There are three main varieties of tea: green, black, and oolong. All three varieties are made from the leaves of the same species of plant called Camellia sinensis; the difference is in how the tea leaves are processed. Green tea is made from unfermented leaves, while oolong tea is made from partially fermented leaves and black tea is fully fermented.
Unsweetened brewed green tea is a zero calorie beverage. The caffeine contained in a cup of tea can vary according to the length of infusing time and the amount of tea infused. In general, green tea contains a relatively small amount of caffeine (approximately 20-45 milligrams per 8 ounce cup), compared with black tea, which contains about 50 milligrams and coffee with 95 milligrams per cup.
The most popular, widely consumed types of green teas hail from the places where green tea originated: China and Japan. Green teas from China and Japan have different flavor profiles based on where and how they are grown, but most distinctively how they are processed—pan fired in China and steamed in Japan. Other countries producing green tea typically take cues from China or Japan and adopt one of these country’s tea production styles.
Rooibos tea is anti-inflammatory in nature, which means that it reduces blood pressure and scavenges free radicals like other antioxidants. Quercetin, another powerful antioxidant found in rooibos tea, has been linked to preventing a wide variety of heart conditions. It promotes an increase in HDL cholesterol (good cholesterol) and inhibits the LDL cholesterol (bad cholesterol) from binding to the walls of arteries and blood vessels.