There was a first large-scale study to examine the effects of coffee and green tea and on stroke risks and is showing that it helps lower the risks of strokes. This study was performed by Yoshihiro Kokubo, M.D., Ph.D., lead author of the study at Japan’s National Cerebral and Cardiovascular Center. The study was published in the American Heart Associations Journal, Stroke.
The researchers questioned over 83,000 Japanese adults regarding their coffee and green tea drinking habits. They then followed the participants for about 13 years. During the 13-year follow-up the researchers reviewed hospital medical records and death certificates. The ages of the participants in the study were from 45 to 74 years old and almost evenly divided in gender and were free from cancer and cardiovascular disease. The Kokubo’s team controlled for factors like age, weight, diet, exercise habits, and alcohol consumption. Those that drank at one cup of coffee or more daily had about a 20% lower risk of stroke compared to those who barely drank it. The average drink in Japan is based on being at least 6 ounces. People who drank two to three cups of green tea daily had a 14% reduced risk for stroke, while those that drank at least four cups daily had a 20% lower risk. These are big percentages. Participants that drank two cups of green tea or one cup of coffee a day experienced a 32 percent lower risk of intracerbral hemorrhage. A intracerebral hemorrhage happens when a blood vessel bursts and bleeds inside the brain. About 13% of strokes are hemorrhagic.
It is known that green tea can help lower death risks from heart disease. Five or more cups of green tea corresponded with 15% decrease in all-cause mortality, and a 26% decrease in dying from cardiovascular disease. Also, people that drink green tea were more likely to exercise than those that do not drink green tea. Researchers are not sure what property is in green tea that lower stroke risks, although they believe it could be the antioxidant, polyphenol called catechins which have antioxidants and anti-inflammatory effects. There is high amounts of this in green tea. This has been linked to anti-cancer activity and heart benefits, according to the Mayo Clinic. There is a chemical in coffee called chlorogenic acid which reduces a person’s risk of developing type 2 diabetes, this could be why coffee drinks are at a reduced risk of stroke. Given that tea and coffee are consumed regularly in many countries, Americans may already be drinking enough coffee and tea to get the benefits.