Roasted green tea, a Japanese staple, could boost cognitive performance

• Roasted green tea is a traditional Japanese tea that is roasted over charcoal.
• A new study suggests that drinking modest amounts of regular and roasted green tea may improve mental task performance.
• Although the research has limitations, starting a daily green tea habit is worthwhile, according to experts.

Roasted green tea, also known as houjicha, is a type Japanese green tea roasted over charcoal to give the tea a unique smoky flavor and dark brown color.

Previous researchTrusted Source has highlighted the cognitive benefits of green tea consumption, though the research has often focused on long-term effects, individual compoundsTrusted Source in isolation, or high consumption.

Now, a recent study published in Scientific ReportsTrusted Source explored the potential acute impacts of roasted green tea and green tea consumption on mental task performance compared to plain water.

The findings suggest that even small daily servings of green tea or roasted green tea may significantly improve task performance and mental well-being.

This study’s participants included 20 healthy adult men from Japan, with an average age of 23. They were tasked with completing a 5-minute mental arithmetic task six times across two sessions in a single day.

In the first session, they consumed hot water before the first three tasks and then hot water again before a rest period, totaling four water intakes.

In the second session, participants either drank green tea or roasted green tea before tackling the remaining three tasks and prior to another rest period, also totaling four tea intakes.

This process was repeated on a second day, 1 month later, with the type of tea being switched so that all participants experienced both teas.

During these tasks, the researchers measured 11 different physiological responses to assess the impact of drinking hot water, green tea, or roasted green tea on their mental task performance.

They also gathered participants’ self-evaluations on fatigue, stress, mental workload, and workflow to complement their physiological data.