Alzheimer's Disease and Ginkgo Biloba
Ginkgo Biloba is the the most well-established herbal treatment for Alzheimer's disease. Its an ancient herb used in Chinese herbology for thousands of years for numerous conditions.
Gingko Biloba may function by stimulating nerve-cell activity directly and protecting nerve cells from further injury. There is also evidence that Gingko Biloba can improve cognitive functions in patients with Alzheimer's disease. Another benefit associated with Gingko Biloba is improvement of circulation--the benefit of improved blood circulation to the brain in Alzheimer's patients may produce an overall beneficial effect.
For more information, including dosage and safety issues, see the full Ginkgo Biloba article.
Effect of Ginkgo Biloba on Alzheimer's Disease
Ginkgo Biloba is prescribed for treating dementia, symptoms of Alzheimer's such as apathy/indifference, anxiety, irritability/lability, depression/dysphoria and sleep/nighttime behavior”79, and to delay decline in cognitive function. The most positive evidence in studying the effect of Gingko Biloba is in the treatment of dementia and the symptoms of Alzheimer's.
Research Evidence on Ginkgo Biloba
Numerous high quality double-blind, placebo-controlled studies indicate that Ginkgo biloba is effective for treating various forms of dementia.1-4,76,79,80,83 One of the largest was a 1997 US trial that enrolled more than 300 participants with Alzheimer’s disease or non-Alzheimer’s dementia.80 Participants were given either 40 mg of Ginkgo biloba extract or placebo 3 times daily for a period of 52 weeks. The results showed significant but not entirely consistent improvements in the treated group.
Another study published in 2007 followed 400 people for 22 weeks, and used twice the dose of ginkgo employed in the study just described.79 The results of this trial indicated that ginkgo was significantly superior to placebo. The areas in which ginkgo showed the most marked superiority as compared to placebo included, “apathy/indifference, anxiety, irritability/lability, depression/dysphoria and sleep/nighttime behavior.”
On the other hand, one fairly large study of ginkgo extract drew headlines for concluding that ginkgo is ineffective.5 This 24-week, double-blind, placebo-controlled study of 214 participants with either mild to moderate dementia or ordinary age-associated memory loss found no effect with ginkgo extract at a dose of 240 mg or 160 mg daily. However, this study has been sharply criticized for a number of serious flaws in its design.6 But in another community-based study among 176 elderly subjects with early-stage dementia, researchers found no beneficial effect for 120 mg of ginko extract given daily for 6 months.86
The ability of Ginkgo Biloba to prevent or delay a decline in cognitive function is less clear. In a placebo-controlled trial of 118 cognitively intact adults 85 years or older, ginkgo extract seemed to effectively slow the decline in memory function over 42 months. The researchers also reported a higher incidence of stroke in the group that took Ginkgo Biloba, a finding that requires more investigation.82
In a 2009 review of 36 randomized trials involving 4,423 patients with declining mental function (including dementia), researchers concluded ginkgo appears safe but there is inconsistent evidence regarding whether it works.89
Side Effects and Warnings
Individuals who fall under one or more of the following categories should consult with their practitioner before taking ginko biloba. Those with:
- blood circulation disorders
- taking antidepressants
- anticoagulants (ibuprofen or aspirin)
- women who are pregnant
Possible side effects include:1,2
- increased risk of bleeding
- gastrointestinal discomfort
- heart palpitations
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