• 7/19/2005
  • Washington, DC
  • Eva A. Sylwester
  • ScienceDaily (www.sciencedaily.com)

New research reaffirms the potential value of green tea as a natural substance able to stop cancer before it starts.

“What we do in our conference every year is focus on what the scientists are talking about,” said Jeffrey Prince, vice president for education and communications of the American Institute for Cancer Research.

Prince and others spoke at a news briefing at AICR’s annual International Research Conference on Food, Nutrition and Cancer in Washington. He said this year’s conference includes six separate presentations on the benefits of green tea — and no tea companies were involved in the research.

The AICR also released the “New American Plate Cookbook,” featuring recipes designed to promote smaller portion sizes and increased consumption of fruits and vegetables.

“The American Institute for Cancer Research recommends a mostly plant-based diet to people concerned with reducing cancer risk,” Prince said.

Many plant-based foods are rich in anti-oxidants, which limit damage to cells and tissues that toxins and pollutants cause by slowing the rate of certain chemical reactions.

The active ingredient in green tea is a compound called epigallocatechin gallate, or EGCG, a stronger anti-oxidant than is contained in either vitamin C or E, according to an AICR fact sheet. Green tea is made from the same plant as black tea and oolong tea, but the leaves are not fermented during processing, which apparently preserves the plant’s cancer-fighting compounds.

In a study using cancer cells in mice, Thomas Gasiewicz, a professor of environmental medicine at the University of Rochester in New York, found EGCG molecules bind to and inhibit the action of hsp90, a protein found disproportionately in cancer cells. Hsp90 also is found in smaller amounts in healthy cells throughout the body, suggesting EGCG could curb cancer development in numerous organs.

“Based on the animal studies, it’s hard for me to believe that, at least at some dose, (EGCG) would not have a protective effect in the human population,” Gasiewicz told reporters.

According to an AICR fact sheet, epidemiological studies have been conducted, mostly in Asian populations, that link green-tea consumption with a lower incidence of many different cancers. Gasiewicz said more research is required to pinpoint the exact dosage of green tea that provides cancer protection.

The benefits of green tea are underutilized in the U.S. population, the AICR fact sheet said. A telephone survey conducted by the organization, only 15 percent of Americans said they drink green tea every day, compared to 62 percent who drink soft drinks every day and 61 percent who drink coffee daily.

“People who drink cola or coffee on a regular basis might consider substituting green tea for one of those servings,” Prince said, adding that for people who avoid caffeine, decaffeinated green tea is also available.

The AICR fact sheet said green tea generally has one-half to one-third of the caffeine in black tea and one-third to one-fourth of the caffeine in coffee.

Maggie Sheen, a food writer and recipe developer for AICR, told United Press International that getting green tea into the American diet requires no more than a trip to the supermarket, where at least two or three brands usually are available. Sheen suggested trying several brands to determine the best tasting variety, because green tea sometimes can seem bitter to the American tongue.

“We have such a sweet tooth and we’re so used to putting sugar in everything that green tea is a shock to the palate,” she said.

In contrast, average per-capita consumption of green tea in Japan and China is three to four 4 ounce cups per day.

In Japan, Sheen said, green tea is used as a flavoring in desserts, and the Japanese equivalent of “Grandma’s chicken soup” is a porridge made from hot rice, leftover fish and green tea. She said she personally has experimented with adding green tea to foods such as cream cheese, pound cake and sorbet.

Prince said foods flavored with green tea may not provide all of the health benefits of a cup of the beverage, but nevertheless are worth a try and can help acclimate people to green tea’s taste.

“The more you process plant foods, you lose some of the phytochemicals and some of the nutritional value,” he noted.