WUSM study will test whether ginseng prevents diabetes

(Republished with permission from the St. Louis Post-Dispatch. This article originally ran in the Science & Medicine section on Wednesday, May 18, 2005)

By Tina Hesman
Of the Post-Dispatch

A fabled ancient remedy could soon become a new diabetes-prevention therapy.

Doctors at Washington University are testing ginseng, a root long used in traditional Asian medicine, to see if it can head off diabetes in overweight adults.

An estimated 18.2 million Americans have diabetes, and 41 million more are considered pre-diabetic, with higher than normal blood sugar, according to the American Diabetic Association. But studies of animals suggest that ginseng may fight insulin resistance, a precursor to diabetes.

Insulin signals cells to take in sugars and burn them for energy. When cells ignore insulin’s message, the body churns out more insulin, which causes the liver to release fats that interfere with insulin receptors. That escalates the need for insulin.

“And where does it all end? Well, the pancreas eventually poops out,” said Dr. David L. Katz, director of medical studies at Yale University’s School of Public Health. Katz spoke during a press conference call on insulin resistance last week.

The result is diabetes.

Insulin resistance is often accompanied by obesity, high triglycerides and low HDL (“good”) cholesterol and high blood pressure in a pre-diabetic condition sometimes called the metabolic syndrome. The syndrome is also a harbinger of heart disease. People with metabolic syndrome may have no symptoms to alert them that they could soon get diabetes or heart problems, but about 47 million in the U.S. have the condition.

Ginseng has been used in Asia for about 2,000 years to treat a variety of ailments, including diabetes, said Dr. Dominic Reeds, an instructor in medicine at Washington University. He and others are testing the root and one of its active ingredients to see if it can improve the body’s response to insulin in overweight people who have pre-diabetes.

The researchers will give volunteers either capsules containing a placebo, whole-root extract of ginseng, or a compound called ginsenoside Re – thought to be an active ingredient isolated from the root. The volunteers will take the capsules three times a day for the duration of the study. The Ginseng Board of Wisconsin donated the ginseng used in the study and the amount of ginsenoside in the extracts has been quality checked, Reeds said.

The study will require an overnight stay at the beginning and end of the multiweek study as well as regular visits during the study. Researchers will measure how well the volunteers respond to insulin and track blood sugars and fats and other measures of health. Even subtle improvements could be good news for people facing diabetes, Reeds said.

In laboratory tests with animals, both the whole ginseng extract and the ginsenoside alone lowered blood sugar in mice after the rodents consumed a sugary drink.

But animal studies with promising results have often gone bust when the medicines were tested on people.

“I think consumers should rely heavily on clinical data (from human tests) rather than on anecdotal evidence or animal studies,” said Dr. Chun-Su Yuan, director of the Tang Center for Herbal Medicine Research at the University of Chicago and editor in chief of the American Journal of Chinese Medicine. Yuan has published studies of ginseng berries and ginsenosides in animal tests.

For all the promise of animal studies, clinical trials using ginseng have failed to improve insulin sensitivity in patients who already have diabetes, Yuan said. It remains to be seen whether the plant or its compounds can stop diabetes before it develops, he said.

Ginseng is not for everyone, Reeds cautions. People who are prone to high blood pressure or heart palpitations should probably avoid taking ginseng, as the root can make the conditions worse. Caffeine intensifies jitters caused by ginseng too, he said. And the root can mix dangerously with drugs, such as warfarin (also known as Coumadin), that keep blood clots at bay. The combination of ginseng with a blood thinner could lead to hemorrhages or stroke.

Herbal medicines and dietary supplements are notoriously inconsistent in quality, researchers warn.

“The problem with ginseng is the variability. This is true of all botanicals,” said Dr. Todd Brown, assistant professor of endocrinology and metabolism at Johns Hopkins University. Brown and his colleagues are testing ginseng to see if the root can counteract the insulin-resistance brought on by some drugs used to treat HIV.

Reeds counts himself a skeptic of botanical remedies, but he is testing the power of ginseng against diabetes in hopes of finding something that can slow the epidemic of the disease now plaguing the nation.

“If people have been doing this for 2,000 years, it’s probably not just hearsay,” Reeds said.

Overweight people who have pre-diabetes and are between ages 18 and 64 may volunteer for the study. For more information, call nurse coordinator Heather Robertson at 314-362-8682.

Reporter Tina Hesman
E-mail: thesman@post-dispatch.com
Phone: 314-340-8325

Copyright 2005 St. Louis Post-Dispatch, Inc.