Gingko Biloba ? Not that 'magical' afterall :\

 

Ginkgo Biloba Ineffective Against Dementia, 

Researchers Find

By RONI CARYN RABIN

Published: November 18, 2008

The largest and longest independent clinical trial to assess ginkgo biloba’s ability to prevent memory loss has found that the supplement does not prevent or delay dementia or Alzheimer’s disease, researchers are reporting.

Joe Raedle/Getty Images

Ginkgo biloba in capsule form.

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Health Guide: Dementia »

The study is the first trial large enough to accurately assess the plant extract’s effect on the incidence of dementia, experts said, and the results dashed hopes that it is an effective preventative. In fact, there were more cases of dementia among participants who were taking ginkgo biloba than among those who were taking a placebo, though the difference was not statistically significant.

“We were disappointed,” said Dr. Steven T. DeKosky, dean of the School of Medicine at the University of Virginia and the principal investigator. “We were hopeful this would work.”

The study appears in Wednesday’s issue of The Journal of the American Medical Association.

For the trial, researchers from five academic medical centers in the United States recruited 3,069 community volunteers 75 and older. Most were cognitively normal, but 482 had mild cognitive impairment.

About half were given two doses of 120 milligrams of ginkgo biloba extract daily, while the other half were provided with placebo pills. Neither the participants nor the doctors knew who was receiving which pills. They were followed for a median of 6.1 years and assessed every six months for dementia.

During the study period, 523 cases of dementia were diagnosed. Of those, 246, or 16.1 percent, were in placebo users, and 277, or 17.9 percent, were in people taking ginkgo biloba.

“If this was really a powerful effect, we would have seen something that would have at least inched its way toward statistical significance,” Dr. DeKosky said. “If you’re in your mid-70s and want to take this drug to protect yourself from developing the disease, my comment is: ‘It doesn’t work.’ ”

An editorial accompanying the study warned not only that the extract was unhelpful, but also that it might be harmful. The trial reported more hemorrhagic strokes among ginkgo users, though the difference was not statistically significant, while patients with cardiovascular disease who took the supplement also faced an increased risk of dementia.

“There is nothing here, no signal of any effect,” said Dr. Lon Schneider, director of the Alzheimer’s Disease Research and Clinical Center at the University of Southern California, who wrote the editorial.

“This gives physicians and advisers the evidence base to be able to say more definitively that using ginkgo extract the way it’s sold in CVS or Walgreens is not likely to help you at all, and gets pretty close to being a waste of resources,” Dr. Schneider said. “These are important studies, disappointing as they are.”

Although previous studies of ginkgo biloba have produced mixed results — a 2007 Cochrane review of 35 clinical trials found “inconsistent and unconvincing” evidence that ginkgo had significant benefits for people with dementia or cognitive impairment — the supplement is widely used. Annual worldwide sales in the United States are $249 million, according to the study’s authors.

Joseph Mix, a professor of health sciences and kinesiology at Liberty University in Lynchburg, Va., “If nothing else, it has powerful antioxidant properties,” said Dr. Mix, who published an industry-financed study that found that ginkgo biloba improved speed of processing in people 60 and older who took it for six weeks. “The thinking is that it helps improve oxygenation and circulation to the brain.”

Dr. Michael Habs, a representative of Dr. Willmar Schwabe GmbH & Co., a large pharmaceutical company in Germany that sells ginkgo biloba, said other studies have found a benefit to use of the extract and noted that adherence to the dosing program in the newly published trial had fallen to 60 percent by the end of the study period. He said another large trial of ginkgo biloba called GUIDAGE, involving 2,800 people in France, is still ongoing. “Taking into account the results of the other studies, it seems prudent to wait for the GUIDAGE study results before allowing a final conclusion on the potential of the extract in dementia prevention,” Dr. Habs said.

SEE ? MICHELLE NGO HEA LIN? :p