Study: Ginkgo Biloba Doesn't Slow Cognitive Decline

Lots of older

adults who purchase the herbal supplement Ginkgo biloba, in hopes it will

keep them mentally sharp, may be wasting their money. That's the finding

of researchers reporting their results in the latest issue of theJournal of American Medicine.

"Ginkgo biloba is marketed widely and used with the hope of improving,

preventing, or delaying cognitive impairment associated with aging and

neurodegenerative disorders such as Alzheimer disease," the authors write.

"Indeed, in the United States and particularly in Europe, Gingko biloba is

perhaps the most widely used herbal treatment consumed specifically to

prevent age-related cognitive decline."

However, evidence from large clinical trials regarding its effect on

long-term cognitive functioning is lacking.

Beth E. Snitz, Ph.D., of the University of Pittsburgh, and colleagues

analyzed outcomes from the Ginkgo Evaluation of Memory (GEM) study to

determine if Gingko biloba slowed the rate of cognitive decline in older adults

who had normal cognition or mild cognitive impairment at the beginning of

the study.

The GEM study previously found that Gingko biloba was not effective in

reducing the incidence of Alzheimer dementia or dementia overall. The

randomized, double-blind, placebo-controlled clinical trial included 3,069

community-dwelling participants, ages 72 to 96 years, who received a

twice-daily dose of 120-mg extract of Gingko biloba or identical-appearing

placebo.

The study was conducted at six academic medical centers in the United

States between 2000 and 2008, with a median (midpoint) follow-up of 6.1

years. Change in cognition was assessed by various tests and measures.

In this study, the largest randomized controlled trial of Gingko biloba to

report on outcomes to date, the researchers said they found no evidence

for an effect of Gingko biloba on global cognitive change and no evidence of

effect on specific cognitive domains of memory, language, attention,

visuospatial abilities and executive functions.

They also found no evidence for differences in treatment effects by

age, sex, race, education or baseline cognitive status.

"In sum, we find no evidence that Gingko biloba slows the rate of cognitive

decline in older adults. These findings are consistent with previous

smaller studies examining prevention of decline and facilitation of

cognitive performance and with the 2009 Cochrane review of Gingko biloba for

dementia and cognitive impairment."