You already know that feeling: how tea can refresh you and provide a break that helps you feel relaxed, focused and alert. Studies found that drinking tea may help maintain cognitive focus and improve alertness throughout the day (1,2). The two compounds in tea most likely responsible for these effects are L-theanine, an amino acid found almost exclusively in tea, and caffeine. (3-6)
Try drinking tea throughout the day to help stay focused.
Hindmarch I, Quinlan PT, Moore KL, Parkin C. The effects of black tea and other beverages on aspects of cognition and psychomotor performance. Psychopharmacol. 1998;139:230-238.
Hindmarch I, Rigney U, Stanley N, Quinlan P, Rycroft J, Lane J. A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality. Psychopharmacol. 2000;149:203-216.
Nobre AC, Rao AR, Owen GN. L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pac J Clin Nutr. 2008;17:167-168.
Gomez-Ramirez M, Higgins BA, Rycroft JA, Owen GN, Mahoney J, Shpaner M, Foxe JJ. The deployment of intersensory selective attention: a high-density electrical mapping study of the effects of theanine. Clin Neuropharmacol. 2007;30:25-38.
Gomez-Ramirez M, Kelly SP, Montesi JL, Foxe JJ. The effects of L-theanine on alpha-band oscillatory brain activity during a visuo-spatial attention task. Brain Topogr. 2009;22(1):44-51.
Kelly SP, Gomez-Ramirez M, Montesi JL, Foxe JJ. L-theanine and caffeine in combination affect human cognition as evidenced by oscillatory alpha-band activity and attention task performance. J Nutr. 2008;138(8):1572S-1577S.