If you are 50-70 years old, drinking a few cups of coffee or tea every day may reduce your risk of stroke and dementia, a new study found.
Coffee and tea may have a protective effect on your brain, according to a new study published this week in the journal PLOS Medicine. The study, led by Dr Yuan Zhang from Tianjin Medical University, in Tianjin, China, followed the health and tea/coffee drinking habits of 365,682 participants from the UK Biobank database.
Participants were recruited between 2006 and 2010 and followed until 2020 and self-reported their coffee and tea intake during this time period, while researchers followed their health. Throughout the study period 5,079 participants developed dementia and 10,053 experienced at least one stroke.
After analysing their data, researchers found that people who drank 2-3 cups of coffee or 3-5 cups of tea per day, or a combination of 4–6 cups of coffee and tea had the lowest incidence of stroke or dementia.
In the case of stroke, the study found that people who drank 2-3 cups of coffee and 2-3 cups of tea daily had a 32% lower risk of stroke compared with those who drank neither coffee nor tea.
According to the authors of the study, “Our findings suggested that moderate consumption of coffee and tea separately or in combination were associated with lower risk of stroke and dementia”.
However, the study comes with some caveats. First, the study only provides evidence of an observed correlation between coffee and tea consumption and the risk of stroke and dementia, not causation. In other words, the study does not provide evidence of how coffee can help reduce the risk of stroke or dementia.
Also, the study did not find an association beyond 4-6 cups of coffee or tea. According to Prof Kevin McConway, an emeritus professor of applied statistics at the Open University, who was not involved in this study, the associations reported did not hold at a higher level of beverage consumption. In other words, drinking more than 4-6 cups of tea of coffee per day would not grant you extra protection from a stroke.
“Instead, what generally happened is that the risk of stroke or dementia was lower in people who drank reasonably small amounts of coffee or tea compared to those who drank none at all, but that after a certain level of consumption, the risk started to increase again until it became higher than the risk to people who drank none,” Prof McConway said in a news report.
“Once the coffee consumption got up to seven or eight cups a day, the stroke risk was greater than for people who drank no coffee, and quite a lot higher than for those who drank two or three cups a day,” he added.