Traditional Chinese herbal medicines hold promise for slowing the progression from prediabetes to an official diabetes diagnosis, according to new research accepted for publication in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).

Prediabetes is diagnosed an individual has developed elevated blood sugar levels, but glucose levels have not yet risen to the point of developing type 2 diabetes. People who are prediabetic face a heightened risk of developing type 2 diabetes as well as heart disease and stroke. According to the Centers for Disease Control and Prevention, about 79 million American adults age 20 years or older have prediabetes.

"With diabetes evolving into a serious public health burden worldwide, it is crucial to take steps to stem the flood of cases," said one of the study's authors, Chun-Su Yuan, MD, PhD, of the University of Chicago. "Patients often struggle to make the necessary lifestyle changes to control blood sugar levels, and current medications have limitations and can have adverse gastrointestinal side effects. Traditional Chinese herbs may offer a new option for managing blood sugar levels, either alone or in combination with other treatments."

During the double-blind, randomized, placebo-controlled trial, 389 participants at 11 research sites in China were randomly assigned to take either a capsule containing a mixture of 10 Chinese herbal medicines or a placebo. For a year, subjects took capsules of either the Chinese herb mixture, called Tianqi, or the placebo three times a day before meals. All participants received a month of lifestyle education at the outset of the trial and met with nutritionists several times during the course of the study. Subjects' glucose tolerance was measured on a quarterly basis.

At the end of the trial, 36 participants in the Tianqi group and 56 in the placebo group had developed diabetes. The analysis found taking Tianqi reduced the risk of diabetes by 32.1 percent compared with the placebo, after adjusting for age and gender. The overall reduction in risk was comparable to that found in studies of diabetes medications acarbose and metformin, and study participants reported few side effects from the Tianqi herbs. Tianqi includes several herbs that have been shown to lower blood glucose levels and improve control of blood glucose levels after meals.

"Few controlled clinical trials have examined traditional Chinese medicine's impact on diabetes, and the findings from our study showed this approach can be very useful in slowing the disease's progression," said one of the study's lead authors, Xiaolin Tong, MD, PhD, of Guang'anmen Hospital in Beijing, China, said. "More research is needed to evaluate the role Chinese herbal medicine can play in preventing and controlling diabetes."