Everyone knows green tea packs an unbeatable health punch-- and a new study shows why, because researchers say this great-tasting drink can actually undo genetic damage inside your body.

And all it takes to get started is just a month of tea- sipping.

The two-part study in the British Journal of Nutrition involved a placebo-controlled trial along with an in vitro lab experiment, and they both revealed the same thing: Tea can actually fight off the oxidative stress associated with aging and disease.

In the trial, 18 volunteers were given either a green tea drink (specifically, the somewhat pricey Longjing variety) or water every day for four weeks. Blood and urine samples taken before and after the study period revealed the true power of tea: a 20 percent reduction in DNA damage after that single month of sipping.

For the other part of the study, researchers incubated human blood cells with green tea. Then, they exposed those cells to hydrogen peroxide, a damaging oxidation agent-- and found that the cells exposed to tea were better able to resist damage from oxidation.

Stress and damage from oxidation leads to aging and disease. The fact the tea can actually undo that damage helps to explain a study published earlier this year, which found that found green tea drinkers have "younger," less- damaged cells.

And that's not the only benefit of tea. The polyphenols in tea--especially green tea, which can have up to 10 times as much as black--have been linked to cancer prevention, vision health and even longer lives. Some studies have also found that green tea may reduce the risk of diabetes, dementia, depression and so much more.

The best way to awaken the polyphenol powers of green tea is with a squeeze of lemon and a pinch of sugar--but if you're having problems with your waistline, skip the sugar and stick to the lemon.

And if you're not--make teatime the only time you use the stuff.