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Alzheimer's Disease Health Center

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Ginkgo Biloba Doesn’t Prevent Dementia

Supplement Fails to Ward Off or Slow Alzheimer’s Disease in Large Study

Is Ginkgo Harmless?

The findings strongly argue against the use of ginkgo biloba for the prevention of mental decline in older populations, University of Southern California psychiatry and neurology professor Lon S. Schneider, MD, tells WebMD.

He notes that the GEM study is far larger and longer than any previous placebo-controlled ginkgo biloba trial.

"The message to take from this is that this intervention doesn't work," he says.

In an editorial accompanying the study, Schneider pointed to earlier trials suggesting a slight increase in strokes and mini-strokes in patients taking ginkgo biloba.

In the GEM study, there was no difference in heart attack or ischemic strokes between the ginkgo and placebo-treated patients. Ischemic strokes, the most common type of stroke, are caused by a blockage in an artery that supplies blood to the brain. There were more hemorrhagic (bleeding) strokes in the ginkgo group, but the overall number of cases was small and the difference was not found to be significant.

"The potential adverse effects of ginkgo biloba extract illustrate why it is untenable to recommend a drug or nutraceutical in the absence of efficacy evidence simply because it could possibly help and initially appears harmless," Schneider writes.

Although he acknowledges that the GEM study was well designed, Mark Blumenthal, who is founder and executive director of the American Botanical Council, tells WebMD that the trial does not represent the last word on ginkgo biloba and dementia.

"There are other trials that will be coming out," he says. "Whether or not they will show a positive result or not remains to be seen."

He cited several studies suggesting a role for ginkgo biloba in slowing the progression of dementia in elderly people already experiencing cognitive decline.

"In reporting the news that ginkgo biloba didn't work for prevention in this study, it is important not to mislead people into thinking that there is no evidence to support treatment," he says.

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