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Black Tea May Slightly Lower Blood Pressure, Study Says

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A new study from researchers from the University of Western Australia shows that black tea won't raise blood pressure in people with hypertension, and may even be able to help to lower it.

The study, published today in the Archives of Internal Medicine, examined the effects of drinking three cups a day of black tea over a six-month period. Researchers found that the tea consumption was linked with a decrease of 2 to 3 millimeters of mercury (more colloquially known as blood pressure "points") for both systolic blood pressure (the top number in a reading) and diastolic blood pressure (the bottom number in a reading).

Because the drop in blood pressure levels is small, it's hard to say that drinking black tea will have a certain benefit for all people with hypertension, said Dr. John D. Bisognano, a professor in the cardiology division of the University of Rochester Medical Center. Bisognano was not involved in the study, but has conducted research on alternative therapies for high blood pressure.

But the study does show that people with high blood pressure -- a condition that affects about 31 percent of all U.S. adults, CNN reported -- should not feel like they are making their condition worse by drinking the beverage.

"We tell hypertensive patients so many things they have to do -- the list is long -- and we don't want to be telling them stuff that just causes them frustration for no good," Bisognano told HuffPost. "This finding suggests that we need not ask them to decrease their tea intake."

Bisognano said that black tea might have a small benefit on blood pressure because it helps make sure the endothelial layer -- the thin layer of cells that lines the inner parts of blood vessels -- is not injured. When this layer is injured, things like cholesterol can get into the wall of the blood vessel, leading to build-up and more serious conditions like coronary disease and stroke.

He also added that other kinds of teas may have the same blood pressure benefit. A past study in the journal Phytomedicine suggested that hibiscus tea could help to lower blood pressure, according to the Bastyr Center for Natural Health.

While Bisognano emphasized that blood pressure medication is an important step to take for people who need to control their blood pressure, he acknowledged that other, more natural therapies can also help to decrease blood pressure.

His past research showed that pure cocoa, relaxation techniques like yoga and even some devices which aid with relaxation can help people with high blood pressure.

CORRECTION: A past version of this article incorrectly stated that researchers from the University of Rochester Medical Center conducted the study. The article has been corrected to say that University of Western Australia researchers conducted the study.

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