γ-Aminobutyric acid (GABA) is a kind of amino acid found in green tea leaves and other foods. Several reports have shown that GABA could affect brain protein synthesis, improve many brain functions such as memory and learning ability, lower blood pressure of spontaneously hypertensive rats, and also have a relaxation effect in humans. However, the evidence for its mood-improving function is still insufficient.
In this study, we investigated how oral ingestion of GABA affects human adults psychologically and physiologically under a psychological stress condition. Sixty-three adults (28 men, 35 women) participated in a randomized, single-blind, placebo-controlled crossover study over two experimental days.
Capsules containing 100 mg GABA or dextrin as placebo were used as test samples. The results showed that EEG activities including alpha and beta band brain waves decreased as a function of exposure to the mental stress task, and the condition 30 minutes after GABA ingestion decreased this decrease compared to the placebo condition.
That is, GABA may have alleviated mental task-induced stress. This effect also corresponded with the results of the POMS scores.
Found at Alkohol adé (german)