But before you rush to health-food stores to stock up on the popular herb, be aware that there is no way to know if the product you buy will be as effective as the preparation used in the studies, researchers caution.
University of Toronto investigators presented both studies here this weekend at the American Diabetes Association's 63rd Scientific Sessions.
Since normalizing blood sugar levels is a critical goal of diabetes treatment, ginseng could someday be an important strategy in managing patients, says Fran Kaufman, MD, president of the American Diabetes Association.
Better Blood Sugar
In one study, people with type 2 diabetes who consumed ginseng and a highly viscous fiber similar to pectin had a notable reduction in blood sugar levels, reports Alexandra Jenkins, a PhD candidate at the University of Surrey, U.K.
The study enrolled 30 people with diabetes in whom medication helped to control -- but did not normalize -- blood sugar levels. The participants received either capsules containing ground, North American-grown ginseng and a highly viscous fiber, or dummy capsules, three times a day for 12 weeks.
After a four-week break, the participants switched to the alternate regimen; those who had received the ginseng capsules then took placebo and vice versa.
Blood samples taken before and after each 12-week period showed that hemoglobin A1C -- a standard measure of blood sugar levels -- dropped into the normal range when participants were taking the ginseng capsules, but not when they were taking placebo, the study showed.
The herbal preparation appeared to be safe, with no adverse effects.
Moreover, ginseng appears to have an effect beyond medication, the American Diabetes Association's Kaufman says, suggesting the two approaches are complementary in treating diabetes.
The Chinese, who use ginseng root to treat a variety of ailments, have been in medicine for 5,000 years, she says. "Just as acupuncture has been proven to have a role in Western medicine, so, too, will ginseng. We need to think globally."
Improved Insulin Performance
In the second study, Korean red ginseng improved insulin sensitivity when compared with placebo, says John L. Sievenpiper, a PhD candidate at the University of Toronto.
One of the key abnormalities behind type 2 diabetes is that the body's tissues are not responsive enough to insulin so they don't process it properly. Ginseng, he says, appears to help the patients process better the insulin they have.
"There is no doubt that natural products such as ginseng have a role in controlling the body's defective response to insulin," says Kaufman, who is also head of the Center for Diabetes at Children's Hospital in Los Angeles.
According to the American Diabetes Association, poor control of blood sugar can lead to severely debilitating and even fatal complications including heart disease, stroke, blindness, and kidney disease.
Not Standard Treatment -- Yet
But exactly how best to incorporate ginseng into diabetes treatment still needs to be determined, Kaufman says, noting that both trails were small.
Sievenpiper agrees. "These are preliminary, short-term studies that indicate a need for more research. They are not a reason to take ginseng," he said.
And because of poor regulation, standardization, and labeling in the herbal industry, there is no way to know if one product will work as well as another, Sievenpiper says.
Most importantly, he says, people with diabetes should be sure to tell their doctor if they are taking ginseng because lowering blood sugar too much can be dangerous.