Ginkgo Supplements : Mind the Claims.

Source: Tufts University
December 15, 2000 (Reviewed: February 17, 2003)

Introduction

As an herbal supplement, ginkgo has gained a reputation as an effective hedge against age-related memory loss. Despite the popular appeal of ginkgo, the extract from ginkgo biloba tree leaves, not all scientists agree that it can help keep people mentally sharp. In fact, a group of Dutch researchers recently reported in the Journal of the American Geriatrics Society that ginkgo supplements did not help a group of older people suffering from memory loss.

Over 200 men and women diagnosed with mild to moderate age-related memory impairment, dementia, or Alzheimer's disease participated in the 6-month study. The mental capability and behavioral functioning of each volunteer was assessed before they were randomly assigned to receive either a daily dose of 160 mg ginkgo, 240 mg of ginkgo, or a sugar pill placebo. After 12 weeks the participants were re-tested to see if they were better able to perform memory tests. Those receiving the ginkgo supplement were divided up again to either continue the supplement or to switch to the placebo. The researchers did this to see if the length of time taking the supplement made a difference. After another 12 weeks, the volunteers were again tested for any improvements in mental performance or behavior.

The researchers found that ginkgo supplements did not improve mental functioning or behavior. Neither the amount of ginkgo nor the length of time one took it made a difference in any of the areas measured. To search further for any possible effect on a subgroup of volunteers--maybe it benefited women but not men, or, younger, but not older participants--the researchers analyzed the results by gender, age, diagnosis, and initial test score. Still, ginkgo supplements showed no benefit.

Different studies yield conflicting results

These findings contradict those of other studies that show ginkgo supplements to be helpful in treating the symptoms of Alzheimer's disease and dementia. So, why did the current study find ginkgo ineffective? Conflicting study results may be explained, in part, by design differences among the studies. The number of individuals enrolled and differences in their degree of mental impairment are two plausible explanations. Differences in methods used to asses impairment level is a third, and there are others.

Caution: use with care

Marketers have touted ginkgo's effectiveness so successfully that it is one of the most widely used supplements in both the US and Europe. But clearly, more research is needed before definite conclusions can be made regarding ginkgo and health. There are some important tips to remember for anyone currently using, or considering using, ginkgo supplements, the evidence for its effectiveness notwithstanding. As with any supplement, people should consult with their doctor before taking it. This is crucial for those with blood circulation or blood clotting disorders and those taking any anti-coagulants, including aspirin. And finally, as a reminder from the US National Institute on Aging: doctors have not yet determined how much ginkgo is an "effective" dose.

Source

• The efficacy of ginkgo for elderly people with dementia and age-associated memory impairment: new results of a randomized clinical trial. M. Van Dongen, E. Van Rossum, A. Kessels, H. Sielhorst, P. Knipschild, Journal of the American Geriatrics Society., 2000, vol. 48, pp. 1183--1194

Related Links
Complementary Medicine Center : Ginkgo Biloba
Healthful Diet Aids Memory-Impaired Seniors
Vitamin E May Keep Memory Sharp
Ginkgo Biloba. National Institute on Aging
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