Habitual Tea Intake and the Risk of Hypertension.




Archives of Internal Medicine

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When your doctor says you have high blood pressure, the medical name for your condition is "hypertension." Blood pressure is created when the heart beats, propelling blood throughout the body. Blood pressure occurs in two distinct phases, corresponding to the contraction and relaxation of the heart muscle. When the heart contracts, it ejects a certain volume of blood out from its right side into the body's largest artery, the aorta. This initial thrust causes "systolic" blood pressure, which is the upper number of your blood pressure reading. As the heart relaxes, the blood presses against the walls of the arteries as it circulates, causing "diastolic" blood pressure, which is the lower number in your reading. Systolic blood pressure is a measure of the heart's blood output, while diastolic is determined by the resistance of arteries in the extremities to the flow of blood. If your blood pressure reading is "120 over 80," this means your systolic pressure is 120 and your diastolic is 80.

Hypertension has many possible causes. Hypertension that results from another disease is called "secondary hypertension." Fewer than 5 percent of people who suffer from hypertension have secondary hypertension, and in the majority of those, kidney disease in the cause. Other disorders known elevate blood pressure include thyroid disorders and Cushing's disease, which is a disorder of the adrenal glands. Certain medications— nervous system stimulants, synthetic estrogen, and NSAIDs (nonsteroidal anti-inflammatory drugs), to name a few— sometimes contribute to hypertension.

A recent study stated that habitual intake of tea in Chinese medicine has been known to have positive effects on blood pressure. Studies have shown inconsistency in determining the accurateness of this claim. This study involved over 1500 participants, of which 600 were habitual tea drinkers for at least one year. All participants were over 20 years of age and did not have a history of high blood pressure. The researchers found that the habitual tea drinkers had a 46% decreased risk of developing hypertension when compared to non-habitual drinkers. Those who drank even more tea daily saw a risk reduction of 65%. The authors concluded that, “Habitual moderate strength green or oolong tea consumption, 120 mL/d or more for 1 year, significantly reduces the risk of developing hypertension in the Chinese population.”1


1. Yang YC, et al. The Protective Effect of Habitual Tea Consumption on Hypertension. Arch Intern Med. 2004;164:1534-1540.