Ginkgo May Not Improve Memory Short Term

Aug. 21, 2002 -- Improved mental sharpness and clarity might be as close as your local supermarket. Well, maybe.

Ads for ginkgo, an ancient Chinese herb whose use may date back as far as 3000 B.C., suggest that "senior moments" like misplacing your keys or forgetting names can be eliminated by taking a simple dietary supplement.

And if sales are any indication, many people are buying into that idea. According to some estimates, more than $200 million is spent in the United States alone on products containing ginkgo.

But new research suggests that what you can actually expect from ginkgo may be less than spectacular.

In a study in this week's issue of the Journal of the American Medical Association, researchers randomly assigned 203 healthy elderly adults to receive ginkgo supplements or sugar pills, then evaluated their performance on 14 neuropsychological tests that measured memory, learning, attention and concentration.

Participants took the supplements for six weeks, two weeks longer than the minimum needed to see results suggested by the manufacturer of the popular ginkgo supplement brand Ginkoba, which was used in the study.

The results: Taking daily ginkgo supplements provides no benefit for cognitive functions like memory and learning.

Findings Don’t Surprise Researchers

The failure to affect short-term memory in healthy adults is far from shocking, say researchers.

"I'm not terribly surprised, based on what I understand ginkgo to do, that it didn't show a change in the short term," said Dr. Steven DeKosky, director of the Alzheimer's Disease Research Center at the University of Pittsburgh. "[Ginkgo] would seem to me to be something that would preserve or fight against age-related [damage]. So that wouldn't increase your thinking function, but it might slow loss or slow progression [of memory decline]."

Additionally, researchers point out that very few drugs are known to take a normally functioning, healthy system and make it better.

But Boehringer Ingelheim Pharmaceuticals, manufacturer of Ginkoba, stands by its product and the research it has conducted to make claims of improved "mental sharpness" in as little as four weeks.

"We really have to put this trial into context," said David Morrison, director of scientific affairs at Boehringer Ingelheim Consumer Health Care in Ridgefield, Conn. "It really is just a single study amidst a wealth of clinical data we've gained over the last 30 years … which shows an improvement in cognitive function."

Spokesman Dean Dimaria cited approximately 120 clinical studies that the company maintains show positive cognitive functions in those taking ginkgo. "There is certainly a wealth of clinical work behind ginkgo biloba that demonstrates the efficacy of the product in healthy volunteers."

Morrison added that the product meets applicable Food and Drug Administration standards.

Another New Study May Provide Clues

For those who take ginkgo in the hopes of improving memory, there seem to be no clear answers about how to proceed.

"I don't think that any single study ought to persuade somebody to take a medication or not to take a medication," acknowledged Paul Solomon, lead author of the JAMA study and clinical director of the memory clinic at Southwestern Vermont Medical Center in Bennington, Vt.

"Ginkgo has probably been beneficial for something, by the observations of people for over a millennium," added DeKosky. "By our Western standards, we haven't shown where it is helpful. And it is going to take more than one study to sort out exactly where it will be useful, especially in aging."

DeKosky is the principal investigator of one large study that may provide answers to many questions. The study, set to conclude in 2006, will enroll more than 3,000 patients and compare the efficacy of two doses of ginkgo and placebo in preventing dementia.