Leading Herbal Experts Urge Perspective on Ginkgo
DC, 20 August 2002
that reports about an article examining the use of ginkgo in healthy
subjects will cause consumers to avoid or abandon the use of this
beneficial herb, two of the natural products industry's leading
trade groups, the American Herbal Products Association (AHPA) and
the National Nutritional Foods Association (NNFA) urge reporters
and consumers to put this new study in context with the total body
of positive research on this therapeutic botanical. The study, which
was published in the recent edition of the Journal of the American
Medical Association, was conducted by researchers at Williams
College from 1996-1998.*
this study shows that ginkgo did not have an effect on elderly adults
with unimpaired mental function, there are more current well-designed
studies** that have also analyzed people with normal mental function
that arrive at directly contradictory conclusions," said Phil Harvey,
PhD, NNFA's director of science and quality assurance. "These more
current studies report significant improvement in the study subjects'
memory, attention and cognitive clarity due to the use of ginkgo."
authors of the new study acknowledge that their "study has limitations"
and that higher doses of ginkgo over a longer period of time may
yield different results.
important to remember is that it's difficult to increase cognitive
ability in healthy adults to a significant or even measurable degree.
To do so would likely require a longer trial, with doses of ginkgo
titrated to a higher level over time," reiterated Harvey.
not forget that over a half a century of controlled trials on ginkgo
have clearly demonstrated that those with even mild to moderate
memory problems and poor concentration -- symptoms often associated
with the onset of Alzheimer's and other dementias -- are helped
by taking ginkgo," said Steven Dentali, PhD, AHPA's vice president
for scientific and technical affairs. "This study should not be
the last word on ginkgo's effectiveness. Previous well-designed
and executed studies have indicated ginkgo's significant benefits
in improving circulation and mental function and should be taken
seriously as a totality of scientific evidence about ginkgo."
of the most clinically studied botanicals, ginkgo has been examined
mainly for its potential to increase circulation to the extremities
as well as the brain, especially in the elderly. It has also been
studied for the treatment of ringing in the ears (tinnitus), male
impotence, degenerative nerve conditions such as multiple sclerosis,
and other conditions.
first large-scale American clinical study on ginkgo was published
in 1997, also in JAMA,*** focusing on ginkgo's effect on
improving the short-term memory of early diagnosed Alzheimer's disease.
The researchers concluded that the herb is safe and stabilizing,
and that, in a significant number of patients, it improves cognitive
performance and social functioning.
in 1983, the American Herbal Products Association (AHPA)
represents the finest manufacturers, growers, suppliers and retailers
of herbal supplement products. AHPA serves its members by promoting
the responsible manufacture and sale of products that contain herbs.
National Nutritional Foods Association (NNFA)
is the nation's largest and oldest non-profit organization dedicated
to the natural products industry. NNFA represents more than 4,000
retailers, manufacturers, wholesalers and distributors of natural
products, including foods, dietary supplements, and health and beauty
Solomon PR, Adams F, Silver A, Zimmer J, Deveaux R. "Ginkgo for
Memory Enhancement: A randomized controlled trial." Journal of
the American Medical Association, 2002;288(7):835-40.
Mix, JA., Crew WD. "A double-blind, placebo controlled randomized
trial of Ginkgo Biloba extract EGb761 in a sample of cognitively
intact older adults: neuropsycological findings." Human Psycophamracology
Clin Exp 2002; 17:267-77.
Lebars PL, et. al. "Ginkgo Biloba for dementia." Journal of the
American Medical Association, 1997;278:1327-1332.
Herbal Products Association & National Nutritional Foods.
Science Group Clarifies Clinically-Documented Benefits of Ginkgo
TX, 20 August 2002
evidence in the scientific and clinical literature supports the
benefits and safety of the popular herb ginkgo, according to the
nonprofit American Botanical Council (ABC). The information from
ABC comes at the same time as a new study published in the Journal
of the American Medical Association (JAMA) in which ginkgo
extract did not increase mental function in normal, healthy older
patients.* The six-week randomized study tested healthy adults for
learning, memory, attention, concentration, and verbal fluency using
the standard dose of 120 mg ginkgo extract per day. The study was
conducted by researchers at Williams College in Williamstown, Massachusetts.
value of ginkgo or any dietary supplement cannot be determined on
the basis of one study alone," said Mark Blumenthal, founder
and executive director of ABC. "There are more than 125 clinical
trials published on ginkgo extract over the past two decades, with
most of them supporting numerous important benefits related to improved
circulation and mental function."
added that several recent articles reviewing the medical literature
have supported the cognitive (mental) benefits of ginkgo in patients
with early stages of dementia, and a one-year study published in
JAMA in 1997 supported the benefits of using ginkgo to retard
the progression of symptoms in early stages of Alzheimer's disease.
