is possible that coffee and tea consumption may be protective against stroke, dementia and post-stroke dementia, researchers say causality cannot be concluded from the associations.