Matcha Does Not Affect Electroencephalography during Sleep but May Enhance Mental Well-Being: A Randomized Placebo-Controlled Clinical Trial.

2024-08-31
Nutrients 16(17)
- Yoshitake Baba
- Takanobu Takihara
- Noritaka Okamura

PubMed: 39275223
DOI: 10.3390/nu16172907

Study Design

Type: Randomized Controlled Trial (RCT)
Population: healthy Japanese men and women aged 27-64 years
Methods: placebo-controlled randomized double-blind parallel-group study, 4 weeks of consuming 2.7 g of matcha daily
Blinding: Double-blind
Duration: 4 weeks
Funding: Unclear

Rigorous Journal

Although theanine in matcha improves sleep quality and cognitive function, the caffeine in green tea is thought to worsen sleep quality. Therefore, this study investigated the factors behind the observed improvements in subjective sleep quality in matcha. A placebo-controlled randomized double-blind parallel-group study was conducted on healthy Japanese men and women aged 27-64 years. After 4 weeks of consuming 2.7 g of matcha daily (containing 50.3 mg theanine, 301.4 mg catechins, and 71.5 mg caffeine), no significant differences were observed between the control and matcha groups on total sleep time, sleep latency, wake after sleep onset, or sleep efficiency measured by electroencephalography (EEG). However, the sleep questionnaire Oguri-Shirakawa-Azumi Sleep Inventory, the Middle-age and Aged version (OSA-MA), administered immediately after waking showed a trend toward increased satisfaction with sleep time (p < 0.1), and EEG measurements indicated significantly shortened wake-up times after waking with matcha intake (p < 0.05). The Beck Depression Inventory-II scores also tended to decrease (p < 0.1). The continuous intake of matcha may offer improved subjective sleep quality and emotional stability despite not offering significant changes in objective sleep parameters.

Research Insights

matcha→Improved Sleep Efficiency
no significant differences were observed between the control and matcha groups on ... sleep efficiency measured by electroencephalography (EEG)
Effect
Neutral
Effect size
Small
Dose
2.7 g daily (containing 50.3 mg theanine, 301.4 mg catechins, and 71.5 mg caffeine)
matcha→Improved Sleep Latency
no significant differences were observed between the control and matcha groups on ... sleep latency
Effect
Neutral
Effect size
Small
Dose
2.7 g daily (containing 50.3 mg theanine, 301.4 mg catechins, and 71.5 mg caffeine)
matcha→Improved Sleep Satisfaction
the sleep questionnaire Oguri-Shirakawa-Azumi Sleep Inventory, the Middle-age and Aged version (OSA-MA), administered immediately after waking showed a trend toward increased satisfaction with sleep time (p < 0.1)
Effect
Neutral
Effect size
Small
Dose
2.7 g matcha daily (containing 50.3 mg theanine, 301.4 mg catechins, and 71.5 mg caffeine)
matcha→Improved Total Sleep Time
no significant differences were observed between the control and matcha groups on total sleep time
Effect
Neutral
Effect size
Small
Dose
2.7 g daily (containing 50.3 mg theanine, 301.4 mg catechins, and 71.5 mg caffeine)
matcha→Increased Sleep Time Satisfaction
the sleep questionnaire ... showed a trend toward increased satisfaction with sleep time (p < 0.1)
Effect
Neutral
Effect size
Small
Dose
2.7 g daily (containing 50.3 mg theanine, 301.4 mg catechins, and 71.5 mg caffeine)
matcha→Increased Total Sleep Time
no significant differences were observed between the control and matcha groups on total sleep time, sleep latency, wake after sleep onset, or sleep efficiency measured by electroencephalography (EEG)
Effect
Neutral
Effect size
Small
Dose
2.7 g matcha daily (containing 50.3 mg theanine, 301.4 mg catechins, and 71.5 mg caffeine)
matcha→Reduced Depression Symptoms
The Beck Depression Inventory-II scores also tended to decrease (p < 0.1)
Effect
Neutral
Effect size
Small
Dose
2.7 g daily (containing 50.3 mg theanine, 301.4 mg catechins, and 71.5 mg caffeine)
matcha→Reduced Sleep Latency
no significant differences were observed between the control and matcha groups on total sleep time, sleep latency, wake after sleep onset, or sleep efficiency measured by electroencephalography (EEG)
Effect
Neutral
Effect size
Small
Dose
2.7 g matcha daily (containing 50.3 mg theanine, 301.4 mg catechins, and 71.5 mg caffeine)
matcha→Reduced Wake After Sleep Onset
EEG measurements indicated significantly shortened wake-up times after waking with matcha intake (p < 0.05)
Effect
Beneficial
Effect size
Small
Dose
2.7 g daily (containing 50.3 mg theanine, 301.4 mg catechins, and 71.5 mg caffeine)