Green tea is hardly oxidized at all, and black tea is oxidized until it is, well, black. That tea spectrum between green and black is where oolong resides. Its medicinal benefits have not been as well-researched as its black and green siblings, but here's what we do know:
Like its green sister, oolong contains potent antioxidants which are big factors in its healthfulness. These include theaflavins, thearubigins and EGCG, which researchers believe help reduce blood sugar and insulin levels and increase insulin sensitivity.
If you are up to drinking 24 ounces of oolong per day, you can expect your risk of developing type 2 diabetes to drop by 16 percent. Still thirsty? Downing 33 ounces of oolong daily should drop your blood sugar levels by 3.3 percent, and 50 ounces (that's a liter-and-a-half, by the way) will reduce your blood sugar up to a whopping 30 percent.
Heart disease is also in oolong's cross-hairs. Research indicates that drinking 8 ounces or more of oolong each day lowers your chance of cardiac disease by 61 percent! The risk of having a stroke is reduced by 39 percent in those who just drank 16 ounces of oolong daily, while sipping merely 4 ounces of green or oolong tea may reduce your risk of developing high blood pressure by up to 46 percent. Of course, oolong also contains caffeine, which has a tendency to raise your blood pressure, That noted, the caffeine content of oolong is only about 25 percent that found in a similar amount of coffee.
Oolong can give you a mental boost as well. Drinkers of oolong gain all the mood-enhancing benefits of caffeine's dopamine and norepinephrine jiggering, and the calming effects of all tea polyphenols. Unique to oolong tea, however, is its imbuing of up to a 64 percent lower risk of brain function decline.
Anyone who drinks black, green or oolong tea daily over a ten year period should accrue an additional 2 percent bone mineral density, but oolong drinkers up the ante: they average a 4.5 to 4.9 percent spike.
The real over-the-top benefits of oolong come into play when you examine the tea's reputation for “negative calories.” The polyphenols which give oolong its antioxidant powers are also thought to activate enzymes that help you use stored fat for energy, with a net effect that oolong tea may boost your metabolism and decrease the amount of fat absorbed from your diet. Another study found that both full-strength and diluted oolong tea helped participants burn 2.9 to 3.4 percent more total calories per day.
Put the kettle on...