Baba Yoshitake, Inagaki Shun, Nakagawa Sae, Kaneko Toshiyuki, Kobayashi Makoto, Takihara Takanobu
Central Research Institute, ITO EN, LTD., Shizuoka, Japan.
Tokyo Skytree Station Medical Clinic, Tokyo, Japan.
J Med Food. 2021 Apr;24(4):333-341. doi: 10.1089/jmf.2020.4803. Epub 2021 Mar 22.
l-theanine (-glutamylethylamide), an amino acid in green tea, has been shown to affect brain functions by relieving stress disorders, improving mood, and maintaining normal sleep. However, the cognitive functions for which theanine is effective are unclear. This study aimed to clarify which cognitive functions are positively affected by intake of l-theanine. A double-blind, randomized, placebo-controlled study was conducted. The subjects were Japanese men and women aged 50-69 years. Mini Mental State Examination-Japanese version score was 24 or higher. Cognitrax was used as a test battery for cognitive function. Evaluations were performed before the intervention, after a single dose of l-theanine, and after 12 weeks of regular intake. The single dose of l-theanine reduced the reaction time to attention tasks (Stroop test, Part 1), and it increased the number of correct answers and decreased the number of omission errors in working memory tasks (4-Part continuous performance test, Part 4). In conclusion, our study indicated that l-theanine may contribute to improving attention, thus enhancing working memory and executive functions. Clinical Trial No.: UMIN000033812.
L-茶氨酸（γ-谷氨酰乙酰胺）是绿茶中的一种氨基酸，已被证明可通过缓解应激障碍、改善情绪和维持正常睡眠来影响大脑功能。然而，茶氨酸有效的认知功能尚不清楚。本研究旨在阐明摄入L-茶氨酸对哪些认知功能有积极影响。进行了一项双盲、随机、安慰剂对照研究。受试者为年龄在50至69岁之间的日本男性和女性。简易精神状态检查表日语版得分在24分及以上。使用认知测试组合（Cognitrax）评估认知功能。在干预前、单次服用L-茶氨酸后以及规律摄入12周后进行评估。单次服用L-茶氨酸缩短了注意力任务（斯特鲁普测试，第1部分）的反应时间，增加了工作记忆任务（四部分连续操作测试，第4部分）的正确答案数量，并减少了遗漏错误数量。总之，我们的研究表明L-茶氨酸可能有助于提高注意力，从而增强工作记忆和执行功能。临床试验编号：UMIN000033812。
