Gingko has no effect on dementia or Alzheimer's Onset

Results of a study of more than 3,000 seniors have revealed that the popular supplement Gingko biloba has no impact on the development of dementia or Alzheimer's disease.

The multi-center Ginkgo biloba for the Evaluation of Memory (GEM) Study evaluated the effects of the dietary supplement Ginkgo biloba on the onset of dementia and Alzheimer's disease. For the trial 3,069 seniors aged 75 and older, who had normal cognition or mild cognitive impairment (MCI), were randomly assigned to receive twice-daily doses of either 120 mg of Ginkgo biloba extract or placebo. Participants were followed for an average of six years.

Results showed that 240 mg/day Gingko biloba had no effect on the onset of dementia or the development of Alzheimer's disease. “It is very unlikely that Ginkgo biloba is effective at any dose over a five-year period and in anyone over 75 years old,” said study author Jeff Williamson in a news release. “It is also ineffective in people with signs of early memory loss. What is not known yet is whether the effect of Ginkgo biloba might require taking the drug for many, many years, say 15 years, before there is even a sign of memory loss.”

The researchers concluded: “In summary, in this randomized clinical trial in 3069 older adults with normal cognitive function or mild deficits, Ginkgo biloba showed no benefit for reducing all-cause dementia or dementia of the Alzheimer type. Based on the results of this trial, Ginkgo biloba cannot be recommended for the purpose of preventing dementia.”

Dekoksy ST, Williamson JD, Fitzpatrick AL, et al. Ginkgo biloba for Prevention of Dementia A Randomized Controlled Trial. JAMA. 2008;300(19):2253-2262.

News release: Ginkgo Proves Ineffective in Preventing Dementia, Alzheimer's Disease. Wake Forest University Baptist Medical Cener. November 18th 2008.