Scientists from the Guilan University of Medical Sciences have found that regularly drinking green tea or black tea may help lower blood pressure—a key risk factor for heart disease.
A blood pressure reading has two numbers:
- Systolic pressure (top number): the pressure in your arteries when your heart beats.
- Diastolic pressure (bottom number): the pressure between beats when the heart is resting.
High blood pressure (hypertension) is diagnosed when systolic pressure is 130 mm Hg or higher or diastolic pressure is 80 mm Hg or higher.
“Elevated” blood pressure means systolic readings between 120–129 mm Hg with diastolic pressure below 80 mm Hg. Without intervention, elevated blood pressure can progress to long-term hypertension.
Why tea?
Green and black teas are rich in antioxidants and other beneficial compounds.
Prior research suggests that drinking tea regularly may help with weight loss and reduce the risk of diabetes, heart disease, and cancer.
Because high blood pressure is a major contributor to cardiovascular disease, scientists are interested in whether tea could be a simple dietary tool for improving heart health.
The team reviewed five published studies involving 408 participants with elevated blood pressure or diagnosed hypertension. They assessed how drinking tea—either green or black—affected blood pressure over time.
Key findings
- Regular tea consumption lowered systolic blood pressure by an average of 3.53 mm Hg, and
- Lowered diastolic blood pressure by about 0.99 mm Hg.
Even small reductions like these are meaningful at the population level and can reduce long-term cardiovascular risk.
Importantly, the longer people drank tea—especially for more than three months—the greater the reduction in both systolic and diastolic pressure.
When comparing tea types, green tea showed a stronger blood-pressure-lowering effect than black tea.
None of the reviewed studies reported negative side effects.
The findings suggest that a simple habit—drinking tea regularly—may help people with elevated or high blood pressure improve their heart health. This may be useful information for health care providers, doctors, and individuals managing hypertension.
The study was published in Complementary Therapies in Medicine and conducted by Marjan Mahdavi-Roshan et al.
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