Ginseng Helps in Controlling Blood Glucose
American and Korean red ginseng may help to normalize blood glucose levels
and improve insulin secretion and sensitivity in patients with type 2
diabetes.
Two studies were presented at the American Diabetes Association 63rd
Scientific Sessions.
In one study, people with type 2 diabetes who consumed ginseng and Konjac
mannan fiber ( a highly viscous fiber similar to pectin) had a notable
reduction in blood glucose levels, reported Alexandra Jenkins, BSc, RD, a
research associate at the University of Toronto in Ontario.
The double-blind, placebo-controlled, crossover-designed study enrolled 30
well-controlled diabetes patients; 23 were receiving oral hypoglycemic
agents, and seven used lifestyle intervention alone. The participants, who
were kept on their standard diabetes regimen, were randomly assigned to
receive either 3 g of ground-up North American-grown ginseng and 7 g of
Konjac mannan fiber blend, or placebo, daily for 12 weeks.
By the end of the study period, hemoglobin A1c (HbA1c) levels had dropped
from an average baseline level of 7.0% to 6.5% in patients were taking the
ginseng preparation compared with 6.8% for those who were taking placebo,
Ms. Jenkins said.
"The drop is comparable to that seen with other hypoglycemic agents, such as
the alpha-glucosidase inhibitors, when used as adjunct therapy," she said.
"The herbal prepartion appeared to be safe, with no adverse effects
observed," she said.
The results suggest that standard pharmacological therapies and ginseng are
complementary in treating diabetes, said Francine R. Kaufman, MD, outgoing
president of the American Diabetes Association. "The Chinese, who use
ginseng root to treat a variety of ailments, have been in medicine for 5,000
years," she said. "Just as acupuncture has been proven to have a role in
Western medicine, so too will ginseng. We need to think globally."
In the second study, Korean red ginseng improved both insulin secretion and
insulin sensitivity when compared with placebo, reported John L.
Sievenpiper, a PhD candidate at the University of Toronto. The trial
enrolled 19 well-controlled diabetic patients, applying the same design used
in the American ginseng study.
Korean red ginseng was safe with liver, kidney, and hemostatic function and
blood pressure not adversely affected compared with placebo, the study
showed.
While HbA1c levels did not significantly change, the ginseng preparation
"was associated with a dramatic 40% drop in both postprandial plasma glucose
and insulin levels," Mr. Sievenpiper said. Also, ginseng treatment led to a
significant improvement in both hepatic insulin sensitivity and whole-body
insulin sensitivity compared with placebo, he reported.
"The baseline HbA1c levels were already at 6.5%, so we couldn't push it down
significantly," he said. "But in patients with slightly higher levels, we
might see an effect."
Dr. Kaufman, who is also head of the Center for Diabetes at Children's
Hospital in Los Angeles, California, agreed. "There is no doubt that
natural products such as ginseng have a role in modulating weight and
insulin sensitivity," she said. But exactly "how adjunctive they may or may
not be" still needs to be determined, she added.
Mr. Sievenpiper emphasized that "these are preliminary, short-term studies
that indicate a need for more research. They are not a reason to recommend
ginseng to patients," 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, Mr. Sievenpiper said.
He pointed out that in a recent survey physicians estimated that three in
four patients take complementary medicines, including herbs.
ADA 63rd Scientific Sessions: Poster 1676, presented June 14, 2003; Poster
587, presented June 15, 2003.