For centuries, tea has been used for far more than quenching thirst. Around the world people drink it to relax, reinvigorate and soothe, and it’s something we need now more than ever.
In the UK, where tea drinkers imbibe 100 million cups every day, according to the UK’s Tea Advisory Panel, the beverage remains part of the national psyche — despite a growing preference for lattes, espressos and flat whites. The sentiment that a restorative cup of tea makes everything better still holds true. With tea consumption growing around the world, the United Nations has designated May 21 “International Tea Day.” Even in the United States, long a coffee-dominated country, tea drinking is growing in popularity, with the country consuming 0.4 kilograms (14 ounces) of tea leaves per person a year compared with 0.36 kilograms (12.7 ounces) in 2007 according to the United Nations, as people switch away from soda, milk and fruit drinks.
Scientists are beginning to look into just how tea might affect mood and cognition. Specifically, they’re investigating whether it’s relaxing and alerting effects are a direct biological outcome of the compounds in tea or whether they come from the context in which the drink is consumed — preparing your brew, choosing your favorite cup and sitting down for a brief respite from the world. Or both. Green, oolong and black tea come from the same plant — Camellia sinensis. Green tea, however, is processed in a different way, which results in higher levels of some of the compounds that scientists believe have positive effects on our mental health.
Drinking green tea has been found to improve brain function in healthy people, said Stefan Borgwardt, chair and director of the department of psychiatry and psychotherapy at the University of Lübeck, Germany. In a 2014 study, he gave green tea extracts equivalent to one or two cups of green tea to 12 healthy volunteers and imaged their brains to analyze changes in connectivity inside certain brain regions. “We noticed an increased connectivity in regions of the brain associated with working memory,” he said via email.