Drinking Coffee and Tea May be Associated with Decreased Rates of Stroke and Dementia

Written by: Anusha Srinivasan '24
Edited by: Elizabeth Zhang '23

​Most people are familiar with the negative connotation associated with drinking significant amounts of coffee, tea, and other caffeinated beverages. Although there are certainly risks which arise from overindulging in these beverages, recent studies show that these habits are actually correlated with decreased rates of stroke and dementia.

In a study which followed participants from the UK from the starting year of between 2006 and 2010 up to 2020, researchers found that coffee and tea intake may decrease the incidence of stroke and dementia. In fact, a coffee intake of 2 to 3 cups per day, a tea intake of 3 to 5 cups per day, or a combined intake of 4 to 6 cups of coffee or tea per day were associated with the lowest incidence of stroke and dementia in the participants this study tested. Drinking 2 to 3 cups of each coffee and tea in a day resulted in a 32% and 28% decrease in rates of stroke and dementia, respectively, compared to participants who did not drink coffee or tea [2].
This study was conducted in response to the ever-growing global concern for stroke and dementia, which incurs significant social and economic burden. Dementia, characterized by deterioration of mental capacity—and therefore, inevitably, the inability to live independently— affected approximately 50 million people globally in 2019. This number is expected to grow to nearly 152 million by 2050. Strokes are an equally formidable threat, accounting for 10% of all deaths globally. Not only are they associated with a significant mortality risk, but strokes cause dementia in nearly 30% of stroke survivors [2]. The significance of the effects of these conditions has made their risk factors a growing field of research.
Although this research does not prove causality, the findings of this study may be interesting to physicians and researchers studying possible prevention and treatment strategies for dementia and strokes.
The results of this study are particularly interesting because of prior research which seems to indicate largely adverse effects of excessive caffeine consumption. In another recent study, researchers linked caffeine intake with declining mental health in college students. While the study notes numerous positive effects of moderate caffeine consumption (including increased alertness, increased attention, and increased cognitive function), college students are likely to consume coffee and other caffeinated beverages in excessive amounts. In fact, college students report consuming an average of 800 mg of caffeine per day, nearly twice  the safe daily dosage [1].
Along with this level of caffeine consumption comes significant increases in symptoms of anxiety and depression. Particularly, participants who reported drinking the most coffee (or other caffeinated beverages) per day also reported changes to appetite, trouble sleeping, irritability, and feeling depressed or hopeless more days of the week than those who drank less or no coffee [1].
It should be noted, however, that this study finds the strongest correlation between anxiety and depression  at excessive levels of caffeine consumption. At moderate levels, it seems that coffee and tea have mostly positive effects.
So while many are often chastised for their dependence on a few cups of coffee per day, recent research suggests that people can enjoy their caffeine sources with a little less guilt, and the knowledge that their risk for stroke and dementia may be lower than their caffeine-abstinent counterparts.

Bertasi, Raphael A O, et al. “Caffeine Intake and Mental Health in College Students.” Cureus, 
Cureus, 5 Apr. 2021, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8099008/.
Zhang, Yuan, et al. “Consumption of Coffee and Tea and Risk of Developing Stroke, Dementia, and Poststroke Dementia: A Cohort Study in the UK Biobank.” PLOS Medicine, Public Library of Science, 16 Nov. 2021.
[Image Citation]: Ines Perkovic, Getty Images File: 1140-cup-coffee-too-much-caffeine-bad.imgcache.rev.web.1140.655. Retrieved 2021, from https://www.aarp.org/health/healthy-living/info-10-2013/coffee-for-health.html.