Tea is one of the world's most popular drinks, and high blood pressure is the most common form of cardiovascular disease. Researchers in Taiwan brought the two together; previous studies have found conflicting results on whether drinking tea lowers blood pressure.

What the researchers wanted to know: Does tea lower your blood pressure?

What they did: The authors used data from a study on chronic diseases in Tainan, a city in southern Taiwan. The 1,600 people in the study were interviewed about their medical history, including hypertension (high blood pressure), and lifestyle, including physical activity and tea drinking. Since tea servings can vary from 30 milliliters (two tablespoons) in traditional "elderly tea" to 750 milliliters (more than three cups) in a plastic cup at a tea shop‑and people drink green, black, and oolong—the tea discussion had to get pretty in-depth. Doctors and nurses weighed each participant and measured their blood pressure.

What they found: After adjusting for age, sex, body mass index, family history of hypertension, and more than a dozen other variables, people who drank two and a half cups or more of tea a day still had lower blood pressure than people who didn't drink tea. The same was true for people who'd drunk tea for more than 10 years. Drinking less tea than that seemed to be beneficial, too; people who drank half a cup to two and a half cups a day had a 46 percent lower chance of developing hypertension. Maybe the conflicting results in earlier studies were because of all the confounding factors, the researchers say. For example, while people who drink tea in the Netherlands, Japan, and the United States tend to be more highly educated and have a healthier lifestyle, people who drink tea in Scotland and Wales tend to be less educated and to eat fattier diets.

What the study means to you: Drinking tea looks like a good idea.

Caveats: It's an observational study—researchers didn't randomly assign people to drink tea or not drink tea—but all the adjustments for different variables make it seem pretty strong.

Find out more: Information on high blood pressure from the American Heart Association: http://www.americanheart.org/

Don't miss the celebrity-designed tea cosies on the Tea Council's tea-promoting website, www.tea.co.uk

Read the article: Yang, Y., et al. "The Protective Effect of Habitual Tea Consumption on Hypertension." Archives of Internal Medicine. July 26, 2004, Vol. 164, pp. 1534‑1540.

Abstract online: http://archinte.ama-assn.org