Drinking coffee and tea linked to reduced risk of dementia and stroke

Drinking two to three cups of coffee and tea a day has been linked to a reduced risk of dementia and stroke, according to a study that looked at the data of over 350,000 people.

The researchers looked at the relationship between dementia and stroke risk and the consumption of tea, coffee, as well as a combination of tea and coffee.

Yuan Zhang and colleagues from Tianjin Medical University, China, examined data from the UK Biobank, a database containing genetic and medical information from 500,000 people in the UK, who were followed up over a period of 10-14 years.

In total 365,682 participants, aged between 50 and 74, took part in the research.

Dr Rosa Sancho, head of research at Alzheimer’s Research UK, said: “For most of us, our risk of dementia depends on the complex interaction of our age, genetics and lifestyle. We know that stroke increases the risk of developing vascular dementia. Understanding which aspects of our lifestyle have the greatest effect on our brain health is key to empowering people to make informed decisions about their lives.”

The scientists found people who drank two to three cups of coffee with two to three cups of tea per day had around 30 per cent lower risk of stroke and dementia when compared to those who didn’t consume either. This association was found for people who just drank either tea or coffee, as well as those who drank both.

People who had the lowest risk of developing dementia or stroke either had two to three cups of coffee a day, three to five cups of tea a day or they had a combination of four to six cups of tea and coffee a day.

Researchers found drinking tea and coffee was linked to a lower risk of having an ischaemic stroke (caused by a blocked blood vessel) and vascular dementia, rather than a haemorrhagic stroke (caused by a burst blood vessel) or Alzheimer’s disease.

Dr Sancho added: “Studies like this one are not able to pinpoint cause and effect, and while the researchers attempted to control for other factors that could affect a person’s risk of stroke and vascular dementia, no firm conclusions can be made about whether tea or coffee cause this lower risk.

“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.”

Of the people in the study, 2.8 per cent had a stroke and 1.4 per cent developed Alzheimer’s disease or vascular dementia.

Previous studies have looked at the relationship between tea and coffee consumption and better brain health, but there has been inconsistency in the findings.

Dr Sancho would like to see future research with people of a range of ages and ethnicities 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 per cent), therefore we cannot infer an association that is relevant to everyone in the UK,” she said.

You can read about ‘Consumption of coffee and tea and risk of developing stroke, dementia, and poststroke dementia: A cohort study in the UK Biobank’ in PLOS Medicine.