Results of oolong tea study show more research is needed, UTHCT physician says at 11th Annual Cohen Lecture

Monday, April 17, 2006

Sometimes the results of one clinical trial tell you that you need more and larger clinical trials, or you need to shift your research focus.

That’s what Dr. David Shafer of The University of Texas Health Science Center at Tyler told the crowd at the 11th Annual Allen B. Cohen Lecture as he gave them a glimpse of how scientific research works. The lecture was held Tuesday, April 11, at the Ornelas Center in Tyler.

Dr. Shafer reported that a small UTHSCT study of 30 people with type 2 diabetes showed that drinking a quart of oolong tea daily for 12 weeks did not lower participants’ blood sugar levels. Several earlier clinical trials in Japan and Taiwan appeared to show drinking the semi-fermented tea did help control blood sugar.

“In our study, there was no effect on glycemic (blood sugar) control despite the enthusiasm of some patients,” said Dr. Shafer, director of UTHSCT’s Center for Diabetes Care.

Yet Dr. Shafer was not discouraged by his study’s results, nor was he quite ready to give up on tea as a possible aid in lowering blood sugar.

“It may be that we need more patients in a clinical trial before tea’s protective effect is evident. We may need to try green or white tea, or perhaps we should focus on people with pre-diabetes – high blood sugar – to see if tea helps prevent them from developing diabetes,” he said.

“Tea is rich in flavonoids, phytochemicals that give fruits and vegetables their characteristic colors. Flavonoids in tea, especially green tea, also exhibit antioxidant properties. They may offer possible protection against heart disease, dementia, inflammation, and cancer – all diseases associated with the aging process,” he said. Green and white teas have the highest concentrations of these chemicals, black tea has the lowest concentration, and oolong tea falls somewhere in between.

“We need well-controlled human studies, with larger numbers of participants to determine the safety and effectiveness of tea. Test tube studies and animal studies are useful, but they do not show how tea affects human health,” Dr. Shafer said.

Clinical research studies such as these are important, because diabetes is a serious health problem in the United States, where 21 million people have type 2 diabetes and another 40 million have pre-diabetes, Dr. Shafer said. Each day, approximately 4,100 new cases of diabetes are diagnosed, and 810 people die from diabetes.

The annual lecture and dinner honors Dr. Cohen, “the father of research at our campus,” UTHSCT President Dr. Calhoun said as he acknowledged Dr. Cohen’s widow, Geri Cohen, who attended the event.

Dr. Cohen was an internationally respected pulmonary physician and researcher who joined UTHSCT in August 1983. The former executive associate director and professor of medicine and biochemistry at UTHSCT died in February 1995.

The three recipients of the 2006 Research Membership Seed Grant Awards also were recognized during the event. They are: Dong-Ming Su, Ph.D.; Hua Tang, Ph.D.; and Christian Zwieb, Ph.D. A total of $28,100 in locally raised funds was awarded this year.

This money will support research into how certain biological processes contribute to aging, as well as investigating whether RNA molecules could be used to build synthetic scaffolds to aid drug delivery. A committee composed of UTHSCT Research Council community members awarded the grants.

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