Green Tea and L-Theanine Support Cognitive Function

Researchers recently reported that the combination of green tea extract and L-theanine improved cognition in individuals with mild cognitive impairment. L-theanine, an amino acid found in green tea, was previously shown to increase the production of alpha brain waves, which are the brain waves related to relaxed wakefulness.

In this new randomized, double-blind, placebo-controlled study, 91 subjects with mild cognitive decline were supplemented with green tea extract plus L-theanine or a placebo of maltodextrin plus lactose for 16 weeks. The subjects were evaluated using the Mini Mental State Examination-K, neuropsychological tests including the Rey-Kim memory test and Stroop color-word test, and electroencephalography (EEG), which measures brain wave activity.

The results of the study showed that supplementation with green tea extract plus L-theanine improved memory and selective attention. In addition, EEG evaluation hourly for 3 hours after a single dose of green tea extract plus L-theanine showed a significant increase in theta waves during eye-open and reading states in the temporal, frontal, parietal and occipital areas of the brain, which are the brain waves associated with cognitive alertness.

Thus, the study authors concluded that the combination of green tea extract and L-theanine has potential for cognitive improvement.

Reference:

Park SK, Jung IC, Lee WK, Lee YS, Park HK, Go HJ, Kim K, Lim NK, Hong JT, Ly SY, Rho SS. A Combination of Green Tea Extract and l-Theanine Improves Memory and Attention in Subjects with Mild Cognitive Impairment: A Double-Blind Placebo-Controlled Study. J Med Food. 2011 Feb 8. Published Online Ahead of Print.