This is an excerpt from an article on Dr. Mercola. I recommend popping over there to read the contents in full (about a 90 second read.)
Black Tea Shows Blood Sugar Benefits: Americans drink about 2.25 billion gallons of tea each year -- that’s about 132 cups of tea per person per year. While this sounds like a lot, you may actually need five to 10 cups of most green or black teas a day to reap many of their protective benefits.
Still, one of the active ingredients in tea, epigallo-catechin gallate (EGCG), really does show potential to fight a wide range of diseases, including:
help to protect your bones.
I still believe that water should be your beverage of choice, and should make up the majority of your fluid intake, but adding tea to your day is a perfectly sensible choice for an additional beverage.