Several recent studies have also shown cognitive benefits of ginkgo
in healthy older adults, he added. In one study recently published
in Human Psychopharmacology using a similar design with a
higher dosage (180 mg per day), researchers observed clinically
significant cognitive benefits in healthy individuals.**
are dozens of positive clinical studies for ginkgo for cognitive
disorders published in the scientific literature. Thirty-four clinical
trials on ginkgo are summarized in an extensive monograph (technical
paper) for healthcare practitioners in ABC's forthcoming new book,
The ABC Clinical Guide to Herbs. All but two show positive
benefits for memory and other mental functions, and for peripheral
arterial occlusive disease, a condition characterized by pain in
leg muscles during walking affecting many older adults. Other potential
benefits suggested by several clinical studies include improved
performance of hikers susceptible to lack of oxygen in high altitudes
(mountain sickness), and male and female sexual dysfunction.
1994 the respected Commission E, the agency that approves the safety
and efficacy of herbal medicines in Germany, considered the scientific
and clinical information on ginkgo to be strong enough to approve
ginkgo extract as safe and beneficial in treating certain cognitive
and circulatory disorders, according to Blumenthal, who is also
the senior editor of an English translation of the Commission E's
potential question about the new study is the important research
protocol of "blinding" the samples, so that neither the
patients nor the researchers are able to distinguish test substances
from placebos. The paper in JAMA noted that the placebo or
dummy pills were made of gelatin capsules, while the actual ginkgo
product is a small, coated tablet. Whether this made any significant
difference in maintaining the blinding necessary to be classed a
"double-blind" trial is not yet determinable, said Blumenthal.
rational perspective on the significance of the new study is provided
by psychopharmacologist Jerry Cott, PhD, an expert on dietary supplements
and drugs that affect the mind and nervous systems: "It is
very difficult to improve cognition in a normal person; it's much
easier to improve in an impaired person. That is, normal functioning
in a healthy person is like an upper limit; a person is already
doing as well as can be expected. It is therefore very difficult
to measure improved mental performance without a precise objective
Cass, MD, a psychiatrist and author in Los Angeles who successfully
uses ginkgo in her clinical practice, expressed concern about the
impact of the publicity that may be generated on the new clinical
trial. "Heavy promotion of the outcomes of this study may result
in a disservice to the public. It can turn people away from a safe,
well-researched product that previous research has proven can improve
their quality of life," she explained. Dr. Cass has also found
ginkgo to be helpful in treating male sexual dysfunction that has
declined with age (often due to impaired circulation), a well as
sexual problems associated with the use of certain types of antidepressant
preparations are made from the leaf of the ginkgo tree (Latin name
Ginkgo biloba), the world's oldest living tree, dating back
250 million years. Ginkgo trees were found living in China and northern
Japan, and are now grown for commercial cultivation in the US and
other countries. Extracts from ginkgo leaves are pharmaceutically
concentrated and standardized to some of ginkgo's unique biologically
active chemical compounds. The leading most well-researched ginkgo
extract from Germany is licensed as a medicine in many countries
worldwide. Ginkgo is also the top-selling herbal dietary supplement
in the US for the past five years, according to information in ABC's
peer-reviewed journal, HerbalGram.
American Botanical Council (ABC)
is the nation's leading nonprofit organization addressing research
and educational issues regarding herbs and medicinal plants. The
13-year-old organization occupies a 2.5 acre site in Austin, Texas
where it publishes HerbalGram, a peer-reviewed journal on
herbal medicine, and will publish a forthcoming book and continuing
education course for healthcare professionals, The ABC Clinical
Guide to Herbs, containing an extensive science-based monograph
on the safety and efficacy of ginkgo.
PR, Adams F, Silver A, Zimmer J, DeVeaux R. "Ginkgo for memory
enhancement: A randomized controlled trial." Journal of
the American Medical Association, 2002;288(7):835-40.
Mix JA, Crews WD. "A double-blind, placebo-controlled, randomized
trial of Ginkgo biloba extract EGb 761 in a sample of cognitively
intact older adults: neuropsychological findings." Human
Psychopharmacol Clin Exp 2002;17:267-77.