Ginkgo trees are the oldest living trees on earth and are considered “living fossils”, dating back 250 million years.
They also have the longest life span, an average of a 1,000 years, but some trees live more than 3,000 years. In addition to its longevity, ginkgo is widely used in traditional Chinese medicine and more recently has been found to help with circulation to both limbs and the brain. It’s also used for its anti-inflammatory and antioxidant properties. Is it possible then, that gingko biloba can help those with Alzheimer’s disease?
Researchers looked at the anti-inflammatory effects of ginkgo on mice with Alzheimer’s. The mice were given enough ginkgo to reach a blood level ratio comparable to the range that humans would have, if they took gingko at 240 mg. per day (assuming a standardized extract). After five months, a number of statistically significant benefits were noted. Cognitive function was significantly improved, anti-inflammatory results in the brain were seen, and beta-amyloid aggregation (clumping of sticky proteins seen in Alzheimer’s disease) was inhibited (Brain Behavior and Immunity, May 2015*1). These effects were not seen at the two month assessment, suggesting a longer period of supplementation is needed to obtain positive results.
Another study looked at the benefits gingko might have on damage in the brain caused by excessive amounts of zinc. Zinc is a trace mineral, which has many benefits, but too much can lead to damaging effects. In the brain, excessive zinc increases beta amyloid deposits as well as increasing a particular version of tau protein (this version of tau protein leads to the tangles found in Alzheimer’s disease). The study found that gingko biloba extract decreased the zinc-induced damage of this particular tau protein (Food & Function, June 2015*2).
These newer studies show promise. In addition to ginkgo helping with age-related memory decline by increasing blood circulation, Alzheimer specific benefits can be also be found. Most clinical studies using ginkgo biloba leaf used a standardized extract of 24% flavone glycosides and 6% terpene lactones (this is what you would see on the label). No daily value has been established for gingko biloba but many of the studies used 40 mg. three times a day. The range is variable and needs to be prescribed individually, on a case by case basis.
Ginkgo biloba can interact with certain drugs (medications for bleeding disorders, diabetes, epilepsy, fertility, etc.) and should not be taken if you are pregnant, have upcoming surgery, experience side effects to gingko or have other health conditions. As always, seeing your health care practitioner can help you make the best decisions for your health. Maybe we can’t get 1,000 years of health from ginkgo but we can add healthier years to our lives.
*1 Long-term treatment with Ginkgo biloba extract EGb 761 improves symptoms and pathology in a transgenic mouse model of Alzheimer’s disease.
Liu X1, Hao W1, Qin Y2, Decker Y1, Wang X3, Burkart M4, Schötz K5, Menger MD6, Fassbender K1, Liu Y7. Brain Behav Immun. 2015 May;46:121-31. doi: 10.1016/j.bbi.2015.01.011. Epub 2015 Jan 28.
http://www.ncbi.nlm.nih.gov/pubmed/25637484
*2 Ginkgo biloba extract (Egb761) attenuates zinc-induced tau phosphorylation at Ser262 by regulating GSK3β activity in rat primary cortical neurons.
Kwon KJ1, Lee EJ, Cho KS, Cho DH, Shin CY, Han SH. Food Funct. 2015 Jun 10;6(6):2058-67. doi: 10.1039/c5fo00219b.
http://www.ncbi.nlm.nih.gov/pubmed/26032477
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