New Study: Green Tea Extract May Protect Against Oral Cancer

Good news for people with at-risk signs of oral cancer: a new study from Texas reveals that green tea extract may be the preventative measure these people need. In fact, the journal Cancer Prevention Research published findings showing that more than 50 percent of study participants at the University of Texas M.D. Anderson Cancer Center had a clinical response to the green tea extract. Keep reading for more information on this important discovery.

“While still very early and not definitive proof that green tea is an effective preventive agent, these results certainly encourage more study for patients at highest risk for oral cancer,” stated lead researcher Vassiliki Papadimitrakopoulou, MD. He also pointed out that the fact that it is very encouraging that this extract is not toxic as these individuals are otherwise healthy and he stressed the importance of not doing any unnecessary additional harm to the patient.

Ito En funded the study that used their green tea extract.

Proof in the Polyphenols?

There are four primary polyphenols found in fresh tealeaves. They are epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), and epicatechin (EC).

• Green tea contains between 30 and 40 percent of water-extractable polyphenols.
• Black tea – which is green tea that has been oxidized by fermentation - contains between 3 and 10 percent.
• Oolong tea is a semi-fermented tea. It is somewhere between green and black tea.

Phase II Study Statistics

A phase II dose-finding trial followed 41 people with oral leukoplakia. Leukoplakia is a condition that is a sign of oral cancer risk. Those that participated were to receive either a placebo or green tea extract at one of three doses. The dosing levels included 500 milligrams per metre squared of body mass (mg/m2), 750 mg/m2, or 1,000 mg/m2 three times a day.

The researchers deemed it essential to collect oral tissue biopsies. According to the researchers “it allowed us to learn that not only did the green tea extract appear to have benefit for some patients, but we pointed to anti-angiogenic effects as a potential mechanism of action,” explained co-researcher Anne Tsao, MD.

Nearly 60 percent of people taking the highest two doses of the green tea extracts had a clinical response.
Of those in the lowest extract dose, just over 36 percent had a clinical response.
In comparison 18 percent in the placebo group displayed a clinical response according to the researchers.

There was an extended follow-up with a mean of 27.5 months. The follow-up showed that 15 participants had developed oral cancer, with the median disease development time being 46.4 months.
 
Safety

According to the researchers, the highest dose group were the one that displayed the most side effects such as insomnia and nervousness. Still no significant toxicity was reported.

“While these are encouraging findings, much more research must be done before we can conclude that green tea may prevent oral or any other type of cancer. It's also important to remind people that this trial enrolled very few participants who, at the highest dose levels took the equivalent of eight cups of green tea three times a day,” cautioned Papadimitrakopoulo. “We need to further understand if green tea offers longer-term prevention effects for patients,” he added.

Still, this research is promising for the future. And it’s probably safe to add one more “thumbs-up” to green tea’s many health benefits!