Habitual coffee, tea consumption may lower risk for dementia, stroke

Drinking multiple cups of coffee or tea a day, or a combination of the two, was associated with a decreased risk for dementia and stroke, according to findings published in PLOS Medicine.

Coffee is “a rich source of antioxidants and other bioactive compounds,” Yuan Zhang, of the school of public health at Tianjin Medical University in China, and colleagues wrote. Tea that contains caffeine, catechin polyphenols and flavonoids has been linked to forms of neuroprotection, “such as antioxidative stress, anti-inflammation, inhibition of amyloid-beta aggregation, and an antiapoptotic effect,” they added.

“Coffee and tea are among the most widely consumed beverages, both in the U.K. and worldwide,” Zhang and colleagues wrote. “Coffee consumption is closely related to tea consumption.”

In a prospective cohort study based in the U.K., Zhang and colleagues compared data on 365,682 participants aged 50 to 74 years from the U.K. Biobank, who gave information about their intake of coffee of any type, including decaffeinated, instant coffee, espresso and filtered, and their intake of tea, including black or green tea. The mean age of participants was 60.4 years, and 45.7% were men.

The researchers enrolled participants from 2006 to 2010 and followed them until 2020 to investigate the association between coffee and tea intake and incidence of stroke and dementia. Clinical outcomes were confirmed using the Hospital Episode Statistics for England, the Scottish Morbidity Record data for Scotland and the Patient Episode Database for Wales.

Coffee and tea consumption trends

Among the participants, 20.8% did not drink coffee and 13.7% did not drink tea. The largest proportion of the cohort (16.29%) drank 0.5 to 1 cup of coffee and 4 cups or more of tea per day. Also, 13.68% of the cohort did not drink coffee but consumed 4 cups or more of tea per day and 12.27% drank 2 to 3 cups of coffee and 2 to 3 cups of tea per day.

Dementia and stroke risk benefits

Overall, 5,079 participants developed dementia and 10,053 participants had a stroke during a median follow-up of 11.4 years. The researchers found that an intake of 2 to 3 cups of coffee, 3 to 5 cups of tea, or a combination of 4 to 6 cups per day were linked to a lower risk for stroke and dementia. Specifically, 2 to 3 cups of coffee and 2 to 3 cups of tea per day were associated with a 32% lower risk for stroke (HR = 0.68; 95% CI, 0.59-0.79) and a 28% lower risk for dementia (HR = 0.72; 95% CI, 0.59-0.89) compared with participants who did not drink either beverage. Also, a combination intake of coffee and tea was associated with a lower risk for ischemic stroke, vascular dementia and poststroke dementia, according to Zhang and colleagues. A combination intake of 3 to 6 cups per day yielded the lowest risk for incident poststroke dementia (HR = 0.52; 95% CI, 0.32-0.83).

“From a public health perspective, because regular tea and coffee drinkers comprise such a large proportion of the population and because these beverages tend to be consumed habitually throughout adult life, even small potential health benefits or risks associated with tea and coffee intake may have important public health implications,” Zhang and colleagues wrote.