Ginkgo: Herbal Medications, What Works
Considered
a "living fossil," Ginkgo biloba is the world's oldest living deciduous
tree. It originated some 200 million years ago, and was almost entirely
destroyed in the last Ice Age, except for a small population that survived in
northern China. The trees live up to one thousand years, and are remarkably
adaptable to a wide range of climates, insects, and diseases.
Ginkgo
biloba
extract, or GBE, is the most frequently used phytomedicine in Europe, available
in Germany by prescription and over-the-counter. Commission E in Germany has
approved GBE for the symptomatic treatment of dementia-related memory deficits,
concentration problems, and depression; for intermittent claudication (pain on
walking due to compromised blood flow to the extremities); and for vertigo and
tinnitus (ringing in the ears) of senile vascular origin. Daily doses of 120 to
240 mg have been shown to elicit response.
Ginkgo
leaves contain many pharmacologically active compounds, including unique
flavonoids and terpenoids, with chemical properties similar to vitamin P, known
as ginkolides, which are found nowhere else in nature. All the many
constituents of ginkgo act together; single components do not show the same
activity as the whole leaf extract. GBE's pharmacological actions include free
radical destruction, reduction of lipid peroxidation, and reduction of blood
platelet aggregation.
- A review of forty trials of GBE by
Kleijnen and Knipschild indicated GBE's effectiveness in treating insufficient
cerebral blood flow to the brain, although many of the studies were poorly
designed.
- During a double-blind trial by Vesper and
Hansgen in 1994, the GBE preparation kaveri was tested on ninety elderly
patients with cerebral insufficiency, and improvement was found with a daily
dose of the ginkgo preparation over twelve weeks.
- From a review of ten studies with people
who had intermittent claudication, or temporary blood flow blockages, ginkgo
appeared to be effective. Based on some of these studies, Commission E
concluded that there was enough evidence to approve the use of ginkgo for such
intermittent claudication.
- Bauer in 1984 used a daily dose of ginkgo
preparation for six months to treat intermittent claudication in a randomized
clinical trial of patients with insufficient circulation to their extremities.
Significant improvement was observed in the ginkgo group after twenty-four
weeks of treatment.
- Ginkgo has been promoted for some time as
a treatment for Alzheimer's disease, and recent studies indicate that it does
have potential benefit in slowing progression of the disease.
- In an important 1997 study of Alzheimer's
patients by LeBars and associates, published in the Journal of the American
Medical Association,
ginkgo induced modest improvement in, or a delay in the decline of, cognitive
function, living skills, and social behavior.
- Claims
have also been made for ginkgo's ability to improve mental functioning among
healthy people. Some studies have been positive. Whether the widely publicized claims
for ginkgo as a "smart pill" for normal individuals will ever be
proved remains a controversial but interesting question. It appears likely that
ginkgo will be definitely proved capable of producing noticeable increases in
intellectual performance in normal, healthy subjects.
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From THE
BEST ALTERNATIVE MEDICINE: WHAT WORKS? WHAT DOES NOT? by Dr. Kenneth R.
Pelletier.
Copyright © 2000 by Dr. Kenneth R.
Pelletier, Inc.
Reprinted by
permission of Simon & Schuster, Inc., New York, New York.
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