The Stress-Reducing Effect of Matcha Green Tea in both Animal and Human Studies

by | Aug 21, 2019 | 2019, Amino Acids, Brain Health, Stress

Written by Joyce Smith, BS. Matcha tea, with a CE/TA ratio of 2 or less was shown to significantly modify the stress response in a mice model of psychological stress as well as in stressed pharmacy students who consumed baked cookies with added matcha. 

matcha teaMatcha, a fine-powdered green tea has a higher amino acid content and is rich in theanine and caffeine and low in catechin compared to other popular green teas. Growing Matcha tea in shade for three weeks before harvest produces leaves with a lower catechin content than teas that are grown in sunlight 1,2. Also, harvesting the buds and young leaves provides a tea of higher caffeine content 3. Green tea, popularized in Asian countries has, along with theanine, exhibited stress-reducing effects on both mice and humans 4. However, the impact of theanine’s stress-reducing effect is mitigated by caffeine and epigallocatechin gallate (EGCG), the two major components of green tea 5 and enhanced by the amino acid arginine (the second most prevalent amino acid in Japanese green tea)6. When matcha tea is consumed as a stress-reducing beverage, the theanine concentration necessary to achieve the stress-reducing effect is 50 mg or more and the molar ratio of caffeine and EGCG to theanine and arginine (CE/TA) must be 2 or less 7.

Researchers Unno and team 8 first examined the effects of the quantity and ratio of matcha tea components on its stress-reducing properties in male mice that were subjected to psychological stress. They found that adrenal hypertrophy, a marker of stress, was significantly suppressed in the stressed mice when they ingested matcha components that had a CE/TA ratio of 2 or less.

The second objective of Unno and team was to evaluate the stress-reducing potential of matcha tea in a human study. Cookies were baked using matcha component ingredients that gave the cookies either a CE/TA ratio of 1.79 or a CE/TA ratio of 10.64. In a randomized double-blind placebo controlled trial, thirty-six 5th year pharmacy students (18 men, 18 women) were allocated to either the test-matcha group (CE/TA=1.79, n=19)  or the placebo- matcha group  (CE/TA=10.64, n=17). They were asked to consume three cookies (a total of 4.5 grams of matcha) daily for 15 consecutive days of stressful work. A state-trait inventory (STAI) test evaluated the student stress levels daily. After 15 days, salivary α-amylase activity, a stress marker, was significantly lower in the test-matcha group than in the placebo group (p=0.002).

This study demonstrated that for optimal stress-relief effect, matcha tea should contain less caffeine and EGCG than twice the molar amount of theanine and arginine. In this study, a stress-reducing effect was observed even when matcha was included in baked cookies. The research team suggests that a daily intake of confectionery products containing a low CE/TA molar ratio may benefit those who are not tea drinkers and serve as a simple and practical way to counteract the accumulation of stress.

Source: Unno, Keiko, Daisuke Furushima, Shingo Hamamoto, Kazuaki Iguchi, Hiroshi Yamada, Akio Morita, Monira Pervin, and Yoriyuki Nakamura. “Stress-reducing effect of cookies containing matcha green tea: essential ratio among theanine, arginine, caffeine and epigallocatechin gallate.” Heliyon 5, no. 5 (2019): e01653.

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

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Posted August 21, 2019.

Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from  the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.

References:

  1. Unno K, Iguchi K, Tanida N, et al. Ingestion of theanine, an amino acid in tea, suppresses psychosocial stress in mice. Experimental physiology. 2013;98(1):290-303.
  2. IKEGAYA K, TAKAYANAGI H, ANAN T. Chemical composition of mat-cha. Chagyo Kenkyu Hokoku (Tea Research Journal). 1984;1984(60):79-81.
  3. Horie H, Ema K, Sumikawa O. Chemical components of Matcha and powdered green tea. J Cook Sci Jpn(Nippon Chourikagaku Kaishi). 2017;50:182-188.
  4. Unno K, Hara A, Nakagawa A, et al. Anti-stress effects of drinking green tea with lowered caffeine and enriched theanine, epigallocatechin and arginine on psychosocial stress induced adrenal hypertrophy in mice. Phytomedicine. 2016;23(12):1365-1374.
  5. Giles GE, Mahoney CR, Brunyé TT, Taylor HA, Kanarek RB. Caffeine and theanine exert opposite effects on attention under emotional arousal. Canadian journal of physiology and pharmacology. 2016;95(1):93-100.
  6. Ruan J, Haerdter R, Gerendás J. Impact of nitrogen supply on carbon/nitrogen allocation: a case study on amino acids and catechins in green tea [Camellia sinensis (L.) O. Kuntze] plants. Plant Biology. 2010;12(5):724-734.
  7. Unno K, Furushima D, Hamamoto S, et al. Stress-reducing function of matcha green tea in animal experiments and clinical trials. Nutrients. 2018;10(10):1468.
  8. Unno K, Furushima D, Hamamoto S, et al. Stress-reducing effect of cookies containing matcha green tea: essential ratio among theanine, arginine, caffeine and epigallocatechin gallate. Heliyon. 2019;5(5):e01653.