Japanese experts have conducted a pilot study of the anti-stress effect of tea with a lower content of caffeine and catechins. The matter is that theanine, contained in tea, in its pure form has an anti-stress effect. But besides theanine, tea contains caffeine and catechins, which block the action of theanine. This is why, for this experiment, tea with a reduced content of caffeine and catechins was chosen.
The tea was prepared in a special way. Fresh tea leaves (harvested in Shizuoka) were treated with a hot water shower at 95°C for three minutes, then the tea leaves were “dried through a standard manufacturing process”. Hot water treatment reduced caffeine content in tea leaves by 75-80%. Moreover, this tea was infused in room-temperature water (3 grams per 500 ml) — so that the remaining caffeine and catechins (primarily EGCG) would go out to infusion badly (they dissolve better in hot water), and theanine, on the contrary, would go out well.
Twenty students of the fifth year were divided into two groups. During 17 days, one group drank tea with a low content of caffeine and catechins, the second — a placebo drink (barley tea). The study was synchronized with the beginning of the extra-university practice period, which, traditionally, is a source of stress for students. All subjects daily filled questionnaires and submitted saliva for analysis in the morning and in the evening.
The results of the experiment are the following. Before the practice period, all subjects had a low level of stress. After the practice began, the morning stress level was low for all students. In the students who drank barley tea, the evening stress level was much higher than the morning one. And in the students who drank low-caffeine tea, the evening stress level tended to be higher, but not significantly, than the morning one. The average score for subjective stress at the end of daily practice was significantly lower in the low-caffeine-group than the placebo-group.
And now you have the recipe for anti-stress green tea.