Many parents have cried “How many times do I have to tell you?” at their young children when trying to get their attention or emphasize specific behaviors. Now, pharmacists and other medical practitioners are beginning to feel like these parents: “How many times do we have to tell you that Ginkgo biloba is not all it’s cracked up to be?” Yet another study in the Journal of the American Medical Association (JAMA) reports that Gingko biloba is not effective in preventing cognitive decline in older adults, but people continue to take it in astounding numbers.

The study presents the results of the largest-scale clinical trial conducted with Ginkgo biloba, assessing more than 3000 adults aged 72 to 96 years. (The investigators have used the same population to investigate other aspects of Gingko treatment, with results published in several journals.) The current study focuses on the prevention of cognitive decline in older adults. The participants received a twice-daily dose of 120 mg of Ginkgo biloba or placebo. Over the 6-year follow-up period, the rate of decline of cognitive function, as assessed by standard cognitive and psychoneurological function exams, was calculated. Overall, there was no difference in the rate of cognitive decline between participants receiving Ginkgo biloba or placebo. These results did not change when modifying factors, such as age, sex, race, education, genetic variations, or baseline cognitive impairment, were considered.

This hardly seems like newsworthy information, given the plethora of studies that say the same thing. To date, there are no large-scale, definitive studies demonstrating that Ginkgo biloba has much of an effect on anything.  Most studies that do report benefits of Ginkgo biloba therapy are not comprehensive and obtained limited data regarding cognitive function. The results lend themselves to statistical misinterpretation and inappropriate extrapolation of the data.

Still, Ginkgo biloba sales are in the hundreds of millions of dollars worldwide every year. It is commonly used in European medicine to improve memory and treat neuronal disorders and improve brain metabolism. In the United States, it enjoys widespread use as a botanical dietary supplement. The current study should leave consumers asking, “Why?” Once again, Ginkgo biloba is verifiably ineffective for preventing a decline in cognitive function. Plus, as with many unregulated over-the-counter supplements, Ginkgo biloba places patients at increased risk for possible side effects and drug interactions.

Growing old gracefully and successfully is of paramount importance with an ever-older population. It is natural to strive for maintaining, and even enhancing, cognitive reserves. But, there is no evidence that proves Ginkgo biloba will help to achieve those goals. Clinicians and patients are better served by identifying and treating known conditions that may reduce brain capacity and cognitive function, including vascular risk factors, diabetes, and sleep disorders, and promote activities and lifestyles that build cognitive reserve.

… And we don’t want to have to tell you again!

References

Canis, M., Olzowy, B., Welz, C., Suckfüll, M., & Stelter, K. (2009). Simvastatin and Ginkgo biloba in the treatment of subacute tinnitus: a retrospective study of 94 patients American Journal of Otolaryngology DOI: 10.1016/j.amjoto.2009.09.004

Daffner KR. Promoting Successful Cognitive Aging: A Comprehensive Review. J Alzheimers Dis. Dec 14 2009.

Kaschel, R. (2009). Ginkgo biloba: specificity of neuropsychological improvement-a selective review in search of differential effects Human Psychopharmacology: Clinical and Experimental, 24 (5), 345-370 DOI: 10.1002/hup.1037

Leistner, E., & Drewke, C. (2010). Ginkgo biloba and Ginkgotoxin. Journal of Natural Products, 73 (1), 86-92 DOI: 10.1021/np9005019

Snitz, B., O’Meara, E., Carlson, M., Arnold, A., Ives, D., Rapp, S., Saxton, J., Lopez, O., Dunn, L., Sink, K., DeKosky, S., & , . (2009). Ginkgo biloba for Preventing Cognitive Decline in Older Adults: A Randomized Trial JAMA: The Journal of the American Medical Association, 302 (24), 2663-2670 DOI: 10.1001/jama.2009.1913