. Theyíre all from the same plant n

. Theyíre all from the same plant not to be confused with herb teas which arenít really teas at all, but infusions of boiling water and dried fruits, herbs or flowers.

When tea leaves are picked, they begin to oxidize, meaning the leaves interact with oxygen and the enzymes inside begin to change. This affects everything from the teaís color to its aroma and taste. A teaís ìtypeî is determined by the amount of oxidation and other processing. Black tea is made from wilted leaves that are fully oxidized. Green tea is made from unwilted leaves that arenít allowed to oxidize. Oolong tea is something in between. White tea is the rarest form because itís made from only young leaves or buds that have undergone the least amount of oxidation.

For such a simple brew, tea is amazingly complicated. Itís got thousands of compounds in it, many of them bioactive. At the center of a wide range of health claims are two: caffeine and antioxidants.

Of all the teas, black tea contains the most caffeine, about 40-120 mg for 8 oz. The same amount of freshly brewed coffee has about twice as much. Some believe that since caffeine speeds up metabolism, it also might help with weight loss. Caffeine can also affect mental alertness. These are just two of the possible health benefits of tea that could be attributed to its caffeine content. Research is promising, but itís way too early to start chugging the stuff thinking tea is a cure-all. And be careful: we know that caffeine raises blood pressure and can irritate the digestive tract. Consuming too much tea could lead to some nasty and potentially serious side effects, including headaches, irritability, nausea, diarrhea, insomnia, and an irregular heartbeat.

Antioxidants are the other substance in tea that some believe could be responsible for teaís healthy reputation. Thatís because we know that antioxidants help the body repair cell damage that happens as part of daily living. They may have a positive effect on a range of chronic conditions from cardiovascular disease to diabetes.

The trouble is, while some studies have found possible benefits of tea (especially green tea), most of that research is based on population studies whose results can be influenced by other factors like genetics and lifestyle.

Hereís what we do know: The potential benefits seem to be in drinking actually hot or cold brewed tea rather than in taking tea extract pills. Thatís because we donít yet know if the compounds in supplements are the same as those found in brewed tea, or that they are even in a form the body can absorb.

What I tell my patients is when drinking tea, just donít go overboard. But especially if a cup or two of tea a day replaces other liquids loaded with empty calories and sugar, choosing tea is tea-rrific.