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similar for both groups. The overall dementia rate was 3.3 per 100 person years in
participants assigned to ginkgo and 2.9 per 100 person-years in the placebo group. The
hazard ratio (HR) for ginkgo compared with placebo for all cause dementia was 1.12
(95% confidence interval [CI], 0.94-1.33; P=.21) and for AD, 1.16 (95% CI, 0.97-1.39;
P=.11). Ginkgo also had no effect on the rate of progression to dementia in participants
with MCI (“mild cognitive impairment”) (HR, 1.13; 95% CI, 0.85-1.50; P=.39).^19
GEM STUDY CONCLUSION: “In this study, ginkgo at 120 mg twice a day was not
effective in reducing either the overall incidence rate of dementia or Alzheimer’s
disease incidence in elderly individuals with normal cognition....”^20 This conclusion cast
doubt on the conclusions quoted above.
THE 2009 COCHRANE COLLABORATION META-ANALYSIS OF GINKGO STUDIES cast
further doubt on the validity of prior, more limited, biomedical research supporting
ginkgo’s effects, concluding that “the evidence that Ginkgo biloba has predictable and
clinically significant benefit for people with dementia or cognitive impairment is
inconsistent and unreliable.”^21
The 2009 Snitz, B.E. et al. study published in the Journal of the American Medical
Association^22 for the “Ginkgo Evaluation of Memory (GEM) Study Investigators”
determined there to be “no evidence that ginkgo slows the rate of cognitive decline in
older adults.”
New York Times, August 28, 2010 review of an NIH panel on Alzheimer’s prevention: “In
the end, [the panel] said it was highly confident in the findings for just one thing, the
herb ginkgo. But in that case the evidence pointed in only one direction: it did not
prevent Alzheimer’s.”
Contra, as part of the large longitudinal EPIDOS study in France, 69 Alzheimer’s patients
were matched with 345 women with normal cognitive functioning. A multivariate
analysis showed that treatment with vasodilators including EGb 761 for at least two
years reduced the risk of developing Alzheimer dementia.^23
Of four recent trials, three found no difference between ginkgo and placebo, but one
reported very large treatment effects in favor of ginkgo. There were no significant