Doubts over benefit of Gingko biloba
Wednesday November 19th, 2008
By Jane Collingwood
Gingko biloba, a herb widely-used to protect the brain, may not have any beneficial effect against dementia or Alzheimer's disease, researchers reported today.
This is the conclusion of a large study led by Dr Steven DeKosky of the University of Pittsburgh, Pasadena, USA. The study involved over 1,500 participants who took either Ginkgo biloba or placebo for approximately six years.
They were all aged 75 years or older, and had either normal cognition or mild cognitive impairment at the start. Those on Ginkgo biloba took a twice-daily dose of 120 mg.
During follow-up, 523 participants were diagnosed with dementia. Among the Ginkgo biloba group, the rate was 18 per cent, and among the placebo group, 16 per cent. The rates of Alzheimer-type dementia were also comparable.
In the Journal of the American Medical Association, the authors write: "Based on the results of this trial, Ginkgo biloba cannot be recommended for the purpose of preventing dementia." They add that randomised trials "remain critical" to the research process necessary to develop new therapies, including complementary therapies.
In an editorial, Dr Lon Schneider of the University of Southern California, Los Angeles, USA, writes that "considerable uncertainty remains over the effects of Ginkgo biloba", despite two decades of research.
This study "adds to the substantial body of evidence that G biloba extract as it is generally used does not prevent dementia in individuals with or without cognitive impairment and is not effective for Alzheimer disease".
He believes: "The potential adverse effects of G 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."
DeKosky, S. T. et al. Ginkgo biloba for Prevention of Dementia: A Randomized Controlled Trial. The Journal of the American Medical Association, Vol. 300, November 19, 2008, pp. 2253-62.
Schneider, L. S. Ginkgo biloba Extract and Preventing Alzheimer Disease. The Journal of the American Medical Association, Vol. 300, November 19, 2008, pp. 2306-08.
Tags: Alternative Therapy | Brain & Neurology | Mental Health | North America
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