Tea or coffee? According to this article, we should probably be switching to tea… The present study conducted by Chinese and British researchers uses brain imaging data for the first time to explore the effects of tea on the brain, particularly on the connections between brain regions. Is drinking tea regularly beneficial for cognition?

As the authors point out in the preamble of their article (published in the journal Aging), previous studies have already highlighted the fact that tea consumption could be beneficial for health, including improving mood, preventing cardiovascular disease, and reducing the risks of cognitive decline. The virtues of tea stem primarily from its constituents: catechins are effective for working memory, and L-theanine limits stress. Moreover, to date, most research has been based on neurocognitive and neuropsychological measures, but little research has been conducted using direct measurements on brain structure or function.

For their study, Junhua Li and his colleagues hypothesized that regular tea consumption would have positive effects on brain organization and lead to greater functional and structural connectivity. The research team recruited 36 healthy adults. Each participant was asked to report how frequently (at about 45 years old and at present) they drank green tea, oolong tea, and black tea on a scale from 1 to 6 (from never or rarely to three times a day or more). This resulted in two groups: tea drinkers (15 subjects, mean age = 70.27) and non tea drinkers (21 subjects; average age = 71.71). Data on the health, lifestyle, and psychological well-being of each participant was collected. Between 2015 and 2018, the participants also underwent neuropsychological tests and MRIs.

Results of the cognitive performance tests and brain imaging showed that consuming tea led to a more efficient structural organization of the brain. Indeed, regular tea drinkers (who consumed tea on average at least four times per week for about 25 years) had more efficient connections between brain regions. The researchers focused on the default mode network (DMN), that is to say, a vast network of interactions between brain areas known to have a strongly correlated activity that is distinct from other brain areas. The researchers found that the strength of functional connectivity was higher in the tea drinker group.

According to Feng Lei of the Department of Psychological Medicine (University of Singapore), as the connections between brain areas become more structured, information processing becomes more efficient; this is why: “Our results offer the first evidence of positive contribution of tea drinking to brain structure, and suggest that drinking tea regularly has a protective effect against age-related decline in brain organization.”

Of course, more research is needed to further examine the effects of the compounds found in tea on brain health.