Use of Ginkgo to Treat and Prevent Alzheimer's

Chinese Herbal Therapy for Alzheimer's Dementia

Nov 9, 2009
Christie Bailey

Ginkgo biloba leaves fall from tree in Oregon. - J. Lurie-Terrell

The herbal remedy ginkgo may prevent, and even treat, Alzheimer's disease. However, research supporting this claim is limited.

Ginkgo (Ginkgo biloba) is sometimes known as the "Fossil Tree," as it is the single survivor of a primitive genus of trees that was common millions of years ago. It has been used to treat a myriad of conditions in Chinese medicine for thousands of years, from circulatory problems to ailments of the mind. Currently, it is best known for its use in dementia and improving memory.

Efficacy Against Alzheimer's Disease

While it is believed that ginkgo may prevent or treat Alzheimer's disease, research supporting these uses is inconclusive at best.

The National Center for Complementary and Alternative Medicine (NCCAM) is funding a large 10-year study called the Ginkgo Evaluation in Memory (GEM) study. Begun in 2000, this program involves more than 3,000 volunteer subjects over the age of 75 who take 240 mg of ginkgo daily. Although the study is not scheduled to end until July 2010, preliminary results show no effectiveness for ginkgo.

Besides this study, a number of papers examining ginkgo's effectiveness against Alzheimer's have shown some positive results. One study published in the journal Aging & Mental Health in March 2009 found that 240 mg daily of EGb 761 (a standardized German ginkgo extract, the same preparation and dose that was used in the GEM study above) was just as effective as donepezil (a prescription Alzheimer's medication known under the brand name Aricept), and that a combination therapy with both substances produced even better results. Two papers that reviewed many small ginkgo trials have concluded that use of ginkgo for Alzheimer's may hold promise, but some of the studies are inadequate and results are mixed.

Ginkgo Biloba Leaf Supplements

Although the seeds are sometimes used therapeutically, the leaf is the most commonly used part. The leaf can be prepared as a tea or purchased as an herbal extract in liquid or tablet form.

Commonly, ginkgo can be found as a "standardized" extract. This means that the product is quality controlled to guarantee that the preparation has a certain percentage of one or more medicinally active compounds. According to the American Botanical Council (ABC), a standardized extract of ginkgo should have 22-27% ginkgo flavonol glycosides and 5–7% terpene lactones. The ABC states that ginkgo extracts must be prepared according to strict guidelines and standardization to be effective.

Ginkgo is a Tonic

Ginkgo is purportedly a "tonic" herb, which means that it gradually strengthens one or more bodily systems over time with extended use. In her book The Family Herbal, Rosemary Gladstar claims that it works as a nutrient and that it must be taken daily in adequate doses for weeks -- or months -- before a benefit can be noted.

Warning: Ginkgo May Be a Blood Thinner

Several research studies seem to agree on one point: ginkgo has very few, very mild side effects -- if any. However, according to Natural Standard published in 2005, evidence shows that ginkgo may interact with "blood thinning" anticoagulant drugs like Coumadin (warfarin sodium) by increasing the amount of time it takes for blood to clot. Consumers with a bleeding disorder or who take anticoagulant drugs should speak to their medical provider before initiating therapy with ginkgo.