According to the largest study of its kind, drinking coffee or tea may reduce the risk of stroke and dementia.

Researchers from Tianjin Medical University in Tianjin, China have found that those who drank two to three cups of coffee, three to five cups of tea, or a combination of four to six cups of coffee or tea a day had the lowest risk of stroke and dementia among over 360,000 participants studied over a period of 10 to 14 years.

Strokes account for 10% of all deaths worldwide, while dementia is one of the world's most serious health problems, with 130 million people predicted to be affected by 2050.

Drinking coffee or tea alone was linked to a lower risk of both conditions, but those who drank two to three cups of coffee and two to three cups of tea daily (a total of four to six cups) fared the best, with a 28% lower risk of dementia and a 3% lower risk of stroke than those who didn't.

The information for the participants came from the U.K. Biobank, a database of anonymized health data collected from roughly half a million volunteers in the United Kingdom between 2006 and 2020. Participants in the study ranged in age from 50 to 74 and self-reported their coffee and tea use.

The study elaborates that 5,079 people developed dementia and 10,053 had at least one stroke over the course of the study, which was published in PLOS Medicine.

While tea has long been regarded as a healthy beverage, coffee has elicited more debate. However, it has recently been clear that coffee isn't the devil's drink and that it may even be beneficial. Recent studies link frequent coffee consumption to a lower risk of cardiovascular disease, some malignancies, and overall early death.

Other studies have suggested that coffee and tea can improve the general function of our blood vessels, which could explain why these beverages appear to reduce the incidence of ischemic strokes rather than hemorrhagic strokes. Ischemic strokes are caused by blood clots obstructing blood flow to the brain, whereas hemorrhagic strokes are caused by arteries breaking and bleeding into the brain.

"Our findings support an association between moderate coffee and tea consumption and risk of stroke and dementia," the study authors wrote. "However, whether the provision of such information can improve stroke and dementia outcomes remains to be determined."