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Does Ginkgo biloba Prevent Dementia?

No benefit was seen in preventing either all-cause or Alzheimer dementia.

Because of Ginkgo biloba’s antioxidant properties and ability to block amyloid aggregation, it has been tested in clinical trials for prevention of dementia; however, such trials have been small and methodologically weak, and they have yielded mostly negative results. Now, in a trial thought to be the largest and longest of its kind, 3069 older adults (mean age, 79) with no (2587 participants) or mild (482 participants) cognitive impairment were randomized to G. biloba (120 mg twice daily of a standardized formulation commonly sold in the U.S.) or to placebo. Exclusion criteria included use of anticoagulants, cholinesterase inhibitors, other drugs with substantial cholinergic effects, or >400 IU of vitamin E daily; and presence of clinical contraindications (e.g., thyroid disease or anemia).

Within roughly 6 years of follow-up — with a very low dropout rate — dementia was diagnosed in 523 people. The treatment and control groups did not differ in incidence of all-cause dementia or Alzheimer disease, nor was any difference noted for the subgroup with mild impairment. The rate of adverse events was similar in both groups, although a nonsignificant trend was noted toward higher risk for hemorrhagic stroke in the treatment group.

Comment: These results show clearly that Ginkgo biloba in its most common formulation and dosage is of no benefit in preventing dementia. These results also are consistent with those of a meta-analysis of 35 smaller trials.

— Thomas L. Schwenk, MD

Published in Journal Watch General Medicine November 26, 2008

Citation(s):

DeKosky ST et al. Ginkgo biloba for prevention of dementia: A randomized controlled trial. JAMA 2008 Nov 19; 300:2253.

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