Regularly drinking tea and coffee associated with a lower risk of stroke and dementia
16 November 2021
Researchers from China and the US found that people who drank two to three cups of tea and coffee a day had a lower risk of stroke and vascular dementia. Findings are published today (Tuesday 16 November) in the journal PLOS Medicine.
What did the scientists do?
This research involved volunteers from an existing large study, the UK Biobank, 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.
Participants self-reported their tea and coffee drinking habits at the beginning of the study. Researchers then recorded the numbers of people who went on to have a stroke (2.8%) or develop Alzheimer’s disease or vascular dementia (1.4%).
What did the scientists find?
People who drank two to three cups of coffee with two to three cups of tea per day had around 30% 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.
- Had three to five cups of tea a day.
- Had a combination of four to six cups of tea and coffee a day.
Researchers in this study found that 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.
Our expert comment:
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.
“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.
“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.”
You can read the full article ‘Consumption of coffee and tea and risk of developing stroke, dementia, and poststroke dementia: A cohort study in the UK Biobank’ in PLOS Medicine.