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Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content

Caffeine, one of the main components in green tea, can interfere with sleep and block the effect of theanine. Since theanine, the main amino acid in tea leaves, has significant anti-stress effects in animals and humans, we examined the effects of green tea with lowered caffeine content, i.e., low-ca...

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Autores principales: Unno, Keiko, Noda, Shigenori, Kawasaki, Yohei, Yamada, Hiroshi, Morita, Akio, Iguchi, Kazuaki, Nakamura, Yoriyuki
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5537891/
https://www.ncbi.nlm.nih.gov/pubmed/28753943
http://dx.doi.org/10.3390/nu9070777
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author Unno, Keiko
Noda, Shigenori
Kawasaki, Yohei
Yamada, Hiroshi
Morita, Akio
Iguchi, Kazuaki
Nakamura, Yoriyuki
author_facet Unno, Keiko
Noda, Shigenori
Kawasaki, Yohei
Yamada, Hiroshi
Morita, Akio
Iguchi, Kazuaki
Nakamura, Yoriyuki
author_sort Unno, Keiko
collection PubMed
description Caffeine, one of the main components in green tea, can interfere with sleep and block the effect of theanine. Since theanine, the main amino acid in tea leaves, has significant anti-stress effects in animals and humans, we examined the effects of green tea with lowered caffeine content, i.e., low-caffeine green tea (LCGT), on stress and quality of sleep of middle–aged individuals (n = 20, mean age 51.3 ± 6.7 years) in a double-blind crossover design. Standard green tea (SGT) was used as the control. These teas (≥300 mL/day), which were eluted with room temperature water, were consumed over a period of seven days after a single washout term. The level of salivary α-amylase activity (sAA), a stress marker, was significantly lower in participants that consumed LCGT (64.7 U/mL) than in those that consumed SGT (73.9 U/mL). Sleep quality was higher in participants that consumed a larger quantity of LCGT. In addition, a self-diagnostic check for accumulated fatigue was significantly lower in those participants that consumed LCGT than SGT. These results indicate that LCGT intake can reduce stress in middle-aged individuals and improve their quality of sleep. The reduction in caffeine is suggested to be a valid reason for enhancing the anti-stress effect of green tea.
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spelling pubmed-55378912017-08-04 Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content Unno, Keiko Noda, Shigenori Kawasaki, Yohei Yamada, Hiroshi Morita, Akio Iguchi, Kazuaki Nakamura, Yoriyuki Nutrients Article Caffeine, one of the main components in green tea, can interfere with sleep and block the effect of theanine. Since theanine, the main amino acid in tea leaves, has significant anti-stress effects in animals and humans, we examined the effects of green tea with lowered caffeine content, i.e., low-caffeine green tea (LCGT), on stress and quality of sleep of middle–aged individuals (n = 20, mean age 51.3 ± 6.7 years) in a double-blind crossover design. Standard green tea (SGT) was used as the control. These teas (≥300 mL/day), which were eluted with room temperature water, were consumed over a period of seven days after a single washout term. The level of salivary α-amylase activity (sAA), a stress marker, was significantly lower in participants that consumed LCGT (64.7 U/mL) than in those that consumed SGT (73.9 U/mL). Sleep quality was higher in participants that consumed a larger quantity of LCGT. In addition, a self-diagnostic check for accumulated fatigue was significantly lower in those participants that consumed LCGT than SGT. These results indicate that LCGT intake can reduce stress in middle-aged individuals and improve their quality of sleep. The reduction in caffeine is suggested to be a valid reason for enhancing the anti-stress effect of green tea. MDPI 2017-07-19 /pmc/articles/PMC5537891/ /pubmed/28753943 http://dx.doi.org/10.3390/nu9070777 Text en © 2017 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/).
spellingShingle Article
Unno, Keiko
Noda, Shigenori
Kawasaki, Yohei
Yamada, Hiroshi
Morita, Akio
Iguchi, Kazuaki
Nakamura, Yoriyuki
Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content
title Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content
title_full Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content
title_fullStr Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content
title_full_unstemmed Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content
title_short Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content
title_sort reduced stress and improved sleep quality caused by green tea are associated with a reduced caffeine content
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5537891/
https://www.ncbi.nlm.nih.gov/pubmed/28753943
http://dx.doi.org/10.3390/nu9070777
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