Green tea could improve the performance of cognitive tasks: A pilot study with wearable brain imaging device

Recently, the consumption of green tea is on the rise due to its potential positive health effects. The main origin for these effects have been attributed to the presence of two compounds found in tea, caffeine and L-theanine with caffine being related to attention, energy, motivation, self-confidence, alertness and concentration and L-theanine related to relaxation. In this study, a wearable functional Near-Infrared Spectroscopy (fNIRS) device was used to monitor neural activity. The device operating at a wavelength of 810 nm could detect absorption changes in total oxyhemoglobin (HbO) due to neural activity and the current study focused on addressing changes in attention under the consumption of green tea and other beverages. In this pilot study, a total of 6 Japanese undergraduate students (3 males and 3 females) participated and the cognitive tasks included multiplication (M) and word generation (W) game in English. It was found that during both the multiplication and word tasks, the relative decrease in total HbO was smaller for green tea in comparison to both control or no drink and other beverages for almost all the subjects. In conclusion, we suggest for the existence of a correlation between drink type and task performance and this could have implications not only in classrooms and but also form the basis of studying the cognitive effects of different drinks available in the market.