Study: Ginkgo no help to normal elderly

WILLIAMSTOWN, Mass., Aug. 20 (UPI) -- A new study of one brand of the popular herbal supplement ginkgo biloba found older adults with normal mental functioning showed no benefit after six weeks of following the manufacturer's instructions.

Researchers chose the brand, Ginkoba, marketed by Pharmaton Natural Health Products, of Ridgefield, Conn., because of its reputation as a high quality product with consistent strength. Pharmaton's Web site claim that, "Our clinical research indicates that with at least four weeks of uninterrupted use of Ginkoba, consumers can begin to enjoy its many benefits -- including improvements in mental sharpness and focus."

However, lead author Paul R. Solomon, professor of psychology and chair of Williams College neuroscience program, told United Press International, "When gingko biloba is taken following the manufacturer's recommendation in terms of dose and length, there is no measurable benefit in terms of memory and related cognitive function."

The study focused on 230 healthy men and women volunteers more than 60 years of age. Participants were placed in two groups at random. One group received 40 milligrams of ginkgo three times a day with meals, per the label recommendation. The other group received gelatin capsules filled with lactose that looked similar but contained none of the herb.

Before the subjects began taking their thrice-daily doses, they were given common tests for learning, memory, attention, concentration and verbal fluency. Also, the participants' memory functions were rated by their spouses, friends and relatives.

After six weeks, when the ginkgo and placebo groups were compared, researchers found no significant differences on test results before or after taking the pills.

"I think the more general message is that manufacturers of over-the-counter memory enhancers -- so-called 'nutriceuticals' -- have made claims about their benefits and I think these claims have to be tested using the quality of study that would be used to test a standard pharmaceutical, following Food and Drug Administration standards," Solomon said.

Solomon and his co-authors wrote they were "unable to identify any well-controlled studies that document the manufacturer's claim for ginkgo biloba's benefits. They pointed out, however, their study has limitations and it is possible higher doses or longer periods of exposure are necessary before results are produced.

The study did not test the contents of the product, which is manufactured by Pharmaton, a division of Boehringer Ingelheim Pharmaceuticals of Germany.

David Morrison, Pharmaton's director of scientific affairs for the U.S. consumer health care division, told UPI, "This study is just a single study amidst a wealth of clinical trials on ginkgo biloba and a single study shouldn't call into question the efficacy of 30 years of research."

Morrison, along with Dean DiMaria, Pharmaton's vice president and general manager for health products, said there were many studies supporting the herb's effectiveness in older adults.

Although some of the summaries of 17 studies posted at the Pharmaton Web site reported some benefits, not one tested older adults with normal cognitive functioning. Almost all tested populations with some form of mental impairment, or they tested much younger people with very high doses for an hour or a few days.

None of the additional ginkgo studies faxed to UPI by Pharmaton were of older adults or followed manufacturers' dose guidelines. For example, one study gave normal subjects 60 years and older three doses of 60 milligrams a day -- about 30 percent higher than in the study conducted by Solomon and colleagues. The research, by Joseph A. Mix, of Liberty University in Lynchburg, Va., and W. David Crews, of Virginia Polytechnic Institute in Blacksburg, found a benefit from ginkgo in three of 13 memory tests.

Steven T. DeKosky, professor of psychiatry, neurology and neurobiology, and director of the Alzheimer's disease research center at the University of Pittsburgh School of Medicine, told UPI, "This is one of a number of studies that are going to have to be done under carefully controlled conditions for us to find out ... where gingko has therapeutic effects and where it may not."

DeKosky is the principal investigator of a $15 million multi-center trial funded by the National Institutes of Health to determine the effect of ginkgo biloba in normal and mildly impaired elderly. The results will be out in 2006.

Kristine Yaffe, neurologist and geriatric psychiatrist at the University of California at San Francisco School of Medicine, called Solomon's study a "well-conducted" trial.

"There are a lot of people out there spending a lot of money and possibly exposing themselves to the side effects and they don't know what the evidence is. The gold standard for evidence are these randomized controlled trials," Yaffe added.

Michael McGuffin, president of the American Herbal Products Association in Silver Spring, Md., told UPI the new study "seems pretty straightforward ... It's more data and more research and that's all to the better. We like more research." McGuffin added that the study needs to be viewed in the context of other ginkgo research.

Other studies that examine the effect of ginkgo biloba on Alzheimer's disease have been completed or are ongoing, with mixed results.

Gingko biloba is made from leaves of the ginkgo biloba tree -- also called the maidenhair tree -- that are processed to concentrate certain active compounds.

The study results will be published in the Aug. 21 issue of the Journal of the American Medical Association.

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(Reported by Joseph Grossman, UPI Science News, in Santa Cruz, Calif.)