Drinking coffee or tea may be linked with a lower risk of stroke and dementia, new research suggests.

The study also indicates drinking coffee may be associated with a lower risk of post-stroke dementia.

Researchers studied 365,682 participants from the UK Biobank study, who were recruited between 2006 and 2010 and followed them until 2020.

At the start, participants self-reported how much coffee and tea they drank.

Our findings suggested that moderate consumption of coffee and tea separately or in combination were associated with lower risk of stroke and dementia

Over the study period, 5,079 participants developed dementia and 10,053 experienced at least one stroke.

Researchers found that people who drank two to three cups of coffee, or three to five cups of tea per day, or a combination of four to six cups of coffee and tea had the lowest incidence of stroke or dementia.

While those who drank two to three cups of coffee and two to three cups of tea daily had a 32% lower risk of stroke.

According to the study they also had a 28% lower risk of dementia compared with those who did not drink tea or coffee.

The research, by Yuan Zhang and colleagues from Tianjin Medical University, China, further suggests that intake of coffee alone or in combination with tea is associated with lower risk of post-stroke dementia.

However, the scientists highlight that the UK Biobank reflects a relatively healthy sample relative to the general population which could restrict the ability to generalise these associations.

Additionally, relatively few people developed dementia or stroke which can make it difficult to extrapolate rates accurately to larger populations.

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

Writing in the Plos Medicine journal, the authors said: “Our findings suggested that moderate consumption of coffee and tea separately or in combination were associated with lower risk of stroke and dementia.”

Dr Rosa Sancho, head of research at Alzheimer’s Research UK, said: “Participants only reported tea and coffee consumption at the beginning of the study, and there is no data on long-term habits, so it’s not clear how relevant the findings are to long-term brain health.

“While previous studies have looked at associations between tea and coffee consumption and better brain health, there has been inconsistency in findings.

“Future research with participants of a range of ages and ethnicities will be needed to fully understand what types of dementia and stroke are associated with tea and coffee drinking.

“Participants in this study reported themselves to be mainly White British (96%), therefore we cannot infer an association that is relevant to everyone in the UK.”