Coffee and tea could lower stroke risks by 32%, Chinese study reveals

17 Nov 2021 --- A study using 365,682 participants from the UK Biobank has found that moderate consumption of coffee and tea separately or in combination were associated with lower risk of stroke and dementia.

The research carried out by Tianjin Medical University, China, revealed that individuals who drank two to three cups of coffee and two to three cups of tea daily had a 32% lower risk of stroke. There was also a 28% lower risk of dementia compared with those who drank neither coffee or tea.

Tentative link between coffee and post-stroke dementia
Strokes cause 10% of deaths across the globe, the research published in Plos Medicine highlights.

As part of the study, a distinction was made between dementia – a general term for symptoms related to declining brain function – with post-stroke dementia, where symptoms of dementia occur after a stroke. 

The findings highlighted that people who drank two to three cups of coffee or three to five cups of tea per day had the lowest incidence of stroke or dementia. The same applied to those who consumed a combination of four to six cups of coffee and tea. 

Drinking coffee alone or combined with tea was also associated with a lower risk of post-stroke dementia. 

Experts suggest milk could also be a factor in reducing strokes.Caution advised
The researchers note that although the findings may be possible in protecting against stroke, dementia and post-stroke dementia, causality cannot be inferred from the associations. 

Providing an opinion on the study, professor Tara Spires-Jones, UK dementia research institute program lead and deputy director at the University of Edinburgh, notes more research needs to be done.

“It is not possible to know from this kind of data whether the tea and coffee drinking are the cause of reduced risk of stroke or dementia. There could be other factors in people that drink tea and coffee that are the real influencers of disease risk,” she underscores.

Additionally, professor of epidemiology and digital health at the University of Exeter, David Llewellyn, highlights that too much coffee or tea, could in fact, increase the risk for stroke. 

“A more balanced conclusion may be that drinking tea and coffee in moderation is associated with a lower risk of stroke and dementia. In theory, people who don’t drink tea or coffee at all may benefit from starting to drink in moderation, and heavy consumers of tea and coffee may benefit from drinking less,” he says. 

Beyond coffee and tea
One limitation flagged is that the results do not consider milk consumption as a confounding factor, according to Dr. Charlotte Mills, lecturer in nutritional sciences at the University of Reading.

“Typically in the UK, most people drink tea and coffee with added milk, and there is some evidence that milk consumption might also reduce the risk of stroke.”

Both tea and coffee contain large quantities of natural bioactive chemicals, particularly polyphenols, which can also be found in blueberries and cocoa, she notes. 

“These have previously been shown to provide many health benefits, including cutting the risk of neurodegenerative diseases. It is possible that these polyphenols in the tea or coffee may be the cause of the benefits observed in this research,” adds Mills.

In this realm, polyphenols have been spotlighted for their cognition benefits, along with MCT oil as individuals seek out focus, concentration, clarity and healthy minds.Strokes cause 10% of deaths around the world.

Research still ongoing
The participants were recruited between 2006 and 2010 and self-reported their coffee and tea intake from the beginning of the study. They were followed until 2020. 

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

Research on the effects of coffee is still ongoing, with a UK study recently highlighting the popular beverage can both aid and harm health.  

As scientists try and study how strokes can be prevented, US research suggests gut microbiome interventions and plant-based diets could help reduce the incidence and severity of strokes. 

Edited by Andria Kades