Scientists have evidence behind what many tea
drinkers already know - a regular cuppa can help you recover more
quickly from everyday life stresses.
The study of black tea - instead of green or herbal
varieties - found it helps cut levels of the stress hormone cortisol
circulating in the blood.
They found people who drank tea were able to de-stress more quickly than those who drank a tea substitute.
The University College London study is in the journal Psychopharmacology.
In the study, 75 young male regular tea drinkers were split into two groups and monitored for six weeks.
They all gave up their normal tea, coffee and
caffeinated beverages, and then one group was given a fruit-flavoured
caffeinated tea mixture made up of the constituents of an average cup
of black tea.
The other group was given a caffeinated placebo identical in taste, but devoid of the active tea ingredients.
All drinks were tea-coloured, but were designed to mask
some of the normal sensory cues associated with tea drinking (such as
smell, taste and familiarity of the brew).
This was designed to eliminate confounding factors such as the 'comforting' effect of drinking a cup of tea.
Both groups were subjected to challenging tasks, while
their cortisol, blood pressure, blood platelet and self-rated levels of
stress were measured.
In one task, volunteers were exposed to one of three
stressful situations (threat of unemployment, a shop-lifting accusation
or an incident in a nursing home), where they had to prepare a verbal
response and argue their case in front of a camera.
The tasks triggered substantial increases in blood pressure, heart rate and subjective stress ratings in both of the groups.
However, 50 minutes after the task, cortisol levels had
dropped by an average of 47% in the tea-drinking group compared with
27% in the fake tea group.
Blood platelet activation - linked to blood clotting and the risk of heart attacks - was also lower in the tea drinkers.
In addition, this group reported a greater degree of relaxation in the recovery period after the task.
