Green tea has been consumed for thousands of years with many reported health benefits including improvements in memory and brain function.
An interesting fact about green tea is that it is actually made from the same plant as black tea. The name of that plant is Camellia sinensis.
Scientists from the University of Basel in Switzerland reported their analysis of green tea research on brain function in the journal Phytomedicine. 
Here is what they found
– 21 studies were analyzed, 4 were randomized controlled trials, 12 were cross over studies, 4 were cross sectional studies and one was a cohort study.
– The average study quality as determined by the DELPHI-list was 8.06 out of 9.
Previously, we have described health benefits of green tea and you can find those studies here.
– The reviewed studies presented evidence that green tea influences psychopathological symptoms (e.g. reduction of anxiety), cognition (e.g. benefits in memory and attention) and brain function (e.g. activation of working memory seen in functional MRI).
– The effects of green tea cannot be attributed to a single constituent of the beverage.
Here are comments by the authors of this study
The studies investigating the controlled administration of green tea extract found short-term benefits in memory and attention as well as an increase in the activation of a brain area responsible for mediating working memory, as demonstrated by fMRI.
And
Administration of EGCG alone was found to have a calming effect on mood as well as an impact on brain functions, as detected by EEG and NIRS. There was an overall increase in alpha, beta and theta activity which could be linked to areas in the frontal gyrus; this is consistent with the increased activity of the working memory indicated in fMRI, since the scrutinised functional structure, which is the dorsolateral prefrontal cortex, is mostly located in the anatomical region of the frontal gyrus.
And
While this systematic review found a reasonable amount of evidence that both EGCG and l-theanine exhibit neuroprotective activity and that l-theanine (and to a lesser degree of EGCG) influence mood, the extracted data suggests that the various improvements in cognitive faculties linked to green tea consumption are not the consequence of a single component.
And
Here are more studies related to plant medicine on brain function.
The extracted data suggests that it would be desirable for more Westerners to change their lifestyle to include habitual, daily consumption of green tea of at least 100 ml per day, in order to protect their neurocognitive function.
And
Those effects appear to increase dose-dependently up to a consumption of 500 ml per day—an even greater consumption of green tea was not investigated. No author reported disparate findings.
Here are more studies related to plant medicine on brain function.
Take away message
The results of this review suggests that the combination of phytochemicals in green tea appear to be beneficial for brain function. What is more interesting is that the authors emphasize that the results suggest that not one ingredient is responsible but rather a combination of phytochemicals is necessary. This is especially important as many people will ask ‘what is the active ingredient?’ of green tea. Our answer should be ‘there are many active ingredients’.
Another interesting point made by the scientists was it would be desirable for Westerners to change their lifestyle to include at least 100 mL of green tea per day.
Reference
Mancini et al. Green tea effects on cognition, mood and human brain function: A systematic review. Phytomedicine. Volume 34, Pages 26-37
His research on plant medicine has led to more than 45 publications and abstracts.This research has been presented at international meetings in the USA, France, Turkey, Peru, Israel, Austria, and Italy.
Categories: Brain, Mood, Plant Medicine