Contrary to some previous reports, a new study from Australia notes that enjoying three cups of black tea per day can lower blood pressure. Although the drop in blood pressure may not seem like much—2 to 3 mmHg for both diastolic and systolic blood pressure—it was enough to be considered significant, as the study’s authors explain below.
Black tea and your heart
Numerous studies have reported that black tea is good for your heart. In an April 2009 issue of the Journal of Hypertension, for example, the authors noted that the flavonoids (potent antioxidants found in plants) present in tea “may protect against cardiovascular disease,” and that black tea “improves endothelial function,” which is a blood pressure indicator.
The authors also noted that the beverage “decreased peripheral arterial stiffness” and “flow-mediated dilation,” leading them to conclude that “all tea drinkers could benefit from protective cardiovascular effects exerted by tea.”
Some of these claims are backed up by a report in the December 2010 issue of Molecular Aspects of Medicine, in which Australian researchers noted that the cardiovascular benefits of tea “are thought to be largely due to flavonoids.” However, the authors also pointed out there is “inadequate” data to support claims that tea helps reduce blood pressure, oxidative damage, or inflammation.
In fact, on a National Institutes of Health website concerning black tea, it states that "Black tea works for this condition [orthostatic hypotension] because it raises blood pressure."
Enter the new study, published in the Archives of Internal Medicine, which enrolled 95 regular tea drinkers, men and women ages 35 to 75, who had a mean systolic blood pressure of 121 mmHg at the beginning of the study.
Before starting the intervention part of the study, all the participants followed a low-flavonoid diet for 4 weeks that included 3 cups of regular leaf tea daily. After the 4 weeks, the participants were randomly assigned to consume 3 cups of either 1,493-mg powdered black tea solids or a placebo drink.
Ambulatory blood pressure readings among volunteers who drank the tea were 2.7 mmHg lower at 3 months and 2.0 mmHg lower at 6 months (systolic), and 2.3 mmHg and 2.1 mmHg, respectively, for diastolic.
Although these declines in blood pressure may seem insignificant, Jonathan Hodgson, PhD, of the University of Western Australia and his colleagues note that the differences are associated with a 10% reduction in the prevalence of high blood pressure and a 7% to 10% reduced risk of cardiovascular disease.
Why black tea lowers blood pressure
What makes black tea a favorable beverage for lowering blood pressure? The authors suggest it may be the positive effect black tea has on endothelial function, or that the flavonoids improve the levels of nitric oxide, a substance that plays a critical role in regulating blood pressure.
Black tea may also improve blood pressure because it helps reduce levels of endothelin 1, which is a powerful vasoconstrictor (constricts the blood vessels and reduces blood flow, raising blood pressure). Another possibility is the positive impact tea flavonoids may have on body weight and abdominal fat.
Where to enjoy tea
So, are you ready to have a cup of tea? If you are looking for a tea room or tea merchant in Rehoboth Beach or surrounding areas, you might try the following locations:
- Boardwalk Plaza Hotel (tea room), 2 Olive Avenue & Boardwalk, Rehoboth Beach DE / 800-332-3224
- The Coffee Mill (yes, sells teas despite its name), 127B Rehoboth Avenue, Rehoboth Beach DE / 302-227-7530
- Tea for Two (tea room), 224 N State Street, Dover DE (opening May 2012)
- Purple Sage Herbs and Gifts (tea merchant), 41 W Main Street, Middletown DE / 302-378-2123
- British Bell Tea Room (tea room and merchant), 890 Peoples Plaza, Newark DE / 302-836-1802
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