A study published in the Annals of Internal Medicine suggested that when compared with those who do not drink tea, people who consumed two or more cups each day had between a 9% and 13% lower risk of mortality. 

The findings suggested the outcome was the same regardless of whether the tea had milk or sugar added, what their preferred temperature was or if genetic variants affected the rate at which individuals metabolize caffeine. From data used from the UK Biobank, researchers from the National Institutes of Health reported that 85% of the half a million men and women, aged 40 to 69, reported that they regularly drank tea and of those, 89% said they drank the black variety of tea. The study was carried out with a questionnaire answered from 2006 to 2010 and revised after over more than a decade.

Fernando Rodriguez Artalejo, professor of preventive medicine and public health at the Autonomous University of Madrid, characterized the research as illustrating “a substantial advance in the field”, adding that most studies had been done in Asia, where green tea is the most commonly consumed, and that the few conducted outside the region were “small in size and inconclusive in their results”.

He further commented: “This article shows that regular consumption of black tea (the most widely consumed tea in Europe) is associated with a modest reduction in total and, especially, cardiovascular disease mortality over 10 years in a middle-aged, mostly white, adult general population.”

Artalejo reiterated that the study did not definitively conclude that tea was the cause of the lower mortality of tea drinkers because it could not exclude that this was also dependent on other health factors associated with tea consumption.

According to The Guardian in November, drinking coffee or tea may be related to a lower risk of stroke and dementia, in the largest study of its kind.

Researchers at Tianjin Medical University in China found that people who consumed two to three cups of coffee or three or five of tea a day, or a combination of four to six cups of both beverages, had the lowest risk of either stroke or dementia. However, those who drank two to three cups of coffee and two to three cups of tea daily had a 32% lower risk of stroke.