Exploring How Green Tea May Protect against Cancer
AICR is funding research into compounds called polyphenols that seem to hold clues about green tea’s tumor-fighting effects.
Over the past few decades, evidence has grown that suggests green tea may help prevent cancer. To continue investigations into its potential, AICR is funding two researchers who are finding more valuable clues about how compounds in green tea work.
These natural substances are called polyphenols. They seem to make it more difficult for a cancer cell to respond to growth signals, thus slowing cancer growth.
Joshua Lambert, PhD, Associate Professor in the Department of Food Science at Pennsylvania State University, is studying whether piperine – the substance that gives black pepper its heat – when taken together with the green tea polyphenol epigallocatechin-3-gallate (EGCG) increases the amount of EGCG that gets into our blood and some tissues, compared with the polyphenol alone. His initial findings indicate that it does.
AICR grantee Bryan Fuchs, PhD, Instructor in Surgery at Harvard Medical School, oversees a lab at Massachusetts General Hospital. Dr. Fuchs is using an animal model with chronic liver disease to determine whether EGCG hinders the development of liver cancer by inhibiting scarring (cirrhosis).
He is testing EGCG alone and in combination with erlotinib, an experimental treatment for liver cancer, to determine if it slows tumor progression. If the results are positive, he hopes to be able to move to human testing.
“Liver cancer is unique because we generally know who is at risk of developing it. Patients have had liver disease, such as fibrosis or cirrhosis, for many years, before they develop cancer,” Dr. Fuchs explains. “It’s a unique setting for prevention. Our hope is to develop something we can give to patients to prevent liver cancer down the road.”
Best Dosage Amounts Still Unknown
Dr. Lambert says it is not yet known how much green tea a person would have to drink in order to be protected against cancer. “Some animal studies suggest it would take 5-10 cups a day while human epidemiological studies suggest as few as 2 cups a day. The data are still lacking.”
Dr. Fuchs’s research involves the equivalent of 8-12 cups a day of green tea. “In Asian cultures it’s not unusual to drink that much,” he notes.
Dr. Lambert cautions that it is also not known how effective green tea supplements might be in protecting against cancer. “We can’t say that taking a pill is the same as drinking five cups of green tea – there are differences in peak blood levels and other measures,” he says.
Combination Benefits Likely
One day, scientists may use green tea as supplemental treatment for cancer, Dr. Lambert says. “It would not necessarily be used as a front-line or single therapy, but perhaps as an adjunct to something else.
“Some interesting animal studies of green tea combined with pharmaceutical agents suggest a better outcome than when either agent is used alone,” he says. “Green tea is most likely to be promising when used with another treatment for early-stage cancer or in post-chemotherapy treatment to prevent a recurrence.”
Published on September 15, 2014