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Article
Ginkgo/
Ginkgo
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JAMA study announces positive results in Alzheimer disease with Ginkgo
extract
October 22, 1997. Results of a multicenter study published in the most
recent issue of the Journal of the American Medical Association (JAMA)
indicate that Ginkgo biloba extract can be of significant benefit in the
treatment of dementia associated with Alzheimer disease and multi-infarct
dementia (LeBars PL, Katz MM, Berman N, et al. A placebo-controlled,
double-blind, randomized trial of an extract of Ginkgo biloba for dementia.
JAMA 1997;278:1327-1332.). The authors asserted that the improvement seen
in patients with Alzheimer could be equated with "a six-month delay in the
progression of the disease." These results are particularly promising in
light of the fact that no satisfactory treatments currently exist for the
management of this common and devastating condition.
The placebo-controlled, double-blind study was designed to investigate the
effects of standardized Ginkgo extract in 309 patients with mild-to-severe
dementia associated with either Alzheimer disease or multi-infarct
dementia. Patients were randomized to receive 52 weeks of treatment with
placebo or Ginkgo extract at a dose of 40 mg three times a day, a total
daily dose of 120 mg. At 52 weeks, 202 patients were included in the
endpoint analysis, which was based on standard tests of cognitive
impairment, daily living and social behavior, and general psychopathology.
The researchers reported that 27% of patients who received 26 or more weeks
of treatment with Ginkgo extract experienced at least a four-point
improvement on the 70-point Alzheimer Disease Assessment Scale-Cognitive
subscale (ADAS-Cog), compared to 14% in the placebo group. Daily living and
social behavior were deemed improved in 37% of Ginkgo patients, compared to
23% of those taking placebo, as measured by the Geriatric Evaluation by
Relative's Rating Instrument (GERRI). In contrast, the GERRI showed that
40% of patients taking placebo experienced a worsening of their condition,
while worsening was seen in only 19% of those taking Ginkgo.
The authors concluded that "EGb appears to stabilize and, in an additional
20 percent of cases (vs. placebo), improves the patient's functioning for
periods of six months to one year. Regarding its safety, adverse events
associated with EGb were no different from those associated with placebo."
The Ginkgo preparation used in the study (EGb 761) is a concentrated leaf
extract standardized to 24% ginkgo flavone glycosides and 6%
terpenelactones, the same extract widely used in Europe for the treatment
of cognitive disorders and other conditions. This extract, manufactured by
Murdock Madaus Schwabe, Inc. in Germany, is currently available in the
United States under the trade names Ginkgold® (from Nature's Way Products,
Inc.) and Ginkoba™ (from Pharmaton Natural Health Products).
Similar encouraging results with Ginkgo were recently reported in the
journal Phytomedicine (Kanowski S, Herrmann WM, Stephan K, et al. Proof of
efficacy of the Ginkgo biloba special extract EGb 761 in outpatients
suffering from mild to moderate primary degenerative dementia of the
Alzheimer type or multi-infarct dementia. Phytomed 1997;4(1):3-13.). This
double-blind, placebo-controlled, randomized study investigated the effects
of Ginkgo extract in 156 patients with either Alzheimer disease or multi-
infarct dementia. A responder rate of 28% for multiple therapeutic effects
(p<0.01) was observed in patients taking Ginkgo extract, as compared to 10%
in the placebo group. A separate analysis of the two different diagnostic
subgroups (Alzheimer or multi-infarct dementia) showed that the differences
in improvements between Ginkgo and placebo after 24 weeks were consistently
slightly higher in patients with Alzheimer disease. The researchers
reported that the Ginkgo extract was well tolerated.
The JAMA study can be accessed at the journal's website at www.ama-
assn.org
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