Roasted green tea is a traditional Japanese tea that is roasted over charcoal. A recent study suggests that drinking modest amounts of regular and roasted green tea may improve mental task performance. Although the research has limitations, experts believe that starting a daily green tea habit is worthwhile. Roasted green tea, also known as houjicha, is a type of Japanese green tea roasted over charcoal to give it a unique smoky flavor and dark brown color. Previous research has highlighted cognitive benefits of green tea consumption, but has often focused on long-term effects, individual compounds, or high consumption. The recent study published in Scientific Reports explored the potential acute impacts of green tea and roasted green tea consumption on mental task performance.
The study included 20 healthy adult men from Japan, averaging 23 years old, who completed a 5-minute mental arithmetic task across two sessions in a single day. They consumed hot water or green tea before each task, and physiological responses were measured to assess the impact on their mental task performance. Results showed that green tea or roasted green tea consumption during tasks led to significantly lower tissue blood volume, blood flow, and near-infrared spectroscopy responses compared to drinking hot water. Participants’ self-evaluations on fatigue, stress, and mental workload also indicated the potential positive effects of tea consumption on task performance and well-being.
The study found that green tea or roasted green tea may have helped moderate participants’ physiological stress responses. The aromatic compounds present in green tea, which have relaxation effects, played a significant role in improving task performance. Task performance was significantly higher with tea consumption compared to water, with roasted green tea showing anti-fatigue properties despite lower caffeine content. A higher number of task repetitions led to a greater improvement in response rate and task performance. The study showed that small amounts of tea consumed within a short time frame can have positive effects on mental task performance.
Experts not involved in the study highlighted the role of aromatic stimulation from tea compounds in influencing mood and enhancing alertness. Aromatic stimulation was also found to activate the parasympathetic nervous system, leading to relaxation and reduced stress responses. While roasted green tea contains more pyrazine and aromatic components that may contribute to these benefits, further research is needed to confirm these mechanisms. Despite the positive findings on mental task performance, additional research is needed to explore long-term implications and potential confounding factors such as practice effects.
Incorporating green tea or roasted green tea into one’s routine can provide numerous health benefits, but it is important to be mindful of certain considerations. Trying various brands and brewing methods, limiting consumption to a few cups daily, and being aware of potential interactions with medications are all important factors to consider. Green tea, with lower caffeine content than coffee or black tea, can be a suitable alternative for those seeking improved focus with lower caffeine intake. Overall, including green tea in one’s diet is advisable due to its abundance in flavan-3-ols and flavonols, which have been linked to enhanced brain health according to experts.
