To get hard science on tea and health, I interviewed Douglas Balentine, Director of Nutrition and Health at Unilever North America (the world's largest tea company, and maker of tea brands Lipton and PG Tips). He has years of experience in researching tea's many health benefits, and shared his expertise on tea and health in the Q&A below.
Lindsey: There are many claims out there about which tea type is the "healthiest." Why is the idea of one tea type being the "healthiest" is not the most constructive way to think about tea?
Doug: True tea, ie. black, green, oolong and white (but not "herbal") teas, are all produced from the leaves of Camellia sinensis. While there are some differences in the amounts of and types of flavonoids and amounts of caffeine, theanine [a factor in the feeling of tea drunkenness] and magnesium between tea types generally all teas contain meaningful amounts of tea phytonutrients. Population-based studies and intervention studies have shown the both green and black teas have similar benefits for maintaining health and wellness.
Lindsey: Can you tell me more about flavonoids?
Doug: Flavonoids are dietary compounds found in tea, wine, cocoa, fruit and vegetables. Tea flavonoids help maintain normal blood vessel function (endothelial function). All teas from the Camellia sinensis plant, such as black, green, oolong and white (but not herbal) teas, naturally contain between 100 to 300 mg of flavonoids per serving.
Lindsey: What the health benefits are shared by all true teas?
- Regular tea drinking can contribute to proper hydration, improves focus and concentration, helps maintain positive mood throughout the day.
- Tea naturally contains zero calories, therefore, when it is used in place of higher calorie beverages, it can help with control caloric intake which is important for managing weight. In Asian populations, green tea consumption has been shown to be able to reduce the amount of fat around the middle (known as "visceral fat"). This has not been confirmed in Western populations, but the findings suggest green tea drinking may help maintain a healthy body composition.
- Three or more cups of tea per day may help maintain cardiovascular health. Population-based studies have shown that regular consumption of black tea is associated with a reduced risk of heart disease and a reduced risk of stroke.
- Recent clinical studies have shown that drinking two to three cups of black tea per day can help maintain healthy blood pressure and promote normal blood vessel function.
Doug: Both green and black tea consumption has been associated with maintaining cardiovascular health and healthy blood vessel function. There are few studies on oolong, white or pu-erh teas so the benefits of these teas are not known.
Lindsey: Is there any new research (as of March, 2012) about tea and health that is particularly compelling or groundbreaking?
Doug: We just announced the results of a recent study supported by Unilever (Lipton's parent company), conducted at the University of Western Australia (UWA) and the National Health and Medical Research Council of Australia. The study found that subjects who drank 3 cups of black tea throughout the day for six month maintained more healthy blood pressure throughout the day.
In the study, 95 Australians, ages 35 to 75, consumed either black tea or a control beverage three times per day for a six month period. After both three months and six months the tea drinkers' systolic and diastolic blood pressure was between 2 and 3 mm Hg lower than those on the placebo tea beverage.
Due to the fact that high blood pressure can significantly impact people's risk of developing cardiovascular disease, the leading cause of death in the U.S., this study suggest that black tea drinking may help maintain cardiovascular health by helping to maintain blood pressure.