For nine months, one group of rats in food scientist Elvira de Mejias University of Illinois lab drank only a Latin American herbal tea, brewed fresh daily from the leaves of Ardisia compressa, a plant that grows on the Pacific coast of Mexico. Other rats drank water. When researchers used chemicals to induce liver cancer in the animals, the results were surprising.
Rats that consumed the tea did not develop malignancies. The group that did not consume tea did develop malignancies, she said.
Ardisia tea was selected for study because the indigenous people of the Mexican Pacific Coast have used the plant for years to treat and prevent cancer.
One group of animals consumed the herbal tea for only two weeks before cancer was induced. The animals did not develop tumors or pre-malignancies, which demonstrates the teas cancer prevention properties, she said.
Her findings will be published in Food and Chemical Toxicology.
According to de Mejia, all teas provide some level of cancer protection because of their potent antioxidant activity, although green tea has more antioxidants than black tea.
If you drink tea, within an hour some antioxidant or cancer-fighting capacity will be circulating in your blood. And thats important because we consume so many oxidants in our food. If you eat broiled steak, very well done, youre eating carcinogens. We need to keep taking in antioxidants to compensate for our exposure to all these carcinogens, she said.
The scientist said recent research has linked tea to reductions in colon, liver, prostate, and oral cancer.
Some researchers suggest rinsing your mouth with tea before bedtime because of its antimicrobial properties. Tea lowers the number of bacteria in your mouthbacteria that produce carcinogens when they act on food residues, she said.
She recommends drinking between three and 10 cups of green tea a day for antioxidant activity and consequent cancer protection. Three cups of tea provide more antioxidant activity than a serving of broccoli.
But, for maximum benefit, you should drink about 10 cups daily. Youll probably want to choose a decaffeinated variety, she said.
Admittedly, thats a lot of tea, but if you drink it instead of the water you should be drinking, you will notice other benefits as well, she added.
An unabashed tea promoter, de Mejia said clinical studies have linked tea to lower blood pressure, lower cholesterol, and improvements in rheumatoid arthritis. In addition, she says studies suggest that three to four cups of tea daily may decrease appetite and lower body weight.
She has also done studies with tea extracts but has achieved better results using the whole plant. When the bioactive compounds interact, there is a synergistic effect, she said. Im interested in learning exactly how these compounds work together to protect the genetic material in cells.
As herbal teas flood the market, de Mejia is keeping an eye out for claims about their safety and efficacy. A current de Mejia study involves mate tea, another tea popular in Latin America, that is believed to have anticarcinogenic properties.
The researcher said more studies are needed to clarify the benefits of tea drinking in humans.