Tokyo (TG) - A daily cup of coffee may cut the risk of stroke by a fifth, say researchers. Green tea could also be beneficial for preventing the devastating event, caused when a blood vessel in or serving the brain is either blocked or bursts. Their study looked at the beverage habits of over 83,000 healthy adults, aged 45 to 74, whose health was tracked for 13 years on average.  They found that people who drank at least one cup of coffee a day had about a 20pc lower risk of stroke, compared to those who rarely drank it.