Ginkgo biloba did not prevent cognitive decline in older adults with normal cognition or with mild cognitive impairment compared with placebo, according to a recent study published in the Journal of the American Medical Association (JAMA).

In the Ginkgo Evaluation of Memory (GEM) study, a randomized, double-blind, placebo-controlled clinical trial of 3069 community-dwelling participants aged 72 to 96 years, subjects received a twice-daily dose of 120 mg extract of G biloba (n = 1545) or identical-appearing placebo (n = 1524).

The study was conducted in six academic medical centers in the U.S. between 2000 and 2008, with a median follow-up of 6.1 years.

Researchers measured rates of change over time in the Modified Mini-Mental State Examination (3MSE), in the cognitive subscale of the Alzheimer Disease Assessment Scale (ADAS-Cog), and in neuropsychological domains of memory, attention, visual-spatial construction, language, and executive functions, based on sums of z scores of individual tests.

Results indicated annual rates of decline in z scores did not differ between G biloba and placebo groups in any domains, including memory, attention, visuospatial abilities, language and executive functions. For the 3MSE and ADAS-Cog, rates of change varied by baseline cognitive status (mild cognitive impairment), but there were no differences in rates of change between treatment groups.

Despite researchers conclusions, Douglas MacKay, ND, vice president, scientific and regulatory affairs, with the Council for Responsible Nutrition (CRN), Washington, D.C., noted, “It is important to put this study into context and to remember that there is a large body of previously published evidence, which suggests that Ginkgo biloba may help improve cognitive impairment in older adults. There are also additional ongoing clinical trials, the results of which may address some of the limitations of the current study.

“The results of this single study add to the overall data on Ginkgo biloba, including valuable evidence in support of Ginkgo’s safety profile, but should not be viewed as the final word,” he continued. “In addition, several studies have demonstrated that Ginkgo biloba can be used to improve blood circulation and reduce oxidative stress, two risk factors associated with the progression of cognitive decline, dementia and Alzheimer’s disease.”

He cautioned that exact causes and mechanisms for cognitive decline, dementia and Alzheimer’s disease are unknown, and there is no magic bullet or cure.

“As a former practicing licensed naturopathic doctor, I have had the benefit of working with patients and have seen first-hand how Ginkgo biloba can be effective in improving cognitive function,” he said. “In an area where there are few other safe, affordable options, I would hate to see this study send the wrong message to consumers.”