Stress-Reducing Function of Matcha Green Tea in Animal Experiments and Clinical Trials.
- 2018-10-10
- Nutrients 10(10)
- Keiko Unno
- Daisuke Furushima
- Shingo Hamamoto
- Kazuaki Iguchi
- Hiroshi Yamada
- Akio Morita
- Hideki Horie
- Yoriyuki Nakamura
- PubMed: 30308973
- DOI: 10.3390/nu10101468
Study Design
- Type
- Randomized Controlled Trial (RCT)
- Population
- Participants (n = 39) consumed test-matcha or placebo-matcha
- Methods
- Animal experiment and a clinical trial; test-matcha expected to have stress-reducing effect vs placebo-matcha
- Rigorous Journal
Theanine, a major amino acid in green tea, exhibits a stress-reducing effect in mice and humans. Matcha, which is essentially theanine-rich powdered green tea, is abundant in caffeine. Caffeine has a strong antagonistic effect against theanine. The stress-reducing effect of matcha was examined with an animal experiment and a clinical trial. The stress-reducing effect of matcha marketed in Japan and abroad was assessed based on its composition. The stress-reducing effect of matcha in mice was evaluated as suppressed adrenal hypertrophy using territorially-based loaded stress. High contents of theanine and arginine in matcha exhibited a high stress-reducing effect. However, an effective stress-reducing outcome was only possible when the molar ratio of caffeine and epigallocatechin gallate (EGCG) to theanine and arginine was less than two. Participants (n = 39) consumed test-matcha, which was expected to have a stress-reducing effect, or placebo-matcha, where no effect was expected. Anxiety, a reaction to stress, was significantly lower in the test-matcha group than in the placebo group. To predict mental function of each matcha, both the quantity of theanine and the ratios of caffeine, EGCG, and arginine against theanine need to be verified.
Research Insights
Anxiety, a reaction to stress, was significantly lower in the test-matcha group than in the placebo group.
- Effect
- Beneficial
- Effect size
- Small