Black Tea May Cut Heart Disease Risk: Study
By Suzanne Rostler
October 8, 2001
NEW YORK (Reuters Health) - Drinking black tea may lower the risk of heart disease by preventing the blood from clumping and forming clots, the results of a preliminary study suggest.
Investigators found that individuals who drank five cups of black tea daily for a month had lower levels of P-selectin, a blood protein associated with coagulation, compared with a month-long period in which they drank equal amounts of hot water. Other blood compounds associated with clumping were not reduced by drinking tea, however.
The study was funded by the Tea Trade Health Research Association and the National Heart Foundation of Australia.
Sticky blood can more easily form clots, which can block the flow of blood through the body and lead to heart attack, researchers explain in the October issue of the European Journal of Clinical Nutrition. While their findings suggest that lower blood levels of P-selectin may be a mechanism by which black tea can cut the risk of heart disease, it is too soon to make any specific recommendations, Dr. Jonathan M. Hodgson, the study's primary author, told Reuters Health.
``At the present time, the overall weight of evidence suggests that a higher intake of tea--black, oolong or green--is associated with a lower risk of cardiovascular disease...but not in all populations,"" said Hodgson, from Royal Perth Hospital in Perth, Australia.
Indeed, a number of studies have linked tea consumption to heart health, probably through compounds known as polyphenols--powerful antioxidants that neutralize disease-causing free radicals. These cell-damaging molecules occur naturally in the body and are linked with aging, cancer and heart disease.
The study included 22 healthy, nonsmoking adults who drank five cups of water daily for 4 weeks and then consumed the same amount of black tea for 4 weeks. Researchers measured levels of several blood compounds that are markers of blood coagulation. They also measured compounds in urine that indicate polyphenol intake. Participants followed their usual diets throughout the study.
``The effect of black tea on soluble P-selectin provides a potential mechanism for cardiovascular benefits of regular tea,"" Hodgson and colleagues conclude.
SOURCE: European Journal of Clinical Nutrition 2001;55:881-886.