Black tea is made from the leaves of a bush called Camellia sinensis. A process called oxidation turns the leaves from green to a dark brownish-black color. Oxidation means the leaves are exposed to moist, oxygen-rich air.
Although green and black tea both contain antioxidants which may aid in the prevention of cancer and other diseases, green tea comes out ahead of black tea in cancer prevention. As green tea is processed minimally, it has more antioxidants than black tea making it a great beverage to include in your weight loss diet.
Black tea is rich in oxalate, a compound found naturally in many foods. Too much of it can also lead to kidney stones. ... Like tea, these foods are known for their health benefits. But as Youngquist says, “Anything consumed to excess can be toxic—including water!”
Many people drink black tea for alertness and energy. There is good scientific evidence to show this works. Black tea contains caffeine. It also contains a little bit of a stimulating substance called theophylline. Both can speed up your heart rate and make you feel more alert.