Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content
| Autor: | Hiroshi Yamada, Yohei Kawasaki, Yoriyuki Nakamura, Keiko Unno, Kazuaki Iguchi, Akio Morita, Shigenori Noda |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Adult Male Quality of sleep green tea lcsh:TX341-641 anti-stress effect Catechin Article 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Animal science Double-Blind Method Glutamates Caffeine Medicine Humans sleep Nutrition and Dietetics Cross-Over Studies Sleep quality Tea business.industry food and beverages salivary α-amylase Mean age middle-aged individuals Middle Aged Green tea Theanine Crossover study Stress marker caffeine 030104 developmental biology Biochemistry chemistry Female alpha-Amylases business lcsh:Nutrition. Foods and food supply 030217 neurology & neurosurgery Stress Psychological Food Science |
| Zdroj: | Nutrients Nutrients; Volume 9; Issue 7; Pages: 777 Nutrients, Vol 9, Iss 7, p 777 (2017) |
| ISSN: | 2072-6643 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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