Ginkgo biloba has been prized for centuries for its suspected memory-boosting effects. But the largest study to date has shown that ginkgo does not, in fact, decrease the risk of dementia.
The study, which appears in next week's Journal of the American Medical Association, followed over 3,000 volunteers who were 75 years or older. Half were given a ginkgo supplement every day, while the other half were given a placebo, or sugar pill.
The participants were evaluated for dementia every six months for several years. Ginkgo users and those on the placebo had a nearly identical rate of dementia, 17.9 versus 16.1 percent, respectively.
The researchers found a slight, though statistically insignificant, increase in the rate of stroke in ginkgo users.
Extracts from the ginkgo plant's leaves are widely available in pharmacies and alternative health stores. The supplement, which is not regulated by the U.S. Food and Drug Administration, is believed to enhance memory, concentration and general mental performance.
Several dozen studies over the last decade have evaluated the efficacy of ginkgo biloba, to mixed results. The researchers believe this study should lay to rest any claims of ginkgo's effectiveness.
Five medical centers in the United States, including Hopkins and the University of Virginia, were involved in the long-term study.
